A microbivore is a speculative future device, a micromachine with numerous internal nanomachines, which would function as an artificial white blood cell, or phagocyte. Although a detailed design for a microbivore has been outlined by its inventor, Robert Freitas, we currently lack the means to fabricate it.
Including moving parts with dimensions as small as 150 nanometers, fabrication of a microbivore would likely require atom-by-atom manufacturing based on mechanosynthesis. “Mechanosynthesis” refers to chemical reactions orchestrated by the specific programmed motions of nanoscale robotic arms. Such a manufacturing technology has been referred to as molecular nanotechnology by its primary conceiver, Dr. Eric Drexler. Some futurists anticipate the development of molecular nanotechnology in the 2020-2030 time range.
The medical necessity for a microbivore is obvious – there are numerous pathologies involving the presence of foreign organisms in the bloodstream. Collectively, these are called sepsis, with ~1.5 million annual cases and ~0.5 million annual deaths worldwide. Foreign infections in the bloodstream are especially dangerous to immunocompromised individuals, such as those suffering from AIDS. Many of the current therapies are crude and merely arrest the growth of foreign organisms in the bloodstream rather than wipe them out entirely. Many physicians would welcome a synthetic device capable of performing search-and-destroy missions on such microbes.
The microbivore is a device with an oblate spheroid shape, 3.4 microns in length and 2.0 microns in width. A micron is a millionth of a meter, similar in size to most eukaryotic cells. A microbivore would consist of 610 billion precisely arranged structural atoms, with about 150 billion gas or water molecules when in operation. To ensure high reliability, the design includes a tenfold redundancy for most internal mechanisms, excepting only the largest structural elements.
Like natural phagocytes, the microbivore would use a “digest and discharge” protocol to devour bacteria, fungi, and viruses unfortunate enough to cross its path. Covered with species-specific reversible binding sites, the offending microbes would stick to the surface of the microbivore. The device would then extend tiny nanorobotic manipulators, secure them to the microbe, then direct it to an ingestion port, similar to a squid wrapping its tentacles around prey then shoving it into its mouth. After entering the ingestion port, the target microbe would be blended using mechanical mincing blades, then passed to a digestion chamber where specifically selected enzymes would break down the target into biologically inactive effluent, thereafter releasing it into the bloodstream.
Microbivores would be administered intravenously and could be directed to leave the bloodstream through the intestines when desired. Initial estimates suggest that microbivores would be about 1000 times faster-acting and 80 times more efficient than natural white blood cells.
The mass fabrication and therapeutic use of microbivores could revolutionize medicine. Unless there are any unforeseen and insurmountable challenges, many people currently living may benefit from microbivore-based therapies. Many diseases could be cured, only if the bodies natural defenses could be given some outside help.