Enhanced Near‐Infrared Photocatalytic Eradication of MRSA Biofilms and Osseointegration Using Oxide Perovskite‐Based P–N Heterojunction

Methicillin‐resistant Staphylococcus aureus (MRSA) biofilm infections after orthopedic implant increase the risk of failure and potentially cause amputation of limbs or life‐threatening sepsis in severe cases. Additionally, satisfactory bone‐implant integration is another important indicator of an ideal implant. Here, an antibiotic‐free antibacterial nanofilm based on oxide perovskite‐type calcium titanate (CTO)/fibrous red phosphorus (RP) on titanium implant surface (Ti‐CTO/RP) in which the P–N heterojunction and internal electric field are established at the heterointerface, is designed. Near‐infrared light‐excited electron–hole pairs are effectively separated and transferred through the synergism of the internal electric field and band offset, which strongly boosts the photocatalytic eradication of MRSA biofilms by reactive oxygen species with an efficacy of 99.42% ± 0.22% in vivo. Additionally, the charge transfer endows the heterostructure with hyperthermia to assist biofilm eradication. Furthermore, CTO/RP nanofilm provides a superior biocompatible and osteoconductive platform that enables the proliferation and osteogenic differentiation of mesenchymal stem cells, thus contributing to the subsequent implant‐to‐bone osseointegration after eradicating MRSA biofilms. Driven by the synergism of internal electric field and band offset after alignment of the Fermi energy at the heterointerface, near‐infrared light excited electron‐hole pairs are effectively separated and transferred, which facilitates the generation of reactive oxygen species and heat to synergistically eradicate methicillin‐resistant Staphylococcus aureus biofilm. Additionally, upregulated osteogenic related genes promote the osseointegration.