Single HeLa and MCF-7 cell measurement using minimized impedance spectroscopy and microfluidic device

This study presents an impedance measurement system for single-cell capture and measurement. The microwell structure which utilizes nDEP force is used to single-cell capture and a minimized impedance spectroscopy which includes a power supply chip, an impedance measurement chip and a USB microcontroller chip is used to single-cell impedance measurement. To improve the measurement accuracy of the proposed system, Biquadratic fitting is used in this study. The measurement accuracy and reliability of the proposed system are compared to those of a conventional precision impedance analyzer. Moreover, a stable material, latex beads, is used to study the impedance measurement using the minimized impedance spectroscopy with cell-trapping device. Finally, the proposed system is used to measure the impedance of HeLa cells and MCF-7 cells. The impedance of single HeLa cells decreased from 9.55 × 10³ to 3.36 × 10³ Ω and the impedance of single MCF-7 cells decreased from 3.48 × 10³ to 1.45 × 10³ Ω at an operate voltage of 0.5 V when the excitation frequency was increased from 11 to 101 kHz. The results demonstrate that the proposed impedance measurement system successfully distinguishes HeLa cells and MCF-7 cells.