Natural protein shows semiconductor potential, opening new path for green electronics

Scientists at the Institute of Nano Science and Technology (INST), Mohali, have discovered that a naturally occurring bacterial protein can function as a light-responsive semiconductor, a finding that could transform the future of eco-friendly and biocompatible electronic devices.

The newly discovered semiconductor property of a known self-assembling bacterial shell protein could pave the way for safe, environmentally friendly electronics, from mobile phones and smart watches to medical instruments and environmental sensor.

The study reveals that a self-assembling bacterial shell protein, previously known for forming stable two-dimensional structures, exhibits photoactive and semiconducting behaviour without the need for synthetic additives, metals or external power sources. The discovery offers a sustainable alternative to conventional semiconductor materials such as silicon, which are rigid, energy-intensive to manufacture and contribute significantly to electronic waste.

The research was carried out by a team led by Dr Sharmistha Sinha, along with researchers Silky Bedi and S. M. Rose. The scientists investigated whether the naturally ordered structure of these proteins, which form large, flat sheets with inherent electron-rich regions, could enable electrical activity when exposed to light.

Their experiments showed that when the protein assembles into thin sheet-like films, it absorbs ultraviolet light and generates an electrical current on its own. This occurs due to the presence of tyrosine, a naturally occurring amino acid within the protein that releases electrons when stimulated by light. The movement of electrons and protons across the ordered protein surface produces an electrical signal, functioning in a manner similar to a miniature solar cell.

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Advanced microscopy and electrical measurements confirmed that this behaviour depends on the protein’s highly organised structure and the specific orientation of tyrosine residues. Comparative studies with disordered proteins containing tyrosine established that the semiconductor-like response is unique to the naturally self-assembled protein sheets.

The findings, published in the journal Chemical Science of the Royal Society of Chemistry, point to a new direction in bio-inspired electronics. Because the material is flexible, non-toxic and compatible with living tissues, it could be used in wearable health monitors, UV-sensing skin patches and implantable medical devices. It also holds potential for biodegradable environmental sensors that safely decompose after use.

Researchers say the discovery highlights the possibility of designing next-generation electronic materials by harnessing nature’s own molecular architectures. Such protein-based semiconductors could enable low-energy, genetically tunable and environmentally responsible technologies for sensors, detectors and medical devices, aligning innovation with sustainability.