COMPUTATIONAL TASKS IN MEDICAL NANOROBOTICS - Bio-Inspired and Nanoscale Integrated Computing - page 403

during a single digestion cycle, progressively reducing the morcellate to mono-
residue amino acids, mononucleotides, glycerol, free fatty acids and simple sugars,
using an appropriate array of molecular sorting rotors. These basic molecules are
then harmlessly discharged back into the bloodstream through the exhaust port at
the rear of the device, completing the 30-second digestion cycle. When treatment is
finished, the doctor may transmit an ultrasound signal to tell the circulating
microbivores that their work is done. The nanorobots then exit the body through
the kidneys and are excreted with the urine in due course.
The microbivore needs a variety of external and internal sensors to complete
its tasks. External sensors include chemical sensors for glucose, oxygen, carbon
dioxide, and so forth, up to 10 different molecular species with 100 sensors per
molecular species. Pressure sensors for acoustic communication are mounted
within the nanorobot hull to permit the microbivore to receive external instruc-
tions from the attending physician during the course of in vivo activities. Ten
(redundant) internal temperature sensors capable of detecting 0.3

C temperature
change [1i] are positioned near each of the 10 independent powerplants.
Microbivores use bloodstream glucose for power like respirocytes, but also
use blood-dissolved oxygen which is available only at much lower concentrations
than in the lung capillary bed, so many more molecular sorting rotors for O 2 must
be present on the microbivore hull. The microbivore is scaled for a maximum
power output of 200 pW, about 1000 times higher than for the respirocyte.
Diamondoid mechanical cables may transmit internal mechanical energy at power
densities of

1

6 10 12 W/m 3 [1x]. To connect every powerplant with each of its
9 neighbors via power cables, permitting rapid load sharing among any pair of
powerplants inside the device, requires 45 power cables; assuming 1000 internal
power cables to accommodate additional power distribution tasks and for
redundancy, total power cable volume is 0.05 micron 3 . By varying the cable
rotation rate, the same power cables can simultaneously be used to convey
necessary internal operational information [1t] including sensor data traffic and
control signals from the computers.
A human neutrophil, the most common type of leukocyte or white cell, can
capture and engulf a microbe in a minute or less, but complete digestion and
excretion of the organism's remains can take an hour or longer. Thus our natural
white cells—even when aided by antibiotics—can sometimes take weeks or
months to completely clear bacteria from the bloodstream. By comparison, a
single terabot (10 12 -nanorobot) dose of microbivores should be able to fully
eliminate bloodborne pathogens in just minutes or hours, even in the case of
locally dense infections. This is accomplished without increasing the risk of sepsis
or septic shock because all bacterial components (including all cell-wall LPS) are
internalized and fully digested into harmless nonantigenic molecules prior to
discharge from the device. No matter that a bacterium has acquired multiple drug
resistance to antibiotics or to any other traditional treatment—the microbivore
will eat it anyway. Microbivores would be up to

B

1000 times faster-acting than
antibiotic-aided natural leukocytes. The nanorobots would digest

B

100 times
more microbial material than an equal volume of natural white cells could digest

B