The problem with current piezoelectric systems is that they're typically made from toxic materials. But boffins at the Berkeley Lab have devised an ingeniously green alternative—current-creating bacteriophages.
The M13 bacteriophage virus normally spends its time infecting and replicating within E. coli bacteria. However, it also has a couple of handy perks including the ability to generate electric current when compressed, readily replicate, and also a habit of aligning itself into orderly rows.
Berkeley Lab scientists shoehorned this virus into battery form by stacking 20 layers of a genetically-modified version of M13 atop a gold substrate and attaching leads. The result—a tiny battery able to output six nanoamperes at 400 millivolts. Granted, that's a very small amount of current—like, snail generator-levels of charge—but still.
If the technology can be scaled up commercial levels, the possible applications are nearly endless. They could be implanted in roads to generate power as cars travel over them, implanted in the soles of your shoes to recharge your mobile devices as you walk, or power an office's lighting simply from the foot traffic in the lobby. [Nature - Berkeley Lab via ExtremeTech]