(266b) Polymer Coatings for Biomedical Applications Using Low Temperature, Atmospheric Pressure Plasma

Polyethylene is used as a biocompatible surface for ball and socket joint replacements, which are under constant wear.  The interface could be improved by the addition of a hydrophilic coating to provide a lubricating effect and possibly reduce wear.  Presently, these coatings can be synthesized using wet chemistry techniques, which can often be time consuming and result in poor adhesion or coating quality.  Current research has been dedicated to investigating the viability of atmospheric pressure plasmas for use in coating technology.  In addition to being more cost effective and efficient, atmospheric pressure plasma offers a more streamlined process, as it can be employed directly into the production line.  Atmospheric pressure plasma has been used in applications including biocompatibility, hydrophilicity/hydrophobicity, and coating with antibacterial films.

Atmospheric pressure plasma was used to change the surface chemistry of polyethylene by grafting various biocompatible polymers to the substrate surface, as methods of providing wear resistance as well as providing a self-lubricating surface.  The organic coatings included biocompatible polymers, such as poly(2-hydroxyethylmethacrylate), polyethylenimine, and polyethylene glycol.  Low temperature, atmospheric pressure plasma was used, along with an in-house constructed spray delivery system, to coat high density polyethylene substrates.  Coatings were characterized with 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 an increased wettability.  Plasma processing conditions, specifically the pretreatment of the substrate and the input power, greatly affected the adhesion and uniformity of the polymerized layer.  Polymer concentrations were varied to understand the effect on coating adhesion and hydrophilicity.