Bionics.
Bionics is the science of replacement of organs, for medical or pleasure purposes. Simply put, it is the legitimate field of study for implanting artificial organs for medical purposes. Some other medical procedures fall under this field as well, but are included under other fields for convenience. Should a character ever lose a lung and is unwilling to get a cybernetic replacement, the local bionics specialist will grow the character a new lung and implant it, all at a reasonable cost.
Bionic organs are typically grown to custom specifications according to the subjects DNA for minimal chance of rejection. However, there are models of bionics that are made with the general consumer in mind that are cheaper and may only need anti-rejection drug therapy to live happily. Of course, the organ might also send their system into shock and cause them an agonizing death.
The process is fairly simple, if not wasteful. The patient allows himself to be DNA scanned by anything from a hand scanner (worst circumstances) to a room-sized walk-in scanner (the best clinics). Armed with this data, the bio-doctor then grows a clone from the data supplied, but never giving it a brain, so it isn't truly alive except by what the vat gives it to ensure its parts remain viable. The procedure is simply extracting the cloned organ and placing it in the patient's body. Observation for two weeks follows for any signs of rejection, and if found, is hopefully treated.
Many critics have noted that this leaves the clinic with a full-grown clone minus a brain and possibly other organs. What the clinics do with these is a point of professional secrecy, although I'm sure the rumours of childish doctors having organ fights after work are grossly exaggerated. Of course, have you ever met a normal bio-doctor?
Bionics have -no- special powers or abilities they are just literally a new lease on life for one or more organs. Have a heart problem? Not for long just put in a new heart and artery trunks.