Deformable U-shaped microelectrodes made of carbon-PDMS for blood coagulation test

Abstract

Blood coagulation test is heavily required for a broad range of diseases. Microfluidic devices with much smaller footprints and sample consumption have emerged as promising tools for blood clotting assay compared with the commercialized instruments. However, the existing microdevices also pose challenges in terms of the dependency on the relatively costly labeling process and optical setup, as well as the complex fabrication process. In this paper, we demonstrate a deformable 3D U-shaped microelectrode made of conducting carbon-PDMS composite, which suspends in a microchannel for measuring blood clotting based on viscosity change. The microelectrode together with the device is fabricated by replica-molding process. Thus, it enables label-free electrical measurements via a mechanically deformed electrode implemented through low-cost and concise fabrication. The device is capable of measuring glycerol solutions, as modeled viscous fluids, with varied viscosities from 3 cP to 30 cP and infusion flow rates from 0.5 ml/min to 1 ml/min. We also demonstrate the device capability in differentiating the normal blood and the blood pre-treated with high and low concentrations of antiplatelet drug. Meanwhile, we further verify that the device output reflects a blood clotting tendency aligned with that indicated by the tests using clinical approach.