Irish researchers have found that squashing a protein found in tears can generate electricity.
The chemical is a bacteria-fighting enzyme called lysozyme, which is present in the tears, saliva and milk of mammals as well as bird egg whites.
The scientists from the University of Limerick discovered that applying pressure to crystallised lysozyme can pretty efficiently release electrical energy.
Squashing things for energy is nothing new – it’s called direct piezoelectricity and is particularly good in the mineral quartz, but is also seen in bones and wood.
These materials can generate electricity when pressure is applied, and vice versa, a technology used to make phones vibrate.
Lysozyme has piezoelectricity levels similar to quartz, making it a promising material to squash for electricity.
Even though they have only just realised the protein can produce energy in this way, scientists have known about lysozyme for years and its structure was only the second protein ever to be solved back in 1965.
It is particularly promising for medical use, being a biological material, and could be used to target medicines to specific areas in the body.
Lead author Aimee Stapleton said: “It is non-toxic, so could have many innovative applications such as electroactive, anti-microbial coatings for medical implants.”
Their paper, published in the journal Applied Physics Letters can be read here.