Design and Demonstration of a Novel Microfluidic Channel for Trapping Circulating Tumor Cells with Magnetophoresis

The effective isolation of circulating tumor cells (CTCs) is significant for early detection of cancer. Recent advances in microfluidics technology enables us to integrate several techniques to increase efficiency and sensitivity in cell sorting and isolation. One of the successful techniques used in microfluidics cell separation is magnetophoresis. In this paper, a novel device is designed and fabricated by integrating a microfluidic channel with crescent-shaped pillars and magnetophoresis force to trap the magnetic nanoparticle (MNP) labeled CTCs. The effectiveness of using pillars and the trapping yield is investigated by simulations in COMSOL Multiphysics and later confirmed with experiments. Due to micron scale features in the channel, direct laser lithography and soft lithography have been used to fabricate the chip. The MNPs are Fe304 and their biocompatibility is examined using the MTT assay. For labeling, 500µg of nanoparticles is mixed with 200,000 cells and are incubated for one hour. Finally, to show the efficiency of isolation, using Neubauer slide and fluorescence imaging, the number of cancer cells in inlet and trapped inside the channel is counted and 60% yield is calculated.