title: Hybrid capillary-inserted microfluidic device for sheathless particle focusing and separation in viscoelastic flow.
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.
authors.affiliation: Department of Biomedical Engineering, National University of Singapore , 9 Engineering Drive 1, Singapore 117575.
authors.forename: Jeonghun
authors.initials: J
authors.lastname: Nam
authors.affiliation: Department of Biomedical Engineering, National University of Singapore , 9 Engineering Drive 1, Singapore 117575.
authors.forename: Justin Kok Soon
authors.initials: JK
authors.lastname: Tan
authors.affiliation: Department of Biomedical Engineering, National University of Singapore , 9 Engineering Drive 1, Singapore 117575.
authors.forename: Bee Luan
authors.initials: BL
authors.lastname: Khoo
authors.affiliation: Department of Biomedical Engineering, National University of Singapore , 9 Engineering Drive 1, Singapore 117575.
authors.forename: Bumseok
authors.initials: B
authors.lastname: Namgung
authors.affiliation: Department of Biomedical Engineering, National University of Singapore , 9 Engineering Drive 1, Singapore 117575.
authors.forename: Hwa Liang
authors.initials: HL
authors.lastname: Leo
authors.affiliation: Department of Biomedical Engineering, National University of Singapore , 9 Engineering Drive 1, Singapore 117575.
authors.forename: Chwee Teck
authors.initials: CT
authors.lastname: Lim
authors.forename: Sangho
authors.initials: S
authors.lastname: Kim