Biopolymers are macromolecular organic compounds derived from living organisms. They can be classified into polysaccharides, proteins, and nucleic acids. Chitosan and starch belong to the group of polysaccharides and are widely investigated for applications in tissue engineering, including wound healing. However, materials based on single biopolymers or their blends often exhibit insufficient physicochemical properties. Therefore, modification strategies, such as chemical cross-linking, are required. Dialdehydes are increasingly explored as natural, non-toxic cross-linking agents. Starch dialdehyde, chitosan dialdehyde, alginate dialdehyde, and other modified polysaccharides have been used for the modification of biopolymer materials.

The aim of this study was to obtain and characterize thin films based on chitosan and starch, modified with alginate dialdehyde. Alginate dialdehyde was synthesized by means of sodium periodate oxidation. The films were prepared using the solvent evaporation method. Structural characterization was performed by means of Fourier Transform Infrared Spectroscopy, while moisture content, hydrophilicity, and antioxidant activity of the obtained materials were also evaluated.

The results demonstrated that the addition of alginate dialdehyde significantly influenced the physicochemical properties of the films. It can be concluded that the properties of biopolymeric materials strongly depend on their weight ratio composition and the applied cross-linking agent. Novel biopolymeric composites based on chitosan and starch, chemically cross-linked with alginate dialdehyde, show promising potential for biomedical applications, particularly in wound healing.