Tailoring of anodic surface layer properties on titanium and its implant alloys for biomedical purposes

Purpose: Presentation of different anodizing methods used for formation of thin, thick, gel like covered and nanostructural titania and alloy component oxides. Evaluation of their properties for various biomedical applications in implantology and biosensing. Design/methodology/approach: Samples of titanium and its alloys were anodized in phosphoric acid solutions at different concentrations (0.5 ~ 4 M) with or without additions according to appropriate polarization regimes. Anodized samples were characterized by SED+EDS, electrochemical and impedance (EIS) tests and biocompability examination. Titanium and its alloys (Ti6Al4V and Ti6Al7Nb) samples were also used to form the nanostructural layer (nanotubes) by anodizing. The latter was used as a platform for glucose biosensing. Findings: Anodizing of titanium materials in phosphoric acid solutions allowed to obtain surface layers of various morphology and topography. They differ in porosity, thickness and chemical composition and according to their specific properties can be used in various biomedical applications. The development of gel-like layer and formation of nanotube layer was observed while anodizing in higher concentration of electrolyte or anodizing in the presence of fluorides. Both surface layers are much more bioactive than anodic barrier oxide layers on titanium. The primary tests to use nanostructured layer as platform for the third generation biosensors were promising. Practical implications: Use of medical implants covered with porous and nanostructural anodic layers tailored to particular biomedical purposes enables new practical applications in implantology and biosensing. Originality/value: Phosphate gel-like layer over surface oxide layer on titanium materials and nanostructural surface layer rich in both: phosphates and fluorides, are highly bioactive, which is the desirable property of implant materials.