서강대학교

초록/요약

In this paper, we propose a microfluidic chip that measures the deformability of single cells by using impedance measurement method. The mechanical deformability of cells strongly depends on the progression of cancer metastasis. Previously, changes of physical and structural properties of cells have been monitored by several methods including atomic force microscopy (AFM) and optical tweezers. However, it is difficult to discern the deformability of cells by using aforementioned methods. Furthermore, physical changes of cells may occur and even be damaged by the induced optical energy. We have fabricated a microfluidic chip which measures the deformability single cells electrically. The proposed microfluidic chip is composed of PDMS channel and a glass substrate with electrode. The pressure is applied to on-chip aspiration channel to capture and deform a single cell. The deformed cell is monitored by impedance measurement. AD 5934 (Analog Devices) impedance converter was used to measure the impedance at the frequency range from 0.5 kHz to 2.5 kHz. Deformability of human breast cancer cell (MCF-7) and normal cell (MCF-10A) were measured at the experiment. Aspiration pressure of 20 kPa to 30 kPa was applied by using a syringe pump to deform the cell. The electrodes located on both sides of the stretched cell membrane measured the electrical impedance. After aspiration of MCF-10A, the length of the stretched cell membrane was 11 µm, where the measured electrical impedance was 11.87 MΩ at 790 Hz. Under same experimental setup conducted with MCF-7, the length of the stretched cell membrane was 30 µm. The impedance of the stretched MCF-7 membrane was 18.08 MΩ at the same frequency. Therefore, we successfully demonstrated that MCF-7 cells are more deformable than MCF-10A cells and proved this by using impedance measurement method.