COLLEGE STATION --
One of the best ways to beat the summer heat is to stay well hydrated. Each swig of tap or bottled water contains fluoride, which promotes dental health. Too much, however, could make bones brittle and lead to other health issues.
Federal authorities recommend no more than 0.7 parts per million, but Texas A&M University chemist François P. Gabbaï
says fluoride detection at such miniscule levels can be tricky. He and his research group specialize in building one possible solution -- organometallic molecules that emit fluorescence when they are mixed with water containing fluoride. Gabbaï recently earned a $440,000 National Science Foundation
grant to further develop the technology.
"The sensors have to physically make contact with fluoride, but we had a fundamental challenge: Water serves as a very efficient buffer and keeps the sensor away from the fluoride anion," said Gabbaï, a professor in the Department of Chemistry
. "So we make organometallic compounds that have a high affinity for small anions. These compounds are Lewis acids -- molecules that are lacking in electrons -- that capture fluoride and brighten when they find it. I think we were the first to consider the use of these metal-based Lewis acids in water. It was a bit of a daring move."
Fluoride, which occurs naturally, is added into water and toothpaste. Federal authorities recently lowered the recommended dosage from 1.2 to 0.7 parts per million -- a limit that previously had been several times higher. Gabbaï has tested local water and found it to be safe. He also said cases of fluorosis and other issues caused by overexposure to fluoride are relatively rare. But Gabbaï's research offers a new tool for monitoring water supplies and ensuring safety standards.
Gabbaï is using the same principles involved in aqueous fluoride detection to discover new methods to image cancer. This work, carried out in collaboration with a group at the University of Southern California, involves the development of new cancer imaging agents containing radioactive Fluorine 18 (F-18). These imaging agents are made by mixing F-18 fluoride with organometallic Lewis acids. Once injected, they allow for the imaging of cancer in patients using a technique called positron emission tomography (PET). Physicians, radiologists and researchers can follow the biological pathway in real time by tracking the emitted gamma rays produced as the F-18 decays. But they only have a window of about two hours to catch the isotope, append it to a biomolecule, inject it into the patient and get an image.
"It's a race against time," Gabbaï said. "And we have very efficient methods to beat the odds and catch Fluorine 18. Now people are making imaging agents that target cancer, for example. And we're involved with that."
For Gabbaï, who joined the Texas A&M faculty in 1998, his research gives him personal satisfaction beyond the societal value it provides. He loved the water growing up, spending his childhood fishing, and now is a frequent visitor to Lake Bryan. Although he wanted to be a marine biologist as a teenager in the French wine country region of Bergerac, he believed that chemistry offered more dynamic job prospects. By integrating water into his chemistry research, he now has a sense of coming full circle.
"Water may be the link between all my interests," Gabbaï said. "In a way, I'm finally professionally happy."
For more information about Gabbaï's research, visit http://www.chem.tamu.edu/rgroup/gabbai/
To learn more about the Texas A&M Department of Chemistry, visit http://www.chem.tamu.edu/
to read a previous feature story on Gabbaï's early work with organometallic molecules.
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Contact: Vimal Patel, (979) 845-7246 or firstname.lastname@example.org or Dr. François P. Gabbaï, (979) 862-2070 or email@example.com