The endocochlear potential, which resides in the inner ear, is the only anatomical structure in the mammalian body that maintains electrochemical potential across such a large region. It’s not a lot of power–something like ten times less than what you can capture with the most efficient non-biological circuitry in existence today–but it’s enough that it could one day be used as a power source for new drug delivery systems or implanted sensors or other devices that function inside a living body. 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. A paper on this research will be published in the upcoming issue of Nature.
