Calcination-Induced Tight Nano-Heterointerface for Highly Effective Eradication of Rib Fracture-Related Infection by Near-Infrared Irradiation

Rib fracture-related infection is a challenging complication of thoracic trauma due to the difficulty of treating it with antibiotics alone and the need for a second operation to remove the infected fixator and sterilize the surrounding infected tissue. In this study, inspired by the photocatalytic performance of and ion release from silver-based materials, including Ag₃PO₄ and Ag₂S, a hybrid Ag₃PO₄-Ag₂S heterojunction was prepared based on in situ anion exchange and a one-step calcination process to design a nonantibiotic coating aimed at preventing and treating rib fracture-related infection with short-term 808 nm near-infrared irradiation. Calcination at 250 °C enhanced the inductive effect of the phosphate radical and led to the formation of a tight nanoheterogeneous interface between Ag₃PO₄ and Ag₂S, thereby promoting interfacial electron transfer and reducing the recombination of photogenerated carriers. The result was improved photodynamic performance of the Ag₃PO₄-Ag₂S coating. Moreover, metal-Ag₃PO₄-Ag₂S had a significant photothermal effect and released only a small amount of Ag⁺. The synergy of Ag₃PO₄-Ag₂S endowed the coating with high antibacterial efficacy, eliminating 99.90 ± 0.05 and 99.95 ± 0.03% of Staphylococcus aureus and Escherichia coli, respectively, after 15 min of NIR irradiation in vitro, and 99.66 ± 0.13% of Staphylococcus aureus in vivo. This biocompatible Ag₃PO₄-Ag₂S coating exhibited superb efficacy in eliminating rib fracture-related infection and reducing the associated inflammation.