Biologically Inspired Design

A Primer
 Synthesis Lectures on
Engineering, Science, and
Technology
Each book in the series is written by a well known expert in the field. Most titles cover subjects
such as professional development, education, and study skills, as well as basic introductory
undergraduate material and other topics appropriate for a broader and less technical audience.
In addition, the series includes several titles written on very specific topics not covered
elsewhere in the Synthesis Digital Library.
Biologically Inspired Design: A Primer
Torben A. Lenau and Akhlesh Lakhtakia
2021

Engineering Design: An Organic Approach to Solving Complex Problems in the Modern

World
George D. Catalano and Karen C. Catalano
2020

Integrated Process Design and Operational Optimization via Multiparametric

Programming
Baris Burnak, Nikolaos A. Diangelakis, and Efstratios N. Pistikopoulos
2020

The Art of Teaching Physics with Ancient Chinese Science and Technology
Matt Marone
2020

Scientific Analysis of Cultural Heritage Objects

Michael Wiescher and Khachatur Manukyan
2020

Case Studies in Forensic Physics

Gregory A. DiLisi and Richard A. Rarick
2020
iv
An Introduction to Numerical Methods for the Physical Sciences
Colm T. Whelan
2020

Nanotechnology Past and Present

Deb Newberry
2020

Introduction to Engineering Research

Wendy C. Crone
2020

Theory of Electromagnetic Beams

John Lekner
2020

The Search for the Absolute: How Magic Became Science

Jeffrey H. Williams
2020

The Big Picture: The Universe in Five S.T.E.P.S.

John Beaver
2020

Relativistic Classical Mechanics and Electrodynamics

Martin Land and Lawrence P. Horwitz
2019

Generating Functions in Engineering and the Applied Sciences

Rajan Chattamvelli and Ramalingam Shanmugam
2019

Transformative Teaching: A Collection of Stories of Engineering Faculty’s Pedagogical

Journeys
Nadia Kellam, Brooke Coley, and Audrey Boklage
2019

Ancient Hindu Science: Its Transmission and Impact on World Cultures

Alok Kumar
2019

Value Rational Engineering

Shuichi Fukuda
2018
 v
Strategic Cost Fundamentals: for Designers, Engineers, Technologists, Estimators,
Project Managers, and Financial Analysts
Robert C. Creese
2018

Concise Introduction to Cement Chemistry and Manufacturing

Tadele Assefa Aragaw
2018

Data Mining and Market Intelligence: Implications for Decision Making

Mustapha Akinkunmi
2018

Empowering Professional Teaching in Engineering: Sustaining the Scholarship of

Teaching
John Heywood
2018

The Human Side of Engineering

John Heywood
2017

Geometric Programming for Design Equation Development and Cost/Profit

Optimization (with illustrative case study problems and solutions), Third Edition
Robert C. Creese
2016

Engineering Principles in Everyday Life for Non-Engineers

Saeed Benjamin Niku
2016

A, B, See... in 3D: A Workbook to Improve 3-D Visualization Skills

Dan G. Dimitriu
2015

The Captains of Energy: Systems Dynamics from an Energy Perspective

Vincent C. Prantil and Timothy Decker
2015

Lying by Approximation: The Truth about Finite Element Analysis

Vincent C. Prantil, Christopher Papadopoulos, and Paul D. Gessler
2013

Simplified Models for Assessing Heat and Mass Transfer in Evaporative Towers
Alessandra De Angelis, Onorio Saro, Giulio Lorenzini, Stefano D’Elia, and Marco Medici
2013
vi
The Engineering Design Challenge: A Creative Process
Charles W. Dolan
2013

The Making of Green Engineers: Sustainable Development and the Hybrid Imagination
Andrew Jamison
2013

Crafting Your Research Future: A Guide to Successful Master’s and Ph.D. Degrees in
Science & Engineering
Charles X. Ling and Qiang Yang
2012

Fundamentals of Engineering Economics and Decision Analysis

David L. Whitman and Ronald E. Terry
2012

A Little Book on Teaching: A Beginner’s Guide for Educators of Engineering and

Applied Science
Steven F. Barrett
2012

Engineering Thermodynamics and 21st Century Energy Problems: A Textbook

Companion for Student Engagement
Donna Riley
2011

MATLAB for Engineering and the Life Sciences

Joseph V. Tranquillo
2011

Systems Engineering: Building Successful Systems

Howard Eisner
2011

Fin Shape Thermal Optimization Using Bejan’s Constructal Theory

Giulio Lorenzini, Simone Moretti, and Alessandra Conti
2011

Geometric Programming for Design and Cost Optimization (with illustrative case study
problems and solutions), Second Edition
Robert C. Creese
2010

Survive and Thrive: A Guide for Untenured Faculty

Wendy C. Crone
2010
 vii
Geometric Programming for Design and Cost Optimization (with Illustrative Case Study
Problems and Solutions)
Robert C. Creese
2009

Style and Ethics of Communication in Science and Engineering

Jay D. Humphrey and Jeffrey W. Holmes
2008

Introduction to Engineering: A Starter’s Guide with Hands-On Analog Multimedia

Explorations
Lina J. Karam and Naji Mounsef
2008

Introduction to Engineering: A Starter’s Guide with Hands-On Digital Multimedia and

Robotics Explorations
Lina J. Karam and Naji Mounsef
2008

CAD/CAM of Sculptured Surfaces on Multi-Axis NC Machine: The DG/K-Based

Approach
Stephen P. Radzevich
2008

Tensor Properties of Solids, Part Two: Transport Properties of Solids

Richard F. Tinder
2007

Tensor Properties of Solids, Part One: Equilibrium Tensor Properties of Solids

Richard F. Tinder
2007

Essentials of Applied Mathematics for Scientists and Engineers

Robert G. Watts
2007

Project Management for Engineering Design

Charles Lessard and Joseph Lessard
2007

Relativistic Flight Mechanics and Space Travel

Richard F. Tinder
2006
© Springer Nature Switzerland AG 2022
Reprint of original edition © Morgan & Claypool 2021

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in printed reviews, without the prior permission of the publisher.

Biologically Inspired Design: A Primer

Torben A. Lenau and Akhlesh Lakhtakia

ISBN: 978-3-031-00963-1 paperback

ISBN: 978-3-031-02091-9 ebook
ISBN: 978-3-031-00163-5 hardcover

DOI 10.1007/978-3-031-02091-9

A Publication in the Springer series

SYNTHESIS LECTURES ON ENGINEERING, SCIENCE, AND TECHNOLOGY

Lecture #14
Series ISSN
Print 2690-0300 Electronic 2690-0327
Biologically Inspired Design
A Primer

Torben A. Lenau
Danmarks Tekniske Universitet

Akhlesh Lakhtakia
The Pennsylvania State University

SYNTHESIS LECTURES ON ENGINEERING, SCIENCE, AND

TECHNOLOGY #14
ABSTRACT
As the existence of all life forms on our planet is currently in grave danger from the climate emer-
gency caused by Homo sapiens, the words “sustainability” and “eco-responsibility” have entered
the daily-use vocabularies of scientists, engineers, economists, business managers, industrialists,
capitalists, and policy makers. Normal activities undertaken for the design of products and sys-
tems in industrialisms must be revamped. As the bioworld is a great resource for eco-responsible
design activities, an overview of biologically inspired design is presented in this book in simple
terms for anyone with even high-school education.
Beginning with an introduction to the process of design in industry, the book presents the
bioworld as a design resource along with the rationale for biologically inspired design. Problem-
driven and solution-driven approaches for biologically inspired design are described next. The
last chapter is focused on biologically inspired design for environment.

KEYWORDS
bioinspiration, biomimicry, biomimetics, bioreplication, bionik, bionics, nature-
inspired design, circular economy, contraindicated performance, design for envi-
ronment, eco-efficiency, engineered biomimicry, multifunctionality, sustainability
 xi

Dedicated to sustainable societies

 xiii

Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix

1 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 What is Design? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Design Thinking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 The Design Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4 Design Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4.1 Task Clarification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4.2 Function Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4.3 Design Brief and Product Specification . . . . . . . . . . . . . . . . . . . . . . . . 15
2.4.4 Conceptual Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.4.5 Concept Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.4.6 Toward Detailed Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.5 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3 Engineered Biomimicry: Solutions from the Bioworld . . . . . . . . . . . . . . . . . . . 21

3.1 The Case for Engineered Biomimicry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.2 Engineered Biomimicry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2.1 Bioinspiration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.2.2 Biomimetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.2.3 Bioreplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.3 Examples of Engineered Biomimicry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.3.1 Bioinspired Computational Techniques . . . . . . . . . . . . . . . . . . . . . . . . 24
3.3.2 Biomimetic Production of Human Insulin . . . . . . . . . . . . . . . . . . . . . 26
3.3.3 Bioreplicated Visual Decoys of Insects . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.4 Design Teams for Bioworld Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.5 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
xiv
4 Rationale for Biologically Inspired Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.1 Energy Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.2 Circular Economy of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.3 Multifunctionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.4 Multicontrollability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.5 Suboptimality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.6 Contraindicated Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.7 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

5 Problem-Driven Biologically Inspired Design . . . . . . . . . . . . . . . . . . . . . . . . . . 47

5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
5.2 Phases of Problem-Driven BID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
5.2.1 First Phase: Problem Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
5.2.2 Second Phase: Search . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
5.2.3 Third Phase: Understand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.2.4 Fourth Phase: Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
5.2.5 Fifth Phase: Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
5.3 Engineers and Biologists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.4 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6 Solution-Driven Biologically Inspired Design . . . . . . . . . . . . . . . . . . . . . . . . . . 61

6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
6.2 Examples of Solution-Driven BID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
6.2.1 Mycelium Bio-Composites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
6.2.2 Bombardier-Beetle Spray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
6.2.3 Tubercles for Flow Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
6.2.4 Abalone-Shell Armor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
6.3 Steps for Solution-Driven BID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.3.1 Application Search . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.3.2 Eight-Step Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.4 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

7 Biologically Inspired Design for the Environment . . . . . . . . . . . . . . . . . . . . . . . 77

7.1 Sustainability and the Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
7.2 Matter of Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
7.3 Sustainable Practices from Nature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
 xv
7.4 Circular Economy of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
7.5 Mutually Beneficial Coexistence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
7.6 Energy Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
7.7 Design Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
7.7.1 Environmental Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
7.7.2 Circular Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
7.7.3 Impact Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
7.8 Grafting “Biologically Inspired Design” onto “Design for Environment” . . . . 87
7.9 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Authors’ Biographies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
 xvii

Preface
This primer on biologically inspired design (BID) was initiated during a sabbatical semester
spent by Akhlesh Lakhtakia at Danmarks Tekniske Universitet (DTU) during the second half of
2019, at the invitation of Torben A. Lenau. The close collaboration between both of us resulted
not only in the descriptions of BID approaches and the case stories required to make the reading
of this book interesting to undergraduate students enrolled for BID courses, but it also made
a collaboration possible with Daniela C. A. Pigosso and Tim C. McAloone for grafting BID
onto design for environment. The combination of the two design foci makes it possible to tap into
the enormous knowledge bank that the bioworld represents and apply well-proven solutions in
the quest to secure sustainable societies and ecosystems on our planet.
Torben A. Lenau started in 2009 to teach BID to engineering students at DTU. More
than 400 students have marched through the course since then. The course is focused on the
problem-driven approach to BID illustrated by around a hundred case studies.
The solution-driven approach to BID complements the problem-driven approach. Both
are treated in two chapters in this book. They are described in sufficient detail to allow practi-
tioners as well as students to follow and apply the approaches to their own BID activities. As
this book explains BID in simple terms for anyone with even high-school education, we hope
that not only engineering and design students but also members of the general public interested
in sustainability will profit from the time they will spend on reading this primer on BID.

Torben A. Lenau and Akhlesh Lakhtakia

January 2021
 xix

Acknowledgments
Torben A. Lenau thanks the many students of Danmarks Tekniske Universitet (DTU) who
took his course 41084 Biologically Inspired Design over the years for providing the empirical
experience and contextual setting that stimulated the development of methodological support
tools. He is also highly grateful for insightful discussions with and support from his wife Ingrid.
Akhlesh Lakhtakia is grateful to the Trustees of The Pennsylvania State University for a
sabbatical leave of absence, the Otto Mønsted Foundation for partial financial support, and the
Department of Mechanical Engineering, DTU for gracious hospitality in Fall 2019 semester.
He also thanks Mercedes for wonderful spousal support during that period.
Both of us are grateful to Daniela C. A. Pigosso and Tim C. McAloone for discussions
on grafting biologically inspired design onto design for environment. We thank Patrick D. McAtee
for several suggestions as well as for alerting us to several errors in a draft manuscript, and the
staff of Morgan & Claypool for splendid cooperation in producing this book.

Torben A. Lenau and Akhlesh Lakhtakia

January 2021
 1

CHAPTER 1

Definitions
“Begin at the beginning,” the King said, very gravely,
“and go on till you come to the end: then stop.”
Lewis Carroll, Alice in Wonderland (1865)

First things first, we must begin with definitions. This is all the more necessary for a rapidly
emerging area such as engineered biomimicry, which encompasses both basic research on
outcomes and mechanisms of diverse phenomena displayed by living organisms and the appli-
cation of fundamental principles uncovered by that basic research to devise useful processes and
products [1]. Engineered biomimicry can thrive in an industrialism, which is a society replete
with manufacturing industries for mass production of a diverse array of products.
Biomimicry lies within the ambit of engineered biomimicry. Although the two terms
are often used as synonyms of each other, biomimicry additionally incorporates the attributes of
sustainability evinced by the bioworld. Sustainability is defined as the maintenance of natural
resources for ecological balance; hence, present-day needs are satisfied without endangering the
ability of future generations to do the same [2]. Sustainability mandates the formation of those
industrial ecosystems that are founded on the principles of circular economy. The main out-
puts, byproducts, and wastes of every segment of a circular economy become inputs to one or
more of the other segments of that economy, thereby minimizing the overall resource inputs to
the circular economy [3]. The inter-relationships of engineered biomimicry, biomimicry, sus-
tainability, and industrialism are schematically depicted in Fig. 1.1.
Design and manufacture are the two main engineering activities in any industry. Accord-
ingly, engineered biomimicry encompasses both biologically inspired design and manufacture,
as depicted in Fig. 1.2. The scope of biologically inspired design is the formulation of de-
sign strategies to reproduce desirable outcomes, mechanisms, and structures from the bioworld.
A manufacturing action may or may not be provenanced in the bioworld.
The history of Homo sapiens is marked by numerous approaches to the solution of engineer-
ing problems based on solutions from the bioworld. These approaches of engineered biomimicry
can be classified as bioinspiration, biomimetics, and bioreplication, as shown also in Fig. 1.2.
The goal in bioinspiration is to reproduce a biological outcome without reproducing the
underlying physical mechanism(s) and the biological structure(s). As an example, powered flying
machines were inspired by birds in self-powered flight. But airplanes do not flap their wings like
birds, and the tails of birds are horizontal unlike the vertical tails of aeroplanes. Rotorcraft do
2 1. DEFINITIONS

Sustainable
actions

Biomimicry

Engineered
biomimicry

Industrialism
(mass production)

Figure 1.1: Engineered biomimicry and biomimicry within the contexts of sustainable actions
and mass production.

ion
pi rat Production
i ns
Bio

cs
met i
m i y
Bio m icr
mi
bio
ed ion
e er cat
Biologically g in re p
l i
En
inspired Bio
design

Figure 1.2: Conceptual anatomy of engineered biomimicry.

 1. DEFINITIONS 3
not fly like birds either. But these engineered structures do reproduce the natural outcome of
moving from one location to another without being in physical contact with the ground.
Biomimetics is the reproduction of a physical mechanism responsible for a specific func-
tionality exhibited by a biological structure. The classic example of biomimetics is Velcro™ com-
prising dense assemblies of hooks and loops, the former emulating the hooked barbs on a bur-
dock seed and the latter the fur of a furry animal. When a furry animal brushes against a burdock
seed, the hooks get fastened to the fur. The International Standards Origanization (ISO) has
formulated a set of criteria for whether a product can be considered as biomimetic [4]. The crite-
ria relate to the biomimetic design process which was applied to develop the product and require
that
(i) a function analysis has been performed on an available biological system,
(ii) the essential mechanisms in that biological system have been abstracted into a model, and
(iii) the model has been transferred and applied to design the product.
Bioreplication is the direct replication of a structure found in a biological organism
in order to reproduce one or more functionalities exhibited by the biological structure copied.
Decoys created by nanoscale replication of the actual elytra of a female emerald ash borer for the
purpose of sexually attracting male emerald ash borers provide an example of bioreplication [5].
The term biomaterial refers to either a material harvested from a biological organism
to be used for the same purpose as in the organism or an artificial material used for a biological
purpose. In the latter case, the term biocompatible material is also used. Bovine milk is a
biomaterial of the first kind, being produced in the bioworld as a nutrient for calves and also
used by humans as food. Prostheses for human hips and knees are made of biomaterials of the
second kind.
Biomanufacturing uses a biological process to produce a synthetic product. Thus, syn-
thetic insulin is produced by inserting the human insulin genes in open loops of bacterial DNA to
close the latter, the closed loops are inserted in bacteria which multiply rapidly in a fermentation
chamber, the insulin then being harvested from the bacteria being produced in that chamber.
Escherichia coli and Saccharomyces cerevisiae are commonly used species of bacteria, but yeast, a
fungus, often replaces the bacteria in this biomanufacturing process [6]. A specific biomanufac-
turing process has at least one component that is either biomimetic or bioreplicatory.
A structure is multifunctional if it can perform two or more distinct functions that
are not highly related to each other [7]. An example of multifunctionality is displayed in the
bioworld by skin, which contains the organism, defines its shape and size, hosts a variety of sen-
sors, and may be used to camouflage as well as to advertise. The fuselage of an aircraft functions
both as a thermal isolator and an acoustic isolator. The well-known Swiss Army™ knife is a
multifunctional tool.
The output of a multicontrollable structure can be controlled independently by more
than one mechanisms [8]. As natural examples: the same sound can be uttered using two or three
4 1. DEFINITIONS
different configurations of the tongue and the buccal cavity, and multiple modes of locomotion
can be used by an organism to propel itself from one location to another.

