Modification of zinc-doped polydopamine coating on pure titanium surface and its corrosion resistance:A preliminary study
Objective To prepare zinc-loaded polydopamine coating on the surface of pure titaniumand investigate its biocompatibility and corrosion resistance.Methods Pure titanium specimens were successively immersed in a dopamine alkaline solu-tion and a zinc sulfate solution to form a zinc-loaded polydopamine coating on the surface of the specimens.The smooth titanium surface and the polydopamine-coatedtitanium surface were used as the control group,and the zinc-containing polydopamine-coated titanium sur-face was used as the experimental group.Scanning electron microscopy(SEM)was used to observe the micro-morphology of the speci-men surface,and energy dispersive spectrometer(EDS)was used to determine the binding of zinc elements on the polydopamine coat-ing.The hydrophilicity of the specimen surface was detected by a contact angle meter.L-929 fibroblasts were cultured in vitro and the biocompatibility of the modified titanium surface was evaluated by CCK-8 assay.An electrochemical potentiostat was used to obtain the open-circuit potential and potentiodynamic polarization curves of specimens of each group in artificial saliva to analyze the effect of zinc-doped polydopamine coating on the corrosion resistance of titanium surface.Results SEM and EDS analyses showed that there were differences in the surface micro-morphology among three groups,and the presence of zinccould be detected on the surface of the speci-mens in the zinc-doped polydopamine coating group.The hydrophilicity of the specimen surface was enhanced after coating modification.The results of in vitro experiment revealed that the zinc-doped polydopamine coating had good biocompatibility.The open-circuit potential and potentiodynamic polarization curves obtained from electrochemical tests and their fitting data showed that the zinc-doped polydopamine coating group had the strongest corrosion resistance,followed by the polydopamine coating group,and the smooth titani-um group had the smallest.Conclusion Zinc-doped polydopamine coatingscanbe successfully prepared on titanium surfaces us-ingchemical immersion method,and the modified titanium surfacespossess good biocompatibility and corrosion resistance.