The electrical generator uses bacterial spores to harness the untapped power of evaporating water, according to research conducted at the Wyss Institute of Biologically Inspired Engineering at Harvard University.
Its developers foresee electrical generators driven by changes in humidity from Sun-warmed ponds and harbours.
The prototype generators work by harnessing the movement of a sheet of rubber coated on one side with spores.
The sheet bends when it dries out, much as a pine cone opens as it dries or a freshly fallen leaf curls, and then straightens when humidity rises.
Such bending back and forth means that spore-coated sheets or tiny planks can act as actuators that drive movement, and that movement can be harvested to generate electricity.
"If this technology is developed fully, it has a very promising endgame," said Ozgur Sahin, who led the study.
Water evaporation is the largest power source in nature, said Sahin who collaborated with L Mahadevan from Harvard University, and Adam Driks from Loyola University Chicago Stritch School of Medicine.
As Sahin pursued the idea of a new humidity-driven generator, Mahadevan had been investigating similar problems from a physical perspective.
Specifically, he had characterised how moisture deforms materials, including biological materials such as pinecones, leaves and flowers, as well as man-made materials such as a sheet of tissue paper lying in a dish of water.
"Since changing moisture levels deform these spores, it followed that devices containing these materials should be able to move in response to changing humidity levels," Mahadevan said.
The study was published in the journal Nature Nanotechnology.