Nanomedicine, Volume IIA: Biocompatibility

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

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

All else equal, mechanical damage during histopenetration by medical nanorobots is proportional to the volume of disturbed tissue. The tissue volume required to be displaced by a given population of passing nanorobots is minimized if transit tunnel volumes are reused by successive nanorobots – that is, if nanorobots histopenetrate in linear convoys. More quantitatively, if a population of Nbot cube-shaped nanorobots each of edge d moves at velocity vbot through a cubic tissue block of volume L3 using ctunnel separate histopenetration tunnels each of length L and cross-sectional area d2, then the tissue holing fraction is fhole = ctunnel d2 / L2, the length of each convoy is Lconvoy = d Nbot/ctunnel, and the transit time for the fleet is ttransit = (L + (d Nbot / ctunnel)) / vbot.

For Nbot = 109 nanorobots, L = 1 cm, d = 1 micron, and vbot = 100 microns/sec (Sections and, then randomized single-nanorobot histopenetration (ctunnel ~ Nbot) gives fhole = 1000% and the block of tissue is entirely holed ten times by the passing nanorobot fleet, a massively intrusive event. However, if fhole = 1% is regarded as an acceptable and fully biocompatible maximum degree of tissue intrusion (Section 15.6.3), then ctunnel = 106, giving ttransit = 110 sec and Lconvoy = 1 mm. (See also Section


Last updated on 30 April 2004