Structure and properties of photothermal antibacterial Ce-HA/PPy composite material

To address the limited functionality of pure Hydroxyapatite (HA), cerium-doped hydroxyapatite (Ce-HA) with different Ce contents was synthesized by a hydrothermal method, and Ce-HA/PPy composites were further prepared by in situ polymerization of pyrrole. The crystal structure, micromorphology, and surface chemical properties of the materials were analyzed. Their photothermal performance, in vitro ion release behavior, and antibacterial properties were systematically studied. Ce was introduced into the HA lattice in mixed valence states (Ce 3+ /Ce 4+ ), and PPy formed a continuous surface-associated coating on Ce-HA, yielding a stable composite structure. The Ce-HA/PPy composite containing 1.0 mol% Ce exhibited the most favorable photothermal properties. This optimal performance was demonstrated by a photothermal conversion efficiency of 37.6% and good stability when irradiated with an 808 nm laser at 2 W/cm 2 The composite material exhibited antibacterial rates of up to 95.26% and 93.59% toward Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ), respectively, under laser irradiation, and its antibacterial mechanism stems from the synergistic effect between the high photothermal conversion efficiency of PPy and Ce ions. The release amount of Ce 3+ /Ce 4+ ions from the composite material is within the physiological safety range. The Ce-HA/PPy composite developed in this study exhibits promising photothermal antibacterial performance and potential for biomedical photothermal antibacterial applications.