Modification of chitosan nanofibers with CuS and fucoidan for antibacterial and bone tissue engineering applications

Chitosan (CS) electrospun nanofiber (ENF) membranes were modified with fucoidan (Fu) and CuS NPs through polyelectrolyte complexation and genipin (GP)-involved cross-linking reaction. The formation of Fu/CS complex and cross-linking of CS with GP increased the acid resistance and reduced the swelling rate of CS ENF, while the covalent conjugation of CuS NPs provided CS ENF with durable Fenton-like catalytic activity. The CuS@ENF composite (ENFC) effectively adsorbed H₂O₂ and near-infrared (NIR) light, enabling it to kill bacteria by photothermal and photocatalytic bactericidal effects. Fu and copper ions were able to release from the ENFC in a pH-dependent manner, and promoted the alkaline phosphatase activity of osteoblast cells and capillary tube formation of endothelial cells. This study provides a new approach to modify CS ENF with antibacterial and osteoblast differentiation activities, which may be available for bone infection prevention and tissue regeneration.