Modeling Interactions within and between Peptide Amphiphile Supramolecular Filaments

Ivan R. Sasselli, Zois Syrgiannis, Nicholas A. Sather, Liam C. Palmer, Samuel I. Stupp*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Many peptides are able to self-assemble into one-dimensional (1D) nanostructures, such as cylindrical fibers or ribbons of variable widths, but the relationship between the morphology of 1D objects and their molecular structure is not well understood. Here, we use coarse-grained molecular dynamics (CG-MD) simulations to study the nanostructures formed by self-assembly of different peptide amphiphiles (PAs). The results show that ribbons are hierarchical superstructures formed by laterally assembled cylindrical fibers. Simulations starting from bilayer structures demonstrate the formation of filaments, whereas other simulations starting from filaments indicate varying degrees of interaction among them depending on chemical structure. These interactions are verified by observations using atomic force microscopy of the various systems. The interfilament interactions are predicted to be strongest in supramolecular assemblies that display hydrophilic groups on their surfaces, while those with hydrophobic ones are predicted to interact more weakly as confirmed by viscosity measurements. The simulations also suggest that peptide amphiphiles with hydrophobic termini bend to reduce their interfacial energy with water, which may explain why these systems do not collapse into superstructures of bundled filaments. The simulations suggest that future experiments will need to address mechanistic questions about the self-assembly of these systems into hierarchical structures, namely, the preformation of interactive filaments vs equilibration of large assemblies into superstructures.

Original languageEnglish (US)
Pages (from-to)650-659
Number of pages10
JournalJournal of Physical Chemistry B
Volume126
Issue number3
DOIs
StatePublished - Jan 27 2022

Funding

This work was primarily supported by the US Department of Energy, Office of Science, Basic Energy Sciences, under award numbers DE-SC0020884 (for coarse-grained simulations). Additional support for the AFM characterization was provided by the Center for Bio-Inspired Energy Science (CBES), an Energy Frontier Research Center (EFRC) funded by the US Department of Energy, Office of Science, Basic Energy Sciences under award number DE-SC0000989. This research was supported in part by the computational resources and staff contributions provided by the Quest High Performance Computing Facility at Northwestern University, which is jointly supported by the Office of the Provost, the Office for Research, and Northwestern University Information Technology. Peptide synthesis and purification were performed in the Peptide Synthesis Core Facility of the Simpson Querrey Institute for BioNanotechnology at Northwestern University. I.R.S. wants to dedicate this work to Paula Gonzalez Garcia, without her support this would not have been possible.

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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