A chemist and a parasite expert at Brock University have teamed up to produce and test out a simple device that can detect diseases from DNA samples. It\u2019s a scaled-down version of what is normally an expensive and complicated DNA laboratory technique, yet it\u2019s fast, inexpensive and accurate, making it ideal for use in developing countries.<\/p>\n
Brock University Assistant Professor of Chemistry Feng Li\u2019s device consists of a strip of paper attached onto a glass slide. The paper contains several rows of what look like thermometers, lines with markings projecting out of bulb-like circles.<\/p>\n
DNA samples are loaded onto the circles and move up the lines, much like mercury rises in a thermometer.<\/p>\n
\u201cDifferent concentrations of the genetic disease biomarkers in the samples would migrate different distances,\u201d says Li. \u201cSo, all you need to do is read the distance they penetrate, just like you\u2019d read a ruler.\u201d<\/p>\n
Known as the quantitative paper-based DNA reader, each device costs only about 10 cents. They work with a scaled-down version of a traditionally expensive and complex DNA laboratory technique.<\/p>\n
While testing for the presence of disease markers, health-care workers use a technique called polymerase chain reaction (PCR), which makes millions of copies of a particular section of DNA.<\/p>\n
The PCR technique normally requires highly specialized equipment and expensive molecular probes. But Li\u2019s device is able to read DNA samples through a PCR technique using simple technology and low-cost chemicals.<\/p>\n
\u201cThis is going to be extremely useful in resource-limited settings where you don\u2019t have a lot of facilities to interpret the results,\u201d says Li.<\/p>\n
One such setting is the National Autonomous University of Honduras, where Brock University Professor of Health Sciences Ana Sanchez runs an internationally-renowned research program focusing on parasites.<\/p>\n
She and her research team collected worms that had been expelled by children suspected of having soil-transmitted helminth infection<\/a>, a disease affecting about 1.5 billion people worldwide and a major cause of childhood malnutrition and physical impairment.<\/p>\n The researchers used the quantitative paper-based DNA reader to test the worms for helminth infection.<\/p>\n \u201cThe results are beautiful; there\u2019s no doubt that the system works,\u201d says Sanchez.<\/p>\n She applauds the speed and sensitivity of the device, saying that diagnostic techniques in developing countries are traditional, basic and rely on the expertise of the person observing the sample.<\/p>\n Sanchez says the device goes beyond just a yes or no result by measuring the amount of genetic disease biomarkers in the DNA sample.<\/p>\n \u201cHow many parasites is this child harbouring?\u201d she says. \u201cThat tells you maybe their immune response and nutrition are impaired, that we’d need to consider if treatment needs to be ramped up, even if there could be a possibility of parasitic resistance.<\/p>\n \u201cThe knowledge of parasitic burden of individuals and community will directly lead to public health interventions. What Feng has proven is that his invention works. We\u2019re ready to bring it to the field.\u201d<\/p>\n Both Sanchez and Li say they are happy with their research partnership, which evolved from casual conversations as they worked next to one another in their labs in Brock\u2019s Cairns Family Health and Bioscience Research Complex.<\/p>\n \u201cI think it\u2019s a really nice thing that we talked and realized we could collaborate. There\u2019s a lot of mutual interest between us,\u201d says Li. \u201cIt\u2019s a very fruitful collaboration. We match perfectly in the research field.\u201d<\/p>\n The research team\u2019s results are in their study \u201cPaper-Based DNA Reader for Visualized Quantification of Soil-Transmitted Helminth Infections,\u201d<\/a> published Tuesday, Jan. 16 in the journal ACS Sensors. <\/em>PhD student Alex Guan Wang and master\u2019s student Tianyu Dong are the study\u2019s first authors.<\/p>\n Li says he is working with Brock\u2019s business incubation facility BioLinc to create a plastic container that will house the paper-based DNA reader.<\/p>\n