Equatorial cutaway view of respirocyte. The oxygen gas chamber is at left (south pole), the carbon dioxide gas chamber is at right (north pole), and the water (ballast) chamber occupies the center, surrounding the onboard computer system. The equatorial bulkhead separates the north and south hemispheres of the device.
Robert A. Freitas Jr., "Respirocytes: High Performance Artificial Nanotechnology Red Blood Cells," NanoTechnology Magazine 2 (October 1996):1, 8-13 (11); Robert A. Freitas Jr., "Exploratory Design in Medical Nanotechnology: A Mechanical Artificial Red Cell," Artificial Cells, Blood Substitutes, and Immobil. Biotech. 26 (1998):411-430 (422).