Fluorescein - Lukas Syriste

Whenever you might use a glow stick, or go clubbing and see all the cool fluorescent lights, you might wonder to yourself, “Self, how does that work?”. The thing that’s doing the work is a chemical compound called a fluorophore!  Fluorophores have an interesting quality where you can shoot them with a certain wavelength of light, and they will emit a completely different wavelength of light! That glow stick you swing around at a Skrillex concert may be using a fluorophore to convert the lights into different colors! Rad.  So besides looking cool, are there any practical scientific applications to using a fluorescent molecule?

Let’s take one particular fluorescent molecule: fluorescein, which absorbs blue light and emits green. Fluorescein can be dabbed in your eye and excited by blue light to show if you have any corneal scratches. It’ll give you a case of orange-eye for a few hours (better than pink-eye)¹. Fluorescein is also used to measure the health of your blood vessels in a technique called angiography. When injected and excited by blue light, it will show if you have a block or leaky vein². It can also be used to paint your chromosomes with a technique called FISH³.

By far the coolest use is labelling structures in cells⁵! Fluorescein and other fluorophores can be attached to antibodies for different cell structures, like actin or tubulin, and when excited by light, will show you the distribution of cellular structures, like in the picture above! Different fluorescent molecules are labelling the nucleus, actin cytoskeleton, and tubulin in a cell. Can you guess which structures are dyed here?

Fluorescein is pretty groovy in the environment. It doesn’t react with much and can be degraded by the sun⁶. It was even used to color the Chicago River green during St. Patrick’s Day⁷! Just don’t try to eat it, you wouldn’t enjoy it⁸.

Fluorescent molecules like fluorescein have wide-ranging uses in art, lighting, biochemical, and cell biology studies.

1.      Fluorescein eye stain: MedlinePlus Medical Encyclopedia. (n.d.). Retrieved March 13,                   2014, from http://www.nlm.nih.gov/medlineplus/ency/article/003845.htm

2.      Fluorescein angiography: MedlinePlus Medical Encyclopedia. (n.d.). Retrieved March 13, 2014, from http://www.nlm.nih.gov/medlineplus/ency/article/003846.htm

3.      O'Connor, C. (2008). Fluorescence In Situ Hybridization (FISH) | Learn Science at Scitable. Retrieved March 13, 2014, from http://www.nature.com/scitable/topicpage/fluorescence-in-situ-hybridization-fish-327

4.       Syriste, L. (2014, March 24). Stained fibroblast [Fibroblast stained by immunolabeling

5.      Immunofluorescence Labeling Method. (n.d.). Retrieved March 13, 2014, from                               http://www.bio.davidson.edu/courses/genomics/method/IMF.html

6.      FLUORESCEIN - National Library of Medicine HSDB Database. (n.d.).                                        Retrieved March 13, 2014, from http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@rn+2321-07-5

7.      The Story Behind Dyeing the River Green. (n.d.). Retrieved March 13, 2014, from                         http://www.greenchicagoriver.com/story.html

       8. Lewis, R. J. (1992). Sax's dangerous properties of industrial materials: 3. New York: Van Nostrand Reinhold.