COMPUTATIONAL TASKS IN MEDICAL NANOROBOTICS - Bio-Inspired and Nanoscale Integrated Computing - page 401

suppressing erythropoiesis. It may be possible to avoid the resulting decimation of
the natural erythrocyte population by adjusting respirocyte P O2 /P CO2 response
thresholds so that these devices activate only when red cells are stressed.
Command messages of these and similar types should require lengthy authoriza-
tion codes (Section 15.4.5) to prevent accidental or malicious triggering of
respirocyte behaviors having potentially harmful consequences.
15.2.2. Microbivores
15.2.2.1. Nanorobot Description. A second theoretical design study of a
medical nanorobot describes an artificial mechanical white cell or ''microbivore''—
an oval-shaped device (Fig. 15.2) measuring a few microns in size and made of
diamond and sapphire—that would seek out and digest unwanted bloodborne
pathogens [5]. One main task of natural white cells is to absorb and consume
microbial invaders in the bloodstream, called phagocytosis. Microbivore nanor-
obots would also perform phagocytosis, but would operate much faster, more
reliably, and under human control.
The microbivore is an oblate spheroidal nanomedical device measuring
3.4 microns in diameter along its major axis and 2.0 microns in diameter along
Figure 15.2. An artificial white cell: the microbivore [5]. Designer Robert A.
Freitas, Jr.; illustration and additional design Forrest Bishop. (r 2001 Zyvex
Corp. and Robert A., Freitas Jr.)