A Thermostable Protein Matrix for Spectroscopic Analysis of Organic Semiconductors

George A. Sutherland, Daniel Polak, David J.K. Swainsbury, Shuangqing Wang, Frank C. Spano, Dirk B. Auman, David G. Bossanyi, James P. Pidgeon, Andrew Hitchcock, Andrew J. Musser, John E. Anthony, P. Leslie Dutton, Jenny Clark, C. Neil Hunter

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Advances in protein design and engineering have yielded peptide assemblies with enhanced and non-native functionalities. Here, various molecular organic semiconductors (OSCs), with known excitonic up- and down-conversion properties, are attached to a de novo-designed protein, conferring entirely novel functions on the peptide scaffolds. The protein-OSC complexes form similarly sized, stable, water-soluble nanoparticles that are robust to cryogenic freezing and processing into the solid-state. The peptide matrix enables the formation of protein-OSC-trehalose glasses that fix the proteins in their folded states under oxygen-limited conditions. The encapsulation dramatically enhances the stability of protein-OSC complexes to photodamage, increasing the lifetime of the chromophores from several hours to more than 10 weeks under constant illumination. Comparison of the photophysical properties of astaxanthin aggregates in mixed-solvent systems and proteins shows that the peptide environment does not alter the underlying electronic processes of the incorporated materials, exemplified here by singlet exciton fission followed by separation into weakly bound, localized triplets. This adaptable protein-based approach lays the foundation for spectroscopic assessment of a broad range of molecular OSCs in aqueous solutions and the solid-state, circumventing the laborious procedure of identifying the experimental conditions necessary for aggregate generation or film formation. The non-native protein functions also raise the prospect of future biocompatible devices where peptide assemblies could complex with native and non-native systems to generate novel functional materials.

Original languageEnglish
Pages (from-to)13898-13907
Number of pages10
JournalJournal of the American Chemical Society
Volume142
Issue number32
DOIs
StatePublished - Aug 12 2020

Bibliographical note

Funding Information:
G.A.S., S.W., J.C., and C.N.H. acknowledge the Engineering and Physical Sciences Research Council (EPSRC) grant EP/S002103/1. D.P. was funded by Faculty of Science Studentships from The University of Sheffield. D.J.K.S., A.H., and C.N.H. were supported by research grant BB/M000265/1 from the Biotechnology and Biological Sciences Research Council (UK). A.H. also acknowledges support from a Royal Society University Research Fellowship, award number URF\R1\191548. C.N.H. also acknowledges European Research Council Synergy Award 854126. D.B.A. was supported by National Institutes of Health Graduate Fellowship T32 GM008275, the Structural Biology & Molecular Biophysics Training Program. A.J.M. would like to acknowledge EPSRC grant EP/M025330/1. F.C.S was supported by the National Science Foundation (DMR-1810838). J.A. was supported by NSF CHE 1609974. Spectroscopic work was supported by the Lord Porter Laser Facility (EP/R042802/1, EP/L022613/1).

Publisher Copyright:
Copyright © 2020 American Chemical Society.

ASJC Scopus subject areas

  • Catalysis
  • Chemistry (all)
  • Biochemistry
  • Colloid and Surface Chemistry

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