If The Matrix is to be taken as a serious manifesto for the future of technology, then living organisms are a great source of potential energy. Now, a team at Oxford University has given some weight to the idea after successfully simulating a biological power station. Researchers used computers to model the behaviour of bacteria as it swam around a liquid suspension. When they subsequently added a network of donkey wheel-like structures, the bacteria began moving in predictable patterns around the wheels. The motion was sufficient to generate tiny amounts of energy that could be used to power microscopic gadgets.