Detecting Single Viruses in Urine: A New and Novel Approach

University of Texas at Austin researchers appear to have developed a novel technique based on electrochemical collisions to selectively, rapidly, and sensitively detect single viruses in urine. The approach—reported on in the March 28, 2016 issue of Proceedings of the National Academy of Sciences—currently works on just one virus at a time, but the scientists say it could be adapted to detect various human viruses, including Ebola, Zika, and HIV.

However, being highly selective to just one type of virus, the approach filters out possible false negatives due to other viruses or contaminants.

“The ultimate goal is to build a cheap, easy-to-use device to take into the field and measure the presence of a virus like Ebola in people on the spot,” said co-lead author Jeffrey Dick, a chemistry graduate student at UT Austin. “While we are still pretty far from this, this work is a leap in the right direction.”

Two other commonly used techniques for detecting viruses in biological samples both have drawbacks. One requires high concentrations of viruses, while the other requires samples to be purified to remove contaminants. The new method requires neither, enabling use with urine samples provided straight from a person or animal.

The other co-lead author was Adam Hilterbrand, a microbiology graduate student at UT Austin, and co-authors include Lauren Strawsine, a postdoctoral fellow in chemistry, Jason Upton, an assistant professor of molecular biosciences, and Allen Bard, a professor of chemistry and director of the Center for Electrochemistry, all at UT Austin. The group reported the specific collision of a single murine cytomegalovirus (MCMV), a virus belonging to the same family as the herpes virus, on a platinum ultramicroelectrode (UME).

“Antibody directed against the viral surface protein glycoprotein B functionalized with glucose oxidase (GOx) allowed for specific detection of the virus in solution and a biological sample (urine)...” the team wrote of the process, “…Negative controls (i) without glucose, (ii) with an irrelevant virus (murine gammaherpesvirus 68), and (iii) without either virus do not display these current increases.”

In other words, the researchers placed an electrode in a sample of mouse urine and then to that urine added special molecules made up of enzymes and antibodies that naturally stick to the targeted virus. When all three stick together and bump into the electrode, an easily detectable spike occurs in electric current.

Dick and colleagues admit that various refinements are needed before the technique sees general use. Presently, the electrodes lose sensitivity over time, due to numerous other naturally occurring compounds sticking to them and leaving less surface area for viruses to interact with them. Also, the technique will need to be engineered into a rugged, compact device that is able to be operated in various real-world settings.