Dual Cross-Linked Chitosan-Based Films with pH-Sensitive Coloration and Drug Release Kinetics for Smart Wound Dressings.

In this study, we developed dual-cross-linked hydrogel films based on carboxyethyl chitosan (CECS) and sodium alginate (SA), utilizing dialdehyde β-cyclodextrin (DA-βCD) and gluconic acid δ-lactone (GDL) as cross-linkers. Designed as smart wound dressings, the films exhibit pH sensitivity due to the incorporation of carboxyethylated phenol red-grafted chitosan (CS-PR-AA), which allows them to change color from orange to purple in response to pH variations. FT-IR and TGA analyses confirmed the formation of imine bonds and polyelectrolyte complexes, indicating successful cross-linking.

Advanced chitosan hybrid dye labels for dynamic monitoring of shrimp and milk freshness.

This study presents the development of intelligent screen-printed labels for real-time food freshness monitoring. Using chitosan grafted with rosolic acid (RA) and immobilized on montmorillonite (MMT) through cationic exchange, a hybrid dye was synthesized and applied in screen-printing inks. The hybrid structure was characterized by XRD, TGA, and UV-vis, confirming improved thermal stability and maintained halochromic properties.