(274i) Biocompatibility and Wear Properties of Polymer Coatings Created with Atmospheric Pressure Plasma

Atmospheric pressure plasma was used to alter the surface of high molecular weight polyethylene (HMWPE) by grafting various biocompatible polymers, to provide a more hydrophilic surface to improve wear resistance for use in applications, such as prosthetics and orthopedic implants. 

For this study, the organic coatings included biocompatible polymers such as poly(2-hydroxyethylmethacrylate), polyethylenimine, and polyethylene glycol.  Atmospheric pressure plasma was used, along with an in-house constructed spray delivery system, to graft the molecules to HMWPE substrates. The surface of the substrates was maintained at a temperature below 80^oC during the coating process.  Coatings were characterized by Fourier transform infrared spectroscopy (FTIR), contact angle analysis, and adhesion testing.  A significant decrease in contact angle was noted for various coatings produced with this method, indicating increased hydrophilicity.  Plasma processing conditions, specifically the pretreatment of the substrate and the input power, affected the adhesion and uniformity of the polymerized layer.  Trends varied for the polymers used in this study, indicating the need for optimization of plasma parameters for the desired polymer coating.

The biocompatibility of the surface was characterized using various techniques described in literature.  The wear properties of the coatings were determined by weight loss under conditions of a random motion pin-on-plate apparatus with the coated polyethylene plaques immersed in serum albumin solution.  The results indicate that the biocompatible polymer coatings on HMWPE surfaces may improve the performance and longevity of these surfaces when used in biomedical applications such as orthopedic implants and implanted medical devices.