Development and Characterization of a Gelatin-Based Photoactive Hydrogel for Biomedical Application

Photoactive hydrogels facilitate light-triggered photochemical processes, positioning them as innovative solutions in biomedical applications, especially in antimicrobial photodynamic therapy. This study presents a novel methylene blue-based photoactive hydrogel designed as a topical gel solution to overcome the limitations of traditional pad-based systems by offering enhanced adaptability to irregular wound surfaces, uniform photosensitizer distribution, and deeper therapeutic light penetration. This study investigated the development of hydrogels by cross-linking gelatin with glutaraldehyde (GA) and incorporating methylene blue (MB) to investigate the effects of cross-linking density, network structure, and small molecule inclusion on hydrogel properties. The results showed that while glutaraldehyde concentration influenced swelling behavior and network structure, the inclusion of MB altered these properties, particularly reducing swelling and MB retention at higher GA concentrations. Rheological and thermal analyses confirmed that higher GA concentrations made the hydrogels more rigid, with MB influencing both mechanical and thermal properties. Additionally, the hydrogels exhibited enhanced antimicrobial properties through increased reactive oxygen species production, particularly in light-activated conditions, demonstrating the potential of MB-based photoactive hydrogels for improving antimicrobial efficacy, especially against S. aureus, E. coli, and C. albicans, offering as a possible alternative to traditional antimicrobial treatments.