Sr-doped surfaces with 2D black phosphorus nanosheets for enhanced photothermal antibacterial activity and zirconia implant osseointegration.

Zirconia (ZrO₂) has emerged as a preferred material for dental implants due to its excellent chemical inertness, absence of metal allergies and esthetic appeal. However, its limited bioactivity regarding infection resistance and early osseointegration hinders its implantation success rate compared to titanium implants. Herein, we developed a PDPA@Sr/BP coating for ZrO₂ implants to address these limitations. First, inspired by the adhesive properties of mussel foot proteins, a PDPA@Sr coating enriched with positively charged amine groups and strontium (Sr) ions was applied to the ZrO₂ surface. This coating stably anchored black phosphorus (BP) to the implant, effectively regulating its degradation rate and ensuring long-lasting antibacterial properties. Under near-infrared (NIR) light irradiation, BP generated localized heat, efficiently killing bacteria. Simultaneously, the release of Sr and phosphate ions from the PDPA@Sr/BP coating promoted bone formation and enhanced osseointegration. This study systematically evaluated the antibacterial effects and osseointegration-promoting properties of the PDPA@Sr/BP coating through both in vitro and in vivo experiments. The results demonstrated that compared to untreated ZrO₂ surfaces, the coating significantly enhances the implant's antibacterial properties and accelerates its surface osseointegration. This study proposes an innovative strategy to improve the clinical performance of ZrO₂ implants, demonstrating substantial potential for clinical translation.