Localization of low-abundant cancer cells in a sharply expanded microfluidic step-channel using dielectrophoresis

Abstract

An efficient method for cell trapping onto a designated location and reduction of the sample volume is required to reduce the risk of sample losses during the discrimination and molecular characterization of low-abundant cells suspended in a large volume of the sample. In this study, we propose a novel microfluidic device that allows for highly efficient trapping of the cancer cells onto a designated location and correction of the trapped cells with a significantly reduced sample volume. The microfluidic device, which utilizes dielectrophoresis cell trapping, consists of an attraction-zone to control the vertical position of the cells and a trap-zone to capture the target cells by drastically decreasing the flow velocity around the cells with a sharply increased channel height. The device showed that 92 ± 9% of the introduced cancer cells were trapped on a designated location (500-μm behind the step) with a high inlet flow rate of 100 μl min−1. The trapped cells were corrected with a one-hundredth volume by introducing reagents for the downstream analysis to the outlet of the device. The feasibility of the system with regard to the localization and recovery of target cells was successfully demonstrated by trapping a mixture of cancer cells and white blood cells and detecting single nucleotide variants from the collected samples. We believe that our system is suitable for the sample preparation of low-abundant cells suspended in a large sample volume, owing to its ability to perform the localization and recovery of trapped cells with minimal target cell loss.