Although small amounts of fluoride in drinking water may help to strengthen teeth and bones, too much can be dangerous, potentially causing a disease known as skeletal fluorosis. With that in mind, a simple new test has been designed to determine if fluoride levels are too high.
Of course, it is already possible to measure fluoride levels in water. Doing so typically requires trained personnel in a lab, however, and costs hundreds of dollars per test. Scientists at Illinois' Northwestern University set out to develop a much simpler, cheaper testing system that could be utilized onsite by just about anyone.
The resulting setup incorporates a small cotton ball-like object containing freeze-dried specially-engineered RNA. That ball is placed in a supplied test tube. An included pipette is then used to draw just 20 micoliters of water from the source being tested. The water is added to the test tube, rehydrating the RNA.
If any fluoride ions are present in the sample, they will slot into a molecular "pocket" in the RNA, causing it to express a gene that turns the water yellow. The greater the number of fluoride ions that are present, the yellower the water appears to the naked eye.
Although the reaction currently takes about two hours to occur, the researchers are working on speeding that up considerably. They are also looking into using different types of engineered RNA to test for other potentially-harmful substances.
And while fluoride levels may not be particularly high in North American water supplies, naturally-occurring fluoride can definitely cause problems in regions such as Africa, Asia and Central America. The scientists have therefore field-tested the system in Costa Rica, where it proved to be accurate.
"Every test on these field samples worked," says Assoc. Prof. Julius Lucks, who is leading the project. "It’s exciting that it works in the lab, but it’s much more important to know that it works in the field. We want it to be an easy, practical solution for people who have the greatest need. Our goal is to empower individuals to monitor the presence of fluoride in their own water."
The research is described in a paper that was recently published in the journal ACS Synthetic Biology.
Source: Northwestern University