1.1 REFERENCES
[1] A. Lakhtakia and R. J. Martín-Palma (Eds.), Engineered Biomimicry, Elsevier, Waltham,
MA, 2013. DOI: 10.1016/c2011-0-06814-x. 1
[2] M. Mulligan, An Introduction to Sustainability: Environmental, Social and Personal Perspec-
tives, 2nd ed., Routledge, Abingdon, Oxford, UK, 2018. DOI: 10.4324/978131588852.
1
[3] W. R. Stahel, Circular Economy: A User’s Guide, Routledge, Abingdon, Oxford, UK, 2019.
1
[4] ISO 18458:2015, Biomimetics—Terminology, Concepts and Methodology, International
Standards Organization, Geneva, Switzerland, 2015. https://www.iso.org/standard/
62500.html DOI: 10.3403/30274979. 3
[5] M. J. Domingue, A. Lakhtakia, D. P. Pulsifer, L. P. Hall, J. V. Badding, J. L. Bischof, R. J.
Martín-Palma, Z. Imrei, G. Janik, V. C. Mastro, M. Hazen, and T. C. Baker, Bioreplicated
visual features of nanofabricated buprestid beetle decoys evoke stereotypical male mating
flights, Proceedings of U.S. National Academy of Sciences, 111:14106–14111, 2014. DOI:
10.1073/pnas.1412810111. 3
[6] N. A. Baeshen, M. N. Baeshen, A. Sheikh, R. S. Bora, M. M. M. Ahmed, H. A. I.
Ramadan, K. S. Saini, and E. M. Redwan, Cell factories for insulin production, Microbial
Cell Factories, 13:141, 2014. DOI: 10.1186/s12934-014-0141-0. 3
[7] A. Lakhtakia, From bioinspired multifunctionality to mimumes, Bioinspired, Biomimetic
and Nanobiomaterials, 4:168–173, 2015. DOI: 10.1117/12.2258683. 3
[8] A. Lakhtakia, D. E. Wolfe, M. W. Horn, J. Mazurowski, A. Burger, and P. P. Banerjee,
Bioinspired multicontrollable metasurfaces and metamaterials for terahertz applications,
Proceedings of SPIE, 10162:101620V, 2017. DOI: 10.1117/12.2258683. 3
 5

CHAPTER 2

What is Design?
It is not enough that we build products that function, that are
understandable and usable, we also need to build products
that bring joy and excitement, pleasure and fun,
and, yes, beauty to people’s lives.
Donald A. Norman (2004)1

2.1 INTRODUCTION
Design has been around for as long as humans have created things. Design and making were not
separate until the rise of the age of factories, since the craft-person designed the product while
making it [1]. For example, a potter would make a pot by working with clay without first making
drawings. This was possible as long as the product was simple and the production process was
implemented close to the people using the product. However, modern products are usually very
complicated and are often produced at locations far away from their users’.
This development engendered the need for more formalized design activity whereby
designers analyze user needs and create documentation so that the product can be later man-
ufactured by others elsewhere. The documentation must be detailed and accurate in specifying
form, materials, dimensions, and other variable parameters.
A design activity need not be formal and often it is not; however, it must be effective.
Methods and tools are therefore developed to improve the likelihood of matching user needs to
a good new product whose production is cost effective and which can be expediently disposed
off after use. In writing this book, we expect that biologically inspired design will help
designers in identifying good solution principles and even get detailed inputs for how to realize
the product structure and functionality.
Apart from finding solutions to functional needs, design is also about product appearance
and the messages the product sends. This is clearly obvious for clothing and automobiles, because
high premiums are paid for exclusive looks. Many automobiles are designed to communicate the
impression of speed and power. This is done by borrowing design features from animals with
those characteristics. For example, automobile headlights are designed to remind the bystander
of the eyes of tigers or lions. Cute animals inspire children’s toys and sports equipment draw
1 D.A. Norman, Introduction to this special section on beauty, goodness, and usability, Human-Computer Interaction,
19:311–318, 2004.
6 2. WHAT IS DESIGN?
on visual inspiration from agile animals such as cheetahs. Biological inspiration for product
appearance is a huge area, but this book is focused on how to utilize functional solutions found
in the bioworld.

2.2 DESIGN THINKING

The concept of design thinking is often invoked to distinguish design activities from scientific
problem solving wherein underlying principles are uncovered systematically to find optimal so-
lutions. In contrast, design thinking requires multiple explorations to identify a range of possible
solutions from which a satisfactory one is identified.
The major difference in the thought processes of scientists and designers was exposed in
an experiment more than four decades ago [2]. A group of fifth-year students from architecture
and a similar group from science were asked to arrange building blocks with colored sides with
the goal of maximizing the number of sides of a specific color. The results suggested that science
students selected blocks in order to discover the structure of the problem, whereas architecture
students generated sequences of blocks until a combination proved acceptable.
Design thinking is claimed to be suitable for solving an ill-posed problem by sketching
several possible solutions to understand it from different viewpoints [1, 3]. It calls for a mindset,
as can be seen from analyzing the preferred ways of working of many designers. The mindset
includes a strong user focus and the will to understand the core of the problem by generating a
large space of many solutions. Several of these solutions will be visualized and even prototyped
before a solution is finally selected for production.

2.3 THE DESIGN OBJECT

From a first look, it seems obvious that the product is the design object. However, further
analysis clarifies that the design object also includes other elements such as single components
or parts within the product; the overall system within which the product functions; and the
non-material services associated with its merchandizing, use, and eventual disposal.
When designing, the goal is to produce a thing to satisfy a need. This thing can be a phys-
ical product such as a toothbrush or an automobile, or it can be a service such as linen laundry
in a hotel. Clearly, the complexity of the design process varies with the type of the product or
service to be designed. The delimitation of the design object is therefore important. The tooth-
brush is a single component even though it is permanently assembled from a plastic handle
and several clumps of brushing hairs. On the other hand, an automobile is a larger collection
of single components that are configured in subsystems which together are assembled into the
complete product: the automobile. However, an automobile is part of a larger system includ-
ing gas stations, repair shops, roads, and parking spots, which together are necessary to provide
the transportation functionality to the user. Furthermore, the product is part of a larger con-
text which has a major impact on how the product is designed. Automobiles of different types
 2.4. DESIGN PROCESS 7
are made to satisfy needs in diverse contexts, as exemplified by minivans to transport families
with children, mobile homes for leisure activities, mobile workshops for mechanics, and taxis to
transport visitors with luggage.
The bioworld shows similar features. Organisms of many different types co-exist in a
mutualistic relationship system that is the prerequisite for the existence of a single organism in
that system. In other words, the system comprises its constituent organisms as subunits with
specific roles and interfaces to the rest of the organisms. Removal of organisms of a certain
type from the system can seriously alter, and even demolish, the latter. In the same way, each
organism consists of several organs and other subunits with specific roles and interfaces to the
rest of the organism. When seeking inspiration from the bioworld, it is therefore beneficial to
also look at the larger system that the organism is part of.
One major difference between the bioworld and design activity must be noted. A new
feature in an organism arises in the bioworld as a result of random modifications of parental
DNA. Most of these mutations are either inconsequential or harmful, but a certain mutation
may confer reproductive success in the prevailing environment. That mutation becomes more
prevalent in succeeding generations. A new species emerges in consequence of a succession of
numerous mutations, which makes sudden innovation impossible in the bioworld [4], the oc-
currence of elevated emergence rates of new species in the fossil record [5, 6] notwithstanding.
For example, a marine species cannot evolve into an avian one through just one mutation. In
contrast, although design activity is greatly limited by the availability of materials, tools, and
expertise, disruptive innovation is possible by the interjection of a radically new concept. As
an example, the emergence of the smartphones in 1992 from the predecessor telephones was
a single-step achievement inasmuch as a smartphone possesses a touch screen, can email, store
notes, keep a calender, and run diverse apps and widgets that would become widespread within
a decade. Furthermore, smartphones began to provide very convenient access to the internet,
thereby taking away a market segment from laptop manufacturers [7].

2.4 DESIGN PROCESS

While there is a general agreement that every design process starts with a user need and is
expected to end with a solution, there are many models for structuring, organizing, and docu-
menting design processes. The Pahl–Beitz model shown in Fig. 2.1 encompasses the following
stages in sequence: task clarification, development of concepts (i.e., principal solutions), pre-
liminary layout, definitive layout, and documentation [8]. Even though the model is sequential,
it is recognized that many iterative loops will be made if the result of an activity is unsatisfactory.
The Cross model shown in Fig. 2.2 is organized so the different stages in a design activity
form a circle [1]. The model makes it more apparent that design is an iterative activity wherein
all decisions are revisited several times before a good final solution is found. Both the Pahl–Beitz
model and the Cross model require a function analysis to be undertaken before the design is
specified. In the Pahl–Beitz model, function analysis takes place during concept development,
8 2. WHAT IS DESIGN?

Task
Market, company, economy

clarifying the task

Analyze the market and company situation

Planning and
Plan and Find and select product ideas
clarify Formulate product proposal
the task: Clarify the task
Elaborate requirement list

Requirements list
(design specification)

Conceptual design
Identify essential problems
Develop the Establish function structures
principal Search for working principles and working structures
solution: Combine and firm up into concept variants
Evaluate against technical and economic criteria

Concept
(principal solution)

Upgrade and improve

Information

Preliminary form design, material selection, and

Develop the calculation
construction Select best preliminary layouts
solution: Refine and improve layouts

Embodiment design
Evaluate against technical and economic criteria

Preliminary layout

Eliminate weak spots

Define the Check for errors, disturbing influences, and
construction minimum costs
structure: Prepare the preliminary parts list and production
and assembly documents

Definitive layout
Detail design

Prepare Elaborate detail drawings and parts list

production Complete production, assembly, transport, and
and operating operating instructions
Check all documents
documents:

Product documentation

Solution

Figure 2.1: The Pahl–Beitz model of systematic design activity [8].

 2.4. DESIGN PROCESS 9

Overall Overall
problem solution

Objectives Opportunities Improvement

Functions Stage flow Evaluation

direction

Requirements Characteristics Alternatives

Sub- Sub-
problem solutions

Figure 2.2: The Cross model of systematic design activity [1].

with problem identification linked to the search for working principles. In the Cross model,
function analysis is used to analyze the overall design problem and break it into subproblems.
A difference between the two models is the explicit focus on alternatives in the Cross model.
Generating alternative solutions is an important way to figure out how the design problem is
best solved. The Pahl–Beitz model, of course, recognizes this matter but the linear format of the
model does not invite consideration of alternatives.
Illustrated in Fig. 2.3, the Tjalve model is a sequential model of design activity contain-
ing iterative loops [9]. With more emphasis on concept development than in the previous two
models, the Tjalve model encompasses the stages of problem analysis; identification of main
functions; identification of sub-functions and means; formulation of the basic structure of the
product; quantification of the product structure; delimitation of materials, dimensions, and sur-
faces; and the overall form of the product. Whereas the Pahl–Beitz and Cross models are well
suited for managing and coordinating design processes, the Tjalve model aims at guiding the
designer in creative activities.
Indeed, the Tjalve model defines the product in terms of five basic attributes. These are
the structure of the product with its constituent elements and relations, along with the form,
material, dimensions, and surface of each element. Thus, this model is a journey from an abstract
description of the product using functions toward gradually more and more concrete descriptions
of the overall structure and the constituent elements. Solutions are identified for each function,
the arrangement of the solutions being called the basic structure. The basic structure is typically
described using symbolic graphs rather than drawings illustrating the appearance of the prod-
uct. The quantified structure developed thereafter contains dimensions as well as the physical
arrangement of the constituent elements.
10 2. WHAT IS DESIGN?

Problem
analysis

Main
functions

C
r
i Sub-functions
t and means
e
r
i
a
Basic
structure

Quantified
structure

Form of
Total form
the elements
Material
Dimension
Surface

Figure 2.3: The Tjalve model of systematic design activity [9].

The Tjalve model emphasizes the need for alternatives and gives detailed inspiration for
how to systematically explore different basic structures that will satisfy the functional require-
ments. Several alternatives are also generated for the quantified structure, wherein the con-
stituent elements can be configured differently in relation to each other. A useful division be-
tween the total form of the product and the forms of the constituent elements allows for the
search for partial solutions for single functions which later are combined into the total solution.
Finally, the integrated-product-development model shown in Fig. 2.4 emphasizes that
product design is not done in isolation but in parallel and close collaboration with market- and
production-oriented activities [10]. While designers consider the type of product to design, the
marketing team investigates competing products and determines whether there is room for a new
 2.4. DESIGN PROCESS 11
* INTEGRATED PRODUCT DEVELOPMENT

Determining
User Market Preparation
the basic Sales
investigation investigation for sales
need

Determining Product Preliminary Modification

The Product
the type of principle product for
Need adaptation
product design design manufacture

Consideration Determining Determining Preparation

of product type of production for Production
type production principles production

0 1 2 3 4 5
Recognition Investigation Product Product Production Execution
of need of need principle design preparation phase
phase phase phase phase phase

Figure 2.4: The integrated-product-development model of systematic design activity [10].

product in the market, and the production team investigates diverse options for manufacturing
the product.

2.4.1 TASK CLARIFICATION

A design process can be initiated by many different triggers [11]. A common trigger is the user
need for a good solution, inadequate and barely adequate solutions being unsatisfactory. Another
trigger is the introduction of a new technology, as exemplified by the emergence of social media
triggered by the introduction of smartphones. Yet another trigger is the economic affordability
of a technology. For instance, the low prices of efficient batteries have caused a boom in the use
of electrical scooters and bicycles.
Once a user need has been identified, the design process has to be articulated. This is most
often done either verbally or in writing, but a powerful alternative way is to provide diagrams. In
order not to restrict the design process, the focus should be on highlighting the need but not on
describing how it has been solved previously. This can be done by describing the consequences
of satisfying the need through before/after pictures like the ones commonly used in advertise-
ments for diet pills and other weight-reduction regimen. By visualizing the need, the designer
avoids fixation on existing solutions and becomes receptive to innovative solutions. Being readily
understood, graphics are also effective in communicating with stakeholders.
Many design processes actually involve re-design of existing products. Re-design can be
initiated either for improved functionality or to alleviate shortcomings experienced in existing
products. A detailed analysis of how users behave in the situations calling for the use of a product
12 2. WHAT IS DESIGN?

1
A 2

B 3

Skin
Vein

Figure 2.5: Three stages in the use of a venflon catheter for injecting a polymer tube in a vein.
(1) A metal needle labeled A penetrates the skin and guides a soft polymer tube labled B into
the vein. (2) The metal needle is retracted and disposed of, leaving the polymer tube in the vein.
(3) The polymer tube is ready for use.

and interact with that product is typically carried out by the marketing department, but personal
experiences of the designers will often lead to better results. Many companies therefore encour-
age their designers to directly meet users in order to understand their needs and constraints as
well as how the users will actually interact with the product. User contact is also valuable for
getting feedback on design proposals comprising sketches and/or prototypes.
An example of re-design is furnished by new types of the venflon catheter. A soft polymer
tube in the venflon catheter is injected into a vein with the help of a stiff metal needle, as shown
in Fig. 2.5. The metal needle is retracted after the polymer tube is in place and is then disposed
of. Nurses revealed in interviews that the retraction as well as the disposal of the metal needle
are problematic for them. Not only have two extra processes to be carried out, but the sharp
needle also represents a hazard. For this reason, the venflon catheter is nowadays equipped with
a small safety device which prevents the nurse from touching the needle tip after it has been
retracted.
When analyzing the needs and constraints during a design activity, it can be advantageous
to meet not only the direct users but also other stakeholders such as sales personnel, repair and
maintenance personnel, and other persons who will come in contact with the product. Face-to-
face interviews, questionnaires requiring both qualitative and quantitative answers, and personal
observations provide insights. Personal experience of the product can also benefit similarly, but
it also carries the risk of introducing bias. The observations and experiences of a designer are
not necessarily the same as those of users. Observations are valuable since they reveal the true
behavior of a user. When interviewed, users tend to give more favorable descriptions of their use
patterns.
 2.4. DESIGN PROCESS 13
The results obtained from the analysis of user needs and existing products are described in
a user-need document. This document can include information on the actual use (and misuse) of
the existing products and the context of use. Sometimes, the context is explained using personas
which are descriptions of typical users and their use patterns.

2.4.2 FUNCTION ANALYSIS

A way to stimulate creativity and generate new and better ways of solving problems is to for-
mulate an abstract description of how a product functions. Instead of describing a product as an
assemblage of its components, it can be described as a set of abstract functions. Another advan-
tage is to avoid product fixation which is a risk when the names of previously used components
are used. If a product is described in terms directly coupled to a specific action or form, the
designer may become fixated on a specific solution and find it difficult to imagine alternatives.
For example, a concrete functional description such as “drive a person from point A to point
B” will fixate the designer in thinking of vehicles, whereas the abstract functional description
“transport a person from point A to point B” will foster more open thinking so that a wider
palette of solutions can emerge, e.g., conveyer belts and horseback riding.
A product function is normally formulated using a verb/noun combination, such as “con-
taining a liquid” or “cutting a piece of paper.” A complete description of the functions of and
within a product can be made using a functions-means tree diagram [1, 9]. The sole trapezoid
at the top of the diagram describes the main function that justifies the reason why the product
exists or should exist, whereas sub-functions describe what the constituent elements do. Means
are physical manifestations that carry out a function. Both functions and means are explained in
general terms without considering details such as shape or dimension. Figure 2.6 is a functions-
means tree diagram in which the main function and sub-functions pertinent to drug delivery are
identified along with the various means to accomplish each function. Note a difference in the
way functions and means are described. All of the associated sub-functions are required for the
realization of the main function. The more means that are recorded under a function, the more
numerous are the ways of realizing that function.
A functional surface identifies where a specific function resides within the product [9].
A functional surface is typically marked on a sketch of the design object using hatched lines, as
illustrated in Fig. 2.7. The figure shows that the two knife edges in a pair of scissors can be
marked with hatched lines to indicate where the cutting function resides. Similarly, the holding
function resides in a handle. The hatched lines do not invoke specific shapes, thus leaving the
design assignment more open to innovation. A functional surface indicates the existence of
an interface from the product to something else.
Another notion used to describe the functionality of a product in an abstract way is that
of an organ [11]. Like functional surfaces, an organ does not include information about shape
and materials, but it does describe in abstract terms how a function is carried out. Two or more
14 2. WHAT IS DESIGN?
To deliver
medicine

Absorption Injection Oral

through the skin through the skin intake

To To To To transfer
position fixate skin penetrate skin liquid

Stretch skin Use impulse Cutting process Tearing process With pressure Using vacuum

Initiate Propagate Reduce Prevent

fracture fracture resistance buckling

Figure 2.6: A functions-means tree diagram for ways of delivering medicine inside a patient.
Each trapezoidal block contains a function, each rectangular block a means.

Connecting
organ

2 cutting surfaces
= Holding
cutting organ surface

Figure 2.7: Examples of functional surfaces and organs for a pair of scissors.

functional surfaces can be combined into an organ. For example, the two cutting surfaces in a
pair of scissors form a cutting organ.
Another example of an organ is the sealing organ in a container such as a bottle or a jar. A
sealing organ can be realized as a lid with sealing surfaces in the lid and on the container. Using
the term “lid” will automatically bring up mental pictures of existing solutions for bottles and
jars. But referring to a “sealing organ” instead will make it easier to think freely of conceptually
 2.4. DESIGN PROCESS 15
different solutions. The designer could then propose a flexible bottle where the opening is closed
like a bag or the sealing organ could be a valve.

2.4.3 DESIGN BRIEF AND PRODUCT SPECIFICATION

A design assignment is typically specified using two different documents: the design brief
and the product specification. The design brief is a visionary document that explains the
context of the intended product and how future users will benefit, without going into details of
the specification. The design brief is targeted toward the conceptual-design phase discussed in
Section 2.4.4.
The product specification includes more detailed descriptions and is targeted toward the
design phases that follow the conceptual-design phase. The product specification can be formu-
lated in various ways. In the performance-specification approach [1], several requirements are
formulated, e.g., the performance metrics that the product must satisfy and the performance
characteristics that it must exhibit. For instance, the product must be manufactured in a certain
range of colors and/or that it must be small enough to be stored in a standard storage space. The
performance-specification approach is useful as it delivers a checklist to ensure that a design
proposal is within acceptable limits. However, this approach is less helpful when comparing
different design proposals and existing solutions.
The product-specification approach [10] overcomes that problem. In this approach, both
requirements and criteria are stated. The requirements are fixed and must be met by the design
proposal; otherwise, the design proposal is unviable. The criteria are used to compare different
design proposals using evaluation matrixes (Section 2.4.5) and need to be formulated to indicate
a desirable direction but not set limits. For a new toothbrush as an example, the requirements
could include maximum dimensions and color; the criteria could specify that the toothbrush
should be pleasant to the mouth, be easy to clean, and have a low weight.

2.4.4 CONCEPTUAL DESIGN

Conceptual design is the creative process of generating ideas for solving the overall design
problem and finding partial solutions to each of the functional challenges identified in the
functions-means tree diagram.
A typical way to come up with ideas is to form a brainstorming team. There are many prac-
tical approaches [1] for brainstorming, but all have in common that as large a number of ideas
be generated as possible and that criticism of ideas be avoided during brainstorming sessions.
Different brainstorming approaches introduce different ways of viewing the design problem;
hence, using several different approaches increases the number of ideas.
Brainstorming can be done by single persons on their own, but doing it together with
other people will drastically increase the chance of finding new ideas because participants will
inspire each other. Also, the brainstorming session can have many different formats. One format
involves a whiteboard on which a moderator writes up all the ideas that the participants propose.
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 21

CHAPTER 3

Engineered Biomimicry:
Solutions from the Bioworld
If a group of engineers, mindful of our need to tap natural energy sources,
were to embark on designing a machine that would pump water out of
the ground over an area of 100 square meters continuously, and would
boil off the water into steam, using only the energy directly from the
sun for the whole process, it is possible that they might do it. But
their finished machine would certainly never resemble a tree!
Eric R. Laithwaite (1988)1

Although we humans have long been envious of feats of performance displayed by a variety of an-
imal species [1], and we have been creative in emulating and even surpassing some of those feats,
biomimicry began to acquire an organizational framework only during the 1990s. Coinage of
the term biomimetics is usually attributed to Otto Schmitt during the late 1950s [2]. The simi-
lar term biomimesis coined during the next decade [3] does not have much currency nowadays.
The term bionics, once synonymous with biomimetics [4], is nowadays employed in English
exclusively to the science and practice of replacing an organ in a living being by a prosthesis. The
umbrella term biomimicry has come to subsume its precedents, although one (namely, bionics)
survives as bionik in German.
Biomimicry opens “the possibility of a new industrialism that is more attuned to nature’s
needs” [5] and therefore intersects with the discipline of sustainable design. As discussed
in Chapter 1, engineered biomimicry does not require consideration of sustainability. In this
chapter, we first lay out the case for engineered biomimicry, then present a few representative ex-
amples, identify some characteristics of the solutions available in the bioworld for technological
problems, and finally discuss the importance of having biologists on design teams for bioworld
solutions.

