Bright & Colorful: Fluorescent Markers and FACS Assays

As a top worldwide antibody supplier, we at Novus Biologicals are constantly extending our antibody database to take advantage of the latest technology and product developments. Recently, we added several embryonic stem cell marker antibodies, conjugated for use in FACS (fluorescence activated cell sorting) assays.

FACS involves the sorting of heterogeneous cell populations by use of antibodiestagged with fluorescent dyes, targeted to proteins specific to particular cell types. When excited by laser light, the dye fluoresces at a particular wavelength, allowing easy detection and isolation of the relevant cells.

Our antibodiesare tagged with a variety of fluorescent labels. This is because different applications have different types of laser. For example, the blue argon laser emits light in the blue/green spectrum at 488 nm. An air-cooled device, it is cheap to set up and run, and the most common laser found on single-laser machines.

Fluorescent dyes react to laser light by first absorbing the light, and then emitting light at a different wavelength to that which has been absorbed. Each dye emits its own wavelength, meaning several proteins can be studied in one sample, by using different tags. Dyes which absorb light at 488 nm and emit in the green spectrum include Alexa Fluor 488 and DyLight 488. Fluors emitting in the red channel include PE-Alexa Fluor 700 and PE-Cy5 (TRI-COLOR) conjugates.

Some dyes, for example PE-Alexa Fluor 750, emit in the infra-red spectrum, though not all FACS machines are equipped for this. There are also red diode and violet lasers, which emit at 635 and 405 nm respectively, and are also used with a variety of fluors of different emission spectra. Fluorescent antibodiesare widely used in biological research, providing an infallible method of isolating individual cell populations.

Novus now offers thousands of top quality antibodiesconjugated to fluorescent dyes, as well as Lightning-Link Conjugation Kits for performing quick and easy antibody conjugations in your own lab.