Abstract
This paper presents an automated, miniaturized, and portable system capable of detection and differentiation of cultured tumor cells and non-malignant cells. It is also capable of differentiation between single tumor cells and cell clusters. It is noninvasive, and operates without the need for cell labelling, device functionalization, and cell immobilization. The system is composed of a microfabricated electrical impedance spectroscopy (EIS) based sensor, a custom printed circuit board (PCB) and software running on a computer. The custom PCB replaces costly and specialized impedance analysis instruments and the software with a graphical user interface facilitates automated decisions - thus making the system easy to operate. Performance was tested with three human breast cell lines: healthy cell line BPE-3 and tumor cell lines MCF-7 and MDA-MB-231. The system successfully detected and differentiated between the three cell lines. The observed difference between the healthy cell line and the two tumor cell lines was more pronounced. And as cell detection and differentiation is based solely on biophysical properties of cells, disadvantages arising from affinity-based methods can be avoided. The presented miniaturized system possesses the potential to be developed into a low cost, portable and mass producible device for automated detection of CTCs in blood samples at point of care locations. The figure shows the microfabricated sensor consisting of a microfluidic channel with gold electrodes on the channel sidewalls employed to probe biological cells: (A) final device with PDMS layer to be bonded. (B) Microscope image of an electrode pair. (Scale bars 5mm and 100~\mu \text{m} ).
