Biological Effect of Ultraviolet Photocatalysis on Nanoscale Titanium with a Focus on Physicochemical Mechanism

Abstract

Physicochemical properties, regulated by various surface modifications, influence the biological performance of materials. The interaction between surface charge and biomolecules is key to understanding the mechanism of surface-tissue integration. The objective of this study was to evaluate the biological response to a nanoscale titanium surface after ultraviolet (UVC, λ = 250 ± 20 nm) irradiation and to analyze the effects via a physicochemical mechanism. The surface characteristics were evaluated by field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, surface profilometry, and contact angle assay. In addition, we applied the zeta-potential, a direct method to measure the electrostatic charge on UV-treated and UV-untreated titanium nanotube surfaces. The effect of the Ti surface after UV treatment on the biological process was determined by analyzing bovine serum albumin (BSA) adsorption and osteoblast-like MG-63 early adhesion, morphology, cytoskeletal arrangement, proliferation, and focal adhesion. Compared to an anodized titanium nanotube coating, UV irradiation altered the contact angles on the control surface from 51.5° to 6.2° without changing the surface topography or roughness. Furthermore, titanium nanotubes after UV treatment showed a significant reduction in the content of acidic hydroxyl groups and held less negative charge than the anodized coating. With regard to the biological response, along with an enhanced capability to adsorb BSA, osteoblasts exhibited higher colonization and viability on the UV-treated material. The results suggest that UV treatment enhances the biocompatibility by reducing the electrostatic repulsion between biomaterials and biomolecules.

Time-dependent effects of ultraviolet and nonthermal atmospheric pressure plasma on the biological activity of titanium

“…All statistical analyses were performed using IBM SPSS software, version 21.0 (IBM Korea Inc., Seoul, Korea) for Windows. According to previous studies 16 20 22 , at least four samples for each experiment were used, and each experiment was repeated three times. The results between three groups (the control, UV, and NTAPPJ) at each time point were analysed by one-way analysis of variance (ANOVA) with Tukey’s method.…”

“…Recently, ultraviolet (UV) or nonthermal atmospheric pressure plasma jet (NTAPPJ) treatment has been shown to modify the physicochemical properties of titanium and to enhance its biologic capability without altering topography 13 14 15 16 17 . These treatments can change the titanium surface from hydrophobic to hydrophilic due to removal of surface hydrocarbon and/or formation of chemically reactive hydroxyl radical species with reduced surface negative charge 18 19 20 . Moreover, Bacakova et al reported that cell adhesion was promoted by a moderately hydrophilic and less negatively charged surface 21 .…”

Maintenance and Restoration Effect of the Surface Hydrophilicity of Pure Titanium by Sodium Hydroxide Treatment and its Effect on the Bioactivity of Osteoblasts

“…SPSS 17.0 software was used for all statistical analyses. Based on the results from previous studies [24][25][26][27], data from at least three independent experiments were used. Group means and standard deviations were used to calculate each parameter.…”

Overcoming the biological aging of titanium using a wet storage method after ultraviolet treatment

“…Based on the results of previous studies 8, 24, 31 , we used at least four samples in each experiment, repeating each experiment three times. We analysed the results obtained for the three groups at each time point by means of one-way analysis of variance (ANOVA) using Tukey’s method.…”

“…7 reported that the biological aging of a titanium surface was associated with a greatly reduced ability to attain protein and osteogenic cell adhesion due to the progressive accumulation of hydrocarbons on the titanium surface under ambient conditions. As the percentage of hydrocarbons on a titanium surface increases, the surface zeta potential on the surface changes from electropositive to electronegative, while a cell-attracting terminal consisting of an Arg-Gly-Asp (RGD) sequence can be blocked by the hydrocarbons 8–10 . Thus, this phenomenon prevents negatively charged blood protein and the extracellular matrix of the cells from attaching to the implant surface.…”