Effect of plasma-nitrided titanium on mechanical properties and initial cell adhesion

Abstract

Titanium alloy has been widely used as an implantable material with good biocompatibility and mechanical properties. Particularly, the titanium alloy Ti-6Al-4V with surface modification has been utilized in dental applications for decades. In this study, the plasma-based ion implantation (PBII) technique was applied on the surface of Ti-6Al-4V under gaseous mixtures of N2 and Ar with a flow rate of 30 sccm and 5 sccm, respectively. X-ray photoelectron spectroscopy (XPS) showed that the titanium nitrided layer was formed on the surface of Ti-6Al-4V at the peak of 397 eV for N 1s. The effects of plasma nitride on the Ti-6Al-4V were creating a smooth surface with hydrophilic property (RRMS = 17.93 ± 0.05 nm, θ = 61.4° ± 0.36) and increasing surface hardness by ∼42%. Direct culturing with the primary human alveolar bone cells, the plasma-nitrided Ti-6Al-4V improved cell proliferation (4 and 7 days) and showed no cytotoxicity. The DAPI/rhodamine-phalloidin staining and the scanning electron microscope (SEM) were used to examine cellular morphology and initial cell adhesion. The result demonstrated that the plasma nitride enhanced the human alveolar bone cell adhesion compared with glass slides. Overall, plasma-nitridation with nitrogen and argon on Ti-6Al-4V using the PBII technique enhanced surface properties of Ti-6Al-4V and induced adhesion and proliferation of primary human alveolar bone cells, proposing that it can be a potential surface modification for dental application.