Detecting deadly bacteria in water

The new device could revolutionise water safety in resource-scarce areas

Spotted: New figures estimate that 4.4 billion people lack access to safe drinking water – double the number of previous estimates. That number remains so high because it’s often difficult to access and use water testing equipment. And even where testing equipment is available, results take 18-24 hours, which is impractical for those who need water urgently. Now, researchers believe they have found a technology that could change that – a lens-free fluorometer. 

Past research had already highlighted that fluorescence-based systems are extremely effective at detecting harmful contaminants like faecal matter. Building on this premise, a team of scientists from the Phutung Research Institute, the University of São Paulo, the University of York developed a “native” fluorescence and scattering-based measurement system that doesn’t rely on expensive reagents and costly reagent storage technologies. 

Historically, this kind of system has involved the use of lenses, to maximise the amount of light reaching the target molecules and collect the emitted light from the molecules. Realising that lenses actually reduce performance in applications that don’t require images, like in water testing, the researchers created a lensless system instead. Talking to Springwise, research lead Dr. Ashim Dhakal explained: “A lensless design eliminates costly lenses and the resources needed to align the lenses accurately. It also eliminates the associated weight and volume. These altogether make a lensless system more portable, affordable, and practical in resource-limited settings.”

Unlike typical microbiological water contamination testing, which takes hours or days, the new technology works in a matter of seconds, so that water safety can be tested virtually in real time. And, users don’t need to be experts to interpret the measurements, as they show up as simple numbers and traffic-light indicators. 

The team is seeking funding to help scale its solution and develop pocket-sized field-tested versions of the lensless fluorometers. Dr. Dhakal highlighted: “The target device must withstand the harsh environment in multiple scenarios and fields before it can be widely applied around the world. We are currently working to demonstrate that our approach meets the specificity requirements for specific bacterial contamination by incorporating measurement of multiple parameters.”

Written By: Joshua Solomon and Matilda Cox