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

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

15.4 Systemic Nanorobot Distribution and Phagocytosis

Traditional biocompatibility focuses on the implant-host interface. But a human patient is an interconnected structure with various mechanisms permitting physical exchange among all of its tissues and organs. Of particular interest in nanomedicine is the movement of solid bodies and particulate matter through the various systems of the body. Intact motile nanorobots that can travel purposively inside the human body (Chapters 8 and 9) and can avoid geometrical trapping, phagocytosis, and granulomatization can achieve indefinite persistence without clearance by the natural immune system. The analysis here primarily concerns the fate of free-floating nanorobots (or their material ejecta or fragments), stationkeeping nanorobots such as internal communication (Section 7.3.2) or navigation (Section 8.3.3) networks, or motile nanorobots that have malfunctioned and lost their mobility, and are moving passively through the body or are being driven by cell-mediated processes.

Section 15.4.1 reviews the movement and fate of very large particles in human tissues. This is followed by a lengthy discussion of the potential for geometrical trapping (Section 15.4.2) or phagocytic trapping (Section 15.4.3) of microscopic medical nanorobots in the human body, and how nanorobots may actively avoid this fate. The Chapter concludes with a brief discussion of the biocompatibility of nanorobot fragments in vivo (Section 15.4.4).

Last updated on 30 April 2004