3.1 THE CASE FOR ENGINEERED BIOMIMICRY

Charles Darwin used the word evolve only once in the first edition [6] and just 16 times in the
sixth edition [7] of his most famous book On The Origin of Species. Instead, he used the term

1 E. R. Laithwaite, Gaze in wonder: an engineer looks at biology, Speculations in Science and Technology, 11:341–345, 1988.
22 3. ENGINEERED BIOMIMICRY
descent with modification to describe the origin of new species. Most traits of a child are
derived from those of its parents, but some modifications may occur.
Later scientists realized that genes are the vehicles for heritability or descent and that
imperfect replication of parental DNA results in random modifications called mutations. Most
mutations are either inconsequential or harmful, but a certain mutation may confer reproductive
success in the prevailing environment. That mutation becomes more prevalent in succeeding
generations, the process being called natural selection.
Whereas mutations are random, natural selection is not. Only those mutations that lead
to better adaptation to altering or altered environments are successful. A continuum of mor-
phological varieties thus arises in a species. A series of successful mutations, genetic transfer
from one population to another as a result of migration, and random changes in the frequencies
of certain genes are mechanisms which eventually result in a new species that does not have
morphological intermediates between it and the older species.
As of now, about 1.3 million species have been identified, but some 86% of terrestrial
species and 91% of marine species are estimated to still await description [8]. Add the 4 billion
species that are estimated to have gone extinct [9] since life began on our planet some 4 billion
years ago [10]. Each of those species can be considered as being successful for a certain period,
dying out only when the environmental conditions were no longer conducive enough to sustain
it.
The success of any mutation cannot be predicted and there is no prescient agency for nat-
ural selection. Still, looking at the history of the bioworld, both recent and in the prehistoric
past, we may regard all species as data points in a multidimensional space. The mutually orthog-
onal axes of this space are physical variables (such as ambient temperature, ambient pressure,
and mass density) and performance characteristics (such as speed of locomotion, longevity, and
fecundity). Each species as a data point represents a successful experiment.
Since the laws of physics hold sway over every biological process just as completely as over
every technological operation, we should then consider the bioworld as a repository of answers
to billions of technological questions [11]. Some of those answers may not be optimal for our
technological requirements but can still illuminate possible research directions. Other answers
may be used by us without much fuss. Furthermore, the bioworld contains a plethora of processes
some of whom can be replicated either partially or wholly in industrial operations. No wonder,
humans have long been inspired by attractive outcomes and functionalities evident in plants and
animals.

3.2 ENGINEERED BIOMIMICRY

Engineered biomimicry encompasses both basic research on outcomes and mechanisms of di-
verse phenomena displayed by living organisms and the application of fundamental principles
uncovered by that basic research to devise useful processes and products. Engineered biomimicry
is classified into bioinspiration, biomimetics, and bioreplication, as shown in Fig. 3.1 [12], based
 3.2. ENGINEERED BIOMIMICRY 23

Bioinspiration Outcome

Bioworld
Biomimetics Mechanism

Bioreplication Structure

Figure 3.1: Classification of engineered biomimicry into bioinspiration, biomimetics, and

bioreplication.

on whether outcomes, mechanisms, or structures in the bioworld are aimed for reproduction in
technoscientific settings.

3.2.1 BIOINSPIRATION
Ancient stories provide numerous examples of the human desire to fly. After rescuing two chil-
dren from a sacrificial altar, a flying ram became the constellation Aries in Greek mythology.
Zeus, the king of Greek gods, had a winged steed named Pegasus. Quetzalcoatl, the Aztec god
of wind and learning, was a winged serpent. Hindu mythology is replete with flying chariots
and palaces. Mohammad, the prophet of Islam, was flown to heaven by a white mule-donkey
hybrid named BuraN q.
Some 500 years ago, Leonardo Da Vinci (1452–1519) studied birds to conceptualize sev-
eral flying contraptions which evidently never took off. Sir George Cayley (1773–1857) made a
pilotless glider that did fly in 1804. Orville and Wilbur Wright were to first to successfully fly
a heavier-than-air machine with a person onboard, on December 17, 1903. The emergence of
aeroplanes inspired by birds in self-powered flight is an excellent example of bioinspiration, but
birds and aeroplanes have different flying mechanisms. The goal in bioinspiration is to reproduce
a biological outcome but not the underlying biological mechanism(s) and structure(s).

3.2.2 BIOMIMETICS
Biomimetics is the reproduction of a physical mechanism responsible for a specific outcome or
functionality exhibited by a biological structure. Greek mythology furnishes the classical exam-
ple of biomimetics through Icarus, a flying human who escaped from a Cretan prison using
wings made of feathers and wax. Sadly, he perished after the wax melted when he flew too close
to the sun.
A modern example is that of insulin, a hormone produced naturally in mammalian pan-
creas but nowadays modified and synthesized in either yeasts or Escherichia coli bacteria [13, 14].
Yet another example of biomimetics is Velcro™ that comprises dense assemblies of hooks and
loops, the former emulating the hooked barbs on a burdock seed and the latter, the fur of a furry
animal. The commercialization of this biomimetic analog of a natural mechanism of adhesion
is a fascinating story of determination [15].
24 3. ENGINEERED BIOMIMICRY
3.2.3 BIOREPLICATION
Bioreplication is the direct replication of a structure found in a biological organism in order
to reproduce one or more functionalities exhibited by the biological structure copied. During
the last ten years, diverse physical techniques have been harnessed to replicate several biological
structures such as the eyes and wings of several types of insects [16]. The techniques include the
sol-gel method; atomic layer deposition; physical vapor deposition; and some combination of
imprint lithography, casting, and stamping [17]. Some of these techniques are more suitable for
reproducing surface features, others for bulk three-dimensional structures.

3.3 EXAMPLES OF ENGINEERED BIOMIMICRY

3.3.1 BIOINSPIRED COMPUTATIONAL TECHNIQUES
Every multicellular organism contains one or more networks in which information is sensed,
transmitted, processed, transmitted again, and then acted upon. Relying on physical and chem-
ical phenomena, all of these processes are quantitative and therefore may be mathematically
modeled by us, albeit not always easily.
Mathematical models of many biological processes employ differential equations to re-
late spatial and temporal gradients of physical quantities, such as the concentrations of some
chemicals, partial pressure of various fluids, and the electric charge density transported by ions.
Initial and boundary conditions therefore must be concurrently considered [18, 19]. Successful
examples include models of oxygen-deficient dermal wounds [20] and cancer growth [21].
Often, the data gathered about a biological process is both discrete and huge, as exem-
plified by tumor growths [22] and neuronal activity [23]. To analyze these data, mathematical
methods commonly used for time series [24] and dynamical systems [25] are pressed into service.
The two foregoing paragraphs provide examples of mathematical methods applied to un-
derstand biological processes. Are some mathematical methods to analyze non-biological phe-
nomena inspired by the bioworld? An affirmative answer to that question has emerged in modern
times [26]. Inspired by the structure of animal brains, artificial neural networks (ANNs)
are being used for pattern recognition tasks, including speech recognition, machine translation,
video games, and traffic control; fuzzy logic seeks to emulate human cognition for automated
decision making; swarm intelligence guides mathematical investigations of emergent phe-
nomena; genetic algorithms are often used for optimization; and so on. Let us focus on two
of these bioinspired computational techniques.

Artificial Neural Networks

ANNs have been inspired by animal brains which are networks of neurons connected to other
neurons through synapses [27, 28]. In an ANN, neurons are replaced by nodes and synapses by
connections, as depicted schematically in the top panel of Fig. 3.2.
 3.3. EXAMPLES OF ENGINEERED BIOMIMICRY 25

Weight

Connection
Node (synapse) Node
(neuron) (neuron)

I1
w 1 I1

O
I2 w 2I 2

Hidden
layer
Input Output
layer layer

Figure 3.2: Top: Schematics for artificial neural networks.

The middle panel of Fig. 3.2 shows two nodes providing inputs I1 and I2 to a node whose
output is denoted by O . The output is related to the inputs by a nonlinear function f .x/ such
that (
0; w1 I1 C w2 I2 < b ;
OD (3.1)
f .w1 I1 C w2 I2 / ; w1 I1 C w2 I2  b :
The on/off characteristic of real neurons is simulated by the conditionality on the right side of
Eq. (3.1), with b as the bias or the threshold value of the argument x of f .x/, and the relative
importance of the inputs coded through the weights w1 and w2 .
An ANN can have several input nodes arranged in a layer and several output nodes ar-
ranged in a different layer. In between is at least one layer of hidden nodes, called thus because
these nodes have no direct connection to: (i) the sensors providing data to the input layer and
26 3. ENGINEERED BIOMIMICRY
(ii) the actuators implementing actions controlled by the output layer. The bottom panel of
Fig. 3.2 shows an ANN in which information moves in the forward direction, i.e., from the
input nodes, through the hidden nodes, to the output nodes. ANNs of other types can have
backward connections and even loops.
Known sets of input-output data are used to train an ANN, i.e., determine the weights.
More training data will determine the weights better (usually but not always), the assumption
being that the ANN learns just like a biological brain. After the ANN is deemed to have learned
enough, it can be fed data to predict the output with confidence.

Genetic Algorithms
Genetic algorithms are commonly used to design a device or structure to meet a numerical cri-
terion for performance [29]. The device performance depends on the values of a certain number
(say N ) of characteristic variables. The algorithm begins by randomly selecting M1 > 1 sets of
the N characteristic variables. A performance function denoted by p is calculated for every one
of the M1 sets. If p  b1 for a specific set, where b1 is a threshold value, then that particular set
is retained; if not, that set is eliminated. The result is that MN 1  M1 sets survive to reproduce
the next generation comprising M2 new sets.
The simplest reproduction method is mutation, whereby each new set is based on a single
surviving set of the previous generation. If the population is being doubled by mutation (i.e.,
M2 D 2MN 1 ), each set of the old generation is reproduced twice, once as itself and once by multi-
plying its characteristic variables by a random factor. A more complex method of reproduction is
crossover, whereby each set of the new generation is based on some combination of the surviving
sets of the previous generation. The performance function p is calculated for each one of the M2
sets. If p  b2 for a specific set, where b2 > b1 is a new threshold value, then that particular set
is retained; if not, that set is eliminated.
This process of creating new generations continues until a criterion for terminating it is
satisfied. At that stage, several devices satisfying the performance criterion p  max fb1 ; b2 ; : : :g
could have been identified. Then comes the task of selecting and making at least one of those
devices.

3.3.2 BIOMIMETIC PRODUCTION OF HUMAN INSULIN

The peptide hormone insulin began to be used in 1922 to treat diabetic patients. In a normal
person, insulin is produced in the pancreas where it is stored well in excess of daily needs. A series
of biochemical reactions in response to elevated concentration of glucose in blood triggers the
release of insulin from the pancreas. Its half-life ranging between four and six minutes, it lasts
outside the pancreas for about an hour, and is eventually cleared by the liver and the kidneys.
The human insulin molecule has 51 amino acids, its molecular formula being
C257 H383 N65 O77 S6 . Insulin is produced and stored in the pancreas as a hexamer, i.e., an ag-
 3.3. EXAMPLES OF ENGINEERED BIOMIMICRY 27
gregate of six molecules. The hexamer is very stable. Insulin is released from the pancreas as a
monomer, which acts very rapidly.
Until about three decades ago, virtually all insulin injected into patients was derived from
the glands of either cows or pigs obtained as waste products from abattoirs. Bovine insulin differs
from human insulin in only three amino acids, porcine insulin in just one. Fourteen cattle or 70
pigs had to be slaughtered to harvest enough insulin to last a patient for a year. However, the
responses of some patients were unpredictable and some patients had severe reactions.
Research began in the 1970s for a biomimetic route to synthesize human insulin itself [13].
That research has been wildly successful [14]. The sequence of biochemical reactions in mam-
malian pancreas is replicated in yeasts and bacteria. The reproduction of yeasts and bacteria can
be regulated fairly easily, which then eliminates the need for continually harvesting mammalian
pancreas. Moreover, as the production process is initiated with human insulin, the biomanufac-
tured insulin is maximally compatible with human patients.

Pancreatic Production
The production of a molecule called preproinsulin is encoded in a gene found in chromosome
11 in the nuclei of human cells. A chromosome is a DNA molecule comprising nucleotides
of four different types arranged into two strands that are coupled to each other by hydrogen-
hydrogen bonds. There are also packing proteins in the chromosome to keep the DNA molecule
untangled.
Every nucleotide contains a nitrogenous base. There are four types of nitrogenous bases:
adenine, thymine, guanine, and cytosine. Whereas adenine can form a hydrogen-hydrogen bond
only with thymine, guanine can form a hydrogen-hydrogen bond only with cytosine. Thus, ade-
nine and thymine are mutually complementary, and so are guanine and cytosine. The sequence
of bases in one strand of a DNA molecule is matched by the sequence of complementary bases
on the accompanying strand.
Three consecutive bases form a codon. A codon contains the instructions to produce a
protein-creating amino acid. There are 22 protein-creating amino acids. Of the 64 codons pos-
sible, 61 provide instructions for producing 20 of those amino acids. Some amino acids can be
produced by more than one codon. The final two protein-creating amino acids are synthesized
through complex reactions.
A short sequence of amino acids is called a peptide. A long sequence of amino acids is
called a polypeptide or a protein. Three codons are used to indicate the end of an amino-acid
sequence, the start of that sequence being signaled in a more complex way.
Thus, the DNA molecule in a chromosome comprises two complementary chains of
codons. A gene is a sequence of codons that contains instructions to produce a molecule that
performs a function. Some genes contain instructions to produce proteins, others to produce
different types of RNA molecules. An RNA molecule is a single strand of nucleotides of four
28 3. ENGINEERED BIOMIMICRY
types, each containing either adenine, thymine, guanine, or uracil (different from cytosine found
in DNA molecules).
The DNA molecule can then be considered as two chains of identical genes, but it also
contains codon sequences that may either have no purpose or whose purpose has yet not been
discovered.
The process of insulin production in pancreatic cells begins when an enzyme called RNA
polymerase, accompanied by molecules called transcription factors, attaches to a region in the
DNA molecule just before the start of the preproinsulin-producing gene. Then the two DNA
strands separate, and RNA nucleotides attach via hydrogen-hydrogen bonds to the nucleotides
in one of the two strands of the DNA molecule until the stop codon is encountered. At that
stage, the RNA molecule dissociates from the DNA strand, and the two strands of the DNA
molecule couple again.
The RNA molecule thus synthesized is called a messenger RNA (mRNA). It has the in-
structions to produce preproinsulin. That process begins when a transfer RNA (tRNA) molecule
and a ribosome attach themselves to the start codon of the mRNA molecule. Depending on the
next codon, the appropriate amino acid attaches itself to the end of the tRNA molecule. The
ribosome then translocates to the next codon, and the next appropriate amino acid attaches
itself to the previous amino acid. This elongation of the tRNA molecule continues until the
stop codon is reached. At that stage, the single-chain preproinsulin molecule is attached to the
original tRNA molecule. The two then dissociate.
A chemical reaction in the endoplasmic reticulum in the pancreas causes the removal
of 12 amino acids from the preproinsulin molecule, which then folds into two linear chains
connected by a peptide. The resulting molecule is called proinsulin. Removal of the connecting
peptide turns the proinsulin molecule into the insulin molecule.

Biomimetic Production of Insulin

This complex process had to be reproduced biomimetically. Researchers chose E. coli, a bac-
terium that contains a circular chromosome [13]. Some strains of E. coli also contain a circular
plasmid, which is a genetic structure that is not a chromosome. The gene INS is responsible for
producing preproinsulin in humans. This gene is inserted in the plasmids of some bacteria, as
shown schematically in Fig. 3.3. As the bacteria with the altered plasmids reproduce in a fermen-
tation chamber, the number of the altered plasmids increases. Biochemical reactions are then
used to harvest proinsulin molecules, which are then converted chemically to insulin molecules.
Some manufacturers use yeasts in place of E. coli.
The dominant mode of reproduction in both types of single-celled organisms is asexual.
In a process named mitosis, a cell elongates and then divides once to form two identical cells.
Both of these cells are genetically identical to the cell that underwent mitosis.
 3.3. EXAMPLES OF ENGINEERED BIOMIMICRY 29
Human DNA

Human pancreas cell INS gene

Fermentation chamber
Recombinant E. coli
Nuclear DNA
Extraction
and
purification
Plasmid DNA steps
E. coli
Recombinant
DNA insulin

Figure 3.3: Schematic for biomimetic production of insulin.

The entire biomimetic process is initiated by some copies of INS, but no more are needed
after production begins. The proclivity of single-cell organisms to reproduce rapidly via mitosis
makes the biomimetic production of insulin economically viable.
Fast-acting insulins are produced by slight interchanges of codons in the initiating copies
of the human genes to minimize the tendency to form hexamers. The type of interchange se-
lected regulates the ratio of monomers to hexamers. Intermediate-acting insulins are produced
by adding chemicals that help maintain hexamers. Long-acting insulins are produced by slight
modifications of an amino acid. Thus, a therapeutically significant functionality is imparted to
biomanufactured insulin in comparison to insulin produced in the pancreas.

