Measurement of Impedimetric Ratio of Blood Cells Using Microfluidic Chip with ZnO Nanowires

Abstract

A disposable microfluidic chip for measuring the impedimetric ratio of blood cells was developed. The undiluted blood sample was separated into erythrocytes and leukocytes in the blood separation microchannel of the chip, and the erythrocytes and leukocytes were then driven into the measurement chambers, respectively. Inside each measurement chamber was an interdigitated electrode (IDE) array acting as a sensor for the impedimetric measurement of the blood cells. On the surface of the IDE array, ZnO nanowires were synthesized to promote the sensitivity of the impedimetric measurement. The experimental result showed that the measured impedance was proportional to the number of blood cells. The IDE array with ZnO nanowires was more sensitive than the IDE without nanowires. We also used freshly drawn venous blood samples from five healthy donors and ten informed and consenting patients for comparison. The impedimetric ratios of the five healthy donors were similar with low standard deviation, indicating that the impedimetric ratio would tend to be a reliable threshold as the indicator of erythrocytes to leukocytes. The impedimetric measurements of all patients were below the threshold. Using impedimetric measurement, the change in leukocytes could be easily monitored.