Engineered lysozyme: An eco-friendly bio-mechanical energy harvester

Eco-friendly and antimicrobial globular protein lysozyme is widely produced for several commercial applications. Interestingly, it can also be able to convert mechanical and thermal energy into electricity due to its piezo- and pyroelectric nature. Here, we demonstrate engineering of lysozyme into piezoelectric devices that can exploit the potential of lysozyme as environmentally friendly, biocompatible material for mechanical energy harvesting and sensorics, especially in micropowered electronic applications. Noteworthy that this flexible, shape adaptive devices made of crystalline lysozyme obtained from hen egg white exhibited a longitudinal piezoelectric charge coefficient (d - 2.7 pC N-1 ) and piezoelectric voltage coefficient (g 76.24 mV m N-1 ) which are comparable to those of quartz (-2.3 pC N-1 and 50 mV m N-1 ). Simple finger tapping on bio-organic energy harvester (BEH) made of lysozyme produced up to 350 mV peak-to-peak voltage, and a maximum instantaneous power output of 2.2 nW cm-2 . We also demonstrated that the BEH could be used for self-powered motion sensing for real-time monitoring of different body functions. These results pave the way toward self-powered, autonomous, environmental-friendly bio-organic devices for flexible energy harvesting, storage, and in wearable healthcare monitoring.