Testing water safety with tiny nanodot sensors

A fingernail-sized sensor with nanodots that can detect the presence of heavy metals has been developed by Victorian scientists.

It offers a cheap and simple method of testing whether water is drinkable.

“The dots are extremely small, so several different ones can be embedded in a tiny plastic film, detecting for a range of heavy metals all at once,” says Professor Ivan Cole, Director of the Enabling Capability Platform for Advanced Manufacturing and Fabrication at RMIT University.

Because of their quantum properties, shining light on the nanodots causes them to fluoresce at a specific wavelength. Researchers use this quirk to look for colour changes if a heavy metal binds to the nanodot.

“By monitoring the colour, we can then monitor the concentration of heavy metals,” Ivan says.

The sensor is simply dipped in water and placed in a pocket-sized device that shines light on it and detects the fluorescence of the dots.

“It would give you red or green lights to determine whether the water is drinkable,” Ivan says.

“This could make environmental sensing much cheaper while still being accurate.”

These sensors are so cheap researchers hope their use will become widespread in testing polluted water systems, such as those in China. The technology also has potential uses in agriculture, to spot-test soil and determine which areas of a field need more fertiliser.

The work is a collaboration between CSIRO and RMIT. Researchers are currently working to improve the nanodot accuracy, and Ivan expects the new sensors will hit the market in three to four years.

Red or green lights indicate whether the water is drinkable. Credit: Dr Trinchi (CSIRO)

For more information:

RMIT University Research & Innovation
James Giggacher
+61 03 9925 4143