Dual thermoresponsive mPEG-b-poly(O-benzyl-l-threonine acid) hydrogel based on β-sheet nano-structural disassembly and PEG dehydration. (4th June 2021)

• Record Type: Journal Article
• Authors: Zhu, Hongyu; Liu, Yu; Gu, Dongxu; Rao, Zikun; Li, Yang; Hao, Jianyuan
• Is Part Of: Polymer. Volume 226(2021)
• Publication Date: 2021-06-04
• Subjects: Thermoresponsive -- Polypeptide hydrogel -- β-sheet -- Self-assembled; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2021.123841
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: It is a challenging work to design novel responsive materials by controlling the secondary structure of polypeptide, especially β-sheet. We designed and synthesized a novel dual responsive diblock copolymer of methyl poly (ethylene glycol)- b -poly (O-benzyl-l -threonine) (mPEG- b -PBnLT). The copolymer solutions exhibited unusual and reversible gel-to-sol-to-gel transition behavior with temperature, and the transition temperature window could be easily adjusted by changing copolymer concentration or PBnLT block length. It was confirmed that low temperature gel-to-sol transition was due to the disassembly of the preliminary β-sheet layered nano-assemblies that induced the transformation of self-organized morphology from nanosized fibrils to spherical aggregates, while the high temperature sol-to-gel transition was ascribed to the dehydration of PEG segments. The disassembly of β-sheet structures was caused by the change in the polarity of the pendant benzyl ether bond of PBnLT block in water with temperature. This stimuli-responsiveness of secondary self-assembled nanostructures and the corresponding change in macroscopic phase transition inspires a brand-new strategy for structural design and functional control of polypeptide materials. Graphical abstract: Image 1 Highlights: Well-defined gel-sol-gel transition of methyl poly(ethylene glycol)-poly(O-benzyl-l -threonine acid) copolymer. Dissembling of β-sheet at low temperature and PEG dehydration at high temperature contributed to the dual gel-to-sol transition. Polarity changing of pendant benzyl ether group of PBnLT caused the disassembly of β-sheet.