CD4+ T Cell Counting by Impedance Measurement on a Chip with Fluidic Electrodes

摘要

A practical label-free method for counting CD4+ T cells is proposed on the basis of a microfluidic chip with fluidic electrodes. With the help of hydrodynamic focusing, two sheath flows of KCl solution, serving as electric conductors to replace solid metal electrodes, are used to squeeze the cell suspension. By measuring the electrical impedances between the fluidic electrodes, a linear relationship is found between the logarithmic value of cell concentration and the impedance value (R~2 = 0.97). The detection limit of CD4+ T lymphocytes reaches as low as ～10 cells·μL~(-1), Both the CD4+ T cell concentration of the nude mice group and that of the normal group were counted to further test the function of the chip system, which indicated that there existed significant differences between these groups, showing the approach is valid for identifying immunodeficiency.