Researchers at Queen's University Belfast have developed a new and innovative enzyme biomarker test that has the potential to indicate disease and bacterial contamination, saving time, money and possibly lives.
The test, developed by scientists at the Queen's Institute for Global Food Security, can detect enzyme markers for diseases known as proteases in humans, animals and food products.
Proteases are crucial for the growth of microorganisms and are responsible for the progression of many diseases.
Levels of proteases can be highly elevated in the urine of patients with diabetic kidney disease, or at infected wound sites. Likewise, in cows, elevation of proteases in milk may reveal diseases such as bovine mastitis, a type of infection of the mammary gland. In food, the proteases produced by contaminated bacteria in meat and dairy products can lead to rancidity as well as to decreased shelf life and quality.
Current protease detection methods are expensive, time-consuming and not always effective. Scientists at the Queen's Institute for Global Food Security have developed a nanosensor that has resulted in the detection of sensitive, rapid and cost-effective proteases in milk and urine.
Dr. Claire McVey, researcher and co-author of Queen on the study published in the main journal Nano Research, explains: "The test is not only cheap, but can be used anywhere and does not depend on laboratory conditions. Eliminating the need to perform laboratory tests is a life change. .
The nanosensor based on gold nanoparticles invented by Queen researchers indicates when proteases are present through a visible reaction of color change. Gold nanoparticles are well known for their ability to accelerate the oxidation of a chemical called tetramethylbenzidine (TMB), visible through a vivid blue color formation.
When casein (a molecule present in milk) is added to the gold nanoparticles, it surrounds the nanoparticles, acting as a protective surface barrier. When TMB is introduced, casein prevents the oxidation reaction, which means that there is no or slight color change.
Where proteases are present, they & # 39; the protective barrier of casein, exposing the surface of gold nanoparticles. In this case, when TMB is added, proteases have removed casein, which means oxidation occurs rapidly, causing a rapid change in color.
"When we add TMB to casein-covered gold nanoparticles, we can say virtually instantly whether the proteases are present if the solution turns blue or not," said Cuong Cao, the study's lead academic.
Using this approach, proteases can be detected in 90 minutes without the need for complicated or expensive laboratory equipment.
In addition, the ingredients & # 39; to manufacture the nanosensor are readily available and are low cost. Gold nanoparticles can be produced in abundance, with little restriction on storage requirements, making it a durable and inexpensive substance.
The approach developed by Queen researchers has been tested in milk and urine, but can be adapted for several other applications.
Dr Cao explains, "Using other molecules other than casein to coat the surface has the potential to detect other types of enzyme biomarkers. For example, the coating of lipid nanoparticles could detect the lipase enzyme, which could help in the diagnosis of diseases like pancreatitis ". .
"After the complete validation of this test, we would like to explore how we could expand the application to detect a number of other diseases or contaminated foods." This new approach will allow the identification of enzymatic biomarkers at the point of care. detected and diagnosed, causing an impact not only on food safety, but on the diagnosis of enzyme-related diseases between animals and humans.The potential for this test is enormous. "
Professor Elliott, founder of the Institute for Global Food Security and co-investigator of the study, commented: "The ability to diagnose illness or contamination quickly can have a huge impact on how serious problems can be solved. reduce testing costs and can transform the amount of testing performed in the developing world. "