Antioxidant properties and release of phenolic compounds from hydrogels as wound dressings

Hydrogels are gaining attention in drug delivery systems due to their large surface area and absorption capacity, which enhance interaction with surrounding media. This study focuses on the release of tannic acid (TA) from alginate hydrogels and reduced graphene oxiswe (rGO) in a phosphate-buffered saline (PBS) solution at 37°C and pH 7.4, simulating physiological conditions similar to those found in wounds. The release profiles reveal two distinct patterns: hydrogels with 9% reduced graphene oxide (rGO) release TA rapidly, reaching equilibrium within 80 minutes. This quick release may result from poorly adhered TA transitioning into the medium, which aligns with previous findings on alginate/chitosan/tannic acid hydrogels. Conversely, hydrogels containing 4.5% rGO exhibited a controlled, sustained release throughout the experiment, with the highest TA release noted at 21.3% and 26.4% for Alg/rGO_4.5/TA₉ and Alg/rGO₉/TA₉, respectively. Furthermore, the antioxidant capacity of the hydrogels was evaluated using the DPPH method, which assesses their electron donation capability. The results indicated that only the TA functionalized hydrogels exhibited antioxidant properties, with notable improvement over time, particularly in the Alg/rGO₉/TA₉ material, which reached 15% antioxidant capacity. Comparatively, prior studies showed higher antioxidant capacities due to differences in experimental conditions. Overall, the findings emphasize the potential of these hydrogels as effective agents in reducing reactive oxygen species levels, thereby promoting wound healing.