If you thought that LEGO pirate ship you completed when you were 5 was an historic feat, wait until you hear what engineers from Harvard University are doing with the colorful little building blocks, some bacteria and a piece of rubber.
Researchers from the Wyss Institute of Biologically Inspired Engineering are creating electric currents with a contraption that harnesses the power of a soil bacterium, Bacillus subtilis. According to Discovery, the bacteria can withstand heat, chemical assaults, dehydration and even radiation, and has a novel trick for surviving harsh, dry conditions.
During changes in humidity, the bacteria shrivels up like grapes in the sun and swell when the air around them becomes moist again. Engineers have found a way to use this strange habit to develop an alternative source of electricity by coating a piece of rubber with bacterial spores and allowing it to bend and straighten as humidity fluctuates.
Their study, published in the journal Nature Nanotechnology, describes how as the piece of rubber flips back and forth in response to changes in moisture, it drives a rotating magnet that in turn produces energy.
"If this technology is developed fully, it has a very promising endgame," Ozgur Sahin, lead author of the study and an associate professor from Columbia University in New York, said in a statement, according to Clean Technica. “Water evaporation is the largest power source in nature. Sunlight hits the ocean, heats it up, and energy has to leave the ocean through evaporation. If you think about all the ice on top of Mt. Everest — who took this huge amount of material up there? There’s energy in evaporation, but it’s so subtle [that] we don’t see it.”
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Previous research has led to breakthroughs in this form of energy production, but this is the first time an electric current was actually generated using this technique.
“Materials that respond mechanically to external chemical stimuli have applications in biomedical devices, adaptive architectural systems, robotics and energy harvesting,” the authors of the new study wrote. “Inspired by biological systems, stimuli-responsive materials have been created that can oscillate, transport fluid, provide homeostasis and undergo complex changes in shape.”
While this technology harnesses only a small amount of the energy released during evaporation, researchers believe the technique can be greatly improved upon.