FACS

FACS Automation

One of the more elegant ways to sort a population of cells according to size, particle size and fluorescence characteristics is the FACS. The meaning of the name is cell sorting by fluorescence (Fluorescence Activated Cell Sorting), even though some of the characterizations are done by ordinary light scattering. In this method, the cell population being tested is taken and injected into a thin stream of liquid. The cell passes in front of several light sources and lasers and the light scattering/fluorescence is measured and saved. At the end of the measurement, it is possible to make different segmentations of the huge accumulated information.

FACS main features

also called flow cytometry, is a sophisticated and elegant method to collect a lot of information about individual cells in large and heterogeneous populations of cells. Two basic characteristics that are measured are the size by frontal light scattering, and gurgling – a characteristic of the cell’s complexity, by side light scattering. Beyond that, the different cell populations can be marked with fluorescent substances or antibodies dyed with these substances, and from this, specific populations can be concluded. The information received is tremendous. For each cell in a population that can number millions of cells, it is possible to know the size, granularity, and fluorescence in different wavelengths, and to make cross-references and different segmentations for each of the wavelengths tested. Not only cells can be characterized but also large particles such as chromosomes, special chips and more. Thus, the method can be used to analyze still populations of particles as well.

Advanced FACS

There are even more sophisticated FACS devices which, apart from characterizing the cells, also know how to sort them into separate test tubes. that an additional step of creating the droplet containing the cell, loading it with a certain charge and deflecting it towards the intended test tube is added. When you want to characterize 2 different subpopulations, after defining them, the device charges one with a positive charge and the other with a negative charge, when they pass through the device, and with the help of a special capacitor they are routed each to its designated test tube. In some devices it is possible to sort 4 subpopulations or more using this method.