COMPUTATIONAL TASKS IN MEDICAL NANOROBOTICS - Bio-Inspired and Nanoscale Integrated Computing - page 396

Figure 15.1. An artificial red cell: the respirocyte [4]. Designer Robert A. Freitas,
Jr.; illustration by E-spaces. (r 2002 E-spaces and Robert A. Freitas, Jr.)
carbon dioxide (CO 2 ) may drift into their respective binding sites on the exterior
rotor surface and be carried into the respirocyte interior as the rotor turns in its
casing. Once inside, a small pin is inserted into the binding site, forcibly ejecting
the bound molecule into the interior tank volume. There are 12 identical pumping
stations laid out around the equator of the respirocyte, with oxygen rotors on
the left, carbon dioxide rotors on the right, and water rotors in the middle.
Temperature [1i] and concentration [1j] sensors tell the devices when to release
or pick up gases. Each station has special pressure sensors [1k] to receive
ultrasonic acoustic messages [1m], so doctors can tell the devices to turn on or
off, or change the operating parameters of the devices, while the nanorobots
are inside a patient.
The basic operation of respirocytes is straightforward. These nanorobots, still
entirely theoretical, would mimic the action of the natural hemoglobin-filled red
blood cells. In the tissues, oxygen is pumped out of the device by the sorting rotors
on one side. Carbon dioxide is pumped into the device by the sorting rotors on
the other side, one molecule at a time. Half a minute later, when the respirocyte
reaches the patient's lungs in the normal course of the circulation of the blood,