Development and Characterisation of a Functional Polyvinyl-alcohol-Based Hydrogel for Bio-carrier Applications

Crosslinked chitosan/polyvinyl alcohol (CS/PVA) hydrogels and lectin-functionalised bio interfaces have been extensively investigated; however, approaches that systematically couple structural optimisation with subsequent bio-recognition modification remain limited. In this study, a stepwise strategy was developed using commercially available PVA hydrogel beads (Kuraray PVA gel) as the framework. CS of varying molecular weight and concentration was used to crosslink the PVA beads, forming a defined shell–core architecture. This structural modulation enabled controlled tuning of porosity, mechanical stability, antifouling characteristics, and adsorption behaviour. The optimised formulation (1 wt% medium-molecular-weight CS) exhibited a maximum methylene blue (MB) adsorption capacity of 1000 mg/g, significantly higher than that of unmodified PVA beads. Following optimisation of the physicochemical properties, Concanavalin A (Con-A) was immobilised onto the CS/PVA surface to introduce a lectin-based functional layer with potential for bio-recognition, yielding (Con-A)- g -CS/PVA. This sequential functionalisation separates structural engineering from biological surface modification, resulting in a modular hydrogel system with adjustable interfacial properties. Structural and chemical modifications were confirmed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy-dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and fluorescence microscopy. Overall, this work establishes a rational framework for tailoring commercial hydrogel reconfiguration, providing a scalable, cost-effective strategy for fabricating a bio-carrier platform for bioprocessing applications. Functional CS/ PVA hydrogel bead with Con-A graft. • An innovative chitosan-crosslinked PVA hydrogel (CS/PVA) functionalised with Concanavalin A was developed to serve as a bio-carrier for microbial bioprocessing applications. • The CS/PVA hydrogel exhibited controlled porosity, robust mechanical integrity, and antifouling characteristics, confirmed through SEM, TGA, EDS, FTIR, and fluorescence microscopy. • CS/PVA hydrogel with 1 wt% medium-molecular-weight chitosan achieved a remarkable adsorption, far exceeding unmodified PVA beads. • Con-A functionalisation introduces synergistic bacterial capture capability, positioning the system as a promising platform for wastewater treatment and bioprocessing.