Nanites a microscopic machines which are designed to go inside living tissue to perform a wide variety of tasks. The most common of these tasks is to assist in microsurgery or to conduct medical repairs inside living cells. The kind of therapy has been controversial in the past due.
Nanite Factory
The nanite factory is a device which builds nanites to do a preprogramed task. The device is placed most often inside a living person (though this need not be, computer repair nanites are common enough if less known). The device then produces a constant supply of the small robots in order to perform regular maintenance. The use of this kind of technology is extremely controversial and many medical institutions refuse to do so unless there is no other solution, and even then, they are reluctant.