Nonequilibrium self-assembly of π-conjugated oligopeptides in solution

Bo Li, Songsong Li, Yuecheng Zhou, Herdeline Ann M. Ardoña, Lawrence R. Valverde, William L. Wilson, John D. Tovar, Charles M. Schroeder

Research output: Contribution to journalArticle

Abstract

Supramolecular assembly is a powerful method that can be used to generate materials with well-defined structures across multiple length scales. Supramolecular assemblies consisting of biopolymer-synthetic polymer subunits are specifically known to exhibit exceptional structural and functional diversity as well as programmable control of noncovalent interactions through hydrogen bonding in biopolymer subunits. Despite recent progress, there is a need to control and quantitatively understand assembly under nonequilibrium conditions. In this work, we study the nonequilibrium self-assembly of π-conjugated synthetic oligopeptides using a combination of experiments and analytical modeling. By isolating an aqueous peptide solution droplet within an immiscible organic layer, the rate of peptide assembly in the aqueous solution can be controlled by tuning the transport rate of acid that is used to trigger assembly. Using this approach, peptides are guided to assemble under reaction-dominated and diffusion-dominated conditions, with results showing a transition from a diffusion-limited reaction front to spatially homogeneous assembly as the transport rate of acid decreases. Interestingly, our results show that the morphology of self-assembled peptide fibers is controlled by the assembly kinetics such that increasingly homogeneous structures of self-assembled synthetic oligopeptides were generally obtained using slower rates of assembly. We further developed an analytical reaction-diffusion model to describe oligopeptide assembly, and experimental results are compared to the reaction-diffusion model across a range of parameters. Overall, this work highlights the importance of molecular self-assembly under nonequilibrium conditions, specifically showing that oligopeptide assembly is governed by a delicate balance between reaction kinetics and transport processes.

Original languageEnglish (US)
Pages (from-to)3977-3984
Number of pages8
JournalACS Applied Materials and Interfaces
Volume9
Issue number4
DOIs
StatePublished - Feb 1 2017

Keywords

  • Biohybrid materials
  • Diffusion-controlled
  • Nonequilibrium assembly
  • Optoelectronic materials
  • Reaction-controlled
  • Supramolecular assembly
  • π-conjugated oligopeptides

ASJC Scopus subject areas

  • Materials Science(all)

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  • Cite this

    Li, B., Li, S., Zhou, Y., Ardoña, H. A. M., Valverde, L. R., Wilson, W. L., Tovar, J. D., & Schroeder, C. M. (2017). Nonequilibrium self-assembly of π-conjugated oligopeptides in solution. ACS Applied Materials and Interfaces, 9(4), 3977-3984. https://doi.org/10.1021/acsami.6b15068