Specific ultraviolet-C irradiation energy for functionalization of titanium surface to increase osteoblastic cellular attachment

Abstract

The objective of this in vitro study was to examine the influence of the total energy of ultraviolet-C preirradiation on the number and morphology of osteoblastic cells attached to turned or acid-etched titanium surfaces, and physicochemical properties of the surface. Rat bone marrow-derived osteoblasts were incubated with turned or acid-etched titanium disks preirradiated with ultraviolet-C at 1 or 3 mW/cm(2), resulting in total energies of 10, 100, 250, 400, 500, 600, 750, or 1000 J/cm(2). Osteoblast attachment to the surface was evaluated using the WST-1 assay. Physicochemical changes of the titanium were evaluated by measuring water wettability and X-ray photoelectron spectroscopy analysis. Number of attached cells was greater on turned or acid-etched surface preirradiated with 500 or 750 J/cm(2) of 3 mW/cm(2) ultraviolet-C than on the nonirradiated surface, respectively. However, the further irradiation energy did not increase the numbers on both types of the surfaces. These phenomena were also seen on the surfaces preirradiated at different ultraviolet-C intensities. Ultraviolet-C irradiation induced superhydrophilicity on both types of surface even with the less irradiation energy. The amount of carbon on ultraviolet-C preirradiated titanium surfaces decreased gradually with an increase in the total irradiation energy. Specific ultraviolet-C energy used to irradiate turned or acid-etched surfaces increased the number of osteoblastic cells attached to each of the surface. This was canceled by overirradiation, despite maintenance of both the acquired superhydrophilicity and the accompanying reduction in carbon on each surface.