doi:10.1038/nindia.2018.71 Published online 11 June 2018
Eggshell membrane, usually discarded as bio-waste, has been used to make biocompatible nanogenerators — tiny devices that can generate electricity from simple throat movements during gargling, drinking, coughing and swallowing, reveals a new study1.
Since these nanogenerators are highly sensitive to tiny biomechanical pressures, they can potentially be used to develop wearable biomedical sensors.
Inorganic and organic materials are widely used to make tiny devices that can harness energy from human motion such as walking and jogging. However, most of these materials are toxic and non-biodegradable.
Scientists from the Indian Institute of Technology, Kharagpur, in India synthesised the nanogenerators by using eggshell membrane, a porous protein-rich thin layer between the calcified eggshell and the albumen proteins of an egg.
When subjected to mechanical pressure through hand punching, the generators created an output voltage. Five such generators, when connected in series, were able to power up 90 green-light-emitting diodes, suggesting their potential to power wrist watches, calculators and other portable electronic devices.
They also displayed efficiency in storing charges, indicating their potential role as capacitors. They could even be fitted into shoes to charge mobiles phones by generating electricity from biomechanical pressure created during walking and running.
The devices retained their efficiency in generating power even after being exposed to repeated cycles of mechanical stresses created by hand-punching and sewing-machine vibration. The researchers say that the nanogenerators would be widely applicable to power up various stretchable, flexible medical systems for monitoring biological signals and treating various diseases.
1. Karan, S. K. et al. A new insight towards eggshell membrane as high energy conversion efficient bio-piezoelectric energy harvester. Mater. Today. Energ. 9, 114 – 125 (2018)