Researchers at Queen's University Belfast have developed a highly innovative new enzyme biomarker test that has the potential to indicate diseases and bacterial contamination saving time, money and possibly lives. The test, developed by scientists at the Institute for Global Food Security at Queen's, can detect enzyme markers of disease known as proteases in humans, animals and food products.

Dr Claire McVey, Queen's researcher and co-author on the study published in leading journal Nano Research, explains: "Not only is the test cheap to produce, but it can be used anywhere and is not reliant on laboratory conditions. Eliminating the need to carry out tests in a laboratory setting is life-changing. As well as being cost-effective, it means faster diagnosis."

Gold nanoparticles speed up the oxidization of TMB 

The gold-nanoparticle based nanosensor devised by Queen's researchers indicates when proteases are present through a visible colour-change reaction. Gold nanoparticles are well known for their capability in speeding up the oxidization of a chemical called tetramethylbenzidine (TMB), visible through a vivid blue-colour formation.

Dr Cuong Cao, the lead academic on the study: "When we add TMB to the casein-covered gold nanoparticles, we can tell virtually instantly if proteases are present by whether or not the solution turns blue. Normally such testing takes much longer. "Using this approach, proteases can be detected within 90 minutes without the need for complicated or expensive laboratory equipment.

In addition, the 'ingredients' for making the nanosensor are readily available and low cost. Gold nanoparticles can be produced in abundance, with little restriction on storage requirements, making it a durable and cheap substance. The approach developed by the Queen's researchers was tested on milk and urine but it could be adapted for a number of other applications.

Coating nanoparticles with lipids detect lipase

Dr Cao explains: "Using molecules other than casein to coat the surface has the potential to detect other types of enzyme biomarkers. For example, coating the nanoparticles with lipids could detect the lipase enzyme, which could help in the diagnosis of diseases such as pancreatitis.

"Following full validation of this test, we would like to explore how we could expand the application to detect a host of other diseases or contaminated foods. This new approach will enable the identification of enzyme biomarkers at the point of care. It could change the landscape of how enzyme biomarkers are detected and diagnosed, making an impact on the diagnosis of enzyme-related illnesses among animals and humans. The potential scope for this test is huge."

Professor Elliott commented: "The ability to diagnose disease or contamination quickly can have a huge impact on how serious problems can be dealt with. The ultra-low cost of the system will help reduce costs of testing and could transform the amount of testing performed in the developing world."