Chemiluminescence

Chemiluminescence

Yes, I am sure that you read the title twice because you cannot pronounce it in the first try. Now, you are smiling because what I said before is true. Do not worry I had to pronounce it almost 25 times to explain to my colleagues what that is?  Let’s talk about luminescence in Chemistry or best known as Chemiluminescence.

     Everyone at once has seen glowsticks in a night club, fireflies or beautiful jellyfishes glistening, but from where comes the illumination of those things or species? The answer is simple, is because the Chemiluminescence. This is the production of light from a chemical reaction. Two chemicals react to form an intermediate in excited state (high energy), which is de-energized releasing some of its energy as photons of light.

     For example: Luminescent reactions of fireflies use ATP (adenosine triphosphate) as a source of energy. The structure of molecules that produce the light in fireflies varies from species to species, but they are generically called luciferins. When fireflies glow, the luciferin is oxidized to produce an excited complex, which falls back to the ground state, releasing a photon of light. That light is what we see at night into the woods.

     Fluorescent jellyfish are probably the epitome of chemiluminescence and bioluminescence sophistication. They have a protein capable of receive high-energy light (typically in the range of UV) called GFP (Green Fluorescence Protein) that emits fluorescence in the range of green light (Although biotechnological modifications have gotten proteins that emit virtually the entire visible spectrum). Jellyfish are not nearly the only bioluminescence’s marine life, it is believed that more than 90% of animal species average and abyssal ocean portion emit some kind of bioluminescence. Also, there have been a series of experiments investigating aequorin, a protein found in certain jellyfishes, which produces blue light in the presence of calcium and therefore can be used in molecular biology to measure calcium levels in cells.   

     Other way to see chemiluminescence… I think that everyone in a particular moment has seen Action or Police movies which have scenes where a forensic scientist investigates if in a zone there is blood present. And he or she does it using an apparatus with light that show in seconds the blood stains. Basically, in real life forensic scientists use reactions of luminol to detect blood at the crime scene. A mixture of luminol in a dilute solution of hydrogen peroxide is applied in the area where they suspect that is the blood. The iron in the hemoglobin of blood accelerates the reaction and when the room is dark and if blood is present, a blue glow, lasting 30 seconds is observed. Forensic investigators can record the glow by using photographic film, which can be used as evidence in court of blood in the scene.

Some scientists have proposed other ideas for utilizing chemiluminescence in the future; from detect important ions in biological processes to have fluorescent fishes as decoration. What other alternatives you think is useful for us, based in this natural phenomenon and the concept of chemiluminescence?

Let me know.

Have a great week!!

-Stephanie

References:

https://tallcute.wordpress.com/2008/01/15/colores-vivos-de-la-naturaleza-a-la-biotecnologia/

http://www.scienceinschool.org/node/2355

http://www.bbc.com/mundo/noticias/2013/01/130116_bioluminiscencia_naturaleza_produce_luz

Images from:

http://www.slideshare.net/kendonsmith/electron-configurations-notes

http://bioloblogeo.blogspot.com/2015/03/como-se-iluminan-las-luciernagas.html

http://dciencia.es/c-s-i-dciencia-el-luminol/

http://slickzine.com/nature/stunning-jelly-fish-photography/