Electrical characterization of single tumor cells with high accuracy using a low-cost microfluidic impedance cytometry.

In this paper, we proposed a low-cost and easily fabricated microfluidic impedance cytometer (HF-MIC) based on 3D hydrodynamic focusing for the electrical characterization and identification of tumor cells with high-accuracy. The detection electrodes and detection channel of HF-MIC were easily fabricated by laser cutting conductive film of indium tin oxide (ITO) glass and double-sided adhesive tapes, respectively. The fabrication and assembly period of the HF-MIC is shortened to less than 1 h and the cost is less than $4 per device. First, numerical methods explored the positional dependence of impedance signals and particle focusing behaviors. Then, the performance tests of the HF-MIC using polystyrene particles verified its ability to acquire impedance signals with high focusing efficiency (>94%), high focusing stability (CV < 0.08) and high SNR (>8 dB). Finally, key dielectric parameters-cell diameter (Dcell), impedance amplitude opacity |Z|HF/|Z|LF, phase opacity ϴ(ZHF)/ϴ(ZLF), opacity X (Re(ZHF)/Re(ZLF)), and opacity Y (Im(ZHF)/Im(ZLF))-were used to analyze the cell dielectric properties and divided into four groups to train four BPNN models. For all identification tasks (WBCs vs. tumor cells, tumor cells from different organs, and tumor cells with the same phenotype from the same type of organs), the TPR given by Model Ⅳ all reached 99%. Our HF-MIC enables the detection of cells without causing clogging and offers the advantages of simple fabrication, low cost, and high-accuracy electrical characterization and identification of tumor cells.