© 1999 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Nanomedicine, Volume I: Basic Capabilities, Landes Bioscience, Georgetown, TX, 1999

9.1 Nanorobot Dexterity and Mobility

Manipulation and mobility are crucial basic capabilities in most classes of medical nanodevices. Manipulation includes handling fluids, biological objects such as tissue matrix fibers or cellular elements, and nanomachines or their components. Physicians must be able to direct tissue or cell-repair nanorobots to travel to a specific site where treatment is required, and once there, to manipulate the local environment to achieve the desired results. Nanodevice mobility in vivo makes possible the rapid reconfiguration of nanomedical communication, navigation, and power systems, while ex vivo mobility allows the design of more robust diagnostic and personal defensive systems. In vivo locomotion also permits precise mapping of the internal regions of the human body across many size and time scales, both for diagnostic and for therapeutic purposes.

This Chapter opens with a discussion of adhesion forces at the molecular level and the performance of nanoscale fluid pumps and fluidic circuits (Section 9.2). Several useful classes of nanomanipulators are then presented, along with various tool tips and manipulator configurations such as massively parallel manipulator arrays (Section 9.3). Techniques of in vivo locomotion are next described in the context of biofluid and nanodevice rheology, including bloodstream swimming, cell walking and anchoring, tissue diving, cell penetration, intracellular mobility, and cytocarriage (Section 9.4). The Chapter concludes with a brief consideration of ex vivo locomotion (Section 9.5).

Our evaluation of the biocompatibility³²³⁴ of various manipulation and propulsion systems for medical nanodevices is deferred to Chapter 15.

Finally, the reader should be aware that as of 1999, much of the available experimental data on cellular mechanics and forces in biomolecular systems was still very incomplete and ill-defined. There remained significant uncertainties in the reported numbers, many of which were of necessity compiled from large-area or bulk measurements, or for just one type of easily-studied cell, cell membrane, transmembrane protein, or receptor, and thus might prove inaccurate when applied to other, seemingly similar, cellular systems. Thus the calculations, estimates, and conclusions offered here are highly tentative and must be applied with great caution.

Last updated on 20 February 2003