Antibacterial and osteogenic effect of EGCG/HAP/AgNPs composite coating on titanium surface

Titanium implants are widely used in dental applications; however, their clinical application is still limited by challenges such as bacterial infection and poor osseointegration. In this study, a composite coating consisting of epigallocatechin-3-gallate (EGCG), hydroxyapatite (HAP), and silver nanoparticles (AgNPs) was fabricated on the titanium surface to improve its antibacterial activity and osteogenic potential. The coating was prepared via alkali-thermal treatment, followed by EGCG adhesion and subsequent deposition of HAP and AgNPs. Surface characterization confirmed successful construction of the coating with improved hydrophilicity. The EGCG/HAP/AgNPs coating showed gradual changes in surface morphology and elemental composition after PBS immersion, suggesting partial coating degradation while retaining detectable residual Ag, Ca, and P on the titanium surface. The coating also exhibited effective antibacterial activity against Staphylococcus aureus and significantly promoted osteogenic differentiation of MC3T3-E1 cells, as evidenced by enhanced alkaline phosphatase activity and mineralized nodule formation. These results demonstrate that the EGCG/HAP/AgNPs composite coating possesses good antibacterial capacity, osteogenic activity, and biocompatibility, showing great potential for improving the clinical performance of titanium implants.