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Please use this identifier to cite or link to this item: http://hdl.handle.net/10119/17046

Title: Dual Thermo-and pH-Responsive Behavior of Double Zwitterionic Graft Copolymers for Suppression of Protein Aggregation and Protein Release
Authors: Zhao, Dandan
Rajan, Robin
Matsumura, Kazuaki
Keywords: dual thermo-responsive
pH responsive
polyampholyte
protein aggregation
protein release
Issue Date: 2019-10-08
Publisher: American Chemical Society
Magazine name: ACS applied materials and interfaces
Volume: 11
Number: 43
Start page: 39459
End page: 39469
DOI: 10.1021/acsami.9b12723
Abstract: Graft copolymers consisting of two different zwitterionic blocks were synthesized via reversible addition fragmentation chain transfer polymerization. These polymers showed dual properties of thermo- and pH-responsiveness in an aqueous solution. Ultraviolet-visible spectroscopy and dynamic light scattering were employed to study the phase behavior under varying temperatures and pH values. Unlike the phase transition temperatures of other graft copolymers containing non-ionic blocks, the phase transition temperature of these polymers was easily tuned by changing the polymer concentration. Owing to the biocompatible and stimuli-responsive nature of the polymers, this system was shown to effectively release proteins (lysozyme) while simultaneously protecting them against denaturation. The positively charged lysozyme was shown to bind with the negatively charged polymer at the physiological pH (pH 7.4). However, it was subsequently released at pH 3, at which the polymer exhibits a positive charge. Protein aggregation studies using a residual enzymatic activity assay, circular dichroism, and a Thioflavin T assay revealed that the secondary structure of the lysozyme was retained even after harsh thermal treatment. The addition of these polymers helped the lysozyme retain its enzymatic activity and suppressed its fibrillation. Both polymers showed excellent protein protection properties, with the negatively charged polymer exhibiting slightly superior protein protection properties to those of the neutral polymer. To the best of the authors’ knowledge, this is the first study to develop a graft copolymer system consisting of two different zwitterionic blocks that shows dual thermo- and pH-responsive properties. The presence of the polyampholyte structure enables these polymers to act as protein release agents, while simultaneously protecting the proteins from severe stress.
Rights: Dandan Zhao, Robin Rajan, and Kazuaki Matsumura, ACS applied materials and interfaces, 11(43), 2019, 39459-39469. This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS applied materials and interfaces, copyright (c) American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsami.9b12723.
URI: http://hdl.handle.net/10119/17046
Material Type: author
Appears in Collections:c10-1. 雑誌掲載論文 (Journal Articles)

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