Preparation of chitosan/hydrolyzed collagen/hyaluronic acid based hydrogel composite with caffeic acid addition.

In this work, biopolymer hydrogels were synthesized by mixing hyaluronic acid, hydrolyzed collagen, and chitosan through a solvent evaporation method and incorporating them with caffeic acid as an antioxidant agent. The obtained caffeic acid-loaded chitosan/hydrolyzed collagen/hyaluronic acid hydrogels were characterized by X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis. No significant change on structural and thermal properties was observed. Furthermore, scanning electron microscope reported that the surface morphology of the hydrogels was smooth, and no significant change in porosity was observed after the addition of hyaluronic acid. With high amount of hyaluronic acid, the swelling behaviour was superiority. The hydrogels showed an initial burst release of caffeic acid (~70%) within 60 min, followed by a gradual release of up to 80% by 480 min. The release was slightly higher with the presence of hyaluronic acid. In addition, DPPH, ABTS+, and FRAP assays revealed that the caffeic acid-loaded hyaluronic acid/hydrolyzed collagen/chitosan hydrogels exhibited antioxidant activity. Thus, these composites could potentially be used as dressing materials with antioxidant activity.