Researchers at the University of Massachusetts Amherst have developed a new method of detecting very small amounts of DNA. The breakthrough could allow clinicians to spot genetic markers of disease at the point-of-care, as the approach does not require conventional laboratory analysis, which is usually time-consuming and costly. In fact, the approach has led to a 100-fold increase in DNA detection sensitivity, with no corresponding increase in cost. The technology relies on the tendency of DNA oligomers to ‘dance’ when they are exposed to an alternating electric current, which allows the researchers to identify target DNA by analyzing its oscillation frequency. Happily, the method works with very small amounts of target DNA, and therefore exhibits very high sensitivity.

Detecting DNA is the basis for many diagnostic texts. Conventional approaches cannot detect tiny amounts of DNA, and often require target DNA in a sample to be amplified significantly before detection. This adds lots of extra steps, additional expensive reagents and expensive equipment, and takes a long time. There are also several substances present in biological samples that can interfere with this process and make it more difficult to obtain reliable results. Techniques that allow for small amounts of DNA to be detected successfully, without interference from other factors, could be a game-changer in point-of-care diagnostics.

“DNA detection is in the center of bioengineering,” said Jinglei Ping, a researcher involved in the study. “Everyone wants to detect the DNA at a low concentration with a high sensitivity. And we just developed this method to improve the sensitivity by about 100 times with no cost.”

The key to this new approach is the oscillation frequency of the target DNA when it is exposed to an alternating electric field within the device. “We let the DNA dance,” said Ping. “When the strands of DNA dance, they have a specific oscillation frequency.” This oscillation frequency represents a hallmark that allows the researchers to identify the strands of interest, very rapidly. The approach takes just minutes and given that the device is relatively small and portable, point-of-care analysis is a key attribute.

“This makes it suitable for point of care,” said Ping. “Usually, we provide samples to a lab and they can provide the results quickly or slowly, depending on how fast they go, and it can take 24 hours or longer. It can be used at places where resources are limited. I went to a country and the doctor usually goes to a village once or twice a year, and now, maybe they can have a base that has this kind of tool and they’ll have the chance to test for it quickly and easily.”

Study in Proceedings of the National Academy of Sciences: Nanomechanoelectrical approach to highly sensitive and specific label-free DNA detection

Via: University of Massachusetts Amherst

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