Scientists have developed an accurate, low-cost and easy-to-use test for detecting toxic levels of fluoride in water, according to a press release by Northwestern University.
The test is a biosensor that employs RNA, DNA and protein transcription to produce a signal when a target contaminant is detected.
The new biosensor device has been field tested in rural Kenya, providing evidence that water testing for fluoride can be easily used outside of a lab and accurately interpreted by nonexperts.
The study, “The accuracy and usability of point-of-use fluoride biosensors: a field study in Nakuru County, Kenya,” was published Feb. 8, 2023, in Nature Partner Journals: Clean Water.
The research team collected 57 water samples from 36 households in rural Kenya to evaluate the accuracy of the fluoride concentration measurement when compared with the standard method of fluoride photometer.
They also designed their studies to examine whether test results would be easily interpreted by non-expert users, a key indicator that the technology can have meaningful impact in addressing the global water crisis.
Results showed that the point-of-use had an 84 percent chance of correctly predicting fluoride levels above the World Health Organization limit of more than 1.5 parts per million. The tests also were found to be highly usable, with only 1 of 57 tests with an interpretation discrepancy between the user and scientific team.
“This is a whole new way to measure water quality,” says Sera Young, Northwestern anthropologist and author of the study. “The study shows that we can get a test into people’s hands that is based on some very complex biology but works very simply.”
Potential next steps for the point-of-use fluoride test could include mapping where geogenic fluoride is located globally.
Collaborative Testing Research
The new testing method is the result of a collaboration between researchers in the fields of anthropology and synthetic biology.
The study was co-led by Northwestern anthropologist Sera Young and synthetic biologist Julius Lucks.
In 2017, Young and colleagues developed Water Insecurity Experiences Scales to provide a measurement of global water insecurity that takes human experiences into account. Young partnered with the Gallup World Poll to publish estimates for half of the globe using the WISE scale in 2022 in Lancet Planetary Health.
Prompted by Young’s research, Lucks and his lab began to investigate naturally occurring biosensors — molecules used by microbes to sense for the presence of contaminants. In 2020, they published work on repurposing biosensors in a cell-free synthetic biology system, allowing the detection of harmful water contaminants such as fluoride in the field, naming the technology platform ROSALIND (RNA Output Sensors Activated by Ligand Induction).
To further Young’s research on improving global water security, the latest iteration of the Lucks Lab’s ROSALIND technology improved the speed and usability of the device to allow for easy transport to locations where harmful levels of fluoride are a safety concern.
Closer to home in Chicago, Young and Lucks are interested in investigating the usability of an at-home test for rapidly detecting lead in water, and in leveraging this study as a model for interfacing social sciences with synthetic biology to increase the impact of synthetic biology innovations.
