Hierarchical assemblies of polypeptoids for rational design of advanced functional nanomaterials

Abstract

Polypeptoids (poly‐N‐substituent glycines) are a class of highly tailorable peptidomimetic polymers. Polypeptoids have identical backbones as polypeptides (poly‐C‐substituent glycines), but sidechains of polypeptoids are appended to backbone nitrogen rather than α‐carbon of polypeptides. As a result, peptoid backbone lacks of chirality and hydrogen bond donors. This unique structure gives polypeptoids a combined merit of both high stability as synthetic polymers and biocompatibility as biopolymers. In addition, peptoid sequences can be engineered precisely to assemble specific crystalline patterns such as spheres, fibers, ribbons, tubes, and sheets, which shows promising potentials of polypeptoids for different applications such as antimicrobials, catalysts, drug delivery, and templating inorganic materials. In this review, we summarize recent investigations into hierarchical self‐assembly pathways and molecular structures of peptoid crystals that are of interest as templates for fabricating functional materials for potential biomedical, biochemical, and bioengineering applications. This review provides a summary of recent experimental and computational studies of polypeptoid assembly in solution and solid‐liquid interfaces, current achievements in the field, and discusses future challenges and opportunities for the rational design of self‐assembled polypeptoid nanomaterials.

Imaging Orientation of a Single Molecular Hierarchical Self-Assembled Sheet: The Combined Power of a Vibrational Sum Frequency Generation Microscopy and Neural Network

“…The hyperspectral microscope was based on VSFG spectroscopy, a second-order nonlinear optical phenomenon. As an even-order nonlinear optical process, only noncentrosymmetric systems produce VSFG responses, such as the air/liquid, air/solid, and solid/liquid interfaces. ,− Furthermore, VSFG is also sensitive to materials without inversion centers, − many of which are MSAs, including collagen, , amyloid fibers, artificial materials used in drug delivery, − metal–organic frameworks, − and piezoelectric crystals …”

Imaging Orientation of a Single Molecular Hierarchical Self-Assembled Sheet: The Combined Power of a Vibrational Sum Frequency Generation Microscopy and Neural Network

“…[43][44][45] Another class of systems that can be studied by VSFG that have not been paid much attention are materials without inversion centers. [46][47][48][49][50][51][52][53][54][55] Many MSAs are non-centrosymmetric systems, and widely exist in nature, such as collagen 49,50 and amyloid fibers 56 ; as well as in artificial materials 57 used in drug delivery 58,59 , metal-organicframeworks 60,61,62 and piezoelectric crystals. 63 Thus, VSFG, which probes the molecular vibrations of the subunits in the non-centrosymmetric MSAs, could similarly reveal MSA structures with molecular level detail.…”

Minimal Peptoid Dynamics Inform Self-Assembly Propensity

“… , Peptoids have favorable properties, which make them appealing for diverse applications. Their resistance to proteolysis, enhanced cell permeability with respect to peptides, and properties that promote biocompatibility are highly favorable to therapeutic and biomedical applications. , The convenience of the submonomer solid phase synthesis of peptoids in incorporating residues with functional side chains has promoted their use not only in combinatorial drug discovery but also for investigating the molecular variations required in multifarious polymer and materials applications, e.g., studying ion conduction of fuel cell membranes, as antifreezing agents and antifouling coatings, , and in developing self-assembled nanostructures. , More than 250 different side chains have been demonstrated, and this number is regularly increasing . Many peptoid nanoassemblies have been reported to date including nanosheets, − nanotubes, superhelices, micelles, , and polymersomes .…”