Wire in the Blood!

A Japanese research team has developed a fuel cell that runs on blood
without using toxic substances, opening the way for use in artificial
hearts and other organs. The biological fuel cell uses glucose, a sugar
in blood, with a non-toxic substance used to draw electrons from
glucose.“Since the electron mediator is based on Vitamin K3, which exists in
human bodies, it excels in safety and could in the future generate
power from blood as an implant-type fuel cell,” the group said in a
statement.

Most other bio-fuel cells under study use a metal complex, spawning concern about harm if used for implants.

The newly developed cell in the size of a tiny coin is able to
generate 0,2 milliwatts of electricity, enough to power a device that
measures blood sugar level and transmits data elsewhere, the group said.