The respirocyte is a bloodborne 1-micron-diameter spherical nanomedical device designed by Robert A. Freitas Jr.. The device acts as an artificial mechanical red blood cell It is designed as a diamondoid 1000-atmosphere pressure vessel with active pumping powered by endogenous serum glucose, and can deliver 236 times more oxygen to the tissues per unit volume than natural red cells while simultaneously managing carbonic acidity. An individual respirocyte consists of 18 billion precisely arranged structural atoms plus 9 billion temporarily resident molecules when fully loaded. An onboard nanocomputer and numerous chemical and pressure sensors allow the device to exhibit behaviors of modest complexity, remotely reprogrammable by the physician via externally applied acoustic signals.
Twelve pumping stations are spaced evenly along an equatorial circle. Each station has its own independent glucose-metabolizing powerplant, glucose tank, environmental glucose sensors, and glucose sorting rotors. Each station alone can generate sufficient energy to power the entire respirocyte, and has an array of 3-stage molecular sorting rotor assemblies for pumping O2, CO2, and H2O from the ambient medium into an interior chamber, and vice versa. The number of rotor sorters in each array is determined both by performance requirements and by the anticipated concentration of each target molecule in the bloodstream. The equatorial pumping station network occupies ~50% of respirocyte surface. On the remaining surface, a universal "bar code" consisting of concentric circular patterns of shallow rounded ridges is embossed on each side, centered on the "north pole" and "south pole" of the device. This coding permits easy product identification by an attending physician with a small blood sample and access to an electron microscope, and may also allow rapid reading by other more sophisticated medical nanorobots which might be deployed in the future.