'Pregnancy test' for water identifies pollution
Biologists have developed a low-cost, easy-to-use, hand-held device that can let users know within minutes if water is safe to drink
Julius Lucks and and colleagues at Northwestern University, US, created the 3D-printed handheld biosensor device nicknamed Rosalind 2.0, after the UK chemist Rosalind Franklin, whose work was central to the understanding of the molecular structures of DNA.
To develop Rosalind 2.0, Lucks and his team employed cell-free synthetic biology. With synthetic biology, researchers take molecular machinery — including DNA, RNA, and proteins — out of cells, and then reprogram that machinery to perform new tasks.
“We found out how bacteria naturally taste things in their water,” said Lucks. “They do so with little molecular-level ‘taste buds.’ Cell-free synthetic biology allows us to take those little molecular taste buds out and put them into a test tube. We can then ‘rewire’ them to produce a visual signal."
The device can sense 17 different contaminants in a single drop of water as it contains proteins that react to certain chemicals by producing fluorescent molecules.
It contains a row of eight small test-tubes that glow when a contaminant such as lead is detected. This easily spotted reaction acts as a warning that a water sample is polluted. How much and how many of the test tubes glow is an indication of the levels of contamination.
“Everybody should have these things. You should know your water is safe to drink.”
Ultimately, Lucks and his team hope to empower individuals to test their own water on a regular basis, and with inexpensive, hand-held devices like Rosalind, that may soon become a reality.
“It’s clear that we need to enable people with information to make important, sometimes lifesaving decisions,” Lucks said. “We’re seeing that with at-home tests for covid-19. People need at-home tests because they need that information quickly and regularly. It’s similar with water. There are many cases where water quality needs to be measured routinely. It’s not a one-time thing because contamination levels can change over time.”
The research was published on 17 Feb 2022 in the journal Nature Chemical Biology.