Abstract：
Electrical properties of single cells are important label-free biomarkers of disease and immunity. At present, impedance flow cytometry (IFC) provides important means for high throughput characterization of single-cell electrical properties. However, the accuracy of the spherical single-shell electrical model widely used in IFC has not been well evaluated due to the lack of reliable and reproducible single-shell model particles with true-value electrical parameters as benchmarks. Herein, a method is proposed to evaluate the accuracy of the single-cell electrical model with cell-sized unilamellar liposomes synthesized through double emulsion droplet microfluidics. The influence of three key dimension parameters (i.e., the measurement channel width w, height h, and electrode gap g) in the single-cell electrical model were evaluated through experiment. It was found that the relative error of the electrical intrinsic parameters measured by IFC is less than 10% when the size of the sensing zone is close to the measured particles. It further reveals that h has the greatest influence on the measurement accuracy, and the maximum relative error can reach ∼30%. Error caused by g is slightly larger than w. This provides a solid guideline for the design of IFC measurement system. It is envisioned that this method can advance further improvement of IFC and accurate electrical characterization of single cells.
摘要：
单细胞的电特性是疾病和免疫的重要无标记生物标志物。目前,阻抗流式细胞术（IFC）为高通量表征单细胞电性能提供了重要手段。然而,由于缺乏以真值电参数为基准的可靠和可重现的单壳模型粒子，IFC中广泛使用的球形单壳电模型的准确性尚未得到很好的评估。在这里，提出了一种方法来评估通过双乳液液滴微流体合成的细胞大小的单层脂质体的单细胞电模型的准确性。三个关键尺寸参数的影响(即，测量通道宽度w，高度h,和电极间隙g)在单细胞电模型中通过实验进行评估。发现当传感区的尺寸接近被测颗粒时，IFC测得的电固有参数的相对误差小于10％。这进一步揭示了h对测量精度的影响最大，最大相对误差可达30%。由g引起的误差略大于w。这为IFC测量系统的设计提供了坚实的指导。可以预见,该方法可以促进IFC的进一步改进和单细胞的精确电表征。
