Abstract
Detection and analysis of circulating tumor cells (CTCs) present in human blood is gaining attention as a reliable technique for obtaining information that are vital for diagnostic and research procedures. Only a limited number of semi-automated commercial tools capable of single cell detection and analysis exist; they are expensive and bulky instruments that require highly trained operators. Micro-electromechanical systems (MEMS) are ideal for the application due to their inherent advantages. A method for immobilizing target CTCs at MEMS scale regions of interest was developed. Developed MEMS device utilized superparamagnetic micro beads and micro electromagnets to immobilize MCF-7 cells flowing in a microfluidic channel at a speed of 968.8 µm s-1 at an immobilization rate of 69.2%. Average distance from immobilized cells to center of immobilization region was 50.7 µm. An electrical impedance spectroscopy based microfabricated sensor for tumor cell detection and differentiation while in flow in a microfluidic channel was developed. Cell detection and differentiation between cell lines were demonstrated. This sensor was further developed into a portable standalone system. The healthy breast epithelial cell line BPE3 was found to be distinctly different compared to breast tumor cell lines MCF 7 and MDA MB 231. The differences among tumor cell lines MCF 7, MDA MB 231, SK OV 3 and ES-2 were found to be less pronounced. This system provides a novel and convenient technique to differentiate between single tumor cells and cell clusters. The developed system possess many desirable properties that existing devices lack. It can be further developed to detect circulating tumor cells in blood sample.