Principles of Magnetic Separation of Cells

Two types of magnetic separation can be distinguished when working with cells. In the first type, cells to be separated demonstrate sufficient intrinsic magnetic moment so that magnetic separations can be performed without any modification. There are only two types of such cells in nature: magnetotactic bacteria containing small magnetic particles within their cells and red blood cells (erythrocytes) containing high concentrations of paramagnetic haemoglobin. In the second type, cells of interest have to be tagged by a magnetic label to achieve the required contrast in magnetic susceptibility between the labelled and unlabelled cells. The attachment of magnetic labels is usually attained by the use of affinity ligands of various types, which can interact with target structures on the cell surface. Usually antibodies against specific cells surface epitopes are used, but other specific ligands can also be employed. The newly formed complexes have magnetic properties and can be manipulated using an appropriate magnetic separator.

The magnetic separation process for the purification of target cells usually consists of the following three fundamentals steps:

1. The suspension containing cells of interest is mixed with magnetic labels. Incubation time is usually not longer than 30-60 min. Then the magnetic complex formed is separated using a magnetic separator and the supernatant is discarded or used for another application.

2. The magnetic complex is washed several times to remove unwanted contaminants. The selected cells with attached magnetic labels can be used directly, e.g. for cultivation experiments. Alternatively, cells can be disrupted and the cell content analysed using various methods.

3. If necessary, a variety of detachment procedures can be used to remove the magnetic labels from the separated cells. After detachment, the magnetic label is removed from the suspension in a separator and free cells are ready for further applications and analyses.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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