These researchers are working on rapid real-time detection of pathogens in drinking water

Imagine being able to plant technology into pipes to detect drinking water contamination, as and where it occurs. Associate Professor Helen Stratton is turning this idea into reality, leading research into rapid real-time detection of pathogens in water, and working with a cross-disciplinary team to expand on their discoveries.

“There is a big issue with how long it takes to transport a sample to, and then do a microbial test, in a lab,” Stratton said.

Traditionally, a utility will take a sample of potential contamination in drinking water and analyse it in a laboratory through a culture test or a conventional PCR test.

“This takes several hours to even a week for confirmation of what was in the water. And, with water, you can’t switch off treatment plants. Real-time monitoring of pathogens is essential,” Stratton said.

New method, old tech

While there is currently real-time monitoring of pH levels and turbidity, which are generally seen as raising an alarm that something has gone wrong in a treatment plant, Stratton’s technology is both more agile and has far wider applications.

"We call it a lab on a chip. This is miniaturising what we do,” she said, citing her collaboration with Professor Nam-Trung Nguyen who developed the microfluidic device.

“We take what we do in the lab now, using either a culture-based method or trying to target a protein or a piece of DNA from a microbe, and put that on to the microfluidic chip, which is a pretty old technology, but it hasn’t been applied in this way before.”

Stratton and her team look to unique features of target pathogens, such as genes or proteins, that are unique to the organism of interest. In miniaturising the process – putting the samples on a chip as big as two fingers put together – they have been able to also make the test incredibly sensitive, to the point where they can prove in a lab that they can detect a few cells of a harmful pathogen.

“The test is also what we call multiplex. One chip we’re currently working on can hold up to eight pathogen targets. It’s one device, looking for multiple organisms. Not only that, but there’s a quick turnaround – we can theoretically do it in less than two hours,” Stratton said.

Stratton thinks that in two years this technology will be out on the market. Her team is also working on another project called ‘liquid marbles and core-shell beads’ with digital quantitative-PCR , where they take similar technology and miniaturise it even further.

“Those technologies could eventually be incorporated into pipe materials. Instead of having a probe into the water, that would then be real time. It would set an alarm off, take a sample, and look at it in more detail,” she said.

The inline core-shell and digital PCR technology would be adding to current online technology, which will take a sample and measure it at the source.

Stratton estimated that is around five to 10 years from being released because a lot of validation is necessary.

Broader applications

In the meantime, Stratton believes that the initial real-time pathogen technology they have developed is nothing short of “digital disruption” that will “turn labs on their heads”.

“We’ve developed a chip for a lot of the genes in E. coli, and we’re applying that to something we’re doing routinely in the lab called microbial source tracking,” Stratton said.

“This involves getting a genetic fingerprint and bacteria that have come from faecal contamination.

“We are able to measure against markers from different animals and humans, which means we can tell where the E. coli has come from.

“This is particularly important for drinking water supply, because if it’s not human, you can look to detect where it might have collected in a particular place.”

Another application for the technology is in recycled water, where they track what are referred to as reference pathogens that are commonly seen as waterborne from nine bacteria viruses.

“I want to make a chip that would cover these pathogens, so that when people are implementing a recycling scheme they can use it to validate their water supply,” Stratton said.

The Griffith lab is looking at creating prototypes for a miniature hand-held device that could revolutionise the way that utilities are able to test in the field, which would hook up to a laptop and get on-the-spot readings for contamination. And that’s not all, as Stratton also sees applications for the technology in agriculture, aquaculture, and even medicine.

“Say with the coronavirus, we have this hand-held microfluidic device, you could do a blood or saliva test on it at the point of care for patients,” she said.

“This is enabling us to detect pathogens at low concentrations. The applications are endless.”

How it works

1. Gather lab results from microbial testing
2. Add data to a microfluidic chip
3. Install data-tracking chip into water source pipelines
4. Read real-time contamination events as they occur

Helen Stratton is an Associate Professor and wastewater microbiologist at Griffith University, Queensland. Helen was awarded an AWA Life Membership in 2016.