Amoeboid Robot Navigates Without a Brain shows the value of 'closing the loop':
The clipping Power from the people is intriguing at a number of levels. The original idea of creating a biofuel cell was proposed in the 1970s but languished because the technology available at the time could not generate useable amounts of electricity. That required a combination of carbon nanotubes and research into metabolic enzymes such as glucose oxidase. The team working on this project went further, developing a proof-of-concept prototype