A Texas A&M University chemist, Dr. Francois P. Gabbai, has developed an organometallic molecule that has the ability to emit fluorescence when mixed with water that contains fluoride — a discovery that can facilitate detecting fluoride in water. He has just received a $440,000 National Science Foundation grant to develop this new technology further.
It is known that water containing fluoride helps to promote dental health, however, excessive amounts of fluoride in water can lead to various health issues, including brittle bones. Though there are differing opinions, the recommended amount of fluoride in drinking water has been established to be no more than 0.7 parts per million.
Such a small amount of fluoride in water can be difficult to detect, however. Dr. Gabbai’s new organometallic molecule has the ability to do so.
One of the difficulties with current monitors is that they have to make contact with fluoride anions to detect it. Unfortunately, water makes an efficient buffer, which keeps sensors away from fluoride, essentially masking its presence. According to Dr. Gabbai, “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.”
Currently, fluoride is added to water and toothpaste to prevent tooth decay, however, recently the recommended amount was dropped from 1.2 to 0.7 parts per million. Gabbai has recently tested local waters and found that fluoride levels are in the safe zone. He also points out that fluorosis and other health related issues related to overexposure to fluoride are rare, however, this new monitoring system is an easy way to accurately measure fluoride content to ensure safety standards are met.
Gabbai has utilized his detection system to discover new methods to image cancer. Gabbai and colleagues from the University of Southern California have taken radioactive Fluorine 18 (F-18) and mixed it with organometallic Lewis acids. This mixture can be injected into a cancer patient and imaged using positron emission tomography (PET). This allows radiologists and researchers to track emitted gamma rays from F-18 organometallic mix to follow a biological pathway in real time. This group points out that they have a time frame of around two hours to make the F-18 organometallic mix and inject it into a patient and get an image.
Gabbai has been a faculty member at Texas A&M since 1998. He has always been fascinated with water and often visits Lake Bryan. During his teen years, he had visions of becoming a marine biologist growing up in the Bergerac French wine region. However, he decided to go into chemistry as he felt there were more dynamic job prospects in that discipline. He feels he as come full circle by bringing in water to his chemistry research.