3.3.3 BIOREPLICATED VISUAL DECOYS OF INSECTS

An industrially scalable bioreplication process with nanoscale fidelity has been devised to pro-
duce visual decoys of females of the buprestid insect species Agrilus planipennis, commonly called
the emerald ash borer (EAB). The decoys are more successful than freshly sacrificed females in
luring males of the species toward attempted copulation followed by electrocution [30, 31],
thereby providing forestry managers a tool to limit the spread of the invasive species.
The emerald ash borer is a native of northeast Asia. Its shipborne arrival in North America
was detected in 2002. That very year, it was identified as devastating ash trees. EAB females
deposit eggs in the bark of ash trees; the EAB larvae chew long meandering tunnels in the
30 3. ENGINEERED BIOMIMICRY

Figure 3.4: Top: Female of the species Agrilus planipennis. Middle: Three types of bioreplicated
decoys produced with an industrially scalable process [30]. Bottom: 3D-printed decoy [35].

trunks as they feed, thereby disrupting the transport of nutrients and water to the leaves; and
adults chew their way back to the bark and exit the trunk [32]. EAB are thriving in North
America in the absence of natural predators and parasitoids. Although their populations spread
about 20 km per year, long-distance transport of wood products allows them to colonize far-
flung areas. Ash wood being used for numerous purposes, the destruction of ash trees is having
a severe economic impact. Furthermore, as other invasive species move into the affected areas,
native species suffer from habitat reduction and the soil chemistry changes [32].
EAB do not have sex pheromones to attract mates, relying instead on visual communica-
tion. Adult EAB are conspicuous by their bright metallic green elytra (hardened forewings), as
shown in the top panel of Fig. 3.4. Adult EAB males patrol tree canopies for adult EAB females
resting and feeding on ash leaves. After seeing a female from as high as 100 cm, a male drops
like a paratrooper toward her and makes vigorous attempts to copulate [33].
 3.3. EXAMPLES OF ENGINEERED BIOMIMICRY 31
A visual decoy looking very similar to an EAB female with its elytra folded over its body
would be necessary to lure EAB males. The decoy’s color must be iridescent green to contrast
against the the background of ash foliage. Additionally, 10-m surface features present on the
elytra must be reproduced on the decoy.
An industrially scalable bioreplication process was therefore devised [30]. This process
involved two major stages. In the first stage, a pair of matching positive epoxy and negative
nickel dies were bioreplicated from an euthanized female EAB. The negative die was made
by the deposition of a 500-nm-thick conformal film of nickel on the upper surface of the
euthanized female EAB in a low-pressure chamber. The nickel thin film was then thickened
by electroforming to about 100 m. The female EAB was then plucked out, leaving behind a
negative die with fine-scale features, the conformal film comprising 22-nm-diameter nickel
grains. A positive die of epoxy was made from the negative die of nickel using several casting
steps and the deposition of a conformal thin film of chalcogenide glass.
In the second stage, a sheet of poly(ethylene terephthalate) (PET) was hot stamped be-
tween the pair of matching dies. The PET sheet had been previously coated on the upper side
with a quarter-wave-stack Bragg filter [34] made of two distinct polymers to reflect normally
incident green light and on the lower side by black paint to absorb visible light of all other
colors. Light stamping between the pair of matching dies kept the Bragg filter intact. How-
ever, heavy stamping for better reproduction of the fine-scale features of the elytra pulverized
the Bragg filter, for which reason the lower side of the decoy was spray-painted metallic green,
again to mimic the actual color of the EAB elytra. The middle panel of Fig. 3.4 is a photograph
of bioreplicated decoys of three different types.
In a preliminary field experiment, males of the related species A. bigutattus were targeted,
the inter-species attraction having been previously recorded by entomologists. The bioreplicated
decoys were 40% more effective in luring males than dead EAB females [30]. The lower effective-
ness of the dead EAB females is indicative of the suboptimality of many biological phenomena,
as discussed in Section 4.5.
The effectiveness of the bioreplicated decoys was evaluated against that of 3D-printed
decoys, an example of which is shown in the bottom panel of Fig. 3.4. Although EAB males
were almost equally attracted to decoys of both types, they would fly toward and alight on the
bioreplicated decoys for a couple of seconds, but they would break off midway toward the 3D-
printed decoys and veer away. The absence of the 10-m surface features on the 3D-printed
decoys rendered them insufficiently authentic on closer inspection by the EAB males.
In the third field experiment [31], the bioreplicated decoys were offered to EAB males.
These decoys evoked complete attraction, paratrooper flight, and attempted copulation from
EAB males. Some decoys were electrically wired for alighting males to be electrocuted. The
electrocuting decoys could assist forestry managers in slowing the spread of the pest species.
The bioreplication process for industrial-scale production of these decoys was sped up [36]
by making the negative nickel die from an array of several female EABs instead of only one.
32 3. ENGINEERED BIOMIMICRY
Also, the positive die was eliminated by a decision to fill up the multiple cavities of the negative
die with the thermally curable liquid polymer poly(dimethyl siloxane). Multiple decoys made
simultaneously were painted metallic green.
The tale of EAB decoys is one in which a biological structure is directly replicated by
technoscientists in order to fulfill a societal goal: to eliminate a pest species, or at least reduce its
proliferation. Can this nanoscale bioreplication process also assist biologists in answering certain
questions that cannot be answered otherwise? The answer is a guarded “yes.” For instance, the
spectral ranges of buprestid vision systems could be determined by coloring the decoys red, blue,
or yellow, or even ultraviolet. Of course, humans cannot see ultraviolet, but many insect species
can [37]. The same bioreplication technique could be applied to determine the spectral ranges
of the vision systems of their predator species. Even evolutionary scenarios could be investigated
by determining the aversion or affinity of a predator species to color mutations in a prey species.

3.4 DESIGN TEAMS FOR BIOWORLD SOLUTIONS

The examples of engineered biomimicry presented in some detail in this chapter strongly in-
dicate that this topic transcends the boundary between science and engineering. Until perhaps
the middle of the 19th century, there was no distinction between engineers and scientists. The
explanation of natural phenomena, today considered the domain of scientists, and the commer-
cially viable exploitation of those phenomena for the betterment of the human condition, today
considered the domain of engineers, were conjoint goals of a person who functioned either as a
scientist or as an engineer in different phases of professional life. Sometimes, that person even
functioned concurrently as an engineer and a scientist.
The English word scientist was coined in 1834 for someone dedicated to the pursuit of
new knowledge in any branch of science [38, 39]. In the ensuing decades, scientists were dif-
ferentiated from engineers, the former as the discoverers of new facts in nature and formulators
of potentially verifiable theories to explain those facts, the latter as those who apply scientific
knowledge to solve practical problems at a cost that society can bear.
This differentiation is less pronounced nowadays, especially when multidisciplinary teams
are formed to undertake complex research projects, whether at universities or in industries or
in university-industry consortia. Teams comprise physicists, chemists, materials scientists, me-
chanical engineers, chemical engineers, electrical engineers, medical scientists, etc., as dictated
by project requirements.
The scope of biologically inspired design is the formulation of design strategies to re-
produce desirable outcomes, mechanisms, and structures from the bioworld. The practice of
biologically inspired design requires both scientists and engineers to work collaboratively, just
as for other types of complex research projects with an industrial focus. There is, however, a
crucial issue.
Such a team must have biologists each of whom who specializes in a particular species that
exhibits a desirable outcome, mechanism, or structures. But the expertises of these biologists may
 3.5. REFERENCES 33
not be enough for optimal design. There may be other species—in even other genera, families,
orders, and classes—that could be the sources of better designs than the species that could have
inspired the formation of the biologically inspired design project. The independent evolution
of a similar feature in two very different species is called homoplasy, if that feature was not
inherited from a recent common ancestor [40]. The evolution of a feature that has similar form
or function in widely different species attests to the robustness of that feature. But not every
manifestation of a certain feature would be equally efficacious for the process or product to be
designed. A biologist who is focused on a desirable outcome, mechanism, or structure—instead
of a particular species—could therefore guide the other team members to better choices [41].

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 37

CHAPTER 4

Rationale for Biologically

Inspired Design
Wilful waste makes woeful want.
James Kelly, A Complete Collection of Scottish Proverbs (1721)

Since the laws of physics hold sway over every biological process just as completely as over
every technological operation, the bioworld should be considered as a repository of answers to
billions of technological questions [1]. Some of these answers have already been implemented
by humans. Some answers may not be optimal for our technological requirements but can still
illuminate possible research directions.
The fact is that the bioworld offers a palette of solutions that may be otherwise unavail-
able to humans. An example is furnished by three-dimensional photonic crystals with diamond
crystal structure, which reflect incident electromagnetic waves in a specific spectral regime, re-
gardless of the direction of incidence [2]. These photonic crystals have been made for operation
in the microwave and infrared spectral regimes, but no technique has been successful to fabricate
them for operation in the visible spectral regime [3]. Yet the exocuticle of the Brazilian weevil
Lamprocyphus augustus displays the desired response characteristics in the yellow-green portion
of the visible spectral regime [4], as shown in Fig. 4.1. Clearly, then a fabrication route exists in
the bioworld that is not known yet to humans.
A review of relevant characteristics of bioworld solutions is undertaken in this chapter to
offer the rationale for biologically inspired design.

4.1 ENERGY EFFICIENCY

Neither biological processes nor industrial processes can overcome the fundamental limitations
encoded in the laws of physics. Nevertheless, the contrast between the two types of processes is
remarkable. Chemical routes are commonplace for material transformations in biological pro-
cesses, whereas physical routes are routinely employed in industrial processes. This difference is
quite succinctly captured by just one environmental variable: temperature.
Consider the temperature differences between biological and industrial processes. Al-
though a few animals live in extreme conditions, the range of temperature in the majority of
the bioworld is quite restricted. Deep-sea creatures at 1000 m below sea level have to live at
about 5ı C, polar bears have to contend with 70ı C and desert foxes with 50ı C. But the tem-
38 4. RATIONALE FOR BIOLOGICALLY INSPIRED DESIGN

Figure 4.1: Exocuticle fragment from the Brazilian weevil Lamprocyphus augustus.

peratures of internal tissue vary in a much smaller range, because biological cells are mostly
water. Accordingly, numerous biological processes occur between, say, 5ı C and 45ı C. In con-
trast, very high temperatures are routinely employed in industrial processes. Wood combusts at
about 300ı C, clay bakes at about 760ı C, and iron melts at higher than 1500ı C.
The metal zirconium is produced on reducing zirconium chloride by liquid magnesium at
about 825ı C [5]. The hardness of zirconium on the Mohs scale is 5, the scale ranging from 1
(talc) to 10 (diamond). Tooth enamel, which has the same hardness as zirconium, is formed at
a much lower temperature of about 37ı C.
The production of high temperatures requires considerable expenditure of energy, imply-
ing that biological processes are energy efficient in comparison to industrial processes [6]. This
energy efficiency is a persuasive argument for mimicking biological processes when designing
an industrial production line, especially during the time of climate emergency we are presently
living in [7]. Indeed, one can justifiably argue that an embrace of biologically inspired design
is essential to the survival of the human species as well as numerous other species, in the 21st
century on Earth.

4.2 CIRCULAR ECONOMY OF MATERIALS

About 40,000 metric tons of cosmic dust fall on our planet every year [8], but about 50,000
metric tons of hydrogen and helium escape every year too [9]. These changes to the mass of
Earth are so tiny that it can be regarded as a closed system wherein materials cycle between the
lithosphere, atmosphere, and hydrosphere.
The biosphere comprises parts of each of these three regions of Earth. Biomass, i.e., the
mass of living organisms, varies greatly with time [10]. For example, it reduces significantly
during the autumn season in the northern hemisphere. Despite such variations, the main out-
puts, byproducts, and wastes of every living organism become inputs to living organisms of other
 4.3. MULTIFUNCTIONALITY 39
species. Herbivores eat plants, carnivores eat herbivores, numerous organisms sustain themselves
on the excretions and secretions of other species, and the bodies of dead organisms return nutri-
ents to the ground in which plants grow. Leaving aside the sequestration of materials through
geological processes, materials thus circulate in the bioworld.
In other words, the bioworld exhibits circular economy [11] of materials, especially
when annually averaged over ecologically distinct parts of the biosphere. This circular economy
becomes easily evident when an island subspecies are compared to its continental counterpart
in average size. Adjustment to serious restrictions on the availability of edible matter on islands
is commonly shown by increases and decreases of average sizes of diverse species in relation to
their continental cousins [12].
The circular economy of materials evinced by various swathes of the bioworld is not ac-
companied by the circular economy of energy. This is because our planet is a closed but not an
isolated system thermodynamically. A closed system can exchange energy but not mass with
its surroundings. An isolated system can exchange neither energy nor mass with its surround-
ings. The sun supplies energy to Earth, which is in addition to the energy made available to the
biosphere by the planetary core.
In the bioworld, every organ is functional over a certain period of time that is, on average,
not less than the time needed to reproduce at least once. Many organs are repairable and some
organs are not totally necessary for the survival of the individual. The byproducts and waste
products of bioworld processes are used as inputs to other bioworld processes, not necessarily
in the same organism. Materials in a dead organism provide sustenance to other organisms,
either directly or indirectly. Biologically inspired design can influence the manufacture, use, and
disposal of specific products with minimal depletion of materials and with minimal impact on
the rest of the biosphere; furthermore, energy could be harvested from whatever remains that
cannot be cannibalized after use.

4.3 MULTIFUNCTIONALITY
Multifunctionality is commonplace in living organisms [13–15]. Thus, limbs are used for
moving, signaling, gathering and preparing food, wielding weapons, and initiating as well as
warding off physical assaults, among other things. Mouths are used for ingesting food and fluids,
releasing sounds, breathing, and kissing. As certain organs can perform two or more distinct
functions that are not highly related to each other, fewer organs need to be formed and housed
in the organism and fewer structures need to be coordinated by the organism’s brain.
This economy of multifunctionality is an attractive feature of biologically inspired de-
sign [16, 17]. A multifunctional module can be incorporated in a variety of products, thereby
reducing inventory costs, enhancing repairability and product lifetimes, and promoting stan-
dardization. A multifunctional product may designed and fabricated as an assembly of mono-
functional components. A simple example is a Swiss Army knife. A multifunctional product
could also be made from multifunctional materials, whether natural or composite. The costs of
40 4. RATIONALE FOR BIOLOGICALLY INSPIRED DESIGN
eventual disposal may be higher when composite materials are used, and designers will have to
make choices based on lifecycle audits [18].

4.4 MULTICONTROLLABILITY
The concept of multicontrollability [19] is closely allied to multifunctionality. Multicon-
trollability is also exhibited commonly in the bioworld. Thus, multiple modes of locomotion can
be used by an organism to propel itself from one location to another, and often the same sound
can be uttered using two or three different placements of the tongue in the buccal cavity. We
get alarmed by hearing the sound of an approaching car and/or by seeing it. Reliance on mul-
tiple mechanisms thus builds resilience via redundancy. That’s why multiple control modalities
are used to ensure specific actions in critical facilities such as nuclear power plants and missile
guidance centers.

4.5 SUBOPTIMALITY
When mimicking a bioworld product or process, it is important to remember that biological
phenomena are adapted to a specific context with a given set of constraints. This means that the
solutions derived from a biological phenomenon may not be suitable in contexts with different
constraints. For instance, the wings of an owl are silent but are unsuitable for rapid flight, the
wings of a swan are noisy but can lift a heavy body, and the wings of a swift allow for very high
speed but make it very difficult for the bird to take off from the ground.
A bioworld solution is also constrained by evolutionary history since it arises from succes-
sive mutations of several species [20]. Each mutation could be suboptimal that performs just well
enough in a particular niche. A succession of such mutations will definitely produce a solution
that too is viable in its niche, but that solution could be suboptimal even in that niche.
Suboptimality in the bioworld has long been exemplified by the plethora of visual prob-
lems that plague humans [21], not to mention other mammals. Aberrations, astigmatism, and
blindspots are structural deficiencies that have kept generations of ophthalmologists gainfully
employed. Although all of their patients would like to keep using their eyes for as long as pos-
sible, the human eye can hardly be regarded as the product of a well-designed instrument [22].
As a bioworld solution is not necessarily optimal even in the bioworld, it is likely to re-
quire some modification to optimize it for a specific technoscientific application. This should be
viewed as a welcome opportunity, all the more so as the need for modification may allow the
incorporation of functionalities not associated with the bioworld solution in the bioworld. Thus,
the rapidity of action of biomimetic insulin can be controlled by the alteration of the codon se-
quence, as mentioned in Section 3.3.2. Similarly, bioreplicated decoys can be colored differently
from the the species being replicated, as discussed in Section 3.3.3.
Further opportunities may arise after realizing that several bioworld solutions can be com-
bined for a specific technoscientific application. This is exemplified by the tennis racquets in
 4.6. CONTRAINDICATED PERFORMANCE 41
the Dunlop Biomimetic 200™ series. The racquet beam is made of Dunlop HM6 carbon sand-
wiched between aerogel-enhanced carbon sheets. Dunlop HM6 carbon mimics the morphology
of honeycombs which are extraordinarily strong and lightweight structures [23]. The surface of
the racquet frame is covered by a fabric with overlapping scale-like protrusions to reduce aero-
dynamic drag. These protrusions mimic denticles that reduce hydrodynamic drag and prevent
fouling of shark skins [24, 25]. The surface of the racquet grip mimics the setae on the feet of a
gecko that enable it to walk upside down on smooth surfaces [26, 27].

4.6 CONTRAINDICATED PERFORMANCE

For over two millennia, humans have known that an object denser than water sinks in a bathtub
but an object of lesser density than water floats. Well, boats float in rivers and seas, but that is
because the volume-averaged density of a boat’s hull and superstructures as well as of air below
the waterline is the same as of water.
Air is a liquid and a rigorous scientific study [28] is not needed to prove that a bird is
definitely heavier than air on a unit-volume basis. Although avian flight is thus contraindicated,
birds of most species can fly well, some even at altitudes higher than 10 km [29]. The secret lies
in the arrangement of flight feathers arranged on concave wings that can be flapped to raise the
underwing pressure and provide lift.
Mushrooms and their mycelium roots are well known to be very fragile. But a fungus
growing in a fibrous material functions as a glue that provides the resulting composite material
with surprisingly high stiffness and strength. This can be seen in the forest floor where the soil in
places with fungus can become harder and stiffer, provided the soil is a good mixture of organic
material of various sizes. The same phenomenon can be utilized for making building components
and plates from straw by letting a fungus grow in the humidified material. The mycelium roots
will bind the straw fibers together and form a stiff composite material, as depicted in Fig. 4.2.
Both foams and structural composites are being made of mushrooms [30, 31].
Mollusk shells are calcareous, created by the secretion of calcium carbonate mixed in
a broth of polysaccharides and glycoproteins which controls the position and elongation of
calcium-carbonate crystals [32]. As talc, calcium carbonate is among the softest natural ma-
terials known. As aragonite, the material’s hardness does not exceed 4 on the Mohs scale. Yet,
mollusk shells comprising interlaced plates of aragonite are extremely durable, with a modulus of
elasticity similar to wood’s, tensile strength similar to copper’s, and compressive strength higher
than porcelain’s [33]. The secret lies in the arrangement of aragonite plates that prevents crack
propagation and thereby provides the toughness needed to protect the enclosed body. The same
arrangement of plates of Norwegian slate has been used in the retaining walls constructed on the
undulating terrain of the Lyngby campus of Danmarks Tekniske Universitet (DTU) as shown
in Fig. 4.3.
42 4. RATIONALE FOR BIOLOGICALLY INSPIRED DESIGN

Figure 4.2: Mycelium bio-composite made from straw and other agricultural byproducts.

(a) (b)

Figure 4.3: (a) Retaining wall on the Lyngby campus of DTU. (b) The inter-plate regions of the
wall provide habitat for terrestrial mollusks of the species Cepaea nemoralis.

The examples of contraindicated performance in the bioworld offer unexpected

routes to the seemingly impossible satisfaction of mutually incompatible constraints. Thus, bio-
logically inspired design has the potential to engender innovative products and processes.
 4.7. REFERENCES 43
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 47

CHAPTER 5

Problem-Driven Biologically
Inspired Design
It is, that as existing human inventions have been anticipated
by Nature, so it will surely be found that in Nature lie the proto-
types of inventions not yet revealed to man. The great discoverers of
the future will, therefore, be those who will look to Nature for Art,
Science, or Mechanics, instead of taking pride in some new invention,
and then finding that it has existed in Nature for countless centuries.
Rev. John G. Wood, Nature’s Teachings, Human Invention
Anticipated by Nature ()

5.1 INTRODUCTION
Biologically inspired design (BID) can be approached from two different directions [1–3]. The
approach from the engineering side is referred to as problem-driven BID, whereas the ap-
proach from the biology side leads to solution-driven BID. The former is treated in this
chapter, the latter in Chapter 6.
As the name implies, problem-driven BID is initiated by an engineering problem whose
solutions are sought; hence, it is very similar to traditional engineering design. The major differ-
ence is that the solution principles are searched in the bioworld. As engineering designers will
be familiar with the design-oriented parts of the process but are likely to be less knowledgable
and experienced in the tasks that relate to biology, problem-driven BID should be carried out
in a collaboration between engineers and biologists. However, there are strong limitations for
problem-driven BID in such a collaboration, as explained in Sections 5.2.2–5.2.4.
Problem-driven BID is the term used by researchers at the Georgia Institute of Tech-
nology [1], Arts et Métiers ParisTech [4, 5], and Danmarks Tekniske Universitet (DTU) [2].
The International Standards Organization calls it technology-pull biomimetics because a
technological need initiates it and drives the work [6]. The term top-down bionik has been
used by researchers at the Technische Universität München for many years [7]. It is also this
type of BID that is handled with the design spiral from the Biomimicry Institute [8].
There are other ways than problem-driven BID to generate new ideas for how to design
products and other artifacts. One can look at already existing products or even search patents. Or
48 5. PROBLEM-DRIVEN BID

Problem analysis Search Understand Transfer Design

Formulate Formulate Search Understand Extract key Make biocards Sketch Validate
problem challenge databases biological principles describe conceptual principles
(context- (generalized) phenomena generalized solutions in context
specific Make search principles
terms

Abstraction Functional keyword Select Extraction Abstraction Contextualization Validation

generation

Redefine problem Biological keywords Learn more Refine principles

Redefine problem

Figure 5.1: The five phases of problem-driven BID implemented using the DTU biocard
method.

one could turn to a range of different creativity techniques such as brainstorming, 635-method
or the Scamper method [9, 10]. Two questions naturally arise. First, how well does BID perform
as an idea-generation technique? Second, are its outcomes worth the effort?
Answers to these questions have been sought by comparing the BID methodology to
traditional brainstorming [11]. Several design students were given an assignment to generate
ideas to a given problem, with half of the students asked to use brainstorming and the other
half to use the BID methodology. The novelty of each resulting design proposal was identified
by comparing it with other solutions found on the internet. The comparison was made using
the SAPPhIRE model for causality [12] where the similarity between new and existing design
proposals was compared at seven levels of abstraction. The use of BID methodology resulted in
fewer design proposals, but the ones that were found were more novel (and, therefore, presum-
ably of higher quality). This is a key argument for using the BID methodology. Brainstorming is
easy to learn and requires little preparation or skills, thereby producing many design proposals.
On the contrary, the BID methodology requires a stricter procedure to be followed as well as
some interest in and some knowledge of biology, but results in novel proposals.

