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Zwitterionic poly(carboxybetaine) microgels for enzyme (chymotrypsin) covalent immobilization with extended stability and activity
Author(s) -
Erfani Amir,
Zarrintaj Payam,
Seaberg Joshua,
Ramsey Joshua D.,
Aichele Clint P.
Publication year - 2021
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.50545
Subject(s) - immobilized enzyme , chemistry , covalent bond , polymer chemistry , radical polymerization , enzyme , polymerization , methacrylate , chemical engineering , organic chemistry , polymer , engineering
There is emerging evidence that biocompatible zwitterionic materials can prevent nonspecific interactions within protein systems and increase protein stability. Here, a zwitterionic microgel was synthesized from poly (carboxybetaine methyl methacrylate) (pCB) using an inverse emulsion, free radical polymerization reaction technique. The microgel was loaded with a model enzyme, α‐chymotrypsin (ChT), using a post‐fabrication loading technique. A reaction scheme was developed and studied for covalent immobilization of ChT within the microgel. Confocal laser microscopy studies showed that immobilized ChT (i‐ChT) was distributed within the hydrogel. The enzyme‐immobilized microgels showed excellent reusability (72% of its initial activity after 10 uses) and could undergo several freezing/drying/rehydration cycles while retaining enzymatic activity. The i‐ChT activity, half‐life, and conformational stability were studied at varying pH and temperatures with results compared to free ChT in buffer. ChT immobilized within pCB hydrogel showed increased enzymatic stability as observed by a 13°C increase in the temperature at which i‐ChT loses activity compared to free ChT. Furthermore, enzyme half‐life increased up to seven‐fold for the pCB immobilized ChT, and the increased stability resulted in higher activity at elevated pH. The i‐ChT was most active at pH of 8.5 and was partially active up to the pH of 10.2.