This proposal is directed toward testing hypotheses that can lead to improved polyurethane materials form cardiovascular and other implant devices. Embolic problems with artificial hearts, the proposed use of polyurethane vascular grafts, and the failure of pacemaker leads all point to the need for improved polyurethanes. The central hypothesis of this proposal is that poly(ether urethanes) (PEU's) with surfaces rich in hydrocarbon or fluorocarbon moieties might demonstrate minimal platelet interaction in arterial flows, a reduced tendency to calcify, and a reduced susceptibility to biodegradation. The research proposed has five major components: (1) the synthesis, purification and bulk characterization of PEU's with hydrocarbon or fluorocarbon surfaces; (2) the analysis of the surface structure of these materials in the hydrated and dehydrated condition by ESCA, SIMS and contact angle methods; (3) in vitro studies of the biodegradation of these PEU's directed toward testing out many of the hypotheses formulated about the breakdown mechanism; (4) in vitro modelling of the propensity towards calcification based upon SIMS analysis of the calcium binding ability of PEU surfaces; and (5) biological studies, primarily with external collaborators, including protein adsorption, cell interaction, in vitro laser emboli detection and ex vivo evaluation of platelet interaction using a baboon model.
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