Porous oxides for hemostatic control and oxidative catalysis.

摘要

The original research described in this dissertation is concerned with the development of novel catalytic applications for high-surface-area porous oxides. Designing porous oxides for hemostatic control and oxidative catalysis required looking at old materials in new ways, synthesizing original composites, and identifying the best methods for tuning the oxide interface for the particular catalytic application. The synthesis and characterization of zeolites and porous-siliceous-oxide composites for controlling hemostasis is described in addition to the synthesis of Au and Pt-loaded titania composites for catalyzing the oxidation of adsorbed stearic acid and carbon monoxide.;Porous metal oxides can be tuned to elicit a predictable blood response through the selective adsorption of fluid phase media, control of local electrolyte conditions, heating of blood, and presentation of a charged polar surface. Methods for optimizing the heat response of inorganic-based hemostatic materials, as well as incorporating antibacterial activity, are described. By monitoring both the hemostatic and bone-forming activity of newly prepared hemostatic bioactive glass, we have elucidated an interesting inverse relationship for this class of wound healing materials. To better understand the intrinsic surface activity of oxides to elicit a coagulation response from blood, a survey of the contact-activated clotting properties of a variety of metal oxides was conducted. We have refined the traditional definition of hemocompatibility, as it pertains to very polar substrates like metal oxides, to include both the sign and magnitude of the surface charge density as a better predictor of hemocompatibility. We found that the onset of coagulation, rate of coagulation post-initiation, and ultimate clot strength are dependent on the acid-base character of metal oxides, which can be quantitatively described by the material's isoelectric point. We also report on the sol-gel preparation of a new morphology of mesoporous titania films, which can be prepared for catalyzing the degradation of adsorbed stearic acid and carbon monoxide. The advantages of high-surface-area porous oxides for accelerating the contact-activated blood response and oxidation of organic molecules is explained in terms of the materials ability to concentrate, temporarily immobilize, and retain reactive species while also providing a support for surface-dependent reactions.