Ag-doped TiO2 coatings were successfully fabricated on Ti using plasma electrolytic oxidation (PEO) in the electrolytes containing Ag or Ag2O nanoparticles (NPs).The results showed that the different Ag sources resulted in significant variations of morphology,composition and chemical state.The thermal decomposition of Ag2O during PEO process contributed to the formation of Ag NPs,which might reactively incorporate into TiO2,leading to the presence of a Ca,P-rich amorphous layer between entrapped Ag NPs and the peripheral TiO2.By contrast,Ag specie tends to be present as micro-sized clusters consisting of metallic Ag NPs in the PEO coating fabricated via Ag Nps addition.The different microstructures inevitably affected the Ag ionic release behaviour and thus antibacterial capabilities and cytocompatibilities.It is indicated that the application of Ag2O NPs as Ag source is promising to fabricate Ag-doped PEO coating with both long-term antibacterial activity and acceptable cytocompatibility.