A viscometric method to study the effects of hematocrit of blood and different surfaces of biomaterials on blood clot formation

Abstract

The increasing viscosity of blood during blood coagulation and clot formnation process could be detected by a viscometric method. To characterize the above-mentioned process by a cone/plate viscometer, we defined initial time of coagulation, to, and the intensity of clot formation, dη/dt, as parameters to detect the process at a shear rate of 90 see-1, at which shear stress was about 4. 5 dyne/cm2. Moreover, to test the sensitivity of the method and parameters, we investigated whether they could detect the changes of different hematocrit (Hct) of blood samples, and material surfaces of plate during coagulation process. The results showed that high Hct of blood samples would shorten to but intensify dη/dt. Among those tested materials, PU grafted with PEG (PU-PEG) film could prolong much longer and PU film could dramatically reduce the dη/dt values. PMMA could prolong long but it was not so effective to reduce dη/dt value. Through the study, we suggested that the method and parameters are sensitive to the changes of the above-mentioned factors for detecting blood coagulation process. They can be further applied for studying blood coagulation process or for dynamic testing the blood compatibility of different materials in vitro.