5.2 PHASES OF PROBLEM-DRIVEN BID

Implementation of problem-driven BID is done in five phases, beginning with an initial analysis
of the design problem, followed by a search for biological analogies, then distilling an under-
standing of biological phenomena to extract key principles, followed by a reformulation of design
principles, and ending with the actual design of new objects after validating the principles in the
context of the design problem. The flow chart in Fig. 5.1 illustrates these five phases using the
biocard method developed at DTU.
Abstraction is done at least twice during the problem-driven BID process, as is clear
from Fig. 5.2. First, the technical problem is abstracted from the initial analysis of the design
 5.2. PHASES OF PROBLEM-DRIVEN BID 49

3. Transpose 7. Transpose
to to
biology technology

2. Abstract 4. Identify 8. Implement 6. Abstract

technical potential and test in the biological
problem biological models initial context strategies

1. Problem 5. Select
analysis biological model(s)
of interest

Input Output

Figure 5.2: Interaction of technology and biology in problem-driven BID [5].

problem. Second, key biological principles or strategies are abstracted from the understanding
of a biological phenomenon and brought into a form useful for design work.

5.2.1 FIRST PHASE: PROBLEM ANALYSIS

The first phase in problem-driven BID is no different from those in numerous other goal-
oriented projects, since a thorough understanding of the problem being tackled is required.
Asking the right question(s) is halfway to finding good solutions. The problem-analysis phase
can involve just a single person but is often better carried out as a collaboration of several peo-
ple. Discussions among team members force clarity in the description of the problem so that
every member can get a clear and complete picture. The following tasks have to be undertaken
in the problem-analysis phase: problem description, function analysis, and engineering-biology
translation.

Problem-Description Task
Describing the design problem adequately is among the most important activities in BID, just
as it is in design work in general. Adequate understanding of the core issues and the short-
comings of existing products determines the form and the substance of the remainder of the
design process. Understanding the design problem and describing it clearly for others can be
difficult enough for a single person, but it becomes even more complicated when many persons
50 5. PROBLEM-DRIVEN BID

Figure 5.3: A hand-drawn sketch describing the window problem. The window must allow an
external view but prevent the solar infrared radiation from entering the room.

collaborate in a design team. Therefore, the problem must be described and communicated in
a way that it is easily and uniformly understood by many persons. A sequence of illustrations,
whether drawn by hand or on computers, accompanied by bulleted points in text can docu-
ment the problem reasonably well. Illustrations can be rapidly made and transcend barriers of
language, terminology, and expertise. The technical problem can then be abstracted quite easily.
But, care must be taken that the illustrations focus on the desired functionality but not
on the manner in which the problem is to be solved. As an example, consider the window
problem that architects often encounter when designing buildings in normally sunny locales.
People inside a building are interested both in having sunlight enter rooms through windows
and in being able to view the outside. However, solar radiation contains not only visible light but
also infrared waves that heat the room and may necessitate the increased use of air-conditioning
systems. The design problem is that of a window that allows the occupants of a room to enjoy the
external view but (partially) prevents solar infrared radiation from entering the room. This design
problem can be described by the simple sketch shown in Fig. 5.3. The window pane is represented
by two parallel lines, the external view is illustrated by a dashed straight line that begins at one
eye of a stickperson and crosses the window pane to the exterior, and the infrared restriction
is represented by bouncing arrows. Such an abstract description will stimulate an open-minded
approach to identify the core functionality and allow for a broader and goal-oriented search for
biological organisms displaying that functionality.
Another method that is useful for problem analysis and description is the four-box
method [13]. This method requires the design team to specify
 5.2. PHASES OF PROBLEM-DRIVEN BID 51

Operational Functions
environment

Specifications Performance criteria

Figure 5.4: The four-box method for problem analysis and description [13].

(i) the operational environment for the product (i.e., the context),
(ii) the core functions delivered by the product,
(iii) the main specifications of the product, and
(iv) the performance criteria that the product must satisfy.
The responses are entered as bulleted lines of text in the table shown in Fig. 5.4. For the win-
dow example, the operational environment includes the type of room in which the window is
to placed (i.e., office, school room, bed room, etc.) as well as the geographical location and cli-
matic conditions (e.g., dry/humid, sandy/salty, hot/cold, etc.). Functions could include “provide
transparency,” “prevent solar infrared radiation to pass through,” and “allow cleaning;” see also
Section 5.2.1. Specifications include linear and areal dimensions and orientation toward the sun
in summer. Performance criteria could include the fraction of visible light that is allowed to
pass through the window, the color tint that is acceptable, and the minimum acceptable viewing
angle.

Function-Analysis Task
A problem is typically specified using a terminology which is closely related to the context of the
problem. For instance, will a car driver explain a puncture in a tire as “having a flat tire”? However,
as described in Section 2.4.1, it is important to provide an abstract functional description rather
than a concrete one, in order to prevent fixation. The puncture problem can, of course, be solved
by changing the tire; but if the goal is to prevent punctures, it is advantageous to describe the
function in more abstract terms. The tire is a solution to the functions “provide road grip” and
52 5. PROBLEM-DRIVEN BID
To provide
a view

Window

To allow To prevent excess To prevent To keep To prevent

light to enter heat from entering heat loss out insects transport of sound

Glass pane Blinds Double layer Finely meshed net Glass pane
glazing

Figure 5.5: Functions-means tree diagram for a window. Each trapezoidal block contains a func-
tion, each rectangular block a means.

“provide driving comfort.” By broadening the problem description using such abstract terms, it
is more likely that a completely different solution will be found. The road grip could be provided
by spiked solid wheels and the comfort could be supplied by a sturdy mechanism for wheel
suspension. Such a wheel solution will not suffer from punctures.
More generally, an engineering problem can be analyzed by describing an artifact that
solves the problem. The artifact can be decomposed into functional units each of which is de-
scribed in terms appropriate for the context. The next step is then to formulate the function(s)
of each artifact with a more abstract terminology that allows for a broader search for alternative
means to solve the problem. The overall problem is decomposed into sub-functions, each de-
scribing specific aspects of what the artifact does and defining a set of metrics for the required
performance.
Function analysis for the window problem of Fig. 5.3 can be performed as follows. The
main function of a window is to provide a view. This can be done with glass panes, but an open
hole in the wall will also deliver this function. A functions-means tree diagram, as described in
Section 2.4.2, helps to define which functionalities are required and thus support a search for
alternative solutions. Figure 5.5 shows a functions-means tree diagram for the window problem
with each trapezoidal box containing a function or sub-function and each square box containing
a means to provide the needed functionality. The search for solutions is thus broken down into
identification of various means, each of which solves a specific aspect of the overall problem.
The top-level functionality in the functions-means tree diagram is “to provide a view.” The main
function can be broken down into five sub-functions: “to allow light to enter,” “to prevent ex-
cess heat from entering,” “to prevent heat loss,” “to keep out insects,” and “to prevent sound
 5.2. PHASES OF PROBLEM-DRIVEN BID 53
transport.” The sub-function involving insects can be solved by using a finely meshed net as an
alternative to a glass pane. The last sub-function rules out a hole as a window and also the finely
meshed net. The functions-means tree diagram therefore is a tool for qualifying the search for
solutions and it is also very helpful in the search for analogous solutions from the bioworld.
A challenge in describing functionalities for the functions-means tree diagram is to select
the right phrases that will be helpful in the search phase. Assistance can be taken from on-line
thesauri wherein synonyms and antonyms can be found [14]. Another helpful resource is the
WordNet database from Princeton University [15].

Engineering-Biology Translation Task

After a designer (or a design team) has described the problem and identified the desired func-
tionalities, the formulation is often very technical. This is a good starting point, since the designer
should be familiar with the engineering terminology and therefore should be able to formulate
the problem precisely enough to find good technical terms for searching the literature.
In Fig. 5.1, this task is referred to as the context-specific formulation of the design prob-
lem. However, it is not very likely that exactly the same terms are used to describe similar func-
tions in the engineering and biology literatures. Before searching in the biology literature, it is
therefore beneficial to translate the engineering terms to biology terms. This task can be ap-
proached by looking at synonyms in a thesaurus as well as by looking in those segments of the
biology literature wherein similar phenomena are likely to be found. If, for instance, a new type
of cleaning mechanism is to be designed, then one could consult the literature on how domesti-
cated animals as well as animals housed in diverse research institutions (such as zoological parks)
keep themselves tidy. In that literature, terms such as “washing,” “licking,” and “removing hair
and dirt” are used instead of “cleaning.” The terms from biology literature could be more useful
in finding similar phenomena among other animals. The abstraction activity of finding good
biological search terms is referred to as the formulation of generalized challenges in Fig. 5.1.
For the window example, technical search terms could be “semi-transparent,” “sun block-
ing,” and “shield light.” These would only find a few biological analogies but that is a good
starting point. Once the first biological analogy has been identified, the biology literature could
be consulted to find out what terms are used to describe protection from high-intensity light.
As animal eyes are likely to possess features for such protection, literature on veterinary oph-
thalmology would be appropriate. Animals protect their eyes from high-intensity light by con-
tracting the iris, closing eye lids, moving the eyelashes, and using skin folds that shade. Another
search could be for plants growing in sunny deserts, because those plants somehow avoid being
overheated, e.g., how cacti utilize corrugated surfaces and spines for cooling by convection. The
insight gained could then be used to define search terms more likely to be found in the biology
literature. Examples of search terms could be “eye protection” and “temperature regulation.”
Another helpful approach is to translate the terms used for biological phenomena into
Latin. Latin words are universally used in the scientific literature, especially in the biology lit-
54 5. PROBLEM-DRIVEN BID
erature. Taxonomists use Latin terms for kingdoms, phyla, classes, orders, suborders, families,
genera, and species, each term usually referring to a specific biological attribute. After a Latin
term is found in taxonomy, it is straightforward to move up, down, or sideways in the hierarchy
to find other organisms and then explore other bioworld solutions to the design problem.
Researchers at the University of Toronto have developed a natural search approach for
BID and a method for identifying good biological search terms. They have proposed a set of
techniques for abstraction and identification of relevant search terms to be used for the bio-
logical search [3]. Verbs are recommended instead of nouns since it is more likely that nouns
will lead to pre-conceived analogies. Furthermore, verbs describe actions and hence are better
for finding a greater variety of biological forms. As an example, the verb “protect” helps find a
greater variety of phenomena than the noun “cuticle” does. If certain verbs that can be consid-
ered as biologically meaningful (significant or connotative) occur more commonly than others,
they can be considered as bridge words that are more likely to be helpful in the biological search.

5.2.2 SECOND PHASE: SEARCH

Searches can be done in many different ways. Most straightforwardly today, internet search en-
gines such as Yahoo, Google, and Bing should be used. The challenge is that, as no search engine
is restricted to biology, a large number of hits will result that can be difficult to navigate through.
It is therefore important to identify a good starting point when using an internet engine. One
way is to apply a bio-brainstorm where the person or groups of persons formulate a question of
following kind: “How would this particular problem be overcome in the bioworld?” Based on the
biological knowledge already available in the design team, animals and plants can be identified.
For instance, many people would readily propose mammalian eyes as biological solutions to the
window problem. This first hit will be a good starting point for a wider search.
Another approach is to use dedicated biology databases that will be more likely to propose
relevant biological organisms. Among the better known databases is AskNature developed by
the Biomimicry Institute [16]. AskNature contains a large number of examples of biomimicry,
with biological organisms described alongside how a biological strategy has been transferred
into technical applications. AskNature provides at least two ways to initiate a search. One is a
simple free-text search very similar to the use of internet search engines. Another is to use a
biomimicry taxonomy [17] which describes functions on three hierarchical levels: group, sub-
group, and function. Relevant for the window example could be to focus on the group “protect
from physical harm,” the subgroup “protect from non-living threats,” or the function “(protect
from) light.”
The terms from the biomimicry taxonomy can be used not only for a focused search in
AskNature but also when searching more broadly in other databases or on the internet. As
additional search terms are needed to limit an internet search to biological phenomena, terms
such as “biology,” “animal,” and “plant” or other biology-related terms should be added. The
 5.2. PHASES OF PROBLEM-DRIVEN BID 55
right terms must be found through an iterative approach where relevant hits can be used to
identify relevant biological terms that will guide the search in a fruitful direction.
Yet another approach is to use library search engines to search scientific books and papers.
The library databases are prepared to offer goal-directed searchs where the focus is on recognized
and quality-tested scientific knowledge. What is found using library search engines therefore has
a high degree of trustworthiness. The difficulty in using scientific literature is that is written in
the language of a sub-culture, i.e., it can be difficult for a layperson to understand a paper written
for a specialist journal or book.
There are also other ways to search for biological organisms with relevant mechanisms and
functionalities. An obvious one is to consult a professional biologist. They have broad insights
about the bioworld, they know how many biological organisms function, and they can easily
peruse scientific literature to gather further information. However, as they may require payment
for their services, the value of conducting a biological search must be higher than the cost of
hiring a biologist. Besides, a limitation is the growing specialization within the broad discipline
of biology. Many biologists today have deep knowledge of only a narrow sub-discipline and
therefore are less suited for the broad search for biological phenomena that could help solve a
specific design problem.
Finally, there is the option to visit some parts of the bioworld. Once a mind is tuned to
looking for a functionality, it is natural to wonder about the things that we see in a forrest, a
zoological park, a botanical garden, or a protected area set aside as a nature reserve [18]. For
instance, if one is searching for new strategies for bearing structural loads (e.g., columns for
holding motorway signs, large tents, or bridges), it is natural to wonder about how trees are
structured and anchored in the ground so they can resist high wind pressure in storms. Or, if
one is look for self-cleaning strategies, one will find many plants that stay clean despite dirty
surroundings.
A possible pitfall when searching for biological phenomena is that only well-known ones
are explored. Experiences from teaching BID courses show that many students limit their
searches to the larger animals, i.e., mammals, birds, and insects [19]. By limiting the search
to the more familiar fauna and flora, the probability of finding really novel ideas decreases. If
the search is forced to be broader to cover items such as marine life, microbiology, and single-cell
organisms, more and novel ideas emerge [19].

5.2.3 THIRD PHASE: UNDERSTAND

Once a list of promising biological phenomena has been created, the next step is to understand
the underlying mechanisms. The mechanism is straightforward to understand in some cases,
but not for all. See, for example, Section 3.3.2 for the complexity of insulin production in the
human pancreas. It can also be that the overall functionality is easy to understand but becomes
more complex after additional detail is required for implementation. For the window example, it
is easy to understand that the iris in a mammalian eye functions like a camera aperture with the
56 5. PROBLEM-DRIVEN BID
size of the hole determining how much light is allowed through, but the activation of muscles
causing the contraction and widening of the iris is more complicated for a non-specialist to
understand.
Better understanding normally requires access to trustworthy literature which can inform
about a particular biological phenomenon and explain the underlying mechanism(s) in adequate
but not overwhelming detail. Whereas internet searches will supply the needed insight in some
cases, a proper library search is necessary more often than not. Relevant keywords and descriptive
names of the biological phenomenon combined with boolean operators (and, or, not) will help
identify relevant books and journal papers that can retrieved though the library facilities. Latin
terms will be especially useful in library searches since they precisely define the type of biological
phenomenon that is described, thereby offering the opportunity to select a more general level in
biological taxonomy and find literature for a wider group of organisms.
It can be advantageous to use a dedicated database such as BIOSIS Previews [20] at the li-
brary. Another useful tool is the Encyclopedia of Life [21], a community-driven resource to which
many biologists worldwide supply information about animals and plants. A supplementary valu-
able resource are the biologists themselves. If approached correctly and politely, they will often
help with basic explanations and guide toward the relevant literature for deeper understanding.

5.2.4 FOURTH PHASE: TRANSFER

In the next phase of BID, the findings must be transferred to the design problem by describing
the underlying functional principle of each biological phenomenon found. This is important to
facilitate precise and accurate communication among the members of the design team. If the
findings are communicated too loosely, much is left to interpretation and the final design may
be inspired by something other than what was intended by the person(s) who found a relevant
biological phenomenon.
One way to document the findings is to use biocards [22], an example of which is presented
in Fig. 5.6. The figure shows two similar yet different biocards on the mechanism that keeps
equine eyes clean: a concrete description using biological terminology and graphics in the left
biocard but an abstract description using neutral non-biological terms and graphics in the right
biocard. The biocard on the left mentions a tear film to which dust particles adhere, that is
removed periodically removed by the eyelid, and which is replenished periodically by tears. This
description is suitable for designers to generate ideas, but its scope is limited compared to the
abstract description in the biocard on the right. Terms such “tears” and “liquid” will fixate the
designer in thinking only of solutions that rely on a liquid to collect and clean. The abstract
description replaces both of those terms by the more neutral “substance.” This will make it more
likely for the designer to think freely and consider both liquid and solid substances for collecting
dirt particles. The same argument applies to the graphics in the biocard. Drawings of bioworld
solution should be eschewed in favor of more symbolic drawings.
 5.2. PHASES OF PROBLEM-DRIVEN BID 57

,
,

Figure 5.6: (left) Concrete and (right) abstract descriptions in a biocard. The biocard on the right
is better suited for problem-driven BID.

5.2.5 FIFTH PHASE: DESIGN

The biocards can be used in different ways in the fifth phase of BID. One way is to make a
collection of biocards describing different functional principles based on different biological
phenomena. The designer or design team can then take one card at a time and sketch solutions
based on the functional principle in that biocard. It is important not to evaluate the quality of
that principle but wait until a design proposal utilizing it has emerged. In that way, it will be
the physical embodiment in a given context that will be evaluated.
For each promising design proposal, a physical model should be constructed for demon-
stration in order to convince decision makers about investing resources needed to better investi-
gate the proposal. Students taking a BID course at DTU routinely build such proof-of-principle
models [23]. Figure 5.7 shows an example. The design problem is that of reducing drag on a ship
and thereby lower energy consumption. The model ship in the figure is inspired by emperor pen-
guins [24]. When threatened, an emperor penguin releases air from underneath its feathers. The
resulting air bubbles form a thin layer that encapsulate its body to drastically reduce friction. The
penguin then increases its speed several times and escapes its enemies by rocketing out of the
water to the ice flakes where it will be safer. To prove the air-bubble principle for drag reduction,
58 5. PROBLEM-DRIVEN BID

Figure 5.7: Inspired by the use of air bubbles by emperor penguins to reduce friction in water,
this toy ship as a physical model demonstrated that the same functional principle will reduce
drag on a full-size ship. Courtesy: David Maage, Enzo Hacquin, and Anders Lui Soerensen.

a student team made a toy ship and equipped it with two aquarium pumps. On pumping air in
tubes with tiny holes underneath the toy ship, its bottom and sides were surrounded by a layer
of air bubbles. Measurements of the drag resistance confirmed that a reduced force was needed
to propel the toy ship.

