Image created by Dr. Michael J. Miller
A novel new test for bacteria in fluids makes it as easy as observing a color change to confirm the presence of disease-causing pathogens, promising much easier diagnostic tests and greater food safety.
Engineers and biochemists at McMaster university have brought their skills together to make it possible for untrained users to confirm contamination in fluids using a biogel test that changes color in the presence of such bacteria as E. coli, listeria and other frequent testing targets.
The test uses harmless bacteriophages embedded in the gel to locate target bacteria in a sample of fluid such as lake water, urine or a container of milk, even in low concentrations.
Bacteriophages are the most common form of life on Earth. Each form of bacteriophage is specialized to destroy one form of bacteria.
In the test, phages – as they are called informally – find and attack the target bacteria in a sample, causing the bacteria to release microscopic amounts of intracellular material which the test can read, triggering a color change that is readily visible to the eye. If the sample is clean, the color stays the same.
The new process takes just hours, producing results much more quickly than lab cultures, which can take two days to generate results.
"We've been using phages' destructive power to kill bacteria and resolve infections for years," says Zeinab Hosseinidoust, an associate professor of biomedial and chemical engineering who holds the Canada Research Chair in Bacteriophage Bioengineering. "Here, we're chanelling that power in another way. Because phages can burst bacteria open, they can give us quick access to the biological components of those bacteria that we use to confirm their presence."
The test, described in a new paper published in the journal Advanced Materials, is the latest in a series of technologies the group has developed, all aimed at placing simple technology within reach of producers, retailers, consumers and medical professionals.
"Now we have a tool that can be used in food samples, environmental samples and clinical samples," says corespounding author Tohid Didar, an associate professor of mechanical and biomedical engineering who holds the Canada Research Chair in Nano-Biomaterials. "Today, people who suspect they may have a urinary-tract infection must visit a doctor and sometimes wait days for a result. This technology would make it very easy for people to tests themselves at home and get a result in a matter of hours."
Great information
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