Nanomachine

Nanomachine is the general term for a machine ranging in size from one micrometer (one-thousandth of a millimeter) to one 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.

First-generation nanomachines
In February 2005, during the Shadow Moses Incident, Naomi Hunter injected nanomachines into Solid Snake's body, which included: a nanomachine to supply and administer adrenalin, nutrients, sugar, nootropics, and benzedrine; a nanomachine to recharge a Codec's battery; and a nanomachine to infect the body with the FOXDIE virus. 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. They could be manipulated to reduce the effects of disease, though they were unable to directly administer specific medicines. These nanomachines could also be recharged via a person's body heat, although they will end up lost if the person injected was bleeding. The first-generation nanomachines, however, have a serious side effect: If they are injected into a person, they also have a chance with having a negative interference with someone's heart, especially if the person injected had suffered from rapid aging, as was what happened to Solid Snake.

Second-generation nanomachines
Four years later, during the Big Shell Incident, the second-generation nanomachines were injected into the body of Raiden, who successfully carried out a solo infiltration into Big Shell. These nanomachines were more advanced and their simultaneous function as network terminals had been further enhanced. They also handled tasks such as remotely hacking into terminals and nodes connected to Big Shell's operational support network, communication inside the body, the 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. The Codec during this time was also primarily made up of these nanomachines, and users when in communication with others using the Codec also appeared outwardly silent due to speaking in a nano-based language. One interesting medical function of this generation was that they could effectively replace the use of bandages; by sitting still in one place for long enough, the nanomachines rapidly organized a vast supply of platelets in order to coagulate the wound.

The nanomachines were still limited to very important tasks. Nanomachines functioned as a fail-safe system between the President of the United States and the nuclear launch button as well as VIP-communication system between the President and his Secret Service detail.

Third-generation nanomachines
By 2011, 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 U.S. 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 turn was used to perform ID authorization for system-managed firearms and other such devices.

These nanomachines were designed for use at a pressure of 1 atmosphere. Therefore, in low atmospheric environments such as high mountains, they would malfunction and the secretion of neural substances would increase, 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. If these nanomachines are also damaged during a SOP system lockdown, the PMC soldiers in question will also behave in a similar method to Zombies.

The medical functions of this generation were far wider than any seen previously; they could break down alcohol to prevent intoxication, creating a situation where men like Drebin were forced to drink cola instead in order to replicate a similar sensation. They were also capable of purifying water upon consumption in order to prevent diseases and infections such as diarrhea (this is why Johnny was the only one of his team to be affected by the local water.)

Medical and commercial nanomachines
In addition to the multitude of military nanomachines there existed a wide variety of medical and commercial nanomachines that were available to the public.

Naomi Hunter underwent nanomachine treatment for her terminal cancer. Although unable to heal her completely, they had the effect of stopping or greatly slowing down the progress of the cancer allowing her to lead a normal life. Vamp was equipped with a variety that allowed him to rapidly heal from any injury including gun shots and drowning. However, a flaw with the nanomachines is that they need to be continuously operating in order to benefit the user in its healing properties: If the user of these nanomachines had the nanomachines shut down and they end up reactivating around the same time the user experiences a mortal wound, the nanomachines, while still maintaining their function of rapid healing, will cause unbearable pain to the user in the process. A similar nanomachine base was also placed into Raiden as a blood substitute, after FOXHOUND (actually the Patriots) removed his natural blood and placed it into cold storage.

A "fat burning" nanomachine also existed according to a 2014 TV commercial, which supposedly amplified a person's workout, though the importance of remaining hydrated was also stressed. A similar nanomachine base was also utilized by the Colorado senator and 2020 Presidential Candidate Steven Armstrong to amplify his already physically fit body to reach superhuman levels. In his case, the nanomachines used hardened his body upon receiving or dishing out blunt trauma, causing the side effect of turning dark while doing so. It also caused some disfiguration towards the heart, and also turned it pale white.

Personnel known to have utilized nanomachines

 * Gray Fox (2003-2005)
 * Solid Snake (2005-2014)
 * Donald Anderson/Decoy Octopus (2005)
 * Raiden (2009)
 * Richard Ames (2009)
 * James Johnson (2009)
 * Emma Emmerich (2009)
 * Vamp (2009-2014)
 * Liquid Ocelot (2014)
 * Private military companies (2010s)
 * Outer Heaven PMCs (2014)
 * The Beauty and the Beast Unit (2014)
 * Haven Troopers (2014)
 * United States Army (2014)
 * Rat Patrol Team 01 (2014)
 * Big Boss (2014)
 * Naomi Hunter (2014)
 * Steven Armstrong (2018)

Behind the scenes
During the time of Metal Gear Solid 2: Sons of Liberty, it was originally intended that the use of nanomachines by medical organizations would have already begun. The electromagnetic pulse caused by the detonation of a high-altitude nuclear weapon (launched by the Sons of Liberty terrorists) would have therefore threatened the lives of tens of thousands of people undergoing nanomachine treatment.

Nanomachines in the Metal Gear universe are entirely fictional. Nanotechnology in the real world is predicted to be decades or even centuries away from the effectiveness portrayed in Metal Gear. Today, nanotechnology refers to the development of carbon nano-tubes, very simple molecules of carbon, not machines.