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Publication 17-CNA-006

Design of microfluidic channels for magnetic separation of malaria-infected red blood cells

We-Tao Wu
Department of Biomedical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
weitaow@andrew.cmu.edu

Andrea Blue Martin
Department of Biomedical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213

Alberto Gandini
Department of Biomedical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213

Nadine Aubry
Department of Mechanical and Industrial Engineering
Northeastern University
Boston, MA 02115
n.aubry@northeastern.edu

Mehrdad Massoudi
Center for Nonlinear Analysis
Department of Mathematical Sciences
Carnegie Mellon University
Pittsburgh, PA 15213
and
National Energy Technology Laboratory (NETL)
U.S. Department of Energy
626 Cochrans Mill Road, P.O. Box 10940
Pittsburgh, PA 15236
massoudi@netl.doe.gov

James F. Antaki
Department of Biomedical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
antaki@cmu.edu

Abstract: This study is motivated by the development of a blood cell filtration device for removal of malaria-infected, parasitized red blood cells (pRBCs). The blood was modeled as a multi-component fluid using the computational fluid dynamics discrete element method (CFD-DEM), wherein plasma was treated as a Newtonian fluid and the red blood cells (RBCs) were modeled as soft-sphere solid particles which move under the influence of drag, collisions with other RBCs, and a magnetic force. The CFD-DEM model was first validated by a comparison with experimental data from Han and Frazier (Lab Chip 6:265273, 2006) involving a microfluidic magnetophoretic separator for paramagnetic deoxygenated blood cells. The computational model was then applied to a parametric study of a parallelplate separator having hematocrit of 40 % with 10 % of the RBCs as pRBCs. Specifically, we investigated the hypothesis of introducing an upstream constriction to the channel to divert the magnetic cells within the near-wall layer where the magnetic force is greatest. Simulations compared the efficacy of various geometries upon the stratification efficiency of the pRBCs. For a channel with nominal height of 100 $\mu $ m, the addition of an upstream constriction of 80 % improved the proportion of pRBCs retained adjacent to the magnetic wall (separation efficiency) by almost twofold, from 26 to 49 %. Further addition of a downstream diffuser reduced remixing and hence improved separation efficiency to 72 %. The constriction introduced a greater pressure drop (from 17 to 495 Pa), which should be considered when scaling up this design for a clinical-sized system. Overall, the advantages of this design include its ability to accommodate physiological hematocrit and high throughput, which is critical for clinical implementation as a blood-filtration system.

Get the paper in its entirety as  17-CNA-006.pdf


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