Dielectric Barrier Discharge Plasma Jet Treatment on Additively Manufactured Biomedical Implants for Improved Surface Wettability, In Vitro Bone Mineralization, and Bacterial Decontamination

Abstract

Abstract. Metallic biomedical implants require surfaces with improved wettability, decontamination, and biocompatibility to ensure successful osseointegration and long-term durability. Conventional surface functionalization methods are often hindered by high costs, long process times, and complex setups. The atmospheric pressure dielectric barrier discharge (DBD) plasma jet offers a promising alternative, providing a low-power, cost-effective, and low-temperature approach with rapid processing times. This study investigates the application of a DBD plasma jet for surface modification of additively manufactured Ti-6Al-4V ELI (Ti Gr23) to enhance wettability and promote bone cell mineralization, which is crucial for better osseointegration. Improved surface wettability of the plasma-treated Ti Gr23 samples is demonstrated by a significant reduction in the water contact angle (WCA) following only 2 s of treatment. X-ray photoelectron spectroscopy (XPS) analysis reveals that plasma interaction induces the formation of oxide metallic bonds, such as TiO2 and Ti2O3, while reducing carbon contamination, leading to increased surface energy. A parametric study was conducted to evaluate the effects of treatment time, gas flowrate, and input power on the treated area size, WCA reduction, and process cost. The optimal conditions of 8 s of treatment time, 2 slm gas flowrate, and 7.4 W power achieved the largest treated area (70 mm2), maximum WCA reduction (58 deg), and minimal processing cost ($26/m2). Cytocompatibility tests confirmed that plasma treatment had no cytotoxic effects on Ti Gr23 implants. Additionally, plasma treatment of Ti Gr23 surfaces resulted in a 45% increase in bone cell mineralization, highlighting its dual role as a surface modification strategy for improving cell adhesion and as an effective sterilization approach against hospital-acquired pathogens such as MRSA for smooth and rough surfaces. Overall, plasma treatment enables simultaneous enhancement of wettability, cell adhesion, and decontamination on rough bioimplant surfaces, otherwise difficult to achieve with conventional methods like ethanol rinsing.