General term for machines ranging in size from a micrometer (one-thousandth of a millimeter) to a nanometer (one-millionth of a millimeter) using MEMS (Micro Electro Mechanical Systems) technology. An example of a nanomachine would be a protein aggregate resembling the structure of a man-made motor using biomolecules such as DNA, proteins, and resins as parts.
During the Shadow Moses Island Incident, Naomi Hunter injected nanomachines into Solid Snake's body, including a nanomachine to supply and administer adrenalin, nutrients, sugar, Nootropics, and Benzedrine; a nanomachine to recharge a communication device's battery; and a nanomachine to infect the body with FOXDIE. Nanomachines also made it possible to restrict the host's actions, such as shooting a gun, and to stimulate the host's muscle fibers using ciliary motility.
Four years later, the second-generation nanomachines injected into the body of Raiden, who successfully carried out the solo infiltration into the Big Shell, were more advanced and their simultaneous function as network terminals had been further enhanced. The nanomachines also handled tasks such as remotely hacking into terminals and nodes connected to Big Shell's operational support network, communication inside the body, and dynamic creation of hallucinations through intracranial nanomachines, and the checking and remote management of VS (vital signs).
The number of people with nanomachines implanted had also increased, and almost everyone involved with The Patriots or under their direct control had nanomachines implanted in their bodies.
Five years after the Big Shell Occupation, AT Security succeeded in making nanomachines even more complex and widely-used. The range of users was extended to include the regular armies of allied powers such as US military personnel, as well as PMC soldiers and public organizations such as police agencies. Nanomachines, which in the past were designed to control and manage an individual body, were now used as a tool to control a group. In the nanomachines used in the military battlefield control system, "Sons of the Patriots (SOP)," the user's ID is embedded, which in term is used to perform ID authorization for system-managed firearms and other such devices. Nanomachines are designed for use at a pressure of atmosphere. Therefore, in low atmospheric environments such as high mountains, they will malfunction and the secretion of neural substances will increases, due to changes in the concentration of oxygen in the blood.
Consequently, PMC soldiers in the mountainous regions of South America head into battle in a state of intoxication due to excess secretion of neural anesthetic by nanomachines.