In India, fish is a major part of the diet and any major food source is going to generate a lot of waste. Fish scales, bones and tails end up as a steady stream of bio-waste, but researchers at Jadavpur University in Koltata, India have come up with a way to make something incredibly useful out of what's typically thrown away.
The team has created an energy harvester out of fish scales that could be used in self-powered electronics. Fish scales are made of collagen which has piezoelectric properties. That means that any stress placed on the collagen fibers in the scales by pressure or movement generates an electrical charge. The researchers are calling the resulting device a "bio-piezoelectric nanogenerator."
The researchers used a demineralization process to make the scales transparent and flexible and then experimented to find the right hierarchical arrangement of the fibers within the scales to maximize the energy output. The researchers said they were surprised with just how powerful the piezoelectricity of a fish scale is.
The device they created can harness energy from a wide range of things like body movements, machine and sound vibrations and wind flow and it's very efficient. The repeated touch of a finger was able to power 50 blue LEDs.
The researchers said that this work could greatly impact the field of self-powered electronics because the device was made inexpensively, in a single step and it's also completely biodegradable -- a combination that has never been achieved before. This breakthrough could be used in any application that calls for biodegradable electronics like environmental sensors, edible electronics and especially in implantable medical devices used for monitoring or diagnostics.
"In the future, our goal is to implant a bio-piezoelectric nanogenerator into a heart for pacemaker devices, where it will continuously generate power from heartbeats for the device's operation," said Dipankar Mandal, assistant professor, Organic Nano-Piezoelectric Device Laboratory, Department of Physics, at Jadavpur University. "Then it will degrade when no longer needed. Since heart tissue is also composed of collagen, our bio-piezoelectric nanogenerator is expected to be very compatible with the heart."
The researchers are also very excited about how this could be used in electronics that are ingested from targeted drug delivery devices to diagnostic devices that can make their way through the gastrointestinal system without causing harm.