Dialdehyde Alginate as a Crosslinker for Chitosan/Starch Films: Toward Biocompatible and Antioxidant Wound Dressing Materials.

Biopolymer-based films have attracted increasing attention as sustainable and bioactive materials for wound management. Among them, chitosan (CTS) and starch (ST) blend represent promising candidate due to their natural origin, biodegradability, and intrinsic biological activity; however, their mechanical weakness and limited stability necessitate additional modification. This study reports the development and characterization of CTS-ST thin films crosslinked with dialdehyde alginate (ADA), synthesized via controlled oxidation. Two ADA variants differing in aldehyde group content were prepared to investigate the effect of crosslinking on the structural, physicochemical, and biological performance of the materials. The films were fabricated by blending 2% w/v CTS and ST in varying mass ratios (75/25, 50/50, and 25/75), followed by the addition of ADA (5% w/w) and glycerol (5% w/w) as a plasticizer. The mixtures were then cast onto plates and dried under ambient conditions. Comprehensive characterization included Fourier-transform infrared spectroscopy, moisture content analysis, contact angle measurements, antioxidant activity assay, hemolysis testing, and cytotoxicity evaluation using human keratinocyte cells. The results demonstrated that both the ADA variant and CTS/ST ratio significantly influenced crosslinking efficiency, hydrophilicity, and antioxidant behavior. All samples exhibited non-hemolytic behavior and no significant cytotoxic effects, indicating their favorable biocompatibility. The combination of biostability, antioxidant ability, and absence of cytotoxic effects highlights the potential of ADA-crosslinking CTS/ST films for further development as wound dressing materials and other biomedical applications.