By Patricia Daukantas
Optical technologies such as laser scanning confocal microscopy (LSCM) and multiphoton excited (MPE) fluorescence microscopy have given researchers wonderful new ways to image live cells and biological tissues. Today the Nobel Prize in Chemistry went to three scientists who found something for these state-of-the-art microscopes to see.
Back in 1962, Japanese cell biologist Osamu Shimomura of the Marine Biological Laboratory and Boston University Medical School (both in Massachusetts, U.S.A.) first isolated the substance known as green fluorescent protein (GFP) from the Aequorea victoria jellyfish and discovered that it produced a fluorescent glow under ultraviolet light. American biologist Martin Chalfie of Columbia University (New York, U.S.A.) showed that GFP could act as a luminescent “tag” that traces biological phenomena. American biochemist Roger Y. Tsien of the University of California at San Diego (U.S.A.) studied how the fluorescence mechanism of GFP works and extended the phenomenon to other colors and other proteins.
In the June 2003 issue of OPN, Paul Campagnola and William A. Mohler explained how GFP works: “[T]he gene that encodes for it can be linked to the gene of virtually any cellular protein of interest. The resulting fusion is then placed in cells or a whole organism and the desired protein is expressed with the GFP label.”
Scientific American has a nice article explaining the significance of GFP, and in a statement, the president of the American Chemical Society, Bruce Bursten, said, “Green fluorescent proteins allow scientists quite literally to see the growth of cancer and study Alzheimer’s disease and other conditions that affect millions of people.”
At OSA conferences, I’ve heard many researchers describe how they used fluorescent proteins as part of their experiments to improve biomedical imaging. One example of this work is a “Scattering” published back in February 2008, describing a retinal flow cytometer. A quick search of Optics InfoBase reveals numerous articles on work involving GFP in such OSA journals as Optics Express and JOSA A as well as OSA conference proceedings.
Quantum dots are starting to supplant fluorescent proteins in biomedical imaging because of their longer lifetimes and increased flexibility. Nevertheless, GFP and its glowing-protein cousins will remain an important component of the biomedical imaging toolbox for years to come.
2008-10 October, Biomedical optics