Affordable Access

deepdyve-link
Publisher Website

Dual Thermo- and pH-Responsive Behavior of Double Zwitterionic Graft Copolymers for Suppression of Protein Aggregation and Protein Release.

Authors
  • Zhao, Dandan1
  • Rajan, Robin1
  • Matsumura, Kazuaki1
  • 1 School of Materials Science , Japan Advanced Institute of Science and, Technology , 1-1 Asahidai , Nomi , Ishikawa 923-1292 , Japan. , (Japan)
Type
Published Article
Journal
ACS Applied Materials & Interfaces
Publisher
American Chemical Society
Publication Date
Oct 30, 2019
Volume
11
Issue
43
Pages
39459–39469
Identifiers
DOI: 10.1021/acsami.9b12723
PMID: 31592638
Source
Medline
Keywords
Language
English
License
Unknown

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 nonionic 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.

Report this publication

Statistics

Seen <100 times