Magnetic Cell Separation:  Characterization of Magnetophoretic Mobility

Abstract

Magnetic cell separation has become a popular technique to enrich or deplete cells of interest from a heterogeneous cell population. One important aspect of magnetic cell separation is the degree to which a cell binds paramagnetic material. It is this paramagnetic material that imparts a positive magnetophoretic mobility to the target cell, thus allowing effective cell separation. A mathematical relationship has been developed to correlate magnetic labeling to the magnetophoretic mobility of an immunomagnetically labeled cell. Four parameters have been identified that significantly affect magnetophoretic mobility of an immunomagnetically labeled cell: the antibody binding capacity (ABC) of a cell population, the secondary antibody amplification (psi), the particle-magnetic field interaction parameter (DeltachiV(m)), and the cell diameter (D(c)). The ranges of these parameters are calculated and presented along with how the parameters affect the minimum and maximum range of magnetophoretic mobility. A detailed understanding of these parameters allows predictions of cellular magnetophoretic mobilities and provides control of cell mobility through selection of antibodies and magnetic particle conjugates.

Magnetic bead handling on-chip: new opportunities for analytical applications

“…Of course, the fluid transport velocity should not exceed a maximum limit to enable a correct separation over the magnetic field gradient region. Using such a quadrupole magnetic sorter, magnetic cell separation was shown to be a function of the antibody binding capacity, which is related to the number of magnetic bead labeling sites of a single cell (McCloskey et al 2003a(McCloskey et al , 2003b). An alternative way to obtain an efficient magnetic separation is to loosely pack the flow column with a magnetizable matrix of thin wires or beads (Rheinlander et al 2000;Ebner and Ritter 2001), but such method can suffer from problems of desorption of the magnetic beads from the matrix after the removal of the field.…”

Continuous particle separation based on electrical properties using alternating current dielectrophoresis

“…To achieve these, various techniques have been developed to be used in microsystems such as optical tweezers [1], magnetophoresis [2], acoustic means [3,4,5] and dielectrophoresis (DEP). Among these, DEP is one of the most popular methods for particle manipulation in microsystems due to (i) its favorable scaling effects [6], (ii) the simplicity of the instrumentation and (iii) its ability to induce both negative and positive forces [7].…”

Single Step Isolation and Activation of Primary CD3+ T Lymphocytes Using Alcohol-Dispersed Electrospun Magnetic Nanofibers

“…Taken together, these data suggest that low to intermediate TCR cross-linking with anti-CD3 mAb appeared to drive activation and expansion of CD8 At present, magnetic cell separation is one of the most popular tools for isolating cells of interest. 23,24 Magnetic cell separation utilizes magnetic nanoparticle beads of ∼50 nm that are conjugated with monoclonal antibodies generated against cell-or tissue-specific surface receptors to enrich (positively select) or deplete (negatively select) target cells in a heterogeneous cell mixture. Positive selection often yields higher purity of the intended cell population but may cause unexpected cellular effects due to binding of magnetic nanoparticles on cell surface.…”