Peptoid Self-Assembly: from Minimal Peptoids to Cell Membrane Interactions
King Hang Aaron Lau, PhD
Associate Professor (Senior Lecturer) in Materials and Bionanotechnology
Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK
Abstract- N-substituted glycine “peptoids” are close structural isomers of peptides and can be synthesized with both natural and non-natural sidechains. Their self-assembly is of great interest not only because they represent a “control set” to probe the fundamental requirements of peptide assembly but also because, firstly, they expand the range of assembled structures possible, and secondly, they can exhibit simplified sequence design rules due to the elimination of intra-backbone hydrogen bonding. This presentation will introduce our work in recent years to investigate the behavior and biofunctionality of peptoid assemblies based on a range of sequence lengths and chain-end modifications. In terms of “minimal” peptoids, we recently discovered that certain single C-amidated monomers may form novel 2D crystalline layers at the water-air or water-oil interface that we term interfacial crystals. We were also the first to report the ability of water-soluble peptoid trimers to assemble into pH stable, sequence-dependent morphologies, including uniform nanofibers. The unique π-interactions originally observed in fluorescence spectroscopy are now supported by atomistic computation studies. For longer sequences, by introducing a backbone bending linker in lipo-peptoid amphiphiles and by balancing the peptoid and hydrophobic tail lengths, we have been able to modify the cytotoxicity of antibacterial sequences. Finally, with free-floating peptoid nanosheets assembled from long amphiphilic alternating sequences, we recently are also observing the potential to direct stem cell osteogenesis based simply on physical contact interactions. Based on these synthetic peptoid assemblies, we hope to demonstrate the expanded possibilities in bioinspired materials enabled by non-canonical sequence-specific polymers and considerations of biophysical effects more generally.
BIO– Aaron is associate professor in materials chemistry at the University of Strathclyde. He obtained his ScB and ScM at Brown, PhD at the Max Planck Institute for Polymer Research, and postdoctoral training at Northwestern. He then started his lab at Strathclyde as a founding member of its Bionanotechnology initiative. Aaron’s experimental research seek to deepen our biophysical chemistry understanding of macromolecules at surfaces and interfaces, including self-assembly and membrane interactions. This fundamental knowledge is applied to the development of novel bio-, nano-, and sustainable bioinspired materials. The main molecular platforms are “peptoids”, a highly convenient and designable peptide-mimetic synthetic platform, and tannic acid, a versatile and multifunctional molecular “integrator”. Current projects include peptoid self-assembly, antimicrobial peptoids, acoustically functional structures, and polyphenol water remediation sorbents.