Long-term corrosion behavior and biocompatibility testing of titanium-based alloy covered with nano-crystalline hydroxyapatite

Abstract

In this paper, we applied on the surface of the new Ti%20Nb%10Zr%5Ta alloy nano-crystalline hydroxyapatite (HA) coating by the method of the chemical deposition in a solution supersaturated with Ca2+ and inline image ions. The composition and crystallinity of the obtained coating was determined by X-ray diffraction, micro-Raman, infrared, and energy dispersive X-ray spectroscopies and its morphology and porosity by scanning electron microscopy. The coating long-term corrosion behavior for 3000 soaking hours in simulated human fluids (Ringer's solutions of different pH values) was studied by cyclic potentiodynamic and linear polarization, electrochemical impedance spectroscopy and monitoring of the open circuit potentials and corresponding open circuit potential gradient due to the pH non-uniformity of the biofluid. Also, the coating biocompatibility was performed by cells (human osteoblast % HOS and human immortalized pulmonary fibroblast % Wi-38) adhesion and proliferation testing in the HA coated bioalloy extract compared to respective effects of the un-coated bioalloy extract. The initial HA nano-coating promoted the deposition of new HA layers, thickening itself and showing its ability to induce the formation of this main inorganic component of the human bone, therefore denoting bioactivity of the HA nano-coated alloy.