Let's say that a patient is in hospital suffering a terminal disease or at least a physical injury that's very expensive to treat. The only hope of salvation is to have artificial, or cybernetic, DNA injected into the injury. The unexpected side effect is that the injection won't stay in the injury itself but rather spread through the body, strengthening the bones and tissues, sharpening the senses and censoring pain. The patient would still look like a normal human, walk like a normal human and even talk like a normal human, but his internal anatomy would be a confused blur between organic and mechanic.
This is, of course, a sci-fi scenario, but the question regarding the scenario is this--does it teeter on the Star Trek degree of plausible (believable), or on the Star Wars degree of fantastical?