T-shaped Peptide Amphiphiles Self Assemble into Nanofiber Networks

Abstract

Background: Conventional nanofiber forming peptide amphiphiles comprise a beta sheet forming, short peptide sequence with an alkyl chain attached at one terminus. We report the selfassembly of a peptide amphiphile possessing a mid-chain located alkyl substituent (a T-shaped peptide amphiphile) into nanofiber networks.

Method: Peptide synthesis was carried out using standard 9-fluorenylmethoxycarbonyl solid phase peptide synthesis protocols, followed by covalent attachment of the alkyl chains to yield target peptide amphiphiles. Self-assembly was then studied using electron microscopy and coarse-grained molecular dynamics simulations.

Results: T-shaped peptide amphiphiles self-assembled into nanofibers just like linear peptide amphiphiles, but then unlike linear peptide amphiphiles, T-shaped peptide amphiphiles formed inter-fiber associations and ultimately nanofiber networks.

Conclusion: Changing the position of the alkyl chain in a peptide amphiphile from the terminal end of the peptide to the middle part of the peptide, to form a T-shaped peptide amphiphile, does not disrupt the molecular interactions required for the self-assembly of the peptide amphiphiles into nanofibers.

Keywords: Beta sheet; drug delivery; molecular dynamics simulations; nanofibers; networks; peptide synthesis; peptide amphiphiles; self-assemblies.