This study investigates the synthesis and characterization of chitosan-based hydrogels, incorporating bicyclo[2.2.2]oct‑7-ene-2,3,5,6-tetracarboxylic dianhydride (BOD) as a crosslinker and riboflavin (RB) as a photosensitizer, for photodynamic therapy (PDT) applications. RB, known as vitamin B2, is a water-soluble compound with remarkable antioxidant and anticancer properties, making it a promising candidate for in vitro PDT research. The hydrogels were synthesized via chemical crosslinking and characterized using FT-IR, 1HNMR , UV–Vis spectrophotometry, and FE-SEM. Analysis revealed a three-dimensional porous structure, significant singlet oxygen generation (F = 55.87, p < 0.001), and substantial antibacterial activity with an inhibition zone reaching up to 18 mm at 10 mg/mL RB under 110 J/cm² light exposure. Mechanical tests confirmed the robust stability of the hydrogels (F = 141.68, p < 0.001), while photodynamic studies on MCF-7 cells showed a dose-dependent decrease in viability (F = 157.92, p < 0.001). The hydrogels demonstrated excellent biocompatibility, emphasizing their potential as a promising platform for antibacterial and photodynamic therapy applications.
