On the increase of the chemical reactivity of cp titanium and Ti6Al4V at low electrical current in a protein-rich medium

The aim of this study was to evaluate the effect of two electrical current intensities on titanium surface changes in a simulated physiological environment. Commercially pure titanium (cp Ti) grade IV and Ti6Al4V cylinders were coupled to a potentiostat and immersed in DMEM medium enriched with fetal bovine serum (FBS). Samples were divided into four groups: free of electrical stimulation at (C1) room environment or (C2) immersed in DMEM/FBS; and on 5 μA or 10 μA electrical stimulation in DMEM/FBS. After electrical stimulation, the protein adsorption was evaluated by Lowry method and FTIR. Additionally, titanium surfaces were studied by open circuit potencial (OCP), electrochemical impedance spectroscopy (EIS), optical profilometry, and scanning electron microscopy (SEM). FTIR analysis revealed energy bands indicating the presence of amide groups from proteins on all samples immersed in DMEM enriched with FBS. The highest amount of adsorbed total protein was noted on the control groups (p < 0.05). Regarding surface topography, the profilometric analyses showed higher Ra roughness values for cp Ti samples submitted to 10 μA (p < 0.05). Ti6Al4V surfaces had the highest Ra roughness values on 5 μA although no statistical difference within 10 μA group was noticed (p > 0.05). After electrochemical assays, test samples showed higher corrosion resistance than that recorded on control groups. The electrical stimulation increased the chemical reactivity between titanium-based surfaces resulting in a significant increase in roughness as well as on the thickness of the titanium oxide layer.