Mimicry of peroxidase by co-immobilization of 1-allylimidazole and hemin on N-isopropylacrylamide-based hydrogel Original Research Article

Hemin and 1-allylimidazole (AI) were copolymerized covalently to N,N′-methylene-bis-acrylamide (MBA) cross-linked N-isopropylacrylamide (NIPAAm) hydrogel to form a hemin-based mimetic enzyme of peroxidase, i.e., poly(NIPAAm/MBA/hemin/imidazole). Its catalytic activity was studied in comparison with hemin and a similar hydrogel, poly(NIPAAm/MBA/hemin), that was prepared in the absence of AI. The evaluation was based on their activities in catalyzing oxidation of fluorogenic substrate p-hydroxyphenylacetic (p-HPA) with H2O2 as the oxidant. The results showed that the activity of poly(NIPAAm/MBA/hemin/imidazole) is 21% higher than that of poly(NIPAAm/MBA/hemin) and 102% higher than hemin. This mimetic enzyme can be used for the determination of hydrogen peroxide with a detection limit (S/N = 3) of 26 nmol l−1.