title: Stimuli-Triggered Sol-Gel Transitions of Polypeptides Derived from α-Amino Acid N-Carboxyanhydride (NCA) Polymerizations.
abstract: The past decade has witnessed significantly increased interest in the development of smart polypeptide-based organo- and hydrogel systems with stimuli responsiveness, especially those that exhibit sol-gel phase-transition properties, with an anticipation of their utility in the construction of adaptive materials, sensor designs, and controlled release systems, among other applications. Such developments have been facilitated by dramatic progress in controlled polymerizations of α-amino acid N-carboxyanhydrides (NCAs), together with advanced orthogonal functionalization techniques, which have enabled economical and practical syntheses of well-defined polypeptides and peptide hybrid polymeric materials. One-dimensional stacking of polypeptides or peptide aggregations in the forms of certain ordered conformations, such as α helices and β sheets, in combination with further physical or chemical cross-linking, result in the construction of three-dimensional matrices of polypeptide gel systems. The macroscopic sol-gel transitions, resulting from the construction or deconstruction of gel networks and the conformational changes between secondary structures, can be triggered by external stimuli, including environmental factors, electromagnetic fields, and (bio)chemical species. Herein, the most recent advances in polypeptide gel systems are described, covering synthetic strategies, gelation mechanisms, and stimuli-triggered sol-gel transitions, with the aim of demonstrating the relationships between chemical compositions, supramolecular structures, and responsive properties of polypeptide-based organo- and hydrogels.
authors.affiliation: Departments of Chemistry, Chemical Engineering, and Materials Science and Engineering, Laboratory for Synthetic-Biologic Interactions, Texas A&M University, 3255 TAMU, College Station, TX, 77842, USA.
authors.forename: Xun
authors.initials: X
authors.lastname: He
authors.affiliation: Departments of Chemistry, Chemical Engineering, and Materials Science and Engineering, Laboratory for Synthetic-Biologic Interactions, Texas A&M University, 3255 TAMU, College Station, TX, 77842, USA.
authors.forename: Jingwei
authors.initials: J
authors.lastname: Fan
authors.affiliation: Departments of Chemistry, Chemical Engineering, and Materials Science and Engineering, Laboratory for Synthetic-Biologic Interactions, Texas A&M University, 3255 TAMU, College Station, TX, 77842, USA. wooley@chem.tamu.edu.
authors.forename: Karen L
authors.identifier: http://orcid.org/0000-0003-4086-384X
authors.initials: KL
authors.lastname: Wooley
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis / Q000737:chemistry*; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000138:chemical synthesis / Q000737:chemistry*; D005782:Gels / Q000138:chemical synthesis / Q000737:chemistry; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D044367:Phase Transition; D058105:Polymerization
chemical_list: D000596:Amino Acids; D001672:Biocompatible Materials; D003692:Delayed-Action Preparations; D005782:Gels; D010455:Peptides
keywords: gels; peptides; ring-opening polymerization; sol-gel processes; supramolecular chemistry