Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany.
Institute of Interfacial Process Engineering and Plasma Technology, University of Stuttgart, Nobelstraße 12, 70569, Stuttgart, Germany.
Macromol Biosci. 2022 Sep;22(9):e2200139. doi: 10.1002/mabi.202200139. Epub 2022 Jul 13.
Hydrogel foams provide an aqueous environment that is very attractive for the immobilization of enzymes. To this end, functional polymers are needed that can be converted into hydrogel foams and that enable bioconjugation while maintaining high enzyme activity. The present study demonstrates the potential of biotinylated gelatin methacryloyl (GM10EB) for this purpose. GM10EB is synthesized in a two-step procedure with gelatin methacryloyl (GM10) being the starting point. Successful biotinylation is confirmed by 2,4,6-trinitrobenzene sulfonic acid and 4'-hydroxyazobenzene-2-carboxylic acid/avidin assays. Most importantly, a high methacryloyl group content (DM) is maintained in GM10EB, so that solutions of GM10EB show both a sufficiently low viscosity for microfluidic foaming and a pronounced curing behavior. Thus, foamed and nonfoamed GM10EB hydrogels can be prepared via radical crosslinking of the polymer chains. Within both sample types, biotin groups are available for bioconjugation, as is demonstrated by coupling streptavidin-conjugated horseradish peroxidase to the hydrogels. When assessing the substrate conversion rate r in foamed hydrogels by enzymatic conversion of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), a value for r 12 times higher than the value for nonfoamed hydrogels of the same mass is observed. In other words, r can be successfully tailored by the hydrogel morphology.
水凝胶泡沫提供了一个非常有吸引力的水环境，用于固定酶。为此，需要功能性聚合物，它们可以转化为水凝胶泡沫，并在保持高酶活性的同时实现生物偶联。本研究证明了生物素化明胶甲基丙烯酰（GM10EB）在这方面的潜力。GM10EB 通过两步法合成，以明胶甲基丙烯酰（GM10）为起点。通过 2,4,6-三硝基苯磺酸和 4'-羟基偶氮苯-2-羧酸/亲和素测定证实了成功的生物素化。最重要的是，GM10EB 中保持了高甲基丙烯酰基含量（DM），因此 GM10EB 溶液既具有足够低的用于微流控发泡的粘度，又具有明显的固化行为。因此，可以通过聚合物链的自由基交联来制备发泡和非发泡 GM10EB 水凝胶。在这两种样品类型中，都可以提供生物素基团进行生物偶联，这可以通过将辣根过氧化物酶偶联的链霉亲和素偶联到水凝胶上来证明。当通过 2,2'-偶氮双（3-乙基苯并噻唑啉-6-磺酸）的酶促转化来评估发泡水凝胶中的底物转化率 r 时，观察到 r 值比相同质量的非发泡水凝胶高 12 倍。换句话说，r 可以通过水凝胶形态成功地进行调整。
