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Proton‐Conductive Melanin‐Like Fibers through Enzymatic Oxidation of a Self‐Assembling Peptide
Author(s) -
Reddy Samala Murali Mohan,
Raßlenberg Eileen,
SloanDennison Sian,
Hesketh Travis,
Silberbush Ohad,
Tuttle Tell,
Smith Ewen,
Graham Duncan,
Faulds Karen,
Ulijn Rein V.,
Ashkenasy Nurit,
Lampel Ayala
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202003511
Subject(s) - melanin , materials science , tripeptide , supramolecular chemistry , peptide , raman spectroscopy , fiber , morphology (biology) , tyrosine , nanotechnology , chemical engineering , biophysics , organic chemistry , chemistry , biochemistry , molecule , composite material , biology , physics , optics , genetics , engineering
Melanin pigments have various properties that are of technological interest including photo‐ and radiation protection, rich coloration, and electronic functions. Nevertheless, laboratory‐based synthesis of melanin and melanin‐like materials with morphologies and chemical structures that are specifically optimized for these applications, is currently not possible. Here, melanin‐like materials that are produced by enzymatic oxidation of a supramolecular tripeptide structures that are rich in tyrosine and have a 1D morphology are demonstrated, that are retained during the oxidation process while conducting tracks form through oxidative tyrosine crosslinking. Specifically, a minimalistic self‐assembling peptide, Lys–Tyr–Tyr (KYY) with strong propensity to form supramolecular fibers, is utilized. Analysis by Raman spectroscopy shows that the tyrosines are pre‐organized inside these fibers and, upon enzymatic oxidation, result in connected catechols. These form 1D conducting tracks along the length of the fiber, which gives rise to a level of internal disorder, but retention of the fiber morphology. This results in highly conductive structures demonstrated to be dominated by proton conduction. This work demonstrates the ability to control oxidation but retain a well‐defined fibrous morphology that does not have a known equivalent in biology, and demonstrate exceptional conductivity that is enhanced by enzymatic oxidation.