A photoinitiator-free UV-curable hydrogel with tunable properties using dextrans modified by adamantane, benzophenone, and β-cyclodextrin

• Photoinitiator-free UV-curable hydrogels are formed from the modified dextrans by β-cyclodextrin, benzophenone, and adamantane. • The inclusion complex between β-cyclodextrin and benzophenone enables covalent crosslinking under UV light. • Mechanical properties are tunable by varying the anchor point ratio, molecular weight, solution concentration, and hydrogel composition. • Hydrogels exhibit robust mechanical properties and negligible cytotoxicity in vitro . The backbones of dextran with varying molecular weights were modified utilizing β-cyclodextrin (β-CD) as the host and adamantane (Ada) and benzophenone (Bzp) as guests. The inclusion complex that forms between β-CD and benzophenone facilitates the establishment of covalent bonds under ultraviolet (UV) irradiation without the necessity of photoinitiators, culminating in the creation of covalently cross-linked robust hydrogels. The chemical structures of the modified dextran were confirmed through the characteristic peaks observed in the nuclear magnetic resonance (NMR) and Fourier-transform infrared (FT-IR) spectra. Adjustments in the anchor point ratio, chain length of the dextran backbone, solution concentration, and hydrogel composition effectively fine-tuned the rheological properties. These properties were systematically evaluated through rheometry, revealing non-Newtonian characteristics. Swelling behavior was measured to provide additional evidence of UV-induced covalent cross-linking. In vitro assays demonstrated that the cytotoxicity of the hydrogel was negligible. This study aims to assess the physicochemical and biological properties of these novel hydrogel materials for potential biomedical applications.