Silicon oxycarbide glasses for blood-contact applications.

Silicon oxycarbide (SiOxCy) glass compositions are shown to exhibit a variable propensity to contact activate coagulation of whole human blood plasma that depends on X:Y surface stoichiometry. SiOxCy exhibit activation properties similar to pyrolytic carbon (PC) over a broad range of X:Y ratios. Surface composition of SiOxCy glass powders prepared by pyrolysis of thermosetting polysilsequioxanes roughly correlated with total carbon concentration of precursor resins and could be significantly modified by etching in alkaline solutions. Results suggest that SiOxCy may offer unique properties as a substitute for PC in medical-device applications demanding excellent tribological properties, such as artificial heart valves.