One of the keys to quickly diagnosing anti-malarial drug resistance — potentially saving lives — lies in testing whole blood instead of extracting DNA, eliminating processing steps that can take hours or days. A team of Vanderbilt University biomedical engineers cracked the code to doing just that and are working on applying the method to help patients with HIV, tuberculosis and a host of other diseases.
Mindy Leelawong, research assistant professor of biomedical engineering, said the problem of drug-resistant malaria is prevalent in Southeast Asia and may spread to Africa and beyond. Doctors currently can tell whether powerful malaria drugs will work on someone or not through polymerase chain reaction (PCR), or a DNA duplication method that allows for optical detection of a disease’s biomarkers with only a sample. However, they formerly had to extract the malaria parasite’s DNA first, virtually impossible to do in rural, low-resource areas.
Leelawong and her team took on issues preventing a whole-blood test one at a time until they hit upon two major changes that would work: reinventing dyes typically used in PCR so that they’re more compatible with blood and adding a different type of DNA to the PCR process that allows doctors in the field to see individual mutations. In a new study, they have analyzed a single mutation in a malaria parasite from a single drop of whole blood.
“In my global health work, it was frustrating to collect pinprick samples on paper in the field, ship them back to a central laboratory and then wait,” said Leelawong, who has worked in Zambia and Peru. “There would be hundreds of blood spots stored in a freezer somewhere, awaiting people to sit down and do the DNA extraction process, while patients needed answers. I wanted to eliminate the paper and the bottleneck.”
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