Rapid Biofilm Elimination on Bone Implants Using Near-Infrared-Activated Inorganic Semiconductor Heterostructures

Bacterial infections often cause orthopedic surgery failures. It is hard for the immune system and antibiotics to clear bacteria adhered to implants after they form a mature biofilm, and a secondary surgery is required to remove the infected implants. To avoid this, a hybrid coating of Bi₂ S₃ @Ag₃ PO₄ /Ti is prepared to eliminate biofilm using near-infrared (NIR) light. Bi₂ S₃ nanorod (NR) arrays are prepared on titanium (Ti) implants through hydrothermal methods, and Ag₃ PO₄ nanoparticles (NPs) are loaded on Bi₂ S₃ NR arrays using a stepwise electrostatic adsorption strategy. The introduction of Ag₃ PO₄ NPs enhances the photocatalysis performances of Bi₂ S₃ , and the hybrid coating also exhibits good photothermal effects. After 808 nm light irradiation for 15 min, it shows superior bactericidal efficiency of 99.45% against Staphylococcus aureus, 99.74% against Escherichia coli in vitro, and 94.54% against S. aureus biofilm in vivo. Bi₂ S₃ @Ag₃ PO₄ /Ti also shows good cell viability compared to pure Ti. This NIR-activated-inorganic hybrid semiconductor heterojunction coating is biocompatible and could be employed to eliminate biofilm effectively, which makes it a very promising strategy for the surface modification of bone implant materials.