Paper sensors identify biomarkers in wastewater

The new test device is said to be low-cost and fast and could change how public health measures are directed in future pandemics. The team’s findings are detailed in Cell Reports Physical Science.

Testing wastewater is one of the primary ways to assess the prevalence of infectious diseases in populations. Researchers take samples from water treatment plants and use the results to identify which areas have the highest infection rates. The method was used in the COVID-19 pandemic to track community infection rates and direct public health measures.

Zhugen Yang, Professor of Biosensing and Environmental Health at Cranfield University, led the development of the sentinel sensors. It builds on research he conducted in 2020 to develop a test to detect SARS-CoV-2 (commonly known as COVID-19), Influenza A and Influenza B in wastewater using a paper-based platform and UV torch or mobile phone camera.

Until now, the most accurate ways of testing wastewater samples have been methods like the polymerase chain reaction (PCR) tests which are conducted in centralised laboratories. In the process, samples are collected, stored and transported in a cold chain to the lab location before being processed, which can take many days and is comparatively expensive.

The new test method is rapid, user-friendly and portable. In it, wastewater samples are placed onto a wax-printed paper sheet which is folded. The paper contains chemicals that react to certain disease markers, triggering a fluorescent colour to emerge. Using a mobile phone camera, the results can be read and data collected rapidly.

Professor Yang developed the new method as part of the national COVID-19 wastewater surveillance programme. In 2021, he performed field tests using the test at four quarantine hotels around Heathrow Airport. The sample-to-answer process took under 90mins compared to around four hours for a PCR test.

Results showed that this new device gives results at least as accurate as the PCR test but at a much lower cost and can provide an early warning of disease in the community.

“During COVID-19 we proved that fast community sewage analysis is a really effective way to track infectious diseases and help manage public health,” Professor Yang said in a statement. “The simple test we have developed costs just £1 and uses the commonly available camera function in a mobile phone, making it readily accessible. This could be a real game-changer when it comes to predicting disease rates and improving public health in the face of future pandemics.”

Further development of the test is being sponsored by the Leverhulme Trust Research Leadership Scheme and a grant from the Biotechnology and Biological Sciences Research Council.