A comparative investigation of plasma nitriding and oxy-nitriding treatment on cells and bacterial interaction on titanium surfaces

Abstract

There is a growing interest in obtaining ideal biomaterials that exhibit appropriate cell responses and are not sensitive to bacterial adhesion. For this purpose, titanium is widely used as biomaterial, with several surface modifications to improve their response in implants and medical devices. In this study, titanium grade II is plasma treated using nitrogen gas (termed as plasma nitriding) and a mixture of nitrogen-oxygen (termed as plasma oxy-nitriding) and their structural, topographical, bacterial adhesion (Pseudomonas aeruginosa) and cell adhesion (osteoblast cells) are compared. It is observed that the bacterial adhesion and cell adhesion are significantly changed by modifying the surface properties of titanium, and in particular, the oxy-nitrided sample exhibits a lower density of bacterial adhesion (58 % lower than untreated titanium) and higher cell adhesion (14 % higher than untreated titanium). This modification in surface properties is probably caused by the changes in crystalline phases, with nitrides and oxy-nitrides, chemical composition, and changes in surface roughness. This study shows that surface properties, which result in cellular proliferation and bacterial adhesion, can be tunned, and oxy-nitriding is more beneficial than nitriding of titanium surface. This study's outcomes will help attain more appropriate biomaterials for implants and other biomedical devices.