A solution to easily and effectively testing water

The idea behind an emerging technology to create an easy-to-use, inexpensive water-quality testing device

In many places around the world, clean drinking water doesn’t flow readily from kitchen taps. In those regions, including some Canadian communities, robust, easy-to-use and inexpensive tools capable of testing water quality can potentially save lives. Michael Serpe, a professor in the University of Alberta’s chemistry department, is developing a device that can do just that using smart polymer* technology. This unique advancement can detect bacteria or viruses through distinct protein coatings on the surface of cells. Serpe is planning to create a prototype handheld device using this technology (conceptually illustrated here) by the end of the year to test in Poshina, India, a rural farming community and the base for his fieldwork. If those trials go smoothly, he hopes to deploy the device in rural and remote regions around the world, including some Canadian First Nations communities, by next summer. Here, in brief, is how the technology will work.

Smart polymers that respond to an internally released salt solution are sandwiched between very thin metal layers inside the handheld unit. The set-up initially appears red, but when the salt interacts with the polymer-metal layers the colour changes to green.

Binding agents that detect and fasten themselves to proteins are placed on top of the metal layer. These agents can be designed to bind to different types of proteins in a water source, depending on the type of bacteria or virus the device has been set to detect, such as E. coli.

If a bacteria or virus is present in the water, it will get “stuck” on top of the polymer-metal layers as it enters the unit, blocking the salt solution and preventing a colour change. If a bacteria or virus is not present, the salt will reach the polymer layer and change the colour.

The device then interprets the level of colour change, which depends on how much salt is able to pass through to the polymer layers. A screen displays for the user if and how much of a specific pathogen is present, and indicates whether the water is safe to drink.

* A polymer is made up of many small molecules, called monomers, which are held together by chemical interactions. Serpe uses “smart” polymers made up of special monomers that allow them to respond to their environment.