In-vitro study of the bioactivity and cytotoxicity response of Ti surfaces modified by Nb and Mo diffusion treatments

Abstract

This work focuses on the bioactivity and biological response of modified Ti surfaces produced by powder metallurgy. They are processed by diffusion of two beta-stabilizing elements, Nb and Mo, deposited onto the surface of PM Ti substrates. Moreover, the addition of an activating agent, NH4Cl, to the suspension has been carried out by thermo-reactive diffusion process. The surface modification led to a gradient in composition (Ti-Nb or Ti-Mo) and microstructure (beta / alpha + beta / alpha phases). This work presents the bioactivity results of these Ti-Mo and Ti-Nb surfaces as well as the cell-material response of the Ti-Nb surfaces. The reactivity of the materials was tested through immersion in simulated body fluid considering Ca and P precipitation in order to assess the ability of the materials to induce hydroxyapatite formation. The in-vitro cell response was evaluated by human osteoblast-like cells incubation on the different surfaces for 48 h. The investigation led to positive results in terms of surface bioactivity and an improved cell-material interaction of the PM modified Ti-Nb surfaces compared to the reference Ti material.