5.3 ENGINEERS AND BIOLOGISTS

Since BID is basically about transferring biological knowledge to the engineering domain, it
seems obvious to carry out the design work as a collaboration of people with the two compe-
tences. There are good examples of successful and sustained collaborations. For instance, Julian
Vincent is a biologist who has worked for many years at an engineering college.
Biologists employed at agricultural universities are oriented toward developing more effi-
cient techniques for agriculture and forestry. Although endowed by their education with deep
insights into biology, they are oriented toward development work in institutions where the re-
sults are solutions that keep the citizenry well fed. Furthermore, their orientation must be suf-
ficiently broad to encompass both botany and zoology.
In contrast, typical faculty members in a biology department are highly specialized, be-
cause they achieve professional rewards by focusing on narrow topics within sub-disciplines such
as entomology, mycology, and molecular biology. Although beneficial for conducting novel re-
search on narrow topics, that outlook poses a challenge to engineering-biology collaborations.
When an engineering designer searches the bioworld to find applicable biological strategies,
 5.4. REFERENCES 59
those strategies may have to be searched through the length and breadth of available biolog-
ical knowledge. If the biologist in the collaboration is a marine biologist, they will have little
knowledge about strategies involving insects or mountain plants.
A research group in Paris examined the role of biologists in biologically inspired de-
sign [25]. They found that mixed teams are more effective in coming up with more ideas and
make fewer mistakes. They also found that there is an increase in the diversity of biological
strategies identified as potentially useful in design work.

5.4 REFERENCES
[1] M. Helms, S. S. Vattam, and A. K. Goel, Biologically inspired design: Process and prod-
ucts, Design Studies, 30:606–622, 2009. DOI: 10.1016/j.destud.2009.04.003. 47

[2] T. A. Lenau, A.-L. Metze, and T. Hesselberg, Paradigms for biologically inspired design,
Proceedings of SPIE, 10593:1059302, 2018. DOI: 10.1117/12.2296560. 47

[3] L. H. Shu, K. Ueda, I. Chiu, and H. Cheong, Biologically inspired design, CIRP Annals—
Manufacturing Technology, 60:673–693, 2011. DOI: 10.1016/j.cirp.2011.06.001. 47, 54

[4] P.-E. Fayemi, N. Maranzana, A. Aoussat, and G. Bersano, Bio-inspired design character-
isation and its links with problem solving tools, Proceedings of DESIGN: 13th International
Design Conference, pages 173–182, Dubrovinik, Croatia, May 19–22, 2014. 47

[5] P. E. Fayemi, K. Wanieck, C. Zollfrank, N. Maranzana, and A. Aoussat, Biomimet-

ics: Process, tools and practice, Bioinspiration and Biomimetics, 12:011002, 2017. DOI:
10.1088/1748-3190/12/1/011002. 47, 49

[6] ISO 18458:2015, Biomimetics—Terminology, Concepts and Methodology, International

Standards Organization, Geneva, Switzerland, 2015. https://www.iso.org/standard/
62500.html DOI: 10.3403/30274979. 47

[7] T. Lenau, K. Helten, C. Hepperle, S. Schenkl, and U. Lindemann, Reducing consequences

of car collision using inspiration from nature, Proceedings of IASDR: 4th World Conference
on Design Research, Delft, The Netherlands, Oct. 31–Nov. 4, 2011. 47

[8] D. DeLuca, The Power of the Biomimicry Design Spiral, Biomimicry Institute, Missoula,
MT, 2017. https://biomimicry.org/biomimicry-design-spiral/ 47

[9] N. Cross, Engineering Design Methods—Strategies for Product Design, Wiley, Chichester,
UK, 2008. 48

[10] G. Pahl, W. Beitz, J. Feldhusen, and K.-H. Grote, Engineering Design: A Systematic Ap-
proach, 3rd ed., Springer, London, UK, 2007. DOI: 10.1007/978-1-84628-319-2. 48
60 5. PROBLEM-DRIVEN BID
[11] S. Keshwani, T. A. Lenau, S. Ahmed-Kristensen, and A. Chakrabarti, Comparing novelty
of designs from biological-inspiration with those from brainstorming, Journal of Engineer-
ing Design, 28:654–680, 2017. DOI: 10.1080/09544828.2017.1393504. 48
[12] V. Srinivasan and A. Chakrabarti, Investigating novelty–outcome relationships in engi-
neering design, Artificial Intelligence for Engineering Design, Analysis and Manufacturing,
24:161–178, 2010. DOI: 10.1017/s089006041000003x. 48
[13] M. Helms and A. K. Goel, The four-box method: Problem formulation and analogy evalu-
ation in biologically inspired design, Journal of Mechanical Design, 136:111106, 2014. DOI:
10.1115/1.4028172. 50, 51
[14] Merriam-Webster, Thesaurus, Springfield, MA. https://www.merriam-webster.com/
thesaurus 53
[15] Princeton University, WordNet: A Lexical Database for English, Princeton, NJ. https://
wordnet.princeton.edu/ 53
[16] The Biomimicry Institute, AskNature: Innovation Inspired by Nature, Missoula, MT. https:
//asknature.org/ 54
[17] The Biomimicry Institute, The Biomimicry Taxonomy, Missoula, MT. https://asknature.org/
resource/biomimicry-taxonomy/ 54
[18] Protected Planet, https://www.protectedplanet.net/en 55
[19] T. A. Lenau, Do biomimetic students think outside the box? Proceedings of the 21st In-
ternational Conference on Engineering Design (ICED17), Vol. 4: Design Methods and Tools,
4:543–551, Vancouver, Canada, Aug. 21–25, 2017. 55
[20] BIOSIS Previews® . https://www.ebsco.com/products/research-databases/biosis-previews
56
[21] Encyclopedia of Life. https://eol.org/ 56
[22] T. A. Lenau, S. Keshwani, A. Chakrabarti and S. Ahmed-Kristensen, Biocards and
level of abstraction, Proceedings of the 20th International Conference on Engineering Design
(ICED15), pages 177–186, Milan, Italy, July 27–30, 2015. 56
[23] Posters from DTU-BID course. http://polynet.dk/BID/ 57
[24] J. Davenport, R. N. Hughes, M. Shorten, and P. S. Larsen, Drag reduction by air release
promotes fast ascent in jumping emperor penguins—a novel hypothesis, Marine Ecology
Progress Series, 430:171–182, 2011. DOI: 10.3354/meps08868. 57
[25] E. Graeff, N. Maranzana, and A. Aoussat, Biomimetics, where are the biologists?, Journal
of Engineering Design, 30:289–310, 2019. DOI: 10.1080/09544828.2019.1642462. 59
 61

CHAPTER 6

Solution-Driven Biologically
Inspired Design
I think the biggest innovations of the 21st century will
be at the intersection of biology and technology.
A new era is beginning.
Steven P. Jobs (2011)1

6.1 INTRODUCTION
Biologically inspired design (BID) can be approached from two distinctly different direc-
tions [1–3], leading to problem-driven BID and solution-driven BID. Whereas the former
was described in Chapter 5, this chapter explains the latter approach which is called biology-
push biomimetics by the International Standards Organization because it is the experience
from biology that initiates and drives industrial application [4]. Although the term bottom-up
bionik was initially used by researchers at the Technische Universität München [5], solution-
driven BID is now referred to as solution-based biomimetics by them [6].
The challenge in solution-driven BID is to identify technical applications that will bene-
fit from a set of solution principles identified from the bioworld. Solution-driven BID is often
initiated by biologists with deep insights into biological functionalities but, typically, only lit-
tle knowledge of technical applications and design methodologies. The search for applications
followed by design work can therefore be quite arduous tasks for many biologists. Nevertheless,
several examples of solution-driven BID exist in the literature, two of the most well-known ex-
amples originating from burdock seeds that inspired Velcro™ [7] and the self-cleaning leaves of
the lotus plant [8] that inspired superhydrophobic surfaces [9, 10]. A few examples are described
in this chapter to illustrate how observations of and inspirations from bioworld phenomena have
been transformed into technical applications, followed by a description of the eight steps of an
approach to implement solution-driven BID [11].

1 Walter Isaacson, Steve Jobs, Simon & Schuster, New York, 2011.
62 6. SOLUTION-DRIVEN BIDS
6.2 EXAMPLES OF SOLUTION-DRIVEN BID
6.2.1 MYCELIUM BIO-COMPOSITES
Mycelium is the root system of mushrooms and other types of fungus. It is typically a fine mesh
of tiny white strands referred to as hyphae [12]. The root system grows very rapidly through soil
where it degrades dead lignocellulosic material such as straw and wood into nutrients used by
the fungus. Other organisms also benefit from this process, since many fungi form symbiotic
relationships with plants. The fungus lives at the base of many plants, the mycelium spreading
along the plant’s roots. In a symbiotic relationship, the plant supplies the fungus with carbon in
the form of sugars made via photosynthesis in exchange for water and minerals such as phospho-
rus [13]. The exchange is actually more complex since the mycelium also serves as a connector
between larger plants such as trees and small seedlings for exchange of water and nutrients.
The fungi, especially due to the mycelium, act as important waste-treatment actors in the
bioworld, first degrading organic material and then transforming it into other types of organic
material. This process can be technologically adapted for the production of mycelium bio-
composites that can be used for insulation, packaging material, and other lightweight struc-
tural products [12, 14, 15]. Agricultural waste streams comprise straw and husk which can be
transformed into porous solids using fungi [16].
The left panel of Fig. 6.1 illustrates a corrugated panel made of a mycelium bio-composite.
The surface is similar to that of plastics but is a bit rougher in texture and appearance. The
natural origin of the bio-composite is evident to both eyes and fingers, promoting its use as
a natural and biodegradable alternative to foamed plastics. The American company Ecovative
has commercialized the manufacturing process for a range of foamy products [17, 18]. The first
products were insulation and packaging items to replace foamed polystyrene. In these products,
sometimes referred to as mycocomposites, the mycelium functions as a self-assembling biological
binder for agricultural byproducts. Ecovative has also used the mycelium-based technology to
produce a refined material for clothing fabrics and foamy skincare products.
As the mycelium is edible, mycelium bio-composites can be consumed as food. It is pos-
sible to achieve a texture and flavor similar to meat and in that way offer a vegetarian alternative.
No animal products are used at all, which makes mycelium bio-composites attractive as food for
vegans.
A limitation of the currently available mycelium bio-composites is their relatively high
weight; hence, these materials cannot compete with the very lightweight foamed plastics. This
has to do with the manufacturing method in which the finely chopped agricultural wastes are
kept in shape by loading them into the cavity of a mold, thereby limiting the growth of the
hyphae to the void regions between the fibers of the agricultural material. This was the experi-
ence of a design team at Danmarks Tekniske Universitet (DTU) when making the foam core
of a 2-m-long surfboard of a mycelium bio-composite, shown in the right panel of Fig. 6.1.
Although such a large object could be made with the required strength, it was still too heavy for
the intended purpose.
 6.2. EXAMPLES OF SOLUTION-DRIVEN BID 63

Figure 6.1: (Left) Corrugated panel made of a mycelium bio-composite with a similar but more
natural appearance compared to foamed plastics. (Right) Foam core of a 2-m-long surfboard
made from hemp fibers bound together by mycelium. Courtesy: Dan Skovgaard Jensen, Kristian
Ullum Kristensen, and Lasse Koefoed Sudergaard.

To improve the mycelium bio-composite, DTU researchers are working to combine the
mycelium growing process with 3D printing [16]. One approach is to 3D print a porous matrix
material in which the fungus grows much the same way as it does in the bioworld when degrading
dead lignocellulosic material. Another approach is to use a 3D-printing technique in which the
printing nozzle is maneuvered by a robotic arm to place the matrix material in space in the same
way as spiders make their webs. After the hyphae spread in the 3D web, the resulting foamy
material is very light and highly suitable for high-performance sandwich composites.

6.2.2 BOMBARDIER-BEETLE SPRAY

Ground beetles of many species such as Stenaptinus insignis [19] and Brachinus crepitans [20]
are commonly called bombardier beetles because they exhibit an extraordinary self-protecting
behavior. When approached by a predator such as an ant, a bombardier beetle sprays a boiling
liquid toward the approaching predator, as depicted in Fig. 6.2. The liquid is ejected through
a nozzle at the abdomen which can be directed to point toward the desired target. The amaz-
ing feature is that it is possible for the beetle to generate and handle a boiling liquid without
harming itself. Another remarkable feature is the way in which the very hot aerosol is made.
A gland containing hydrogen peroxide and another gland containing hydroquinone shoot their
respective contents through the anus. When the two liquids mix with the enzymes catalase and
peroxidase, hydrogen peroxide decomposes into water and oxygen and hydroquinone oxidizes
64 6. SOLUTION-DRIVEN BIDS

(a)

(b)

Figure 6.2: Hot spray is used by Stenaptinus insignis as a defense against predators [19]. Copy-
right (1999) National Academy of Sciences, U.S.A.

into p-quinones. Both reactions are exothermic, bringing the mixture to the boiling point and
vaporizing it partially before expulsion along with free oxygen.
At the University of Leeds, the entire defense mechanism of the bombardier beetle species
was found relevant to gas turbine igniters [20, 21]. The initial part of a research project under-
taken at Leeds can be considered to be problem driven, as the desire to improve the combustion
process in a gas turbine led to interest in a biological phenomenon. After studying the spray
mechanism in the beetle, researchers constructed a scaled-up replica of the combustion chamber
to demonstrate a similar spray formation. It was soon realized that the fascinating and remark-
able properties of the bombardier spray mechanism could be useful for pharmaceutical sprays,
fire extinguishers, and fuel injectors in combustion engines. That realization moved the work
from problem-driven BID toward solution-driven BID. This can be seen as a definition of the
attractive characteristics of a biological phenomenon (which is the first step in solution-driven
 6.2. EXAMPLES OF SOLUTION-DRIVEN BID 65

Figure 6.3: Tubercles on the leading edges of the flippers of a humpback whale improve lift and
reduce drag as well as the risk of stalling. Courtesy: Whit Welles (Wwelles14) https://commons.
wikimedia.org/w/index.php?curid=2821387.

BID, as explained in Section 6.3.2) for a spray technology that can reduce the environmental
impact typical of existing spray technologies [21]. That understanding led to the identification
of spray applications, such pharmaceutical sprays and fire extinguishers, that release polluting
gases such as propane into the atmosphere.
The biomimetic spray technology is being applied in other scenarios too. For example,
exhaust from internal combustion engines contains nitrogen oxides (NOx ), which contribute to
smog and acid rain [22]. The release of NOx is normally regulated by flow-restricting mixers.
However, the principles for vapor formation in the bombardier beetles can be exploited to inject
small droplets of a solution of urea into the exhaust and thereby inhibit NOx release [23].
Swedish Biomimetics 3000 is commercializing the bombardier-beetle spray technol-
ogy [24, 25]. This industrial company realized the potential of this biomimetic technology and
began to explore applications in diverse industrial sectors, e.g., for air humidifiers in supermar-
kets.

6.2.3 TUBERCLES FOR FLOW CONTROL

Serendipity can play a big role in solution-driven BID. Frank Fish, a biology professor at West
Chester University, happened to notice a curious feature in a figurine of three humpback whales
(Megaptera novaeangliae) displayed at an antiques store [26]. The leading edges of the large
flippers of the whales in the figurine were not straight but had tubercles. A little research showed
that the artist had not made an error; indeed, the flippers of humpback whales have turbercles,
as illustrated in Fig. 6.3.
Why do whale flippers have this strange geometry? Flippers are adaptations of hands.
The biologist Fish found that the tubercles closely follow the joints in the phalanges of the
66 6. SOLUTION-DRIVEN BIDS
“fingers” in each flipper. The flippers of a fully grown whale are about 3.60 m long, relatively
long for an animal that is four times longer. The natural assumption for the biologist was that
the tubercles serve a special purpose. This turned out to be true because humpback whales are
very agile swimmers and can quickly change direction when swimming at a high speed. Unlike
whales of other species, a group of humpback whales forms a circle when hunting a shoal of
fish. The whales release bubbles from their blowholes to collectively form a cylindrical curtain
to confine the shoal. The curtain is tightened as the radius of the circular formation decreases,
delivering the prey in densely packed mouthfuls to the predators.
Computer models using the equations of fluid dynamics as well as experiments confirmed
that the tubercles affect motion in a fluid significantly: lift is increased and drag is reduced [27].
These features explain the agility of humpback whales. The tubercles also reduce the risk of
stalling which can happen when the lift of the flipper suddenly drops.
Having uncovered the physical principles underlying the fascinating capability of an ani-
mal arising from its anatomy, Fish wondered which technical applications could benefit from the
enhanced flow characteristics when using a flipper or a fin with tubercles on the leading edge.
This is the classic initiation of solution-driven BID, which justifies the appellation biology-
push biomimetics. Many applications were investigated [28]. One is on the fin of a short
surfboard which would enable a surfer to make a more sudden cutback, i.e., change direction
when riding a wave. Another is on the keel of a sailing boat which can allow the boat to make
tighter turns.
Like water, air is a fluid. Could applications in air also benefit from tubercles? Truck mir-
rors can be fitted with tubercles to reduce the drag and thereby improve fuel economy. The same
effect can be achieved by adding tubercles to fins on racing cars. Helicopter rotors can deliver
more lift with a reduced risk of stalling. Fans in stables can save energy while also becoming
quieter. Windmills can generate more energy because of reduced drag.
Many good proposals for possible applications of the tubercles on the flippers of hump-
back whale emerged. Which of those proposals becomes commercial depends on the trade-off
between achievable technical benefits and possible drawbacks as well as on the ease of produc-
tion.

6.2.4 ABALONE-SHELL ARMOR

Abalone is the common name for marine mollusks belonging to the family Haliotidae. An
abalone shell is shown in Fig. 6.4. The inner layer of the shell is made of nacre which is extremely
tough, considering that most of it is aragonite which is very brittle because it is essentially chalk.
The toughness can be measured as the specific work of fracture which is 0.2 J m 2 for aragonite
but 400 J m 2 for nacre [29]. The explanation for nacre being 2,000 times tougher than aragonite
is found in the layered “brick-and-mortar” micromorphology also shown in Fig. 6.4 [30, 31].
The bricks are plates of aragonite and the mortar is a ductile proteinaceous material [32].
 6.2. EXAMPLES OF SOLUTION-DRIVEN BID 67

“Mortar” = protein

“Brick” =
Aragonite chalk

Figure 6.4: (Left) Nacre in an abalone shell. (Right) Schematic of the crack-resistant brick-and-
mortar micromorphology of the abalone shell.

Toughness is often explained as prevention of crack propagation. A propagating crack is

arrested when it encounters the proteinaceous mortar. When the shell experiences an impact
from a crab or another predator, the impact energy causes the formation of microcracks in the
aragonite plates. In a more homogeneous material, the microcracks would propagate and cause
a failure, but the proteinaceous mortar absorbs the impact energy by deforming elastically and
distributing part of the energy for microcrack formation in many other aragonite plates. Shell
failure is thereby averted, the abalone shell thus providing an example of contraindicated per-
formance.
The abalone shell happens to provide a documented example of a misapplication of
solution-driven BID [1]. Fascinated by the impact resistance of the abalone shell, a group of
engineering students at the Georgia Institute of Technology exploited the brick-and-mortar
micromorphology for a bullet-proof vest. It was clearly a solution-driven approach where the
inspiration came from a biological solution and was applied to a technical problem. However,
the design team did not approach the exercise with sufficient rigor, going directly from a de-
scription of a fascinating functionality of a biological structure to a detailed specification of a
solution to an appealing technical problem. They did not spend time on a closer analysis of what
the properties of the abalone shell actually are and what type of impact it is best suited for. The
abalone shell is very good at resisting the force from the jaws of a predator which typically applies
the force at a slow speed. This is very different from the very sudden impact of a bullet flying at a
high speed. Furthermore, the team designed the vest mimicking not only the micromorphology
but also the chemical constituents (small flakes of chalk and elastic matrix) of the shell. Not only
was the vest incapable of resisting bullets, it was much too heavy as well.
68 6. SOLUTION-DRIVEN BIDS
6.3 STEPS FOR SOLUTION-DRIVEN BID
Section 5.2 provides a five-phase implementation scheme along with several ways to adopt in
each phase. In contrast, literature contains much less information on formal implementation
of solution-driven BID. Researchers at the Georgia Institute of Technology have formulated a
seven-step implementation plan as follows [1]:
(i) become aware of a biological phenomenon,

(ii) define the functionalities that brought attention to that biological phenomenon,

(iii) extract the key principles underlying the attractive functionalities,

(iv) specify the usefulness of the biological functionalities for human activities,

(v) search for technical problems that can be solved using the identified functionalities,

(vi) select a technical problem from the ones identified, and

(vii) apply the key principles to that technical problem.

