Nanites

Microscopic, programmable nano-machines invented by Daniel Esterhazy. A breakthrough in fighting cancer and diseases, which can also accelerate natural healing and bodily repair to a seemingly magical degree, as well as being able to speed up or stall growth, including ageing and pregnancies - although some uses are banned. An essential component of tendstims, Revital, and many other things. Still exist in large quantities up on the Mastersphere, from which Ikaanos gets a supply each year. Nanites can be grown, so it is assumed that the stock on the Sphere is sustainable rather than representing a dwindling resource now that Raana's connection to Earth is severed.

Nanites can be obtained by building a Nanite Tubes module in your house or purchasing them at the Doctor's Hall.