Cell sorting facs machine

The FACS (Fluorescence-Activated Cell Sorting) machine is a high-precision instrument that uses lasers and fluorescence to isolate specific cells from a heterogeneous sample.

About this subject

Fluorescence-activated cell sorting, or FACS, is a technology that was pioneered by Leonard Herzenberg and colleagues in the 1970s, transforming cell biology and immunology. The technique works by passing a stream of cells labeled with fluorescent antibodies through a laser beam. Optical sensors detect the fluorescence emitted by each cell, and an electronic system rapidly analyzes desired characteristics such as size, granularity, and the expression of specific proteins. Within milliseconds, the system decides whether to sort a cell based on predefined criteria.

For sorting, the stream is broken into droplets, each containing a single cell. Droplets carrying cells of interest are electrically charged and then deflected by high-voltage plates into collection tubes, while uncharged droplets go to waste. This process can achieve purities above 99%, enabling the isolation of rare cell populations like stem cells or circulating tumor cells. FACS is essential in immunology for separating T lymphocytes, B cells, and dendritic cells, and in cancer research for isolating cancer stem cells or monitoring minimal residual disease.

Modern FACS instruments can process tens of thousands of cells per second and measure up to 20 or more fluorescent parameters simultaneously using multiple lasers and detectors. Examples include the BD FACSAria Fusion and the Beckman Coulter CytoFLEX SRT. The technology demands skilled operators and regular maintenance to ensure alignment of optics and fluidics. Despite the rise of alternative methods like magnetic bead separation, FACS remains the gold standard for high-purity, multiparametric cell sorting in both research and clinical settings, such as in cell therapy manufacturing.

Frequently Asked Questions

What is the difference between FACS and flow cytometry?

Flow cytometry is the technique of analyzing cells in suspension using lasers, while FACS is a specific application that physically separates the analyzed cells. All FACS involves flow cytometry, but not all flow cytometry performs cell sorting.

Which types of markers are used in FACS sorting?

Typically, monoclonal antibodies conjugated to fluorochromes such as FITC, PE, APC, or Pacific Blue are used. Viability dyes like propidium iodide or fluorescent proteins like GFP and mCherry can also be employed.

Is FACS suitable for clinical applications?

Yes, especially in the manufacture of cell therapies like CAR-T, where specific T cells need to be isolated and purified. Clinically certified instruments with validated protocols are used to ensure sterility and traceability.