COMPUTATIONAL TASKS IN MEDICAL NANOROBOTICS - Bio-Inspired and Nanoscale Integrated Computing - page 404

in any given time period, and would have far greater maximum lifetime capacity
for phagocytosis than natural white blood cells. Besides intravenous bacterial,
viral, fungal, and parasitic scavenging, microbivores or related devices could
also be used to help clear respiratory or cerebrospinal bacterial infections,
or infections in other nonsanguinous fluid spaces such as pleural [42], synovial
[43], or urinary fluids; eliminate bacterial toxemias and biofilms [44]; eradicate
viral, fungal, and parasitic infections; disinfect surfaces, foodstuffs, or organic
samples; and help clean up biohazards and toxic chemicals. Related nanorobots
with enhanced tissue mobility could be programmed to quickly recognize
and digest even the tiniest aggregates of early tumor cells with unmatched speed
and surgical precision, eliminating cancer. Similar nanorobots of this class
could be programmed to remove circulatory obstructions in just minutes, quickly
rescuing even the most compromised stroke victim from near-certain ischemic
brain damage, and could have other uses in various veterinary and military
applications.

15.2.2.2. Computational Tasks. An onboard nanocomputer is required to
provide precise control of all basic microbivore operations. These operations
include most of the basic computational tasks already described for the respir-
ocyte (Section 2.1.2) such as onboard tank volume control, sensor coordination,
data and power management, and nanapheresis protocols. Other tasks unique to
the microbivore include management of multiple reversible microbial binding sites
to ensure accurate identification of the targeted microbial species, control of
hundreds of independent grapple elevator and segment rotation mechanisms,
coordination of the grapple motion field to transport trapped microbes in a
controlled manner across the nanorobot surface or for nanorobot locomotion,
and sequence control for morcellation and digestion activities (ingestion port
opening/closing, mincing, transfer pistoning, enzyme cycling, effluent ejection
pistoning, and exhaust port opening/closing).
The microbivore computer is scaled as a 0.01 micron 3 mechanical nanocom-
puter [1y, 12d], in principle capable of W 100 megaflops but normally operated at

5 bits/nm 3 for

1 megaflop to hold power consumption to 60 pW. Assuming

B B B

nanomechanical data storage systems [12d] and a read/write cost of 10 zJ/bit at

B

10 9 bits/sec [1af, 12d], then a comparison with other
software systems of comparable complexity (Table 15.1) suggests that the

a read/write speed of

B

5
megabits of mass nanomechanical memory needed to hold the microbivore
control system displaces a volume of 0.001 micron 3 and draws

B

10 pW while in
continuous operation. The baseline microbivore design includes 10 duplicate
computer/memory systems for redundancy (with only one of the ten computer/
memory systems in active operation at a time), displacing a total of 0.11 micron 3
and consuming

B

70 pW.
As with respirocytes, microbivore behavior is initially governed by a set of
default protocols many of which can be modified at any time by the attend-
ing physician. Basic protocols have already been described for the respirocyte
(Section 2.1.2). Since virtually every medical nanorobot placed inside the human

r