Sickle cell disease (SCD) is primarily associated with episodic vaso-occlusive events. Poorly deformable sickle cells may get stuck in small blood vessels, slow down or block blood flow, leading to local hypoxia that damages tissues and organs. In this paper, we present a novel electrical impedance sensing technique for detection of the progressive occlusion by sickle cells in microfluidic capillary structures. Changes in both resistance and reactance of the sickle blood flow were observed at multiple low frequencies (< 500 kHz), upon the deoxygenation and reoxygenation processes. In contrast, no obvious impedance changes were observed in the flow of normal blood cells and sickle blood cells treated with anti-sickling agent. Accuracy of the impedance-based detection of the vaso-occlusion process was verified by microscopic observation. The results show the distinct sensing performance of sickle cell vaso-occlusion by electrical impedance, which does not require sophisticated optical microscopy or video processing. The low frequency impedance sensing can be achieved by replacing the benchtop equipment with low-cost, high precision impedance converter system, allowing for detection of sickle cell vaso-occlusion in point-of-care settings.
Electrical impedance detection of sickle cell vaso-occlusion in microfluidic capillary structures
