Long-range electron transport in self-assembled fibrils of peptides rich in aromatic residues

Understanding the mechanism of charge transport in proteins and peptides in physiologically relevant environments has been a long-standing interest, as several physiological processes involve ion and electron transfer in proteins. This has attracted the interest of researchers working on biomolecular electronics. However, the discovery that some bacteria can produce proteinaceous nanowires capable of transporting electrons over distances of up to the centimeter range has opened a new paradigm for the development of synthetic biomimetic proteinaceous nanowires as electronic materials. Inspired by the structural models suggesting that closely packed aromatic residues facilitate charge transport through proteinaceous nanowires generated by these bacteria, various groups have developed synthetic peptide-based nanofibrils that allow long-range electron transport along their lengths. This highlight reviews recent developments in the construction and characterization of self-assembled fibrils of aromatic residue-rich peptides designed for long-range electron transport, outlines ongoing challenges, and lays out opportunities in the field. The ability to carry out efficient electron transport via self-assembled peptide nanofibrils and tune their electrical properties by modifying constituent peptide sequences would herald a new era of peptide-based solid-state electronics. This would also provide a sustainable bio-based alternative to current approaches in the development of electronic materials.