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.

Automated summary

The electrical properties of single cells are important biomarkers for disease and immunity. Impedance flow cytometry (IFC) provides a means to characterize the electrical properties of single cells on a high throughput scale. This study proposes a method to evaluate the accuracy of the single-cell electrical model using cell-sized unilamellar liposomes. Experimental results show that the relative error of the electrical parameters measured by IFC is less than 10% when the size of the sensing zone is close to the measured particles. This method can contribute to the improvement of IFC and the accurate characterization of single cells.