Patch to test oestrogen in water
Two Victoria University students want to see our drinking water turn purple.
Omar Alsager and Shalen Kumar have designed a novel test to detect the female hormone oestrogen, which is a known contaminant in our waterways.
Oestrogen can promote ovarian cancer, cause male fertility problems, and affect behaviour. Until now, the only tests available to detect it in drinking water need samples to be sent away to labs, and results can take days to come back.
The PhD students combined the latest advances in design-your-own DNA and nanotechnology to design the "quick, easy and dirty" test.
Kumar, a biologist, designed a special piece of DNA that latches on to oestrogen. Strands of these are mixed in with particles of gold and the DNA wraps itself around the metal, forming a pink-coloured liquid.
But the DNA prefers sticking to oestrogen more than gold, so when the hormone is present in the water, the DNA grabs it and changes shape. This turns the liquid to a purple-blue colour, nanotechnologist Alsager says.
"In 10 minutes, you'll have your answer whether the water is contaminated or not."
The test is also a world-first for its sensitivity, picking up levels of oestrogen equivalent to a pinch of salt in an Olympic-sized swimming pool.
Oestrogen in drinking water can come from dairy farms, if they use it to increase milk production, or from recycled waste contain- ing the urine of women taking contraceptive pills, Kumar says.
Common household products degrading at landfills, including those with BPA plastic, can also give off oestrogen mimics - that is, chemicals that have the same effect on the human body when ingested.
The pair, supervised by Victoria University nanotechnologist Justin Hodgkiss and biologist Ken McNatty, believe the test could become part of councils' monitoring of water quality, or be used by anyone interested in discovering what they are drinking. The ingredients are "dirt cheap", especially as only 1/50,000th of a gram of gold is required per test.
The team imagine the final test, which could hit the market within a couple of years, could take the form of a pregnancy test - a stick dipped in water forming a line if the hormone is present.
The Dominion Post