title: Design of microfluidic channels for magnetic separation of malaria-infected red blood cells.
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 et al. 2006 (Han and Frazier 2006) involving a microfluidic magnetophoretic separator for paramagnetic deoxygenated blood cells. The computational model was then applied to a parametric study of a parallel-plate separator having hematocrit of 40% with a 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 µm, the addition of an upstream constriction of 80% improved the proportion of pRBCs retained adjacent to the magnetic wall (separation efficiency) by almost 2 fold, from 26% to 49%. Further addition of a downstream diffuser reduced remixing, 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.
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
authors.forename: Wei-Tao
authors.initials: WT
authors.lastname: Wu
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
authors.forename: Andrea Blue
authors.initials: AB
authors.lastname: Martin
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
authors.forename: Alberto
authors.initials: A
authors.lastname: Gandini
authors.affiliation: Department of Mechanical Engineering, Northeastern University, Boston, MA, 02115, USA.
authors.forename: Nadine
authors.initials: N
authors.lastname: Aubry
authors.affiliation: U. S. Department of Energy, National Energy Technology Laboratory (NETL), PA, 15236, USA.
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Massoudi
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
authors.forename: James F
authors.initials: JF
authors.lastname: Antaki
keywords: Blood; cell separation; magnetic field; malaria; microchannels