In situ entrapment of urease in cryogels of poly(N-isopropylacrylamide): An effective strategy for noncovalent immobilization of enzymes

• Published in: Journal of applied polymer science 2011-11, Vol.122 (3), p.1742-1748
• Main Authors: Petrov, Petar, Pavlova, Severina, Tsvetanov, Christo B., Topalova, Yana, Dimkov, Raycho
• Format: Article
• Language: English
• Subjects: Applied sciences; Biological and medical sciences; Biotechnology; Diffusion; Enzymes; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Immobilization; Immobilization of enzymes and other molecules; Immobilization techniques; irradiation; macroporous hydrogels; Materials science; Methods. Procedures. Technologies; Morphology; Networks; Organic polymers; Physicochemistry of polymers; PNIPAAm; Polymers; Properties and characterization; Reuse; Solution and gel properties; Ureas; urease; Walls
• ISSN: 0021-8995; 1097-4628; 1097-4628
• DOI: 10.1002/app.34063

Supermacroporous poly(N‐isopropylacrylamide) (PNIPAAm) cryogels containing urease were prepared via UV irradiation technique and hydrogen peroxide as initiator. Specifically, due to the cryostructuration phenomenon urease molecules were embedded into the dense cryogel walls. Thus, although the enzyme is physically entrapped, the system exhibited remarkable resistance against leaking due to the dense polymer network formed in the cryogel walls. The immobilized urease can catalyze the hydrolysis of urea in a broad temperature range in both batch and flow regime. The interconnected macropores assist for unhindered diffusion of the substrate and reaction products through the gel, thus, paving the way for consecutive reuse at a constant activity, in contrast to the conventional PNIPAAm hydrogel. Due to the spongy‐like morphology PNIPAAm cryogels containing urease can be exploited as highly permeable membrane for direct removal of traces of urea from continuously flowing feed solutions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011