Research is under way to design nanoparticles that will be injected into the human bloodstream for treatment of hardening of the arteries. They can potentially detect blockages and even help the arteries to heal themselves. Here's one article on this technique:Nanoparticles
This kind of therapy foreshadows—even though still a long way from—the super-powerful nanotechnology in Lynsay Sands's Argeneau Family vampire series. Her vampire clan originated in ancient Atlantis, where scientists created "nanos" to bestow longevity and perpetual health on the experimental subjects by continuously healing all damage to the body. Effectively, the treatment has transformed these people into a new subspecies of humanity. The miracle cure works, continuously repairing the effects of disease, injury, and age. As an unforeseen side effect, however, a person infected with the nanos has to consume blood to replace the resources used up by the healing process. Furthermore, the submicroscopic particles interpret the effects of ultraviolet radiation as damage, so that the longer an Argeneau immortal is exposed to sunlight, the more blood he or she needs. Fortunately, Sands's immortals have adjusted well to their condition and, with the availability of bagged blood, lead fulfilling lives without having to harm anyone. If you haven't read her amusing, lively, sensual vampire romances, do try them.
Could a similar experimental program—nanotechnology designed for healing or explicitly to "improve" the human race, raging out of control—be the origin of the Sime-Gen mutation?
Margaret L. CarterCarter's Crypt