Enzyme immobilization on thermosensitive hydrogel microspheres

Toshifumi Shiroya, Nobuko Tamura, Mamoru Yasui, Keiji Fujimoto, Haruma Kawaguchi

研究成果: Article査読

77 被引用数 (Scopus)


Precipitation polymerization of N-isopropylacrylamide, acrylamide, and methylenebisacrylamide in water at 70°C resulted in thermosensitive hydrogel microspheres. Carboxyl groups on the microspheres were introduced by hydrolysis, and amino groups by the Hofmann reaction of amide units on the microspheres. Trypsin was immobilized on the carboxylated microspheres using carbodiimide. Phase transitions were detected using a hydrophobic fluorescence probe. The temperatures at which a phase transition occurred were increased by immobilizing enzymes. The enzymatic activity of the immobilized enzymes decreased above the transition temperature. This was attributed to (i) a decrease in the diffusion of substrate; and (ii) entrapment of enzyme in the surface layer of the microspheres. In an attempt to overcome the entrapment, enzymes were immobilized via a hydrophilic spacer (α-(carboxymethyl)-ω-(carboxymethoxy)-poly(oxy-1,2-ethanediyl), PEO acid) to the microspheres. These enzyme-carrying hydrogel microspheres were found to show an enzymatic activity independent of temperature, even though these conjugates show a phase transition at the lower critical solution temperature.

ジャーナルColloids and Surfaces B: Biointerfaces
出版ステータスPublished - 1995 6月 23

ASJC Scopus subject areas

  • バイオテクノロジー
  • 表面および界面
  • 物理化学および理論化学
  • コロイド化学および表面化学


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