© 2003 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Nanomedicine, Volume IIA: Biocompatibility, Landes Bioscience, Georgetown, TX, 2003

15.6 Nanorobot Volumetric Intrusiveness

Even assuming that nanorobots have biocompatible external surfaces that do not activate any of the body’s natural defensive systems, medical nanodevices might still provoke unwanted reactions by physical displacement of critical biological systems or fluids. In nanomedicine, volumetric intrusiveness is a measure of the degree to which artificial nanosystems can safely and harmlessly volumetrically displace natural biological systems. In this Chapter we will briefly consider the acceptable volumetric intrusiveness of nanorobot populations and nanostructured macroscopic objects placed inside the human body (Section 15.6.1), in the human bloodstream (Section 15.6.2), and inside human cells (Section 15.6.3). Issues of functional intrusiveness (Chapter 17) and thermal intrusiveness (Section 6.5.2) are discussed elsewhere, although technological intrusiveness is briefly mentioned in Section 15.6.4.

A more complete analysis would carefully distinguish acute and chronic volumetric intrusions. Acute volumetric loading tests the ability of the current structure (whether whole body, blood vessel, or cellular compartment) to withstand the intrusion. Chronic (i.e., slow, gradual) volumetric loading tests the ability of the structure to adapt to the intrusion. These two processes are quite different in their nature and may result in significantly different tolerance ranges. A. Meretei correctly notes that “nanomedicine should be designed to suit the average organism – deducing ranges from sporadic extremes may make us too bold.” Unfortunately, a more comprehensive analysis is beyond the scope of this book.

Last updated on 30 April 2004