Oxygen plasma surface modification enhances immobilization of simvastatin acid

Abstract

Simvastatin acid (SVA) has been reported to stimulate bone formation with increased expression of BMP-2. Therefore, immobilization of SVA onto dental implants is expected to promote osteogenesis at the bon tissue/implant interface. The aim of this study was to evaluate the immobilization behavior of SVA onto titanium (Ti), O2-plasma treated titanium (Ti + O2), thin-film coatings of hexamethyldisiloxane (HMDSO), and O2-plasma treated HMDSO (HMDSO + O2) by using the quartz crystal microbalance- dissipation (QCM-D) technique. HMDSO surfaces were activated by the introduction of an OH group and/or O2-functional groups by O2-plasma treatment. In contrast, titanium surfaces showed no appreciable compositional changes by O2-Plasma treatment. The QCM-D technique enabled evaluation even at the adsorption behavior of a substance with a low molecular weight such as simvastatin. The largest amount of SVA was adsorbed on O2-Plasma treated HMDSO surfaces compared to untreated titanium, HMDSO-coated titanium, and O2- plasma treated titanium. These findings suggested that the adsorption of SVA was enhanced on more hydrophilic surfaces concomitant with the presence of an OH group and/or O2-functional group resulting from the O2-plasma treatment, and that an organic film of HMDSO followed by O2-plasma treatment is a promising method for the adsorption of SVA in dental implant systems. Copyright © 2006 Biomedical Research Press.