Low-cost sensor could detect contaminated water in developing nations
Undergraduate students from Arizona State University are working to develop a low-cost biosensor that would detect contaminated drinking water in third world countries.
An interdisciplinary team of nine students is participating in the 2012 International Genetically Engineered Machine (iGEM) competition – a prestigious global event that challenges students to design and build simple biological systems made from standard, interchangeable parts.
"We are developing a biosensor that will detect pathogenic bacteria, such as Shigella, Salmonella and E. coli, that cause diarrhoea," said Ryan Muller, an undergraduate student in at the university's School of Life Sciences. "Ideally, you would use our biosensor to check different water supplies in third world countries to determine whether the water is safe to drink."
The team is working on two designs. "The first one targets DNA," explained Muller. "Since each type of pathogen has different DNA, we want to create complementary sequences – sequences that match a specific DNA. We will take bacterial samples from the water, pull out the DNA and check whether it complements our DNA probe. If it does, it will produce a colour response and then we'll know that the water is contaminated."
Made for portability, the second design tests the membranes of bacteria. When using the device to test water, if certain proteins attach to a bacterial membrane, the sample will turn blue – indicating the water is contaminated with a pathogen and would not be safe to drink.
"The advantage of this design over previous designs in the field lies in the cheap production of probes and the enzymatic chain reaction," noted Muller. "Samples can be tested in the field with minimal cost and high sensitivity."
The team will present its device during the iGEM regional competition at Stanford University this October. If successful, they will then go on to the global competition in November at MIT.
