Stable Hydrophilic Polydimethylsiloxane Surfaces Produced by Plasma Treatment for Enhanced Cell Adhesion

Abstract

Polydimethylsiloxane (PDMS) is a widely used polymer for medical implants due to its excellent physical properties, low cost and ease of fabrication. However, in some applications the hydrophobic nature of the material remains an issue. To increase PDMS hydrophillicity, a variety of surface treatments based on plasma discharge have been proposed. In this study, we investigated the effect of water-vapor based plasma on PDMS surfaces. Surface topography was analyzed by means of atomic force microscopy (AFM) while surface chemistry was obtained by Fourier transform infrared spectroscopy (FTIR). To analyze the stability of the treatment, surface wettability was assessed over a period of seven months by contact angle measurement. Furthermore, using primary human fibroblasts,in vitro cell growth and morphology was investigated. It was found that plasma treament produced long-term stable hydrophillic surfaces (contact angle between 70° to 80°). This property was correlated with hydroxylation of the surface and was accompanied by a slight increase in RMS roughness. Concomitantly, there was a significant increase in the number of cells growing on the plasma-treated surfaces, which was linked with a more spread cellular morphology. The results presented here suggest that water-vapor plasma treatment may be useful to enhance cell adhesion on PDMS implants.