A common impediment to effective powered implantation is the issue of powering it. While power requirements may be made very low, and small batteries made very efficient, that may not be good enough for a posthuman intending to live with a prosthetic potentially for the next couple of hundred years. And a battery is one more element that can break down, not to mention that they are usually filled with toxic substances. So what is more elegant than a fuel cell that draws power from one’s own blood? As IOL reports, some Japanese researchers have come up with a little device that generates power from the glucose in blood, using only substances already naturally occurring in the body to catalyze the reaction.