Three-dimensional hydrodynamic focusing with a single sheath flow in a single-layer microfluidic device.
We report a contraction-expansion array (CEA) microchannel that allows three-dimensional hydrodynamic focusing with a single sheath flow in a single-layer device. The CEA microchannel exploits centrifugal forces acting on fluids travelling along the contraction and expansion regions of the microchannel. Around an entrance of the contraction region, the centrifugal forces induce a secondary flow field where two counter-rotating vortices enable to envelop a sample flow with a sheath flow in three dimensions. We herein describe an underlying principle and a design of the CEA microchannel and demonstrate complete sheathing of a sample fluid (water and human red blood cells) in three dimensions. The focusing characteristics of the CEA microchannel are investigated in terms of the number of the rectangular structures, flow rate, and flow ratio between sample and sheath flows. This microfluidic channel for three-dimensional hydrodynamic focusing is easy to fabricate in a single-layer fabrication process and simple to operate with a single sheath flow.
Lee
Myung Gwon
MG
Department of Bio and Brain Engineering, College of Life Science and Bioengineering, KAIST, 335 Gwahangno, Yuseong-gu, Daejeon 305-701, Republic of Korea.
Choi
Sungyoung
S
Park
Je-Kyun
JK
D004867:Equipment Design; D004912:Erythrocytes / Q000166:cytology; D005434:Flow Cytometry / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D056656:Lab-On-A-Chip Devices; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*