Toward Point-of-Care Assessment of Platelet Count-induced Changes in Whole Blood Coagulation with a Dielectric Microsensor

Abstract

This paper reports on the assessment of changes in coagulation dynamics of human whole blood induced by depletion of platelet count using a microfluidic dielectric sensor. The sensor, termed ClotChip, is based on a three-dimensional, parallel-plate, capacitive sensing structure with sensing and floating electrodes integrated into a microfluidic channel. Whole blood samples with quantitative platelet defects are created ex vivo by mixing plasma samples having different platelet counts with red blood cells at a hematocrit level of 0.5. Using an impedance analyzer, the ClotChip readout is shown to be sensitive to changes in the coagulation process dynamics arising from the depleted platelet count. ClotChip performance is benchmarked against rotational thromboelastometry (ROTEM), a clinically important assay for whole blood coagulation. The ClotChip readout parameter, Δe r, max, exhibits a strong positive correlation (r = 0.75 P < 0.001, n = 28) with the ROTEM maximum clot firmness (MCF) parameter. We also demonstrate that the depletion of platelet count affects the time of coagulation onset captured by both the ClotChip and ROTEM assays. This work establishes the ClotChip potential as a point-of-care (POC) platform for rapid assessment of the platelet count-induced changes in coagulation dynamics using only 9µL of whole blood.