Electronics for the body are getting smaller and smaller, but finding a satisfactory power source to keep an insulin pump pumping or a pacemaker pacing continues to be a challenge. But what better way to fire up an implanted pacemaker than to use energy from the body itself? As a first step, scientists have figured out how to make a clam into an electricity generator.
"What we are doing is significantly different from getting electricity for a car," says project lead Evgeny Katz. Batteries powering an electric car work with inorganic (i.e. potentially expensive and unsustainable) catalysts at high pressures. In the clam battery, those roles are played by a natural enzyme that coats a carbon-based electrode, which is then placed between the clam’s body wall and heart.
The star players of the bivalve battery, aside from the clams of course, are a natural enzyme and a form of carbon nanotubing that the authors call "buckypaper." The enzyme replaces the precious metals that sit inside most batteries as catalysts, and the buckypaper serves as the electrode, converting the glucose the clam produces after eating into electricity. Feed the clam, and you make electricity.
The eventual goal of electrifying animals is to design a body-friendly fuel cell that can be implanted in human beings. An in-body power plant would harvest energy from glucose in the bloodstream and power pacemakers and other in-body electronics. But keeping humans alive isn’t the only application. The micro-cyborgs could also be used as cheap, battery-less scouts to record environmental data in the wild, unobserved, without ever having to recharge.
Now that Katz and co. have shown that the setup works in clams and snails, lobsters are next on the list. Soon, we may have an entire kingdom of animal batteries.