Wee spores now offer a renewable source of vroom, researchers report.
A previous study found that bacterial spores, which rapidly shrivel in dry conditions and replump with hydration, are packed with power and could be used to generate electricity. Now, in a follow-up study, researchers have built tiny spore-powered engines, which can run an LED and a miniature car weighing 0.1 kilograms.
Each engine is made of polymer flaps smeared with spores. Varying the humidity within the engine spurs evaporation of water from the spores, which causes the flaps to contract into a curved form; moisture makes the flaps straighten out again. The flexing powers crank the engine, creating a renewable source of energy.
SPIN CYCLE Bacterial spores, which shrink and bloat based on humidity, lend their flexing powers to crank this rotary engine that runs a small car. Credit: Chen et al./Nature Communications 2015