Chemical bonding-driven charge transfer in Z-scheme bimetallic sulfides for rapid wound healing

The rational design of bio-interfaces that efficiently generate reactive oxygen species (ROS) is crucial for antimicrobial therapies. Here, we present a Z-scheme heterojunction of Bi₂S₃-Sv/WS₂, engineered at the interface through in-situ growth to form covalent Bi-S-W bonds. This specific bonding, coupled with introduced sulfur vacancies, creates an asymmetric electron distribution and a built-in electric field. The synergistic effect establishes a direct and rapid pathway for charge carrier transport, which is conclusively verified by femtosecond transient absorption spectroscopy (fs-TAS) to suppress charge recombination and extend carrier lifetimes. Consequently, the system exhibits a significant enhancement in the generation of reactive oxygen species (ROS) under 660 nm light irradiation. The optimized heterojunction demonstrates broad-spectrum antibacterial efficacy, achieving a 99.63 % inhibition rate against both Staphylococcus aureus and Escherichia coli within 15-minute treatment. Furthermore, the material exhibits excellent biocompatibility. This study discloses the role of interfacial chemical bonding and defect engineering in tailoring charge dynamics at the bio-interface, thereby providing a promising strategy for the rational design of highly efficient photocatalytic agents for biomedical applications, such as wound healing and infection control.