Cellulose-based dual-network hydrogels combining reversible Schiff base interactions and photopolymerized covalent networks.

Polysaccharide-based hydrogels have attracted considerable interest for biomedical applications due to their inherent biocompatibility, structural flexibility, and renewable origin. Among them, cellulose and its derivatives represent particularly promising building blocks; however, the limited mechanical stability and rapid degradation of conventional polysaccharide hydrogels under physiological conditions remain major challenges for their practical implementation. In this work, we report the development of cellulose-based dual-network hydrogels combining reversible Schiff base interactions and photopolymerized covalent networks through the rational integration of selectively oxidized and methacrylated cellulose (CoxM) or hydroxypropyl cellulose (HoxM) with methacrylated gelatin (GM). The first network was formed by dynamic Schiff base interactions, while the second, permanent network was formed by riboflavin-mediated UV (365 nm) photopolymerization of methacrylate groups. In addition to its structural contribution, GM acted as a co-initiator by promoting radical generation through its primary amine groups, eliminating the need for conventional cytotoxic photoinitiators. Rheological and mechanical investigations demonstrated that hydrogel properties could be tailored the oxidation chemistry and methacrylation degree of the cellulose derivatives. The resulting dual-network hydrogels exhibited enhanced viscoelasticity and structural integrity, making them promising candidates for tissue engineering, wound healing, and controlled drug delivery, pending further biological validation.