Effect of the ultraviolet light treatment and storage methods on the biological activity of a titanium implant surface

Abstract

OBJECTIVE: We evaluated whether the biological activity of the surface of titanium, when stored in an aqueous solution, in low vacuum, and under ambient conditions after ultraviolet light (UV) treatment is comparable to that of the surface immediately after UV treatment for 15min and that after dielectric barrier discharge (DBD) plasma treatment for 15min.

METHODS: Grade IV titanium discs with machined surfaces were irradiated with UV and their surface properties were evaluated immediately and after storage for 28days in distilled H2O (dH2O), a vacuum desiccator (31.325kPa), and a sealed container under air. Their surface characteristics were evaluated by atomic force microscopy, X-ray diffraction, contact angle analysis, and X-ray photoelectron spectroscopy. Biological activities were determined by analyzing the albumin adsorption, MC3T3-E1 cell adhesion, and cytoskeleton development.

RESULTS: Hydrophilicity of titanium surfaces stored in dH2O was comparable to that immediately after UV treatment and higher than that immediately after DBD plasma treatment (P<0.001). Storage in dH2O and in low vacuum immediately after UV treatment prevented hydrocarbon contamination and maintained elevated amounts of titanium and oxygen. After 28 days, protein adsorption, cellular adhesion, and cytoskeletal development of MC3T3-E1 cells on the titanium surfaces stored in dH2O were significantly enhanced compared to those stored in low vacuum and under ambient conditions while being comparable to those immediately after UV and DBD plasma treatments.

SIGNIFICANCE: UV treatment of the titanium implants followed by wet storage is useful for maintaining enhanced biological activity and overcoming biological aging during shelf storage.