Peptide nanophotonics – from bio-waveguides to integrated photonic devices

Optical waveguiding phenomena in bioinspired chemically synthesized peptide nanostructures can be used to revolutionize emerging fields of precision medical trials and health monitoring. New biomedical light therapy tools and implantable optical biochips can be produced using bioinspired peptide nanostructures due to a unique combination of their intrinsic biocompatibility and remarkable multifunctional optical properties. This essay highlights a new field of peptide nanophotonics. It covers peptide nanotechnology and fabrication processes of peptide integrated optical circuits, basic studies of linear and nonlinear optical phenomena in biological and bioinspired nanostructures, and passive and active optical waveguiding in peptide nanostructures. We show that optical properties of this new generation of biooptical materials are governed by fundamental biological processes. Refolding of the peptide secondary structure is followed by wideband optical absorption and visible tunable fluorescence. In peptide optical waveguides, such a new biooptical effect leads to switching from a passive waveguiding mode in native α-helical phase to an active one in β-sheet phase. Discovery of an active waveguiding effect in β-sheet fiber structures below the optical diffraction limit opens an avenue for future development of new bionanophotonics devices using ultrathin peptide/protein fibrillar structures for advanced biomedical and nanotechnology applications.