Quantification of cell number in 3-dimensional cell culture construct by impedance measurement using microfluidic technology

This paper presents a technique to determine cell number in 3D cell culture construct quantitatively. A measurement platform embedded with on-chip vertical electrodes has been developed and is capable of onsite impedimetric detecting cell number without sacrificing the cultured cells. In vitro 3D cell culture has been interpreted for faithfully representation of the in vivo cellular behavior in living tissues. However, monitoring of the cell number in 3D cell culture construct is normally based on the detection of the indicative cellular components, e.g., DNA assay, which requires sacrificing the cultured cells and hampers the subsequent cellular assays. In this study, the total impedance of the cells/agarose construct can be measured across the vertical electrodes and the cell number in the construct can be determined. The impedance amplitude of the construct was proportional to the cell number in the construct. Breast cancer cells in cell numbers of 10⁴, 10⁵, and 10⁶ cells/ml were estimated using the proposed method. The proposed technique provides a fast and easy method compared with the conventional cell analysis techniques. It has a high potential to be integrated into a microfluidic chip for on-chip cell analysis during 3D cell culture process.