Construction of a nanobismuth-loaded hydroxyapatite coating on titanium surface and its antibacterial-osteogenic performance study

Peri-implantitis and early osseointegration at the implant interface are critical challenges in dental implantation. An effective strategy to tackle these issues involves loading bioactive components onto the titanium surface and controlling their release. This research utilizes phase-transited lysozyme (PTL)to functionalize implant titanium surfaces, with the objective of fabricating a hydroxyapatite coating infused with bismuth nanoparticles to inhibit bacterial colonization and promote osteogenesis in vitro, thereby addressing key factors in the prevention of peri-implantitis. First, use PTL to modify the surface of pristine titanium. On this basis, prepare a hydroxyapatite coating through the biomimetic mineralization method. Then, load the bismuth nanoparticles onto the titanium sheet by electrostatic adsorption. Finally, obtain a bismuth-loaded hydroxyapatite composite coating. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) analyses confirmed that hydroxyapatite and bismuth nanoparticle composite coatings had been successfully laid down on modified titanium substrates with PTL treatment. SEM and transmission electron microscope (TEM) images revealed the microstructural characteristics of the coatings and the size distribution of the spherical BiNPs (approximately 20–30 nm). Bacterial assays and confocal microscopy observations demonstrated that the bismuth-loaded samples possessed potent early-stage antibacterial activity, effectively inhibiting both planktonic and adherent bacterial viability over a 5-day period, though efficacy gradually decreased over time. Laboratory cell tests indicated the coated titanium discs demonstrated minimal cytotoxicity and positively influenced osteoblast proliferation and adhesion, indicative of favorable biocompatibility. The resultant Ti-HA-BiNPs coating conferred both enhanced antibacterial properties (>90 % initial inhibition) and osteogenic promotion, offering a promising dual-functional strategy for the prevention of peri-implantitis and enhancement of implant stability in the early postoperative period.