(149a) Droplet-Based Microfluidic Rheometer for Real-Time Viscosity Monitoring of Blood Coagulation Process

Abnormality in blood coagulation is a major cause of morbidity and mortality worldwide. Although efforts have been made to develop tests that are able to monitor blood clotting and the subsequent fibrinolysis process, these tests suffer from low sensitivity and poor reproducibility across laboratories, and have failed to become standardized. Here we report a droplet-based microfluidic rheometer to monitor the blood coagulation process continuously over an hour or more period. Droplets of blood samples are generated in the rheometer, and the size of the droplets is highly correlated to the sample viscosity. We have calibrated the rheometer using glycerol/water solutions, and the droplet sizes change by more than 4-fold over the viscosity range of 1-100 cP. With the calibrated rheometer, we have measured the viscosities of whole blood during the blood coagulation process with a sensitivity of about 1 cP (<3%). The total blood consumption over an hour period is typically less than 5 µl.