Membrane capacitance of thousands of single white blood cells

As label-free biomarkers, the electrical properties of single cells arewidely used for cell type classification and cellular status evaluation. However, as intrinsic cellular electrical markers, previously reported membrane capacitances (e.g. specific membrane capacitance Cspec and total membrane capacitance Cmem) of white blood cellswere derived from tens of single cells, lacking statistical significance due to low cell numbers. In this study, white blood cells were first separated into granulocytes and lymphocytes by density gradient centrifugation and were then aspirated through a microfluidic constriction channel to characterize both Cspec and Cmem. Thousands of granulocytes (ncell = 3327) and lymphocytes (ncell = 3302) from 10 healthy blood donors were characterized, resulting in Cspec values of 1.95+0.22 mF cm22 versus 2.39+0.39 mF cm22 and Cmem values of 6.81+1.09 pF versus 4.63+0.57 pF. Statistically significant differences between granulocytes and lymphocytes were located for both Cspec andCmem. In addition, neural network-based pattern recognition was used to classify white blood cells, producing successful classification rates of 78.1% for Cspec and 91.3% for Cmem, respectively. These results indicate that as intrinsic bioelectrical markers, membrane capacitances may contribute to the classification of white blood cells.