Enhancing cell adhesion and corrosion performance of titanium alloy by surface and sub-surface engineering using WEDM

Abstract

Ti-6Al-4V (grade 5 titanium alloy) is a widely used material for biomedical implant and prostheses. The objective of this study is to investigate the effect of surface and sub-surface characteristics (i.e., surface roughness, microstructure, phase transformation, and recast layer) of Ti-6Al-4V alloy on the cell attachment and corrosion performance after machined by Wire Electric Discharge Machining (WEDM) process. The biocompatibility of titanium alloy has been studied based on the cell adhesion and cell proliferation response of mouse osteoblastic cell MC3T3-E1 to the machined surface of different levels of surface roughness and sub-surface microstructural and phase composition. One conventionally machined surface and one tissue culture treated plastic surface were used for comparison with those four WEDM machined surfaces. It was found that cell attachment increased with increasing surface smoothness, and WEDMed Ti-6Al-4V alloy sample exhibited higher cell attachment compared to even smoother conventionally machined samples. It was found that β phase at the sub-surface favored the cell adhesion on the machined surfaces for EDMed samples. The corrosion rate of machined Ti-6Al-4V alloy samples under simulated body fluid decreases with decreasing surface roughness. The findings suggest that WEDM has the capability of producing implant surface that can promote cell adhesion with improved corrosion performance under body fluid, thus, has the capability to manufacture implants with improved biocompatibility.