A novel PVA/gelatin hydrogel hybrid integrated with polydopamine-modified microcrystalline cellulose particles for...

Polymer hydrogels offer a promising platform for enzyme immobilization due to their three-dimensional networks and strong adsorption properties. However, conventional surface-modification strategies often limited active site availability and enzyme loading. To overcome the above problems, a novel strategy called bulk-doping was developed. Different from other methods, such as coating PDA on the surface of carriers, the bulk-doping approach uniformly incorporated polydopamine-functionalized microcrystalline cellulose (PDA-MCC) throughout the polyvinyl alcohol/gelatin (PVA/Gel) hydrogel during synthesis. This three-dimensional network provided a high density of evenly distributed binding sites, which addressed the diffusion and loading constraints of previous methods. Under optimal conditions, the immobilized naringinase achieved an enzyme activity of 666.91 U/g carrier. It also retained 85.26% of the initial enzyme activity after one month of storage at 4 °C, and maintained 59.31% enzyme activity after ten cycles of reuse. These results demonstrated that the PMPG hydrogel engineered via the bulk-doping approach served as a highly efficient and stable carrier for naringinase, providing a robust alternative to conventional hydrogel-based immobilization systems.