Integrated polydopamine-mediated PB@BP nanohybrid coating on titanium implants for synergistic antibacterial, antioxidant, and pro-osteogenic functionalities

Titanium (Ti) implants face significant clinical challenges due to their biological inertness and susceptibility to peri-implant infections and oxidative stress. In this study, a multifunctional composite coating was engineered by immobilizing Prussian blue@black phosphorus (PB@BP) nanohybrids onto alkali-heat-treated titanium surfaces via a polydopamine (PDA) adhesive layer. The coating exhibited superior structural stability and improved hydrophilicity. Under 808 nm near-infrared (NIR) irradiation, it demonstrated power density-dependent photothermal antibacterial efficacy, reaching temperatures up to 59.6 °C. Specifically, the PDA/PB@BP + NIR group achieved remarkable inhibition rates of 99.76 ± 0.24 % against Escherichia coli and 99.27 ± 0.23 % against Staphylococcus aureus , effectively minimizing the risk of implant-associated infections. Furthermore, the coating promoted HUVECs migration, achieving a scratch healing rate of 70.57 % within 36 h. The PB@BP nanostructures functioned as potent nanozymes, effectively scavenging excessive reactive oxygen species (ROS) to protect cells from oxidative damage. Meanwhile, the sustained degradation of BP nanosheets provided a continuous supply of phosphate ions, which synergistically with the PDA layer, accelerated the differentiation and biomineralization of MC3T3-E1 cells. Collectively, the PDA/PB@BP composite coating orchestrates a bioactive microenvironment that integrates photothermal antibacterial, antioxidant, pro-angiogenic, and pro-osteogenic functionalities. This study provides a versatile strategy and a solid experimental foundation for the design of next-generation titanium-based implants with advanced regenerative and anti-infective capabilities.