9623920 James Dr. James' plans for integrating research and education are presented. The overall objective of her research is to engineer a new polymeric material for the articulating surfaces of total joint replacement implants which should decrease the wear and thus increase the longevity of these implants. This award will support the experimental research and development of novel gradient, interpenetrating polymer network (IPN) materials with positively charged surfaces which will have good bearing properties and will attract the polyanionic lubricating molecules in synovial joint fluid. Ultra high molecular weight polyethylene (UHMWPE) will be made biomimetic by incorporating cationic groups, similar to those in articular cartilage, into it. Specifically, an IPN will be formed at the surface of UHMWPE between crosslinked polylysine (PL) and UHMWPE by swelling UHMWPE, diffusing PL into it and subsequently crosslinking the PL. The IPN will have a gradient nature in which the surface regions have a higher concentration of PL than the interior. Variation of swelling solvents, solvent temperature, PL oligomer size and crosslinkers will result in IPNs with different gradient thickness, characteristics and charge densities. In order to characterize the mechanical and physical properties of the novel materials, the following tests will be performed: conditioning, surface charge measurement, measurement of the thickness and gradient characteristics, dimensional changes from initial thickness, synovial fluid adsorption and tribological characterization. The results of these tests will determine the most desirable experimental methods to be used in the preparation of the implant materials for the cell toxicity, mechanical testing and hip simulator studies. Dr. James tries to use cooperative learning in the classroom and to integrate undergraduates in her research program during the academic years and summers. This proposal will also help support the out reach activities of Dr. James and her students, such as a snow sled design contest for girls interested in math and science at regional public elementary schools. ***
