(349d) Microfluidic Device to Measure Blood Health

The rheological properties of whole blood can indicate several adverse health conditions. For instance, high values of blood viscosity are correlated with cardiovascular and cerebrovascular diseases, while abnormal blood coagulation indicate possible higher mortalities in patients suffering traumatic brain injury. Despite these relationships, assessment of blood’s rheological variables in clinical practice is uncommon due to difficulties in the procedures to obtain this data. Viscosity measurements of complex fluids have been generally accomplished using rheometers and capillary viscometers, which are reliable methods but require cumbersome procedures, expensive equipment, and large amounts of blood to function.

To make rheological information accessible, we propose the use of simple and inexpensive microfluidic device to measure blood flow properties. We have designed a microfluidic droplet-based viscometer where the length of the droplets created is inversely proportional to the viscosity of the sample. The device can operate at different shear rates and has been optimized to use with complex fluids including blood, polymer solutions, and various non-Newtonian fluids. In addition, the device is capable of measuring the coagulation process in blood by continuously measuring viscosity. The device can detect both the onset of the clotting reaction and the time necessary for clot formation, both vital to assessing a patient’s clotting function. The device can also study the coagulation process at different shear rates. The measurements for all variables can be done under ten minutes using micro volume samples.

Our goal is for the viscosity and coagulation measurements to be integrated in a single device to obtain “vital signs” for blood health from a single sample. Reliable and simple devices to measure the rheological properties of blood could improve the diagnostic and treatment of patients. Additional blood properties could also be added including a measurement of the deformability of red blood cells, an important factor in many diseases including sickle-cell anemia and malaria. In addition, these technologies can be used in a variety of industries for the study of flocculation, complex fluids rheology, particles stiffness, and polymerization reactions.