Lasers for Flow Cytometry

Flow cytometers is a bioanalytical tool in which single or multiple cellular properties are determined by analyzing large populations of cells. In a standard configuration the fluorescence labelled cells pass through the laser beam in a hydro-dynamically focused jet stream in a flow cell.

More advanced systems can be used for Fluorescence-Activated Cell Sorting (FACS). Cytometry instruments are commonly used tools in the fields of hematology and immunology, and are used in biomedical research as well as in clinical diagnostics applications.

All Cobolt lasers offer high power, excellent beam quality and low noise, which are important properties in order to maximize resolution and sensitivity (often referred to in terms of a low CV value) of the instruments, and for applications with high throughput requirements.

Flow_2_3spalt Flow cytometry principle

Flow_3spalt Typical 2D plot of data showing the number of particles in a certain volume


Cobolt’s introduction of the world’s first compact CW 355 nm laser, the Cobolt Zouk, has opened up new possibilities for integration high performance UV lasers into bench-top cytometers. This has lead to much wider access to the important UV spectral range for endusers in the flow cytometry community. Hoechst 33342 (Invitrogen) is an example of a fluorophore which is very attractive for use in the UV. It can be used to stain DNA to visualize nuclei and mitochondria and is actively transported out of the cells and thus can be used to sort mixed populations of cells. Hoechst 33342 is therefore used in stem cell research to look at side population phenotypes. Changes in stem cell activity, indicating possible presence of cancer, can be seen in the side population. The figure below shows an example of side population using Hoechst 33342 excited by the Cobolt Zouk 10mW laser in mouse bonemarrow. The Cobolt Zouk is a single-frequency DPSS laser at 355 nm emitting up to 20 mW output power in a TE M00 beam and with <0,2% RMS intensity noise.

See all Cobolt CW Visible 04-01 Series DPSS lasers, CW UV-Visible-NIR 05-01 Series DPSS lasers and ultra-compact 06-01 Series lasers for flow cytometry.