At the National University of Singapore, scientists have developed a portable, point-of-care nucleic acid test platform that can be used to diagnose a variety of diseases. It comes in the form of a cartridge that does not need to be kept refrigerated or handled specially in any other way and once used it provides results faster than existing methods.
new
Called enVision (enzyme-assisted nanocomplexes for visual identification of nucleic acids), the testing device has everything needed to perform the test and does not require any external heating elements or pumps, so can be used at the point of care. “Conventional technologies – such as tests that rely on polymerase chain reaction to amplify and detect specific DNA molecules – require bulky and expensive equipment, as well as trained personnel to operate these machines. With enVision, we are essentially bringing the clinical laboratory to the patient. Minimal training is needed to administer the ,test and interpret the results, so more patients can have access to effective, lab-quality diagnostics that will substantially improve the quality of care and treatment,” said Dr Nicholas Ho, co-first author of the study appearing in Nature Communications
The critical component of the enVision platform are the “DNA molecular machines” that the researchers developed that connect with targeted nucleic acid strings and perform simple tasks once there. “The enVision platform has three key steps – target recognition, target-independent signal enhancement, and visual detection. It employs a unique set of molecular switches, composed of enzyme-DNA nanostructures, to accurately detect, as well as convert and amplify molecular information into visible signals for disease diagnosis,” said Dr Lim Geok Soon, co-first author of the study.
Within the enVision device are plastic chips housing DNA molecular machines that cling onto the wanted nucleic acid patterns. These are added to another set of molecular machines that, once activated, change the color of the sample and therefore can be detected with the naked eye.
The researchers have already tested enVision on human papillomavirus (HPV), demonstrating its ability to detect the virus with “superior sensitivity and specificity” compared to the clinical “gold standard,” according to National University of Singapore.
While the testing system is impressive, it’s quite cheap. The researchers believe that each test kit can be manufactured for less than $1 a piece.
Study in Nature Communications: Visual and modular detection of pathogen nucleic acids with enzyme–DNA molecular complexes