High gradient magnetic cell separation with MACS

Abstract

A flexible, fast and simple magnetic cell sorting system for separation of large numbers of cells according to specific cell surface markers was developed and tested. Cells stained sequentially with biotinylated antibodies, fluorochrome‐conjugated avidin, and superparamagnetic biotinylated‐microparticles (about 100 nm diameter) are separated on high gradient magnetic (HGM) columns. Unlabelled cells pass through the column, while labelled cells are retained. The retained cells can be easily eluted. More than 109 cells can be processed in about 15 min. Enrichment rates of more than 100‐fold and depletion rates of several 1,000‐fold can be achieved. The simultaneous tagging of cells with fluorochromes and very small, invisible magnetic beads makes this system an ideal complement to flow cytometry. Light scatter and fluorescent parameters of the cells are not changed by the bound particles. Magnetically separated cells can be analysed by fluorescence microscopy or flow cytometry or sorted by fluorescence‐activated cell sorting without further treatment. Magnetic tagging and separation does not affect cell viability and proliferation.

Culture system for extensive production of CD19+IgM+ cells by human cord blood CD34+ progenitors

“…The non-adherent mononuclear cells were further enriched for CD34 + cells using a MACS CD34 Progenitor Cell Isolation Kit (Miltenyi Biotec, BergischGladbach, Germany) as described in detail elsewhere. 21,22 Briefly, nonadherent mononuclear cells were indirectly magnetically labeled using a hapten-conjugated primary monoclonal antibody (mAb) against CD34 (QBEND/10) and an antihapten antibody (Ab) coupled to MACS MicroBeads. The magnetically labeled CD34 + cells were enriched on a positive selection column.…”

Combining Step Gradients and Linear Gradients in Density

“…Solutions of high concentrations of metal sulfates mixed with PEG phase separate and form AMPS with a much higher concentration of salt in one phase than the other. 43−45 We predicted that a large step in magnetic susceptibility could be formed in an AMPS comprising a polymer, such as PEG, and a paramagnetic sulfate salt, such as MnSO 4 . We, thus, chose a PEG−MnSO 4 system to explore a gradient with a large step in the magnetic susceptibility.…”

“…We measured the intensity of the Mn-specific wavelength (λ = 257.610 nm) from diluted aliquots of each phase. We compared these intensities to those from a standard curve that we generated using known concentrations of MnCl 2 or MnSO 4 .…”

“…Preparing unequal gradients in density using an aqueous multiphase system (AMPS) formed from a paramagnetic salt as a medium for magnetic levitation (MagLev). A mixture of 16.7% (wt/ vol) poly(ethylene glycol) and 875 mM MnSO 4 generates an AMPS with a large step in both density and magnetic susceptibility between phases. The gradients in density are illustrated by five density standard beads: 1.045 g/cm 3 (yellow), 1.081 g/cm 3 (red), 1.100 g/cm 3 (clear, middle), 1.250 g/cm 3 (green), and 1.500 g/cm 3 (clear, bottom).…”

Continuous-flow ferrohydrodynamic sorting of particles and cells in microfluidic devices

“…Compared to high-specificity and label-based cell sorting techniques such as 0fluorescence-activated cell sorter (FACS) (Bonner et al 1972) and magnetic-activated cell sorter (MACS) (Miltenyi et al 1990), microfluidic sortings are mostly label-free, relying on cells' intrinsic properties such as size, shape, density, deformability, electric and magnetic properties for manipulation specificity (Pamme 2007;Tsutsui and Ho 2009;Gossett et al 2010;Lenshof and Laurell 2010). When applicable, microfluidic sortings are favored over label-based ones, because they are inexpensive and require minimal user training for operation (Gossett et al 2010).…”