Hybrid capillary-inserted microfluidic device for sheathless particle focusing and separation in viscoelastic flow |
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Authors: | Jeonghun Nam Justin Kok Soon Tan Bee Luan Khoo Bumseok Namgung Hwa Liang Leo Chwee Teck Lim Sangho Kim |
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Institution: | 1.Department of Biomedical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575;2.Department of Surgery, National University of Singapore, 1E Kent Ridge Road, Singapore, 119228 |
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Abstract: | A novel microfluidic device which consists of two stages for particle focusing and separation using a viscoelastic fluid has been developed. A circular capillary tube was used for three-dimensional particle pre-alignment before the separation process, which was inserted in a polydimethylsiloxane microchannel. Particles with diameters of 5 and 10 μm were focused at the centerline in the capillary tube, and the location of particles was initialized at the first bifurcation. Then, 5 and 10 μm particles were successfully separated in the expansion region based on size-dependent lateral migration, with ∼99% separation efficiency. The proposed device was further applied to separation of MCF-7 cells from leukocytes. Based on the cell size distribution, an approximate size cutoff for separation was determined to be 16 μm. At 200 μl/min, 94% of MCF-7 cells were separated with the purity of ∼97%. According to the trypan blue exclusion assay, high viability (∼90%) could be achieved for the separated MCF-7 cells. The use of a commercially available capillary tube enables the device to be highly versatile in dealing with particles in a wide size range by using capillary tubes with different inner diameters. |
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