A team of Irish scientists has recently discovered that the process of applying pressure to a protein found in egg whites and tears is capable of producing energy. The researchers from the Bernal Institute, observed that crystals of lysozyme, a model protein that is abundant in egg whites of birds, as well as in the tears, saliva and milk of mammals can generate electricity when pressed.

The ability to generate electricity by applying pressure is known as direct piezoelectricity, which is a property of materials, such as quartz, that can convert mechanical energy into electrical energy and vice versa. Such materials are used in a variety of applications ranging from resonators and vibrators found in mobile phones, to deep ocean sonars to ultrasound imaging. Other sources of piezoelectricity are bones, tendons and wood.

The extent of piezoelectricity in lysozyme crystals is significant, having the same order of magnitude fond in quartz. Due to the fact that it is a biological material, and it is non-toxic, having multiple applications such as electroactive, anti-microbial coatings for medical implants.

Crystals represent the gold standard for measuring piezoelectricity in non-biological materials. Our team has shown that the same approach can be taken in understanding this effect in biology. This represents a new approach that the scientists have tried to understand by using complex hierarchical structures, such as tissues, cells or polypeptides, rather than investigating simpler fundamental building blocks.

This discovery may have wide reaching applications and could eventually lead to further research in the area of energy harvesting and flexible electronics for biomedical devices. Some of the future applications of the discovery may include controlling the release of drugs in the body by using lysozyme as a physiologically mediated pump that scavenges energy from its surroundings.