"Using an anesthetized guinea pig as their power source, the researchers were able to attach electrodes to the cochlea and extract enough power to run a small wireless radio transmitter. That’s just a single nanowatt, but small electronics (and they get smaller all the time) don’t require much power to function. It’s an interesting idea, if a somewhat bizarre one. Tiny nanomachines in the future could be powered not by synthetic nano-batteries but by bio-batteries produced by living mammals."