However, the instructions available in the design literature for some of these steps are scant.
DTU researchers therefore developed an eight-step procedure to implement solution-driven
BID, with inspiration from the way application search is done for conventional technology [11].

6.3.1 APPLICATION SEARCH

Application search is routinely carried out in any company that is focused on using a specific
production technology. In order to ensure future sales, the company will regularly evaluate its
present portfolio of products and search for new areas that will benefit from its production tech-
nology. The company will encounter challenges when seeking expansion into industrial sectors
that it has no experience in. Due to this limitation, the company will serve as a subcontractor to
companies that have both the required experience and contacts with end users.
Another limiting factor for such a company is that its principals are not trained in design
thinking and are less experienced in working with open problems and large spaces of solutions.
Instead, their forte is a deep knowledge of the specific production technology which enables their
company to mass produce at a competitive price. The company will also be good at improving
the technology to incorporate new features. But unlike companies with end-user contact (such
as manufacturers of furniture or household appliances), it does not have a well-defined user
group that can be explored to identify expansion potential. Identification of industrial sectors
for expansion can therefore be a challenge. Application search is a way to meet this challenge.
As an example, consider application search carried out by a company that specializes in re-
action molding of polyurethane, which is used to make toilet seats, panels for interior decoration,
and dashboards of cars. A design-oriented approach to application search for this company is to
 6.3. STEPS FOR SOLUTION-DRIVEN BID 69

Figure 6.5: Pinart toy for children.

first identify the attractive characteristics of the reaction-molding technology and then search
for end-user applications in order to identify candidate companies that will benefit from its tech-
nology. The low tooling price for manufacturing polyurethane objects enables: (i) the production
of small batches of custom-designed objects, (ii) a high degree of freedom for free-form geom-
etry, and (iii) the production of lightweight components with foamed core that can be inserted
in metal, wood, and textile items. For each of these three enabling attributes, an open search for
applications can be made, in brainstorming sessions and/or on internet search engines.
Another example is a project carried out by two engineering students to develop a new
type of production technology based on the pinart toy shown in Fig. 6.5 [11]. The production
technology is based on a mold that can change shape on demand and hence be useful for casting
individually shaped items. An application search to justify the development of the mold iden-
tified 136 quite different applications encompassing prosthetics, contact lenses, hearing aids,
chocolates, compact-disk covers, jewelry, propellers for sailing boats, and concrete bridges. A
specific application must be selected in the development phase, since many parameters for the
production tool (in this case, the mold), such as dimensions, accuracy, resolution, and through-
put rate depend on the application. Based on an analysis of the applications and dialogue with
possible collaborators for each of the application areas, two applications were selected: (i) a tool
to fabricate individually shaped curved concrete facade elements and (ii) a tool for inscribing
marks on casts to enable subsequent traceability during manufacture. The two resulting tools
are shown in Fig. 6.6. Both applications are very different and addressed very different business
areas.
70 6. SOLUTION-DRIVEN BIDS

Figure 6.6: (Left) A tool for the fabrication of individually shaped curved concrete facade ele-
ments [33] and (right) a tool for inscribing marks on casts [34], both developed based on the
pinart toy shown in Fig. 6.5.

Figure 6.7: Lotus leaves repel water and stay clean thereby.

6.3.2 EIGHT-STEP PROCEDURE

With the knowledge that application searches are routinely carried out in some industrial sectors,
DTU researchers devised an eight-step procedure that has some overlap with the seven-step
implementation plan from the Georgia Institute of Technology. The eight steps of the DTU
approach for solution-driven BID are provided in Table 6.1.
The eight-step procedure is exemplified in Table 6.1 by the leaves of the lotus (Nelumbo
nucifera), a plant native to many tropical countries. Considered sacred by Hindus, Buddhists,
and Jains, lotus grow in wetlands, ponds, and lakes. The remarkable characteristic of this plant is
that the ventral surfaces of its leaves stay clean even in dirty surroundings because those surfaces
are superhydrophobic [9], as may be noticed in Fig. 6.7.
 6.3. STEPS FOR SOLUTION-DRIVEN BID 71
Table 6.1: The eight steps of the DTU approach for solution-driven BID along with the lotus-
leaf example of self-cleaning surfaces in the bioworld

No. Step Lotus-Leaf Example

1 Characteristic: Water repellence
biological phenomenon
2 Make an open search for applications Self-cleaning vehicles
3 Formulate constraints to limit the Constraint: Only applications for which
scope of the search
4 Apply constraints one by one to Inside the shield of a lawn mower
eliminate some results of Step 2
5 Create a concept for each result of Coat the inside of the shield of the lawn
Step 4 mower for cleaning with a garden water hose
6 Consult selected stakeholders Talk to a few gardeners
7 Repeat Step 5 for new application Wheelbarrows

8 Assess every concept against Criteria: (i) Longer life time for lawn mower
and (ii) lower risk of spreading pests

Step 1. Solution-driven BID begins with the awareness of a biological phenomenon that
could either constitute or provide a solution to a technical problem that has not been identified.
Thus, solution-driven BID can be initiated by merely an interest in an animal or a plant with a
fascinating behavior or capability. It can also be initiated by a biologist who has studied biological
organisms of a certain species or genus for many years and begins to wonder which engineering
applications could benefit from the biological insight. Defining the biological solution then
requires a description of its characteristics that may be relevant to some applications. Biological
organs are typically multifunctional, so it may be arduous to describe all of its characteristics.
Fortunately, a complete description is not called for, since it was a specific characteristic that drew
attention. In the first step, that attractive characteristic of the biological phenomenon must be
defined.
The persistent clean condition of lotus leaves can be explained by its water-repellence char-
acteristic which prevents dust particles and other detritus from attaching to its ventral surface.
The superhydrophobicity is responsible for the formation of water beads that roll off the surface,
thereby removing foreign matter. In turn, this superhydrophobicity arises from surface topol-
ogy at the 10-m length scale [35]. However, as the matte appearance of lotus leaves is quite
72 6. SOLUTION-DRIVEN BIDS
different from the glossy appearance of clean and hygienic surfaces, the superhydrophicity due
to surface topology may not be attractive enough for certain applications.
Step 2. Next, an open search is made for applications that will benefit from the attractive
characteristic defined in the first step. This can be done in different ways, but a simple one is
for the design team to brainstorm in order to answer the following question: “In what situations
can the described characteristic be advantageous?”
The question for the lotus-leaf example is: “Where can self cleaning be advantageous?” A
more general question is: “In which situations do surfaces become dirty?” The unwanted con-
sequence of having a matte surface could lead to the following question: “Where are clean but
non-glossy surfaces required?”
Step 3. The characteristic defined in the first step will most likely result in finding a large
number of possible applications in the second step. Therefore, the third step requires the for-
mulation of constraints that will not only limit the scope of the search but also force deeper
explorations of the fewer possible applications.
A constraint can require focus on items of specific types—e.g., household items, leisure
and sports equipment, hospital articles, professional tools, etc. Another constraint can be on the
type of materials deemed acceptable. A third way to approach setting up constraints could be to
analyze daily or professional routines while looking for activities that benefit from the defined
characteristic. Such a routine could be what a person does while working in an office or while
traveling every week to meet clients on site. Professional routines can also be incorporated by
choosing a professional activity such as gardening, hospital sanitation, painting houses, and graf-
fiti removal. The framing of a context makes it easier to imagine where the defined characteristic
of the biological solution may be beneficial.
A simple constraint for the lotus-leaf example is to focus on situations in which particle
accumulation is undesirable and the particles are difficult to remove.
Step 4. Application of the constraints formulated in the third step will eliminate many
of the possible applications identified in the second step. The constraints can be applied either
sequentially or concurrently. Brainstorming by the design team will deliver context-specific ap-
plications.
For the lotus-leaf example, application may be sought for lawn mowers in which the oper-
ator is protected from the cutting blade by a shield. The cut grass often sticks to the inside surface
of the shield and is not easy to remove. Another possible application is for a house painter’s tools
to have non-stick surfaces. Likewise, exterior walls of office buildings require treatment to pre-
vent becoming canvases for graffiti artists.
Step 5. For each of the results of the constrained search undertaken in the fourth step, a
concept has to be created. As explained in Section 2.4.4, whereas an idea is merely a principle for
how to solve a problem, the application of that principle in a specific context leads to a concept
 6.3. STEPS FOR SOLUTION-DRIVEN BID 73
because it satisfies the context-specific constraints. The intended performance of each concept
must be described in concrete terms in the fifth step.
For the lotus-leaf example, a concept for the lawnmower is to endow the internal surface
of the shield with topology at the 10-m length scale to prevent wet cut grass from attaching
to that surface. Likewise, a concept for the house painter’s tools is have the exposed surface of
every tool with a similar topology to prevent paint from adhering to the exposed surface. Finally,
providing the surfaces of walls with a similar topology will deter graffiti artists.
Step 6. Each concept for every application has to be discussed with knowledgeable stake-
holders in the sixth step. The stakeholders should be presented with the relevant concept(s)
instead of being asked about possible applications. Some stakeholders are very likely to have
reservations about why a concept may not work well in the real world, but the main point is to
stimulate their creativity so they may come up with their own application proposals. Often it is
easier to be creative when criticizing a concept.
For the lotus-leaf example, the stakeholders to be consulted should be gardeners for the
lawn-mower concept, house painters for the painting-tools concept, and janitors for the graffiti-
prevention concept.
In the case of the production technology based on the pinart toy shown in Fig. 6.5 [11], a
concept was of a flexible mold for use by sandcasting companies. When sandcasting personnel
were consulted on this concept, they informed the design team that the need for flexible molds
is insignificant but a major need exists for traceability during the manufacturing process. If
an individual code or number could be inscribed on each cast by the mold, then it would be
possible to trace each cast subsequently. The quality of representative casts from a batch could be
assessed and related to the personnel who produced that batch as well as to the specific material
composition used. The company could in this way get a better quality-assurance system. The
design team had not been aware of the need for traceability, but consultation with knowledgeable
stakeholders led to a new application of their technology.
Step 7. The penultimate step is a repetition of the fifth step for the new applications iden-
tified by knowledgeable stakeholders during the sixth step.
For the lotus-leaf example, gardeners could suggest superhydrophobic surfaces for wheel-
barrows, house painters could suggest similar surfaces for lunchboxes, and janitors for walls in
children’s bedrooms and school rooms.
Step 8. The final step of the DTU approach for solution-driven BID is to assess every
concept with respect to a set of predefined criteria which could include the expected market
capacity and societal impact.
74 6. SOLUTION-DRIVEN BIDS
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 77

CHAPTER 7

Biologically Inspired Design

for the Environment
The earth, the air, the land and the water are not an inheritance
from our forefathers but on loan from our children. So we have
to handover to them at least as it was handed over to us.
Mohandas K. Gandhi1

7.1 SUSTAINABILITY AND THE ENVIRONMENT

Concern about sustainable development is mounting as the number of people on our planet in-
creases. In 1987 the Brundtland Commission of the United Nations [1, 2] defined sustainable
development as “development that meets the needs of the present without compromising the
ability of future generations to meet their own needs.” The commission considered three ar-
eas of concern for sustainable development: (i) the environment, (ii) social organization, and
(iii) economy. Technological development as well the global organization of human society cur-
rently require the imposition of serious curbs on consumption, especially considering the limited
ability of the biosphere to absorb diverse types of waste excreted by human activities. However,
both technological development and social organization can be managed and improved to make
way for enhanced economic growth and poverty removal. Sustainable development requires that
the more affluent humans adopt lifestyles that are consistent with the planet’s ecological well
being—for instance, in their consumption of energy. Also, population increase needs to be in
harmony with the changing productive potential of the ecosystem.
The quest for sustainable development was taken further in the 2030 Agenda for Sustain-
able Development which, in 2015, resulted in the United Nations General Assembly adopting
17 sustainable development goals (SDGs) [3]. The SDGs are operational goals focused on con-
crete actions. Figure 7.1 classifies all 17 SDGs in relation to the previously mentioned three
areas of concern: the environment (also referred to as the biosphere), social organization, and
economy [4].

1 https://bestquotes.wordpress.com/2007/03/24/hello-world/
78 7. BID FOR ENVIRONMENT

Figure 7.1: The 17 sustainable development goals classified for relevance to the biosphere, social
organization, and economy. Credit: Azote Images for Stockholm Resilience Center, Stockholm
University.

Biomimicry can help in addressing current actions and proposing new actions within all
three areas, with focus on using inspiration from the bioworld to solve problems relating to the
biosphere. The following SDGs can be impacted by biomimicry:

SDG 6: clean water and sanitation,

SDG 7: affordable and clean energy,

SDG 13: climate action,

SDG 14: life below water, and

SDG 15: life on land.

 7.2. MATTER OF SCALE 79
Both economy and social organization are human constructs and, even though inspirations for
their improvement can be found in the bioworld, the dominant application of biomimicry is
for technological solutions in line with SDGs 6, 7, 13, 14, and 15. The bioworld presents many
avenues that can be adapted for circular economy, resource efficiency, and ecosystem balances.

7.2 MATTER OF SCALE

A crucial challenge to sustainable development is posed by the growing number of people on the
planet. More people share the limited resources available, more people produce waste, and more
people pollute. Equal opportunities for everyone being a human right, countries should aim at
providing the highest standard of living consistent with the overall health of the biosphere that
includes not only all humans but all other living organisms too.
An activity that seems to be only a small problem when carried out by a few people can
turn out to be a huge problem when carried out by many people. Numerous examples show how
small problems grow out of proportion when scaled to larger populations. In Jakarta, Indonesia,
it is common practice for landowners to pump water from aquifers deep underground since piped
water is not reliably available. However, with 10 million inhabitants this practice has caused land
subsidence of as much as 4 m in the coastal areas of the city, thereby making it highly vulnerable
to flooding [5]. Another example is eutrophication of lakes and rivers [6]. The use of fertilizers is
desirable to increase agricultural yields, but the right amounts may not be applied at the correct
times. Excess fertilizer will run off during rain and/or irrigation to cause increased growth of
algae in rivers and lakes, leading to oxygen depletion and fish deaths on a large scale. This would
not be a problem if confined to a few locations. However, widespread use of excess fertilizers
impacts not only water bodies in landmasses but also causes dead zones in seas and oceans. Thus,
a supposedly harmless action when undertaken by an individual can have grave repercussions on
a large population in a large area when that same action is simultaneously implemented by more
than a few individuals.
The global environmental impact (GEI) can be quantified as the product of three factors [7]:
the number N of people on our planet, the per-capita economic activity E, and the eco-efficiency F
defined as the environmental impact per economic activity. That is,

GEI D N  F  E:

The global population N in 2019 is around 7.5 billion, rising from 4 billion in 1974 and projected
to rise to 10 billion in 2057 [8]. Concurrently, living standards (i.e., E) have improved for many
people. In 1990, 36% of the global population was living in extreme poverty [9], defined by the
World Bank as an income of US$ 1.9 a day [10]. Extreme poverty was reduced to 8% of the
world population in 2018, which illustrates the fast pace at which the standard of life is being
enhanced globally. To maintain an unchanged GEI, the eco-efficiency F must be decreased, i.e.,
the environmental impact for the economic activity must be lowered.
80 7. BID FOR ENVIRONMENT
U.S., Canada, most European countries, Japan, Taiwan, South Korea, Saudi Arabia,
Qatar, Bahrain, and, increasingly, parts of China and India have an opportunity in being role
models for sustainable life-styles of desirable quality. These regions can demonstrate that it is
possible to maintain a high standard of living that is consistent with sustainable development—
a win-win situation. Sustainable development does not overburden planetary resources, and a
high quality of life allows the citizen to reap the benefits of techoscientific advances.
A major requirement to engender this win-win situation is the low-cost production of
energy from nonpolluting sources for millions of years to come. These sources include the sun,
winds, tides, and reservoirs. Another major requirement is the minimization of the extraction
of ores, minerals, and petroleum from the planetary crust by industrywide recycling of ma-
terials that have already been extracted. Improved quality of life for a growing population is
possible only if both resource consumption and waste production are greatly reduced, resulting
in improved eco-efficiency. Highly efficient systems in the bioworld can inspire technological
developments for an effective transition toward sustainable development.

7.3 SUSTAINABLE PRACTICES FROM NATURE

The biosphere and the sun together can act as an ecosystem to sustain our species and countless
others for very long periods of time compared to the human lifespan. Photosynthesis transforms
solar energy into organic matter that is the basis of the food chain for other living organisms.
The organic matter consists mainly of a few elements—carbon, oxygen, hydrogen, nitrogen,
phosphorus, and sulfur—which can be combined into a large number of materials that later
can be decomposed to form new materials. All materials are synthesized by self assembly into
living organisms at ambient temperatures, and those organisms either excrete or decompose into
materials that can be re-synthesized into living organisms. There is no external agent following
some masterplan that determines the sequence and method of assembly. Instead, the entire
process is embedded within the organisms so they can self replicate.
A good example of how nature produces materials with remarkable properties at ambient
temperatures is the iridescent nacre found in mollusks. The material is very stiff and its hardness
equals that of manufactured materials such as ceramics which require very high production tem-
peratures. Located on the inside of the shell, nacre is a composite layered structure consisting
of aragonite crystals (calcium carbonate) separated by very thin layers of a cross-linked protein.
The structure is often referred to as brick-and-mortar structure due to its visual similarity to
building materials [11].
The material-shaping mechanism is not completely understood but a good model has
been described by Addadi et al. [12]. The layered structure is made through a long sequence of
steps. The epithelial cells in the mollusk’s mantle secrete the highly cross-linked periostracum
protein layer under which a gel-like matrix is formed. The matrix includes both hydrophobic and
hydrophilic proteins as well as colloidal particles of the chemically unstable amorphous calcium
carbonate. Aragonite crystals form at nucleation sites and grow until the periostracum layer
 7.4. CIRCULAR ECONOMY OF MATERIALS 81
is reached. In between the crystals, chitin molecules are trapped so that the brick-and-mortar
structure is formed.
An example from nature, but not the bioworld, is the way sediments are transported by
sea currents along coasts. Soil is removed from places along coastlines, thereby causing land
to disappear while cliffs are formed. The soil is moved by the sea currents and deposited at
other places, typically forming headlands. Amazingly thus, water breaks down solid material
and carries it over long distances simply through the persistent application of fairly small forces
over long periods of time.
A similar mechanism is applied by humans to convert seabed into agricultural land. In
Denmark, Germany, and the Netherlands, the tides are fairly large and the coastal areas are
usually wide and flat. By deliberately placing obstacles to delay water brought over by the tides,
the deposition of sediments is promoted causing the land to form above the sea level. This
approach of using many repeated actions to create a shape abounds in nature. Each individual
action is in itself not very powerful. In contrast, humans typically apply a lot of force for a short
while to create similar formations—e.g., when an excavator is used to move soil.
The bioworld thus presents a very different approach for manufacturing materials com-
pared to the approaches humans take. When considering length scales of up to 1 m, humans
manufacture objects primarily by using high levels of energy and through a planned selection
of materials [13]. For instance, polymers are typically processed by pressing the melted poly-
mer into a mould while applying large forces. The bonding energies for polymerization are quite
similar in magnitude for a large variety of polymers, whether manufactured in a factory or in the
bioworld. But, biological systems do not use elevated temperatures and rely instead on chemical
reactions when building blocks of the right basic materials are brought into position. Biological
polymers are mainly proteins and polysaccharides in fibrous form, found in collagen, silk, mus-
cles, and arthropod exoskeletons. Hard tissue in biology is mostly made from calcium and silicon
with smaller fractions of iron, zinc, and manganese—all processed at ambient temperature [14].

