Source: University of Limerick
Summary: A team of Irish researchers had discovered that applying pressure to a globular protein found in egg whites and tears can produce electricity.
A team of researchers from the Bernal Institute, University of Limerick, Ireland discovered that applying pressure to the crystals of lysozyme (globular protein abundant in egg whites of birds, tears, saliva and milk of mammals) can produce electricity. This property of generating electricity by applying pressure is known as direct piezoelectricity, it is exhibited by some materials such as quartz which can convert mechanical energy into electrical energy and vice versa. Bone, tendon and wood are all well known to possess piezoelectricity. The study is published in the journal Applied Physics Letters.
Lysozyme crystals can be easily made from natural resources. This discovery may have wide range applications in the field of energy harvesting and flexible electronics for biomedical devices. Lysozyme can be an alternative to the conventional piezoelectric energy harvesters (contain lead) as it is naturally biocompatible even piezoelectric.
Aimee Stapleton, the lead author, explained, “While piezoelectricity is used all around us, the capacity to generate electricity from this particular protein had not been explored. The extent of the piezoelectricity in lysozyme crystals is significant. It is of the same order of magnitude found in quartz. However, because it is a biological material, it is non-toxic so could have many innovative applications such as electroactive, anti-microbial coatings for medical implants”.
Co-author Professor Tewfik Soulimane said, “The high precision structure of lysozyme crystals has been known since 1965, in fact, it is the second protein structure and the first enzyme structure that was ever solved” and added, “but we are the first to use these crystals to show the evidence of piezoelectricity”.
More Information: A. Stapleton et al, “The direct piezoelectric effect in the globular protein lysozyme”, Applied Physics Letters (2017). DOI: 10.1063/1.4997446