Isolation of circulating tumor cells with high recovery and purity by cell size amplification and a miro slit filter having extremely high aspect ratio

We have developed a novel circulating tumor cell (CTC) isolation platform for high recovery and purity. It is composed of two processes: 1) selective size amplification of cancer cells using microbeads conjugated with anti-EpCAM to discriminate the size between WBCs and CTCs more clearly, 2) filtration of CTCs using a micro slit filter chip. We designed a micro slit filter having very long single rectangle shape with dimension of 27900 μm × 8 μm (aspect ratio = 3488) to prevent clogging. Clogging causes unwanted aggregation of cells, sticking of WBCs and decrease of purity. An automatic fluid control system was also implemented to conduct the whole fluidic procedures including cell separation and chemical treatments for cell analysis with high reproducibility. We could separate the size amplified CTCs with 91 % recovery and 52 % purity from 5ml of normal whole blood spiked with 100 MCF-7 cells at the flow rate of 100 μl/min.