Microfluidic Paper Analytic Device for Assessment of Blood Coagulation

Abstract

Monitoring blood coagulation while a patient is on cardiopulmonary bypass (CPB) is critical in preventing clots from arising in the bypass machine and consequently being sent into the patient’s bloodstream. Current methods used to monitor blood coagulation such as Activated Clotting Time (ACT) yield results that do not correlate coagulation time to heparin or protamine dosage and will typically take at least 400 s to yield a result that is safe to initiate bypass. Microfluidic paper-based analytical devices (μPAD) are advanced sensors based on a wide range of recently developed techniques for complex analytical methods. In this research, a point-of-care (POC) sensor was developed based on techniques adapted from lateral flow and µPAD. The effects of varied dosages of heparin and protamine were observed using this POC µPAD and an accompanying Raspberry pi-based monitoring device. Paper microfluidic channels were printed on nitrocellulose paper with a wax pattern. Human whole blood was added to an absorbent fiber glass sample pad preloaded with known amount of heparin or protamine. By having this absorbent pad on the inlet of the channel, the blood sample is able to travel through the channel via capillary flow. Significantly different (p < 0.05) rates of flow between blood samples with different doses of heparin and protamine show that the device can monitor the extent of coagulation and patient-specific responses to each drug. Thus a low-cost device was built that monitors the extent of blood coagulation and allows for individualized dosing of heparin and protamine in as little at 20 s and no more than 180 s.