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The hydroxyapatite (HA) coating doped with multiple ions has attracted much attention due to its potential to impart various functions (antibacterial and osteogenic activity, etc.) to plastic surgery and dental implants. In this work, novel nano fluorohydroxyapatite (FHA) coatings substituted simultaneously with Sr2+ and Ag+ (SrAgFHA) were designed and successfully synthesized by one-step electrodeposition. Ag was used to impart antibacterial ability to SrAgFHA, and Sr can balance the potential cytotoxicity of Ag, thereby improving the cell compatibility of the composite coating. The SrAgFHA coating was consisted of closely aggregated/fused hexagonal columnar nanorods of ~100–150 nm. The nano-coating has higher corrosion resistance than FHA coating and uncoated Ti. Due to the doping of F, SrAgFHA nanorods have a complete single crystal structure and exhibit low degradability, which can ensure the long-term and slow release of Sr2+ and Ag+ ions. This nanorod coating with a low roughness and zeta potential was superhydrophobic and displayed good in vitro bioactivities, such as excellent apatite forming ability, which proves the osteoconductive nature. The results of electrochemical impedance spectroscopy confirmed that by electrodepositing the SrAgFHA coating on the Ti surface, the corrosion resistance was significantly improved. SrAgFHA coating has the best antibacterial effect and osteogenesis ability, for example, the broad-spectrum antibacterial effect on E. coli and S. aureus is 96.5 and 96.8%, respectively, and it can induce osteoblast adhesion, proliferation and differentiation. The rabbit bone defect experiment showed that a large amount of new bone was formed around the SrAgFHA coated implant, and its early bone integration ability was the strongest. In summary, SrAgFHA strikes a balance between superior corrosion resistance, cytocompatibility and excellent antibacterial properties. The multi-element co-doped HA coating has huge clinical application potential in anti-infective repair. [ABSTRACT FROM AUTHOR]

Effective bone repair applications of titanium-based biometals must have excellent self-antibacterial properties and osteogenesis. Due to the special nano-geometric structure of titanium dioxide nanotubes (TN), the modified TN can confer various biological functions on the surface of titanium-based biometals. In this study, we used anodization, hydrothermal synthesis, and dopamine self-assembly to develop a Sm/Sr-doped TN (SSNT) array that integrated the antibacterial properties of Sm and the bone formation properties of Sr. AFM, SEM, FTIR, EDS, and XPS methods were used to characterize the SSTN, and the antibacterial and cell compatibility of the SSTN were systematically studied. Sm ions and Sr ions were slowly and stably released from the surface of dopamine and SrTiO 3 crystals, respectively. Compared with TN, SSTN had a smaller roughness and significantly improved hydrophilicity. The colony count, inhibition zone and turbidity experiments demonstrated that the SSTN structure containing Sm had obvious antibacterial effect on E. coli and S. aureus. The nanotube structure containing strontium ions can promote the early differentiation and osteogenic gene expression of MC3T3-E1 cells adhered to the SSTN surface. Based on the above results, the dual doping of Sm and Sr, and the ideal hydrophilicity can not only improve the osteogenesis of titanium-based biometals, but also make such bone implant biometals have effective self-infection resistance. [ABSTRACT FROM AUTHOR]