Leukocyte analysis and differentiation using high speed microfluidic single cell impedance cytometry

TLDR

Miniature high‑speed label‑free cell analysis systems could enable fast, inexpensive, routine full‑blood analysis, yet have not yet been developed. The study demonstrates a microfluidic single‑cell impedance cytometer that performs a white‑blood‑cell differential count. The microfluidic chip, equipped with micro‑electrodes measuring impedance at two frequencies, processes saponin/formic‑acid‑lysed blood and verifies cell dielectric parameters via simultaneous fluorescence from CD‑antibody‑conjugated cells. Impedance signals correlated directly with cell phenotype, and patient sample tests showed 95 % agreement with commercial optical/Coulter analyzers, indicating clinical utility.

Abstract

Miniature high speed label-free cell analysis systems have yet to be developed, but have the potential to deliver fast, inexpensive and simple full blood cell analysis systems that could be used routinely in clinical practice. We demonstrate a microfluidic single cell impedance cytometer that performs a white blood cell differential count. The device consists of a microfluidic chip with micro-electrodes that measure the impedance of single cells at two frequencies. Human blood, treated with saponin/formic acid to lyse erythrocytes, flows through the device and a complete blood count is performed in a few minutes. Verification of cell dielectric parameters was performed by simultaneously measuring fluorescence from CD antibody-conjugated cells. This enabled direct correlation of impedance signals from individual cells with phenotype. Tests with patient samples showed 95% correlation against commercial (optical/Coulter) blood analysis equipment, demonstrating the potential clinical utility of the impedance microcytometer for a point-of-care blood analysis system.