Electrospinning Fibers Modified with Near Infrared Light-Excited Copper Nanoparticles for Antibacterial and Bone Regeneration

Bone infection is an inflammatory bone disease caused by infectious microorganisms, which can lead to progressive bone destruction and loss. It is still an urgent and unmet clinical need to develop a rapid and effective sterilized method to reduce bone infection. In this study, near-infrared (NIR) light-responsive polydopamine (PDA) adherent Copper nanoparticles (Cu-NPs) are constructed using electrospun poly lactic acid (PLLA) fibers as a substrate (PLLA@PDA/Cu). Dopamine (DA) is self-polymerized to synthesize the PDA on the fiber surface, which can reduce Cu2+ to form Cu-NPs. Results show that the addition of PDA and Cu2+ significantly improves the hydrophilicity and bioactivity of the prepared PLLA@PDA/Cu composite fibers, demonstrating superior physiological stability. Due to the unique photothermal properties of Cu-NPs, PLLA@PDA/Cu is able to generate a large amount of reactive oxygen species under 808 nm NIR laser irradiation, with a photothermal conversion efficiency of 23.7%. The antimicrobial effect of Cu-NPs is synergistic with their photothermal effect, which potentiated the antibacterial rate of composite fibers . The results of cell experiments show that this composite fiber demonstrates satisfactory osteogenic and angiogenic properties. In conclusion, a photothermal antibacterial PLLA@PDA/Cu composite fiber with great potential in healing infectious bone defects is successfully engineered.