How a Canadian-made paper strip could revolutionize E. coli testing
ctvnews.ca, by Graham Slaughter, Sept. 7, 2017
Testing water for E. coli may soon be faster and cheaper than ever thanks to a Canadian-made test that inventors say could prevent billions of people from getting sick with the potentially deadly bacteria.
At the moment, a single E. coli test costs about $70 and can take three days to confirm results. Researchers at the University of Waterloo developed a simple test using paper strips laced with sugar that react with E. coli to reveal the presence of the bacteria.
The so-called DipTests cost 50 cents each and can confirm results as quickly as 30 minutes.
Sushanta Mitra, the executive director of the Waterloo Institute for Nanotechnology, called the invention a “breakthrough” that could improve water safety in rural areas and developing countries worldwide.
“Simple ideas create paradigm shifts in technology and this is a simple, frugal innovation,” said Mitra, who is also a mechanical and mechatronics engineering professor at Waterloo.
Details of the test were published Wednesday in the scientific journal PLOS ONE.
How it works
Similar to a litmus test, the DipTest can be dabbed in water suspected of containing E. coli. The sugar infused into the paper seeps into the water and attracts the bacteria, which then becomes caught in the paper.
If a water sample tests positive, the bacteria then reacts with a mixture of chemicals inside the paper and turns the paper a pinkish-red hue.
How quickly the results come back depends on a sample’s contamination level. In severe cases, results can be confirmed within 30 minutes, but it can take up to three hours in cases of low levels of contamination.
Researchers said they are developing ways to further reduce wait times.
Continued work on the DipTest is being conducted by Glacierclean Technologies Inc., a start-up company co-founded by Mitra. The company aims to have the tests on the market in 2018.
E. coli is a bacteria commonly found in the lower-intestines of warm-blooded mammals, including humans. Most strains are harmless, but some can cause severe illness. It can be spread through contaminated water, food and person-to-person contact.