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Anal Bioanal Chem (2014) 406:16611670 DOI 10.1007/s00216-013-7394-z
RESEARCH PAPER
Feasibility study of red blood cell debulking by magnetic field-flow fractionation with step-programmed flow
Lee R. Moore & P. Stephen Williams & Franziska Nehl &
Koji Abe & Jeffrey J. Chalmers & Maciej Zborowski
Received: 16 July 2013 /Revised: 20 September 2013 /Accepted: 23 September 2013 /Published online: 19 October 2013 # Springer-Verlag Berlin Heidelberg 2013
Abstract Emerging applications of rare cell separation and analysis, such as separation of mature red blood cells from hematopoietic cell cultures, require efficient methods of red blood cell (RBC) debulking. We have tested the feasibility of magnetic RBC separation as an alternative to centrifugal separation using an approach based on the mechanism of magnetic field-flow fractionation (MgFFF). A specially designed permanent magnet assembly generated a quadrupole field having a maximum field of 1.68 T at the magnet pole tips, zero field at the aperture axis, and a nearly constant radial field gradient of 1.75 T/mm (with a negligible angular component) inside a cylindrical aperture of 1.9 mm (diameter) and 76 mm (length). The cell samples included high-spin hemoglobin RBCs obtained by chemical conversion of hemoglobin
to methemoglobin (met RBC) or by exposure to anoxic conditions (deoxy RBC), low-spin hemoglobin obtained by exposure of RBC suspension to ambient air (oxy RBC), and mixtures of deoxy RBC and cells from a KG-1a white blood cell (WBC) line. The observation that met RBCs did not elute from the channel at the lower flow rate of 0.05 mL/min applied for 15 min but quickly eluted at the subsequent higher flow rate of 2.0 mL/min was in agreement with FFF theory. The well-defined experimental conditions (precise field and flow characteristics) and a well-established FFF theory verified by studies with model cell systems provided us with a strong basis for making predictions about potential practical applications of the magnetic RBC separation.
Keywords Magnetic cell separation . Label-free separation . Magnetophoresis . Magnetic field-flow fractionation . FFF . Hemoglobin magnetic susceptibility
Introduction
Centrifugation plays an important role in the separation of blood into its basic components of red blood cells (RBCs), white blood cells (WBCs), platelets, and plasma [1]. It is widely used for blood sample enrichment of nucleated cells (leukocytes) for use in diagnostic and therapeutic...