Photodynamic therapy can be used to clear bacterial infections. However, light disinfection primarily relies on reactive oxygen species (ROS), which are nonselective, leading to undesired damage to normal cells. Therefore, developing a photosensitizer that can selectively kill bacteria and protect normal cells is highly desirable based on the structural difference between normal cells and bacteria. In this study, a bacterial redox potential-boosted photocatalytic concept is proposed. Here, we designed a selectively bacteria-killing photosensitizer, hydroxyapatite/MoS₂ coating in Ti6 implant (HA/MoS₂-Ti6), which could accept the electrons from bacteria due to the potential difference between HA/MoS₂ and the bacterial outer membrane. Then it further boosted the separation of electrons and holes of HA/MoS₂ produced by 660 nm light irradiation, which enhanced the photocatalytic activity of HA/MoS₂-Ti6. Density functional theory calculation further demonstrated the complete electron transfer circulation between HA/MoS₂-Ti6 and the bacterial outer membrane. The produced ROS and changed electrons transfer pathway altered bacterial membrane potential and intracellular ROS, leading to bacterial death (92.99 ± 0.84% against Staphylococcus aureus and 94.70 ± 3.60% against Escherichia coli). Meanwhile, HA/MoS₂-Ti6 has great biocompatibility with Raw 264.7, L929, and MC3T3-E1 with/without light irradiation. HA/MoS₂-Ti6 can also enhance MC3T3-E1 into osteoblasts due to the osteoinduction of HA. HA/MoS₂-Ti6 induced macrophages to differentiate into M2 under light irradiation. The strategy-based nano-bio interface offered a new platform to clear microbes and enhance cell differentiation simultaneously.

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