Cytotoxicity and tribological property of DLC films deposited on polymeric materials

Abstract

To evaluate the cytotoxicity and the tribological properties for diamond-like carbon films (DLC), DLC films were deposited on high-polymer materials such as polymethylmethacrylate, polycarbonate, polyurethane and polytetrafluoroethylene using a radio-frequency chemical vapor deposition (CVD) system. Adhesion strength between these materials and DLC films is generically poor. To improve adhesion strength of DLC films and high-polymer materials, oxygen plasma pretreatment was performed before DLC films deposited. Evaluation of the tribological properties was performed using ball-on disc system. Especially, in the DLC films deposited on PMMA with oxygen plasma pretreatment, the friction coefficient was significantly reduced from 0.456 to 0.310. Influence of DLC films on cytotoxicity were studied in vitro cell culture by counting cells. Mouse fibroblasts (NIH-3T3) were seeded in 24 well culture plates, and four kinds of high-polymer PMMA, PC, PU and PTFE substrates, DLC-deposited and non-deposited high-polymer substrates, were immersed in each well directly for 24, 48, 72, and 96 h. Multiplication of cell number with DLC-deposited substrates is similar in that with non-deposited substrates. Consequently, these studies reveal that the DLC films have excellent tribological properties and cytocompatibility.