Evaluating the Accuracy of Impedance Flow Cytometry with Cell-Sized Liposomes

Electrical properties of single cells are important label-freebiomarkers of disease and immunity. At present, impedance flow cytometry(IFC) provides important means for high throughput characterizationof single-cell electrical properties. However, the accuracy of thespherical single-shell electrical model widely used in IFC has notbeen well evaluated due to the lack of reliable and reproducible single-shellmodel particles with true-value electrical parameters as benchmarks.Herein, a method is proposed to evaluate the accuracy of the single-cellelectrical model with cell-sized unilamellar liposomes synthesizedthrough double emulsion droplet microfluidics. The influence of threekey dimension parameters (i.e., the measurement channel width w, height h, and electrode gap g) in the single-cell electrical model were evaluated throughexperiment. It was found that the relative error of the electricalintrinsic parameters measured by IFC is less than 10% when the sizeof the sensing zone is close to the measured particles. It furtherreveals that h has the greatest influence on themeasurement accuracy, and the maximum relative error can reach & SIM;30%.Error caused by g is slightly larger than w. This provides a solid guideline for the design of IFCmeasurement system. It is envisioned that this method can advancefurther improvement of IFC and accurate electrical characterizationof single cells.