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Title: Concentration-Driven Assembly and Sol–Gel Transition of π-Conjugated Oligopeptides

Abstract

Advances in supramolecular assembly have enabled the design and synthesis of functional materials with well-defined structures across multiple length scales. Biopolymer-synthetic hybrid materials can assemble into supramolecular structures with a broad range of structural and functional diversity through precisely controlled noncovalent interactions between subunits. Despite recent progress, there is a need to understand the mechanisms underlying the assembly of biohybrid/synthetic molecular building blocks, which ultimately control the emergent properties of hierarchical assemblies. Here in this work, we study the concentration-driven self-assembly and gelation of π-conjugated synthetic oligopeptides containing different π-conjugated cores (quaterthiophene and perylene diimide) using a combination of particle tracking microrheology, confocal fluorescence microscopy, optical spectroscopy, and electron microscopy. Our results show that π-conjugated oligopeptides self-assemble into β-sheet-rich fiber-like structures at neutral pH, even in the absence of electrostatic screening of charged residues. A critical fiber formation concentration cfiber and a critical gel concentration cgel are determined for fiber-forming π-conjugated oligopeptides, and the linear viscoelastic moduli (storage modulus G' and loss modulus G") are determined across a wide range of peptide concentrations. These results suggest that the underlying chemical structure of the synthetic π-conjugated cores greatly influences the self-assembly process, such that oligopeptides appended to π-conjugated cores with greatermore » torsional flexibility tend to form more robust fibers upon increasing peptide concentration compared to oligopeptides with sterically constrained cores. Overall, our work focuses on the molecular assembly of π-conjugated oligopeptides driven by concentration, which is controlled by a combination of enthalpic and entropic interactions between oligopeptide subunits.« less

Authors:
; ; ; ORCiD logo;  [1]; ORCiD logo; ORCiD logo
  1. Center for Nanoscale Systems, Faculty of Arts and Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
Publication Date:
Research Org.:
Univ. of Illinois, Urbana-Champaign, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1375504
Alternate Identifier(s):
OSTI ID: 1421386
Grant/Contract Number:  
SC0011847
Resource Type:
Published Article
Journal Name:
ACS Central Science
Additional Journal Information:
Journal Name: ACS Central Science Journal Volume: 3 Journal Issue: 9; Journal ID: ISSN 2374-7943
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY

Citation Formats

Zhou, Yuecheng, Li, Bo, Li, Songsong, Ardoña, Herdeline Ann M., Wilson, William L., Tovar, John D., and Schroeder, Charles M. Concentration-Driven Assembly and Sol–Gel Transition of π-Conjugated Oligopeptides. United States: N. p., 2017. Web. doi:10.1021/acscentsci.7b00260.
Zhou, Yuecheng, Li, Bo, Li, Songsong, Ardoña, Herdeline Ann M., Wilson, William L., Tovar, John D., & Schroeder, Charles M. Concentration-Driven Assembly and Sol–Gel Transition of π-Conjugated Oligopeptides. United States. doi:10.1021/acscentsci.7b00260.
Zhou, Yuecheng, Li, Bo, Li, Songsong, Ardoña, Herdeline Ann M., Wilson, William L., Tovar, John D., and Schroeder, Charles M. Thu . "Concentration-Driven Assembly and Sol–Gel Transition of π-Conjugated Oligopeptides". United States. doi:10.1021/acscentsci.7b00260.
@article{osti_1375504,
title = {Concentration-Driven Assembly and Sol–Gel Transition of π-Conjugated Oligopeptides},
author = {Zhou, Yuecheng and Li, Bo and Li, Songsong and Ardoña, Herdeline Ann M. and Wilson, William L. and Tovar, John D. and Schroeder, Charles M.},
abstractNote = {Advances in supramolecular assembly have enabled the design and synthesis of functional materials with well-defined structures across multiple length scales. Biopolymer-synthetic hybrid materials can assemble into supramolecular structures with a broad range of structural and functional diversity through precisely controlled noncovalent interactions between subunits. Despite recent progress, there is a need to understand the mechanisms underlying the assembly of biohybrid/synthetic molecular building blocks, which ultimately control the emergent properties of hierarchical assemblies. Here in this work, we study the concentration-driven self-assembly and gelation of π-conjugated synthetic oligopeptides containing different π-conjugated cores (quaterthiophene and perylene diimide) using a combination of particle tracking microrheology, confocal fluorescence microscopy, optical spectroscopy, and electron microscopy. Our results show that π-conjugated oligopeptides self-assemble into β-sheet-rich fiber-like structures at neutral pH, even in the absence of electrostatic screening of charged residues. A critical fiber formation concentration cfiber and a critical gel concentration cgel are determined for fiber-forming π-conjugated oligopeptides, and the linear viscoelastic moduli (storage modulus G' and loss modulus G") are determined across a wide range of peptide concentrations. These results suggest that the underlying chemical structure of the synthetic π-conjugated cores greatly influences the self-assembly process, such that oligopeptides appended to π-conjugated cores with greater torsional flexibility tend to form more robust fibers upon increasing peptide concentration compared to oligopeptides with sterically constrained cores. Overall, our work focuses on the molecular assembly of π-conjugated oligopeptides driven by concentration, which is controlled by a combination of enthalpic and entropic interactions between oligopeptide subunits.},
doi = {10.1021/acscentsci.7b00260},
journal = {ACS Central Science},
number = 9,
volume = 3,
place = {United States},
year = {2017},
month = {8}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1021/acscentsci.7b00260

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Cited by: 5 works
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