A Functionalized Chitosan with Unsaturated Aldehyde Conjugated Moiety for UV-Shielding and Antioxidation

To address the critical issues of poor biocompatibility and phototoxicity in traditional UV-shielding materials, a functionalized chitosan derivative (CS-MCD) featuring unsaturated aldehyde conjugated moieties was successfully prepared by covalently grafting trans-4-methoxycinnamaldehyde (MCD) onto chitosan (CS) via a Schiff base reaction. The conjugated structure of MCD enables CS-MCD to exhibit strong UV absorption in the range of 280-350 nm, thereby delivering efficient UV-shielding performance. Meanwhile, CS not only improves the water dispersibility of the composite but also mitigates the potential toxicity of MCD while enhancing its biocompatibility. Furthermore, CS-MCD displays prominent antioxidant activity and broad-spectrum antibacterial activity against both Staphylococcus aureus and Escherichia coli . This simple, green preparation strategy endows CS-MCD with great application potential in skin protection, implant surface modification, wound dressings, and packaging materials. Graphical To address UV radiation-induced damage to biological tissues and products, as well as drawbacks (poor biocompatibility, phototoxicity) of conventional UV blockers, a kind of functional macromolecule (CS-MCD) was fabricated by grafting molecules containing conjugated unsaturated aldehyde onto chitosan via a Schiff base reaction. CS-MCD exhibits strong UV absorption at 280–350 nm, along with prominent reactive oxygen species (ROS) scavenging capacity, excellent water dispersibility, low toxicity, and broad-spectrum antibacterial activity with great potential for skin protection, implant surface modification, and tissue engineering.