Cars and other vehicles may be the first thing that springs to mind at the mention of fuel cells, but the technology can of course also be used for plenty of other devices big and small, and a team of researchers at Carnegie Mellon University are now looking to take them to a few new places that haven't been possible so far. To that end, they've developed what they claim is the world's smallest biological fuel cell, which is the size of a single human hair and "generates energy from the metabolism of bacteria on thin gold plates in micro-manufactured channels." That, they say, could make it ideal for use in places like deep ocean environments where batteries are impractical -- or
