In vitro corrosion study of different TiO2 nanotube layers on titanium in solution with serum proteins

Titanium oxide nanotubes prepared by anodization have received considerable attention in the biomaterials domain. The objective of this study was to demonstrate the electrochemical behavior of different diameter TiO2 nanotube layers on titanium in phosphate buffered saline (PBS) and Dulbecco's minimum essential medium + 10% fetal calf serum (D-FCS) using open circuit potentials (OCP), electrical impedance spectroscopy (EIS), and a potentiodynamic polarization test. The results showed that the nanotubes had higher OCP, higher resistance of the inter barrier layer (Rb), and lower Ipass in the two test solutions compared to the smooth Ti, especially the 30 nm diameter nanotubes. The corrosion resistance of the nanotubes in D-FCS was higher than in PBS because of protein adsorption from the D-FCS solution as suggested by scanning electron microscope (SEM) images. In addition, protein aggregates of 30 nm diameter nanotubes caused the model of EIS spectra to transform from two-layer to three-layer. The corrosion behavior of the nanotubes for use as a dental implant material is discussed.

The model of EIS spectra can transform from a two-layer to a three-layer because of protein depositing from D-FCS solution, which indicates that it should be careful to choose the model of EIS spectra when investigating nano-implant materials’ corrosion behavior in solution with serum proteins.Figure optionsDownload as PowerPoint slideHighlights
► Titanium oxide nanotube as a new implant material.
► We examine the corrosion behavior of nanotubes in physiological environment.
► The nanotubes improve the corrosion resistance of titanium.
► The model of EIS spectra could transform because of protein depositing on nanotubes.