Biofilm Inactivation and Prevention on Common Implant Material Surfaces by Nonthermal DBD Plasma Treatment

摘要

Two stainless steels (SSs)—304 and 316L—as well as a titanium-aluminum-vanadium alloy (Ti6A14V) and ultra-high-molecular-weight polyethylene (UHMWPE) are common metallic and polymeric materials used in medicine for various applications such as bone fracture fixation, dental and cardiac implants, production of medical devices. Implanted materials are highly susceptible to infections that lead may implant failure. The method used to sterilize implant materials plays an important role in the success and performance of an implant. Mechanical properties of UHMWPE are compromised as a consequence of gamma irradiation. Repetitive autoclaving of implants and surgical tools reduces material performance. Also, custom orthopedic prosthesis production requires cheap, on-site, and quick sterilization procedures. In this study we evaluated the inactivation and prevention of biofilm formation of Escherichia coli and Staphy-lococcus aureus on UHMWPE, a Ti6A14V, 304 SS, and 316L SS surfaces. Plasma treatment of discs was evaluated by an XTT (2,3-bis-(methoxy-4-nitro-5-sulfophenyl)- 2H-tetrazolium-5-carboxanilide]) viability assay, which showed that 95% of both bacterial biofilms were inactivated after 3 minutes of plasma treatment. For the biofilm prevention tests, UHMWPE, Ti6A14V, 304 SS, and 316L SS discs were first treated with nonthermal dielectric barrier discharge plasma; then, 1-day-old biofilms of E. coli and S. aureus were grown on the disc surfaces, and biofilm formation was similarly evaluated using an XTT assay. Plasma treatment of implant surfaces prevents biofilm formation up to 50%. Safranin assay, which was used to evaluate extracellular polymeric substances, also has shown that plasma treatment of UHMWPE, Ti6A14V, 304 SS, and 316L SS discs not only inactivates biofilms but also but also disrupts extracellular polymeric substances that are secreted by bacteria during biofilm growth.