Poly(acrylamide/vinylsulfonic acid) hydrogel for invertase immobilization

Abstract

Poly (acrylamide/vinylsulfonic acid) PA/VSA and poly (acrylamide) PA hydrogels were prepared by free radical polymerization in the presence of a crosslinker, to be used as a support for the invertase enzyme. Spectrophotometric, thermal analysis methods, swelling, and diffusion experiments were used for the characterization of hydrogels. SEM images show that the hydrogels have a smooth, homogeneous, highly porous and spongy morphology. The swelling of PA/VSA was higher than that of PA in water. The diffusion of water within the hydrogel was found to be non-Fickian. Invertase was immobilized onto PA and PA/VSA (immobilized invertases named PA-I and PA/VSA-I, respectively). The optimum pH values were found to be; 5.0, 3.0, and 3.0 for free invertase, PA-I, and PA/VSA-I, respectively. The optimum temperature values were 40 C, 50 C, and 60 C for free invertase, PA-I and PA/VSA-I respectively. Michaelis Constant, K m ; for free invertase and PA-I and PA/VSA-I were found to be 11.80, 21.40, and 18.42 mM, respectively. Maximum reaction rate; V max value for free invertase and PA-I and PA/VSA-I were found to be 7.46 μmol min −1 , 5.91 μmol min −1 , and 6.35 μmol min −1 , respectively. PA/VSA-I showed excellent thermal, operational, storage, and pH stability.

Hydrogels and Their Role in Biosensing Applications

“…It was found to preserve the native protein conformation and thereby improve enzyme activity. [64,65] For example, super-porous agarose gel was used in a flow-through electrochemical sensor to immobilize the signal-producing enzymes in larger amounts. This increased the signal intensity by a factor of more than five while retaining good flow properties.…”

Polymers fromS-vinyl monomers: reactivities and properties

“…Azo initiators or peroxides such as AIBN, 4,4′-azobis-4-cyanovaleric acid or ammonium peroxydisulfate, respectively, can successfully initiate the radical polymerization of vinyl sulfonic acid, although most polymerizations result only in low molar masses compared to other monomer classes. 155–160 The Q - and e -values ( Q = 0.17 and e = 1.1) determined in copolymerization with styrene show only a low stabilization of the radicals similar to sulfones, which also explains the difficulties in homopolymerizing this class of substances. 155 Moreover, it can also be copolymerized with methacrylate, methyl methacrylate and acrylonitrile.…”

“…6). 159 This is important because isolated enzymes lose their activity over extended periods of time and quickly degrade if not stabilized, which limits their use for industrial applications. Immobilized enzymes, on the other hand, exhibit higher stability and the corresponding hydrogel is suitable to protect the enzyme from denaturation by the environment.…”

Functional Thermoresponsive Hydrogel Molecule to Material Design for Biomedical Applications

“…These will give excellent loading capacity and accessibility. Some attempts have been reported for enzymes to hydrogels to preserve intact protein structure, leading to enhanced enzyme activity [ 149 , 150 ]. In a flow-through electrochemical sensor, super-porous agarose gel is used to immobilize the signal-producing enzymes, which will increase the signal intensity with retention of good flow [ 151 ].…”