Modeling Interactions within and between Peptide Amphiphile Supramolecular Filaments

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Computational Chemistry

Background:

• Peptides self-assemble into diverse one-dimensional (1D) nanostructures, including fibers and ribbons.
• The precise relationship between peptide molecular structure and the resulting nanostructure morphology remains poorly understood.

Purpose of the Study:

• To investigate the self-assembly of peptide amphiphiles (PAs) into 1D nanostructures using coarse-grained molecular dynamics (CG-MD) simulations.
• To elucidate the relationship between PA chemical structure and the formation of hierarchical nanostructures.

Main Methods:

• Coarse-grained molecular dynamics (CG-MD) simulations were employed to model PA self-assembly.
• Atomic force microscopy (AFM) and viscosity measurements were used to experimentally validate simulation predictions.

Main Results:

• Ribbons were identified as hierarchical superstructures formed by the lateral assembly of cylindrical fibers.
• Simulation results indicated that filament interactions vary based on PA chemical structure, with hydrophilic groups promoting stronger interactions and hydrophobic groups weaker interactions.
• Peptide amphiphiles with hydrophobic termini were observed to bend, potentially preventing collapse into bundled filament superstructures.

Conclusions:

• The study provides insights into the mechanisms governing the self-assembly of peptide amphiphiles into hierarchical nanostructures.
• Future research should focus on mechanistic questions regarding filament preformation versus equilibration in the formation of complex assemblies.