Preparation of citric acid crosslinked starch-chitosan hydrogels and their application in resveratrol delivery

Abstract To develop a green and functional hydrogel for potential application as a wound dressing, in this study, composite hydrogels were prepared using corn starch and chitosan as the matrix, with citric acid (CA) at a series of concentrations (5%–20%, wt/wt) serving as a green crosslinking agent. Resveratrol (Res) was loaded into these hydrogels, and the influences of CA concentration on the swelling and gel characteristics of the composite hydrogels were systematically investigated. The results demonstrated that the hydrogel crosslinked with 10% CA (designated as SCA10%) exhibited the optimal comprehensive performance, achieving an equilibrium swelling ratio of 228% and appropriate gel strength. Structural analysis confirmed the formation of crosslinking between CA and starch/chitosan, as well as the successful loading of Res into the hydrogel matrix. Notably, microscopic images revealed that the incorporation of Res resulted in a more well-developed and uniform porous structure in SCA10%-Res. Additionally, this composite hydrogel showed robust antibacterial activity. Collectively, the prepared starch-chitosan-CA-Res hydrogel holds significant potential for applications in wound repair and localised drug delivery. It also provides a valuable reference for the green fabrication of natural polymer-based functional materials.