Inexpensive Device Can Diagnose Zika in Just a Few Hours

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All of the cellular components necessary for this process — including proteins, nucleic acids, and ribosomes — can be extracted from living cells and freeze-dried onto paper. These paper discs can be stored at room temperature, making it easy to ship them to any location. Once rehydrated, all of the components function just as they would inside a living cell.

The researchers also incorporated a step that boosts the amount of viral RNA in the blood sample before exposing it to the sensor, using a system called NASBA (nucleic acid sequence based amplification). This amplification step, which takes one to two hours, increases the test’s sensitivity 1 million-fold.

Julius Lucks, an assistant professor of chemical and biomolecular engineering at Cornell University, says that this demonstration of rapidly customizable molecular sensors represents a huge leap for the field of synthetic biology.

“What’s really exciting here is you can leverage all this expertise that synthetic biologists are gaining in constructing genetic networks and use it in a real-world application that is important and can potentially transform how we do diagnostics,” says Lucks, who was not involved in the research.

Distinguishing viruses

The team tested the new device using synthesized RNA sequences corresponding to the Zika genome, which were were then added to human blood serum. The researchers showed that the device could detect very low viral RNA concentrations in those samples and could also distinguish Zika from dengue.

The researchers then tested the device with samples taken from monkeys infected with the Zika virus. (Samples from human patients affected by the current Zika outbreak are very difficult to obtain.) They found that in these samples, the device could detect viral RNA concentrations as low as 2 or 3 parts per quadrillion.

The researchers envision that this approach could also be adapted to other viruses that may emerge in the future. Collins now hopes to team up with other scientists to further develop the technology for diagnosing Zika.

“Here we’ve done a nice proof-of-principle demonstration, but more work and additional testing would be needed to ensure safety and efficacy before actual deployment,” he says. “We’re not far off.”

The research was funded by the Wyss Institute for Biologically Inspired Engineering, MIT’s Center for Microbiome Informatics and Therapeutics, the Defense Threat Reduction Agency, and the National Institutes of Health.