7.4 CIRCULAR ECONOMY OF MATERIALS

Most biological materials can be used directly or indirectly by other organisms. Many mammals,
for instance, eat the placenta after the birth of an offspring. All spiders produce silk but not all
spiders spin webs. Webmaking saves a spider the energy-consuming effort of hunting by rapid
locomotion, but it requires a sizable investment of proteins that the web is made of [15]. Many
spiders eat their old webs so that the proteins are recycled to make new webs [16, 17].
Less directly, biological materials are broken down to simpler molecules by bacteria, mak-
ing them useful for other organisms. Biodegradation is a well-known process whereby bacteria
in the ground decompose dead organic material into carbon dioxide, nitrogenous compounds,
and other materials [18]. Mycelia from fungi break down lignin and cellulose from plants. Fungi
grow on dead trees on the forest floor after the wood has been moisturized, and the same can be
82 7. BID FOR ENVIRONMENT
seen in buildings with wooden structures. Thus, moisturized wood provides a good environment
for fungi to grow and eventually break down the lignin and cellulose in the wood [18].
Colors in plants are usually produced using pigments [19] though sometimes structural
colors are also found [20]. A structural color arises due to spectrally selective scattering of visible
light in response to the morphology of a physical structure [21, 22]. Usually, the morphology
has a repeat pattern that is tuned to a certain color. Whether dull or brilliant, a structural color
is not produced by pigments, which is immensely important for biologically inspired design for
environment in that material diversity is not enhanced by incorporating a structurally colored
object.
Multifunctionality is commonplace in living organisms [23, 24], because fewer organs
need to be formed, housed, and coordinated if those organs are multifunctional. As an example,
a mouth is used for ingesting nutrients, releasing sounds, breathing, and showing affection. A
multifunctional module can be incorporated in a variety of products, thereby reducing inven-
tory costs, enhancing repairability, extending product lifetimes, and promoting standardization.
Lifetime extension slows down the depletion of raw materials, reduces the consumption of en-
ergy for manufacturing, and reduces the volume of waste for disposal.

7.5 MUTUALLY BENEFICIAL COEXISTENCE

No organism in the bioworld exists on its own but is dependent on interactions with other
organisms, whether of the same species or not. Within a species, wolves and dingoes hunt in
coordinated groups for greater success, starlings fly in coordinated murmurations to confuse
predators such as falcons, and fish similarly form schools (not to be confused with the much less
coordinated shoals) to elude predators. Mammal mothers rely on kin to bring food and even
look after infant offsprings.
Mammals rely heavily on symbiosis with microorganisms in their digestive tract. On aver-
age, a human has 0.2 kg of bacteria primarily in the intestines [25], not only to help break down
food into substances that can be adsorbed through the intestine wall but also to supply signaling
compounds essential to the mental health of the person [26]. Transplants of fecal matter can
improve the health of humans suffering from a range of diseases [27].
Plants can produce carbohydrate building blocks through photosynthesis by extracting
carbon from the air and water from the ground. However, they cannot extract minerals such
as phosphorus from the soil and therefore benefit from a symbiotic relationship called mycor-
rhiza between their roots and mushrooms [18]. In exchange, the mushrooms get carbohydrates.
Similarly, some bacteria extract nitrogen from air and supply it to plants as ammonia [18]. Ni-
trogen fixation is essential for the biosynthesis of amino acids, proteins, nucleic acids, and other
nirogenous compounds.
Many animal species rely on social relationships to thrive and even exist. These relation-
ships are very pronounced in social insects such as bees, ants, and termites. They are characterized
by a division of labor whereby some individuals provide food, others nurture the eggs and lar-
 7.6. ENERGY EFFICIENCY 83
vae, and still others build and maintain the physical living facility. The individuals communicate
using a range of signals including visual (e.g., color in flowers and waggle dance among bees),
olfactory (e.g., pheromone trails made by ants) and acoustic (e.g., bees buzz with their wings).
The role of the individual appears to be centrally controlled only to a limited degree, with guards
allowing entry only to the inhabitants of the hive or pit. So, how do individuals know their roles
and how to perform tasks without feedback from a central authority?
A very subtle type of communication to control flock behavior involves pheromones. A
pheromone is an olfactory agent that, unlike many fragrances that animals consciously recognize,
makes a short cut to the brain and produces almost instantaneous recognition. Pheromones assist
in a range of different activities such as initiating alarms, attracting mates, and marking trails to
be followed by others [28].
Inter-species communication is also commonplace. The approach of a fearsome predator
leads to a single alarm signal that warns birds and mammals of diverse species to take evasive
action [29]. Not only animals but plants also communicate. The roots of grasses and cereals
of many types excrete chemical compounds that are processed by other plants to determine if
the secreting plants belong to their family. This phenomenon has been deduced from the way in
which the growth of roots of a certain plant is influenced by the roots of neighboring plants [30].
Human society too can benefit from symbiosis whereby the residual energy and materials
from one company become resources for another company. Industrial symbiosis is an element
in the circular economy which, apart from better utilization of resources, benefits society by
increasing the number of jobs and boosting the Gross Domestic Product [31]. In the city of
Kalundborg in Denmark, 11 public and private companies have formed a partnership facilitating
a circular approach for the refinement of crude oil; production of insulin, fertilizers, and gypsum
wallboards; and heating residences and office buildings [32]. The symbiotic activities direct waste
energy, water, and materials from one company to another. For example, the insulin factory uses
fermented sugars resulting in residual yeast biomass which is directed to a factory for producing
fertilizers and biogas, the biogas is used in the gypsum factory for heating, and the residual
thermal energy is transferred to a central heating plant. The result is better utilization of resources
and materials combined with enhanced economy and employment.
Another example is the Danish Pig-City project that aims at combining different types
of agri-businesses [33]. The project combines the husbandry of pigs and production of tomatoes
with a slaughter house, an energy generation plant, and a bio-refinery. Heat from the piggery
on the ground level is used for growing tomatoes in a greenhouse on the floor over the piggery.
Organic waste from both the piggery and the greenhouse is treated in the bio-refinery to produce
biogas for heating and fertilizers for the greenhouse.

7.6 ENERGY EFFICIENCY

Access to enough energy is a limiting factor for all physical and chemical processes in the
bioworld. Just as for aeroplanes and helicopters, the range and duration of avian flight depend
84 7. BID FOR ENVIRONMENT
on how much energy does a bird have when it takes off into the air. Avian bodies have therefore
evolved to have lightweight structures. Many large birds such as albatrosses, condors, and eagles
exploit the warmer air currents for lift and thus minimize energy consumption by their pec-
toral and supracoracoideus muscles [34, 35]. Mammals regain energy cyclically when running.
On the downstroke of a leg, the tendons, ligaments, and muscles stretch to store energy that is
released on the offset. This is true for most animals, but a surprising phenomenon is seen for
kangaroos which are very efficient energy regainers. At moderate speeds they are more energy
efficient in terms of oxygen consumption compared to running bipeds and quadrupeds of similar
size [36].
The force that impedes forward motion in a fluid is called drag. Several species have intri-
cate mechanisms for reducing drag. Sharks are covered with tiny corrugated scales which intro-
duce microturbulence close to the body surface. The microturbulence allows for a more laminar
flow of seawater, thereby reducing the overall drag. The phenomenon has been mimicked in
polymer films applied on aircraft to reduce drag [37]. The sharkskin scales are multifunctional
since their corrugated shape also prevents fouling [38], because barnacles are not able to get a
good grip and therefore fail to attach. Penguins reduce drag by releasing microbubbles of air
trapped under their feathers. If necessary, a penguin can thus increase its speed several times
over short distances, e.g., when chased by a predator [39].

7.7 DESIGN APPROACHES

Several approaches have been devised to support the designer toward the goal of sustainability
enhancement. Formal guidelines help keep a tight focus toward that goal. The system-oriented
approach of circular design orients the designer not solely toward the manufacture of a spe-
cific product, but on its entire lifecycle to encompass raw materials, the use phase, and the
utilization of waste products. A third approach is to assess the environmental footprint of the
product.

7.7.1 ENVIRONMENTAL GUIDELINES

An approach suitable for the early-design stages when many product details are yet unknown
is to use Green Design Guidelines (GDG) [40]. The widely used GDGs may have either very
concrete forms such as the specification of acceptable materials, or be abstract by exhorting
the embrace of techniques that produce less waste than those techniques that require remedial
cleanup of the produced waste.
Another approach involves a systematic methodology to aim for efficiency in the use of
energy and materials [41]. This approach comprises different types of efficiency (such as me-
chanical, material, and thermal efficiencies) and a framework to use bioinspiration. Once a type
of efficiency is selected, analogies from the bioworld can help the designer by providing insight
into functioning and efficient solutions.
 7.7. DESIGN APPROACHES 85
The International Standards Organization defines biomimicry as “philosophy and inter-
disciplinary design approaches taking nature as a model to meet the challenges of sustainable
development (social, environmental, and economic)” [42]. A distinction has been made in Chap-
ter 1 between biomimicry and engineered biomimicry, the former being contained in the
latter. Whereas engineered biomimicry does not need to be focused on reaching for sustainabil-
ity goals, the term biomimicry—often associated with the Biomimicry Institute, an American
non-profit organization—is focused on using inspiration from the bioworld to design solutions
that contribute to sustainable development.
The Biomimicry Institute has a sister organization called Biomimicry 3.8 which is a con-
sultancy working together with companies to solve design problems. One of the founding mem-
bers of both organizations is Janine Benyus. The two organizations have developed a basic frame-
work for design work [43] and the database Asknature [44] which allow searches for biological
strategies to solve specific functional challenges. To support sustainable development, the orga-
nizations have formulated the following six lessons from the bioworld:
• evolve to survive,
• adapt to changing conditions,
• be locally attuned and responsive,
• use life-friendly chemistry,
• be resource efficient, and
• integrate development with growth.
Each lesson leads to specific guidelines, such as incorporate diversity and use low-energy pro-
cesses, that are mainly concerned with the environmental part of sustainable development. These
guidelines function in the same way as the criteria for evaluation of design proposals described
in Chapter 2. When two proposed solutions are compared, the preferred one has to satisfy more
guidelines in the best way. Thus, these guidelines are not absolute but indicate desirable out-
comes.
In a study of biomimicry practices in the Nordic countries, it was found that only a
few companies have combined biologically inspired design and environmentally conscious de-
sign [45]. But there are many examples of companies adopting either biologically inspired design
or environmentally conscious design, so that their amalgamation is a realistic goal. In another
study, designers were found to use several different sustainability frameworks when working
with bio-inspiration, but without an established system of accountability [46].

7.7.2 CIRCULAR DESIGN

Designing a product with circularity in mind entails an insurance that recycled materials are
used for production and that the product at the end of its life can be reused or recycled.
86 7. BID FOR ENVIRONMENT
Circular economy is an approach to promote sustainable development with parallels to
how resources are circulated in the bioworld. The Ellen MacArthur Foundation defines circular
economy as an industrial economy that is restorative by intention [47]. Motivated by lessons
learned from studies of living nonlinear systems, circularity is premised on the use of renewable
energy, minimum consumption of chemicals, and eradication of waste. Circularity aims to op-
timize systems rather than their components. This is done by managing the flows of materials of
two types: (i) biological nutrients that re-enter the biosphere safely and (ii) technical nutrients
designed to circulate without diminishing in quality and without entering the biosphere.
Consequently, circular economy distinguishes between consumption and use of materi-
als. It promotes a functional service model whereby the ownership of a product is retained with
the manufacturer who acts as a service provider rather than as a product seller. The manufac-
turer therefore does not promote one-way consumption but ensures that the product will be
reabsorbed in the economy after the end of its life.
Circularity can be applied to all types of industrial production. An example is the cloth-
ing industry. The current system is regarded as extremely wasteful and polluting from the initial
production of textile fibers, through the production of fabrics and a wearable followed by re-
peated washes during use to the final after-use destiny of the wearable [48]. Typically, an item
of clothing is discarded after the wearer is no longer interested in wearing it, although sometimes
it can be passed on to another person. A cotton wearable may be collected by rag pickers as a
raw material for producing paper and industrial wiping rags, there is hope that blended poly-
mer/cotton wearables could be reprocessed after recovering and separating fibers of different
materials, wool extracted from woolen wearables can be used for insulation panels for housing,
acrylics and nylons can be reprocessed into blankets, but polyester wearables are mostly inciner-
ated [49]. Circular economy in the clothing industry would be greatly facilitated by fiber-to-fiber
recycling.
Cradle-to-cradle is an approach to maximize the positive effect of human activities on
the environment as opposed to eco-efficiency that focuses on reducing damage to the environ-
ment [50, 51]. It is based on three key principles:

• waste equals food,

• use only energy provided currently by the sun, and

• celebrate diversity.

The first principle is inspired by the nutrient cycles seen in the bioworld. Instead of reducing
waste, only that waste should be produced which another process can use as an input. The sec-
ond principle dictates that all energy should come from the sun, i.e., from photovoltaic solar
cells, solar thermal heaters, wind turbines, hydroelectric generators, and biomass incinerators.
The third principle encourages design that respects local cultures and environments and also
recognizes that nonhuman species have the right to thrive in their own ecosystems. A criticism
 7.8. BIOLOGICALLY INSPIRED DESIGN FOR ENVIRONMENT 87
of the cradle-to-cradle approach is that is does not address trade-offs between energy use and
resource conservation, because even healthy emissions can adversely affect the ecosystem [50].

7.7.3 IMPACT ASSESSMENT

Life-cycle analysis is an approach to assess the eco-efficiency of a design. A comprehensive
inventory is made of materials, energy, and chemicals used to make, distribute, use, and dispose
of the product. The impacts of the materials, energy, and chemicals on the environment are also
cataloged. In order to compare the eco-efficiencies of two different designs, a functional unit
is defined to represent the desired functional performance. As an example, the functional unit
can be used to facilitate the comparison of the eco-efficiencies of different ways of maintaining
a golf course. A functional unit could be defined as the acreage of a certain terrain in which the
height of grass must be maintained, which makes it possible to compare different methods to
maintain grass height—e.g., using lawn mowers or letting a ruminant species such as goats or
sheep graze.
Assessing the environmental impact is a fairly complex task since a design can have envi-
ronmental effects through several mechanisms such as the emission of greenhouse gases leading
to global warming, the emission of chlorofluorocarbons and halons leading to ozone-hole for-
mation, and the acidification of lakes and rivers. When designing products, a simpler and less
precise method is often used—namely, the use of indicators such as CO2 -equivalents. The in-
dicators make it possible to compare quite different designs. For example, they can be used to
compare the production of vegetables in heated greenhouses in a cold region with the production
of vegetables produced in a warm region followed by transportation to the same cold region.
The use of life-cycle analyses has been criticized for not including the full potential of
approaches such as biomimicry and cradle-to-cradle [50, 52]. Instead, a life-cycle analysis can
become so easily focused on the function of a specific product that its goal can be best charac-
terized as the reduction of unsustainability. Formulation of the functional unit can in some cases
lead to ignoring ancillary issues whose consideration could have enhanced sustainability. Thus,
a life-cycle analysis can lessen the use of energy and materials in a factory, but it will not address
the improvement of air quality which could be very important for public health.
The life-cycle analysis of a product can be supplemented with clear criteria of when a
product can be considered sustainable and when not. This is not an easy task, but attempts are
in progress to define green products as having zero waste, producing zero emissions, and being
environmentally safe.

7.8 GRAFTING “BIOLOGICALLY INSPIRED DESIGN”

ONTO “DESIGN FOR ENVIRONMENT”
Design for environment aims at developing products to enhance sustainability without com-
promising functionality, cost, quality, etc. The bioworld presents many approaches that can be
88 7. BID FOR ENVIRONMENT
adapted for circular economy, resource efficiency, and ecosystem balance. As an example, micro-
scopic scales on sharkskin swimsuits indeed reduce drag; likewise, sharkskin polymer films on
aircraft and ships lower energy consumption [37]. But care must be exercised when transferring
solution principles from the bioworld to industrial activities [53]. A bioworld phenomenon may
appear simple at first glance but it may actually involve many intricate mechanisms to assure
a desirable outcome. Its complexity may be inimical for adoption by designers. Additionally, a
bioinspired solution may not comply with our ethics; for instance, the predator-prey relation-
ship [54] is highly undesirable as a model for controlling the human population. Finally, an
attractive solution principle may simply be impractical for adoption. As an example, a penguin
can increase its speed several times over short distances underwater by releasing microbubbles
of air trapped under its feathers [39], but the application of the same mechanism to reduce drag
on a regular ship appears practically unimplementable.
The grafting of biologically inspired design onto design for environment requires a careful
delineation of the design object. Design for environment is often focused on reducing the overall
environmental impact of a specific product. An automobile engine that consumes less gasoline
than its competitors delivering the same performance and driver satisfaction will comply with
the objectives of design for environment. In other cases, a system involving many products and
processes has to be considered. An example is the introduction of electric vehicles or hydrogen-
powered vehicles that will necessitate the development of a comprehensive new infrastructure.
In the bioworld, any organism relies on being part of a larger system comprising organisms of
the same and different species. Environmental sustainability must therefore be addressed at both
the product level and the system level, when a bioinspired solution principle has to be considered
for adoption. The mutualistic relationship between plants, rhizobial bacteria, and mycorrhizal
fungi which benefit from an exchange of nutrients and energy [18] illustrates how it can be
insufficient only to consider an isolated object as the design object.
The design of a product or system typically involves the following four phases [55] de-
scribed in detail in Chapter 2:

• definition and clarification of the need for the product or system (Sections 2.4.1–2.4.3),

• conceptualization of the product or system and the production/realization process (Sec-

tions 2.4.4–2.4.5),

• preparation of its embodiment to focus the attentions of all stakeholders (Sec-

tion 2.4.6), and

• creation of the necessary detail for production and realization (Section 2.4.6).

Of these four phases, the conceptualization phase offers the most opportunities for implement-
ing strategies associated with design for environment. These strategies include: reduction of
material diversity, ease of disassembly and repairability for longer useful life, use of recyclable
 7.9. REFERENCES 89
and recycled components, reduced use of toxic materials and nonrenewable resources, and ease
of disassembly for circularity and recyclability.
An ever-growing compendium of bioinspired solution principles needs to be established
for each of these strategies. This compendium could lead to the identification of new generic
design principles for disruptive innovation. For example, egg shells and sea shells illustrate how
chalk, a soft material, can be microstructured to bear huge static and dynamic loads. Thus, in-
ferior materials can be biomimetically reformulated to deliver superior performance. The com-
pendium would also promote multifunctionality, as exemplified by avian plumage being used for
flight without significant increase of weight, water repellency, and conservation of body heat.
Design for environment brings additional constraints for biologically inspired design,
which may considerably minimize the solution space. However, a clear environmental goal will
facilitate a more focused search in the compendium and would stimulate creativity in finding
new solutions. As an example, the nests of most birds are made from waste materials held to-
gether with friction and thus exemplify temporary structures that require very low investment
but fulfill short-term needs for temporary housing.
The grafting of biologically inspired design onto design for environment will bring certain
challenges. The evaluation of a radical solution from the bioworld may be difficult not only due
to lack of data but also because of uncertainty in how it will affect use patterns and impact
associated products. For example: inspired by the way spiders eat their own web every second
day in order to regenerate the proteins [16, 17], a solution could be the local reuse of building
materials. However, this will impact the business system for building materials and the working
procedures of the construction industry. The uncertainty may be especially high when the context
and the expected-use scenario for a product or system are not yet defined.
In summary, well-established theories and tools exists to analyze environmental impact
and design to enhance sustainability. Still, design for environment can benefit from biologically
inspired design to create novel solutions. For their integration into Biologically Inspired De-
sign for Environment, successful case stories and an ever-growing compendium of solution
principles from the bioworld are needed.
Hopefully, dear reader, you will contribute.

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