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Detector spots respiratory infections much earlier

VANDERBILT (US)—A new ultrasensitive detector can identify a respiratory infection at a very early stage with a test simple enough to be performed in a pediatrician’s office—and results take only minutes.

A chemist and biomedical engineer from Vanderbilt University developed the technique, which uses DNA hairpins attached to gold filaments. The researchers have shown that the new method can identify the presence of respiratory syncytial virus (RSV)—a leading cause of respiratory infections in infants and young children—at substantially lower levels than the standard laboratory assay.

“We hope that our research will help us break out of the catch-22 that is holding back major advances in the treatment of respiratory viruses,” says David Wright, an associate professor of chemistry, who is working with Frederick Haselton, professor of biomedical engineering, on the new detection method.

Wright says major pharmaceutical companies are not investing in the development of antiviral drugs for RSV and the other major respiratory viruses because there is no way to detect the infections early enough for the drugs to work effectively without harmful side-effects.

“There are antiviral compounds out there—we have discovered some of them in my lab—that would work if we can detect the virus early enough, before there is too much virus in the system,” he adds.

The lack of a reliable early detection system adds to the growing problem of antibiotic resistance. The symptoms of respiratory infections caused by viral agents are nearly identical to those caused by bacteria. As a result, antibiotics, which target bacteria, are often incorrectly prescribed for viral infections. Not only is this ineffective, but it also increases the number of antibiotic-resistant strains.

With current standard RSV tests, doctors often must wait a day or more for lab results. Respiratory viruses multiply so rapidly that this can be too late for antiviral drugs to work, Wright says.

By contrast, “our system could easily be packaged in a disposable device about the size of a ballpoint pen,” says Haselton. To perform a test, all that would be required is to pull off a cap that will expose a length of gold wire, dip the wire in the sample, pull the wire through the device, and put the exposed wire into a fluorescence scanner. If it lights up, then the virus is present.

This research was supported by grants from Vanderbilt University and the National Institutes of Health. The findings were reported in The Analyst, a journal published by the Royal Society of Chemistry.

Read more in Exploration, Vanderbilt’s online research magazine.

Vanderbilt University news: www.vanderbilt.edu/news

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