A new paper-based test developed at MIT can diagnose Zika virus infection within a few hours. The test, which distinguishes Zika from the very similar dengue virus, can be stored at room temperature and read with a simple electronic reader, making it potentially practical for widespread use.
An outbreak of the Zika virus that began in Brazil in April 2015 has been linked to a birth defect known as microcephaly. Many infected people experience no symptoms, and when symptoms do appear they are very similar to those of related viruses such as dengue and chikungunya.
Currently, patients are diagnosed by testing whether they have antibodies against Zika in their bloodstream, or by looking for pieces of the viral genome in a patient’s blood sample, using a test known as polymerase chain reaction (PCR). However, these tests can take days or weeks to yield results, and the antibody test cannot discriminate accurately between Zika and dengue.
The new device is based on technology that the researchers previously developed to detect the Ebola virus. In October 2014, the researchers demonstrated that they could create synthetic gene networks and embed them on small discs of paper. These gene networks can be programmed to detect a particular genetic sequence, which causes the paper to change color.
Upon learning about the Zika outbreak, the researchers decided to try adapting their device to diagnose Zika, which has spread to other parts of South and North America since the outbreak began in Brazil.
They developed sensors, embedded in the paper discs, that can detect 24 different RNA sequences found in the Zika viral genome. When the target RNA sequence is present, it initiates a series of interactions that turns the paper from yellow to purple.
