Nanosecond-rise-time-pulsed plasma surface modification of titanium for enhanced hydrophilicity, antibacterial activity, and biocompatibility

Abstract

The success of dental implants depends critically on osseointegration, a process highly influenced by the surface properties of the titanium material. This study presents a comprehensive evaluation of a nanosecond-pulse driven, low-pressure nitrogen-hydrogen plasma treatment designed to modify the surface characteristics of titanium, aiming to enhance its performance for dental applications. The treatment's effects on surface morphology and chemistry were characterized using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Its biological performance was assessed through antibacterial assays against Streptococcus mutans and by evaluating the adhesion and cytotoxicity of mouse pre-osteoblastic cells (MC3T3-E1). The results demonstrate that the N2/H2 plasma treatment effectively removes surface carbon contaminants and introduces nitrogen-containing functional groups (probably -NH3+), which successfully transitions the titanium surface from hydrophobic to hydrophilic. This modified surface exhibits a significant reduction in bacterial adhesion, exceeding a 4-log reduction. Concurrently, osteoblast cell adhesion is substantially improved to approximately 70%, with no observed cytotoxic effects. In conclusion, this N2/H2 plasma treatment stands out as a highly efficient surface modification technique that, without altering surface topography, imparts robust hydrophilicity, significant antibacterial properties, and biocompatibility to smooth titanium surfaces, presenting a compelling balance of performance and cost.