Magnetic Cell Separation
Magnetic Cell Separation , also known as Magnetic Activated Cell Sorting and often abbreviated as MACS , is an examination method for cells in biology and medicine that was developed in the early 1990s . It is used to sort cell mixtures or to separate certain cells from a mixture on the basis of certain surface structures of the cells. The developer of the method and market leader for the corresponding devices and reagents is the company Miltenyi Biotec .
Principle and implementation
To do this , the cells in a suspension are incubated with so-called MicroBeads. These are magnetic particles around 50 nanometers in size to which antibodies are bound. These antibodies recognize specific structures on the surface of cells and thus ensure that the MicroBeads bind to the desired cell population. When the cell mixture flows through a column surrounded by a strong magnetic field, the cells marked with the MicroBeads are retained. In this way, only unlabeled cells are obtained when the column is rinsed, so that the labeled cell population was removed from the original cell mixture. After removing the magnetic field, the marked cell population can also be obtained by rinsing the column and is thus also available for further experiments. Repeated treatment of a cell mixture with different MicroBeads enables so-called fractional separation, i.e. the separation into several cell populations.
If the selected cells (English target cells target cells ) are for further experiments is called the method also positive selection (English positive selection ). If it is on the other hand with the unlabeled cells to the target cells, is called the separation of a specific population of cells by MACS well depletion (English depletion ). This strategy can also be used to obtain a certain cell fraction for which no specific antibodies or MicroBeads are available or if labeling with MicroBeads is disadvantageous for further experiments. In this case, all other cell populations are removed by repeated depletion until only the desired cells are left in unlabeled form.
The MicroBeads consist of iron oxide and a coating of polysaccharides , to which the antibodies are bound. They are therefore biodegradable and no longer bound to the cells after a few days of cell culture, for example . By enzymatic treatment, a rapid separation of MicroBeads of the cells is also possible.
MACS is typically done manually. Automated solutions are also available for applications with high throughput and for clinical questions.
Individual evidence
- ↑ S. Miltenyi, W. Müller, W. Weichel, A. Radbruch (1990): High gradient magnetic cell separation with MACS. In: Cytometry. 11 (2): 231-238. PMID 1690625 doi : 10.1002 / cyto.990110203