title: Label-free cell separation using a tunable magnetophoretic repulsion force.
abstract: This paper describes a new label-free cell separation method using a magnetic repulsion force resulting from the magnetic susceptibility difference between cells and a paramagnetic buffer solution in a microchannel. The difference in the magnetic forces acting on different-sized cells is enhanced by adjusting the magnetic susceptibility of the surrounding medium, which depends on the concentration of paramagnetic salts, such as biocompatible gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), dissolved therein. As a proof-of-concept demonstration, Gd-DTPA solutions at concentrations of 0-80 mM were applied to separate U937 cells from red blood cells (RBCs) and to distinguish two different-sized polystyrene (PS) beads (8 and 10 μm in diameter). By increasing the Gd-DTPA concentration from 0 to 40 mM, the separation resolution of PS beads was increased from 0.08 to 0.91. Additionally, we successfully achieved label-free separation of U937 cells from RBCs with >90% purity and 1 × 10(5) cells/h throughput using a 40 mM Gd-DTPA solution.
authors.affiliation: Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Fengshan
authors.initials: F
authors.lastname: Shen
authors.forename: Hyundoo
authors.initials: H
authors.lastname: Hwang
authors.forename: Young Ki
authors.initials: YK
authors.lastname: Hahn
authors.forename: Je-Kyun
authors.initials: JK
authors.lastname: Park
mesh_terms: D002460:Cell Line; D002469:Cell Separation / Q000295:instrumentation / Q000379:methods*; D004912:Erythrocytes / Q000166:cytology; D019786:Gadolinium DTPA / Q000737:chemistry; D006801:Humans; D060328:Magnetic Phenomena; D046210:Microfluidic Analytical Techniques; D011137:Polystyrenes / Q000737:chemistry; D012492:Salts / Q000737:chemistry
chemical_list: D011137:Polystyrenes; D012492:Salts; D019786:Gadolinium DTPA