Cell isolation techniques are methods to separate and transfer certain cells from a complex mixture of cells to obtain single cells or to sort the cells according to a property of choice and thus generate a homogenous cell population. One approach to separating cells is magnetic-activated cell sorting (MACS), which uses magnets to isolate targeted cells from the rest of a biological sample.
Why is Cell Separation Important?
The ability to study individual cells provides insight into their specific functions and roles within the human body. Technologies that isolate rare cell types to high purity are essential to the cell biology researcher. Understanding cell development pathways becomes increasingly significant as diagnosis and treatment of disease turn more to the molecular level.
What are the Approaches to Isolating Cells?
- Positive selection is when the cell type of interest is targeted by the removal mechanism and retained for downstream applications. This approach involves targeting the desired cell population with an affinity molecule specific to a surface marker of the cell, leaving behind unwanted cells in the sample.
- Negative selection is when unwanted cell types are labeled with affinity molecules such as antibodies or proteins that target specific cell markers or populations and then removed, leaving one cell type untouched. The untouched cell sample is then collected for downstream applications.
- Cell depletion is the third and simplest approach in which a single cell type is removed from a biological sample.
How Magnetic-Activated Cell Sorting Works?
Magnetic-activated cell sorting (MACS) is a form of immunomagnetic separation that involves binding magnetic particles to target cells through an affinity molecule/surface marker interaction. Then, the sample is subjected to a magnetic field that suspends cells in a liquid solution, letting other cells flow through freely.
- Magnetic beads coated with antibodies, lectins, or enzymes that are associated with surface markers or antigens of the targeted cell group are added to a biological sample.
- Cells with those surface markers are labeled by the magnetic beads.
- The solution is transferred to a column, and a magnetic field is applied.
- Targeted cells, those attached to the magnetic beads, are magnetized to the walls of the column while non-targeted cells flow through the column.
- The magnetic field is turned off, and the bead-carrying cells are released for recovery.
Magnetic Labeling Strategies
Direct magnetic labeling
Direct labeling with MACS beads is the fastest way of magnetic labeling. MACS beads specifically bind to antigens on the cell surface. Only one incubation step is required. Direct magnetic labeling requires a minimal number of washing steps and therefore minimizes cell loss.
Indirect magnetic labeling
Indirect magnetic labeling using primary antibodies and beads is based on a two-step procedure. First, the cells are labeled with a primary antibody directed against a cell surface marker. Subsequently, the cells are magnetically labeled with a MACS bead, which either binds directly to the primary antibody or to a molecule that is conjugated to the primary antibody. Conjugated molecules include biotin and fluorochromes. Accordingly, magnetic labeling is achieved with Anti-Immunoglobulin beads, Anti-Biotin beads, or Anti-Fluorochrome beads.
Creative Bioarray Relevant Recommendations
Creative Bioarray is dedicated to delivering thoroughly tested and high-quality products that do not adversely affect cells during isolation. Our magnetic isolation technology can be used to isolate pure, viable, and functional cells of the immune system to advance your immunology research. In addition, we offer a ready-to-use density gradient medium and PBMC Isolation Kit for purifying lymphocytes in high yield and purity from small or large volumes of peripheral blood from different species.