Peptoid self-assembly: from minimal sequences to functional nano-assemblies and biomedical applications

This chapter provides a tutorial review on peptoid nano-assemblies and their biomedically relevant properties and applications. Peptoids are biomimetic molecules that differ from natural peptides only by a one-atom shift in the attachment position of the functional sidechain along the backbone. This minor change in chemical structure however enables major changes in molecular properties and synthetic protocol that can be very attractive for bioactive supramolecular nanotechnology. In the recent decade, peptoids have gained recognition in self-assembled and functional materials due to the sophistication of nano-assemblies demonstrated, the intrinsic bioactivity of specific sequences discovered, and the importance now placed on bioinspired materials. Indeed, there has been a diversity of inspirations for peptoid supramolecular chemistry, from peptide assembly and block copolymer polymersomes to crystallization and protein folding. Peptoid research is also greatly facilitated by the versatility of peptoid synthesis to enable systematic investigations of sidechain and sequence control for directing assembly of a wide range of nanostructures. These include nanofibers, nanotubes, nanosheets, micellar worms and nested vesicles, and this chapter emphasizes the links between sequence and assembled morphologies. Applications from biosensing to stimuli-responsive drug delivery are reviewed to illustrate the potential of peptoids in tailoring nano-assemblies for bioscience and biomedical applications. While the research from many groups which have been examined, some of our recent results in “minimal” assembling sequences as well as applications towards stem cell culture and antimicrobial lipopeptoids are also highlighted.