Buddy, Ratner DKim, Kyunghoon2025-01-232025-01-232025-01-232024Kim_washington_0250E_27793.pdfhttps://hdl.handle.net/1773/52711Thesis (Ph.D.)--University of Washington, 2024Blood-compatible surfaces are essential for advancing blood-contacting medical devices to prevent complications, enhance therapeutic outcomes, and reduce post-care costs. This dissertation evaluates the blood compatibility of diverse polymer surfaces, including commercial fluoropolymers, plasma-polymerized fluoropolymers, medical polymers, and zwitterionic polymers. The primary scope of studies focuses on the intrinsic pathway of coagulation, which is a dominant thrombus formation mechanism in low-shear hemodynamic flow conditions. Through comprehensive assessment of Factor XII adsorption/activation, thrombin generation, and fibrin clot formation, we demonstrate that zwitterionic poly(carboxybetaine) copolymer surfaces exhibit superior blood compatibility, while plasma-polymerized hexafluoropropylene (ppC₃F₆) shows the second-best performance. These materials achieve their enhanced blood compatibility through distinct mechanisms: zwitterionic polymers prevent protein fouling through a strong hydration layer, particularly preventing Factor XII adsorption and subsequent activation, while ppC₃F₆ surfaces demonstrate unique protein tight-binding properties that promote stable albumin retention and reduce Factor XIIa activity. The ultralow protein fouling property of zwitterionic polymer effectively prevents the initiation of the intrinsic coagulation pathway by creating a barrier against Factor XII adsorption and activation. Conversely, ppC₃F₆ exhibits remarkable protein tight-binding characteristics that maintain a stable albumin passivation layer resistant to displacement by larger thrombogenic proteins such as FXII or fibrinogen, while simultaneously reducing Factor XIIa activity through tight surface binding that diminishes the bioactivity of adsorbed Factor XII. These findings suggest two promising but mechanistically distinct approaches to achieving enhanced blood compatibility: prevention of protein adsorption through surface hydration, and protein tight binding that promotes beneficial interactions while minimizing thrombogenic responses.application/pdfen-USCC BY-NC-SAbiomaterialsblood compatibilityintrinsic pathwayRFGD plasma polymerizationsurface analysiszwitterionic polymerBioengineeringBioengineeringThesis