Light waveguiding in bioinspired peptide nanostructures. (21st March 2019)

• Record Type: Journal Article
• Authors: Apter, Boris; Lapshina, Nadezda; Handelman, Amir; Rosenman, Gil
• Other Names: Morelli Giancarlo guestEditor.
• Is Part Of: Journal of peptide science. Volume 25:Number 5(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-03-21
• Subjects: optical absorption -- passive and active peptide optical waveguides -- peptide nanophotonics -- refolding of peptide secondary structure -- requirements to peptide waveguiding materials -- visible fluorescence; Peptides -- Periodicals; Peptides -- Periodicals; 572.65
• DOI: 10.1002/psc.3164
• Languages: English
• ISSNs: 1075-2617

Abstract

Abstract: Basic optical properties of bioinspired peptide nanostructures are deeply modified by thermally mediated refolding of peptide secondary structure from α‐helical to β‐sheet. This conformational transition is followed by the appearance in the β‐sheet structures of a wideband optical absorption and fluorescence in the visible region. We demonstrate that a new biophotonic effect of optical waveguiding recently observed in peptide/protein nanoensembles is a structure‐sensitive bimodal phenomenon. In the primary α‐helical structure input, light propagates via optical transmission window demonstrating conventional passive waveguiding, based on classical optics. In the β‐sheet structure, fluorescent (active) light waveguiding is revealed. The latter can be attributed to completely different physical mechanism of exciton‐polariton propagation, characterized by high effective refractive index, and can be observed in nanoscale fibers below diffraction limit. It has been shown that peptide material requirements for passive and active waveguiding are dissimilar. Original biocompatibility and biodegradability indicate high potential future applications of these bioinspired waveguiding materials in precise photobiomedicine towards advanced highly selective bioimaging, photon diagnostics, and optogenetics. Abstract : Short peptide biomolecules self‐assembled into elongated nanostructure and microstructures demonstrate effective light confinement and optical waveguiding. Thermally mediated transition of α‐helical peptide secondary structure to β‐sheet deeply modifies optical properties and leads to the appearance of visible fluorescence making optical waveguiding effect bimodal. Passive waveguiding is observed in α‐helical structure whereas β‐sheet exhibits another mode of fluorescence waveguiding. These new biophotonic effects are attractive for photobiomedicine towards advanced bioimaging, optogenetics, and more.