Doctors working hundreds of miles away from the nearest hospital could soon have a way to quickly detect Zika virus in blood or saliva samples for less than a dollar per patient. In a proof-of-concept demonstration published May 6 in Cell, Wyss Institute for Biologically Inspired Engineering researchers at Harvard University show how a new Zika diagnostic, which can be freeze-dried and stored for up to a year, successfully detects the virus in the serum of infected macaques.
The platform is the next-generation of synthetic biology diagnostics to emerge out of the lab of James Collins, who previously developed sensors to detect RNA molecules, including those found in viruses such as Ebola (Cell, 10.1016/j.cell.2014.10.004). The Zika test can be used on the serum (blood or possibly saliva) of infected individuals to detect viruses at significantly lower concentrations than previously possible. By coupling RNA amplification and a CRISPR-based module, the platform can communicate results through a simple "color-change" assay, which an untrained eye can easily use to evaluate whether Zika is present or not in a biological sample.
"We had been working on advancing the paper-based platform we published in 2014 toward a more field-ready format when the Zika outbreak was reported, and we felt, given the critical need for low cost, field-based diagnostics, that our approach could make an impact," says Collins, who also holds positions at MIT and the Broad Institute. "We can now demonstrate a rapid prototyping and sensor assembly pipeline that can be applied to other emerging pathogens or health crises."
This image shows a black cartridge containing a paper-based diagnostic for detecting the Zika virus is held up by a researcher at Harvard's Wyss Institute. Areas that have turned purple indicate samples infected with Zika, while yellow areas indicate samples that are free of the virus. Credit: Wyss Institute at Harvard University
While still a proof-of-concept demonstration, with the necessary product development, scaling, and manufacturing, the Zika diagnostic approach could be ready in several months for use in clinical or laboratory settings with the capability to incubate reactions at 37-41 degrees Celsius (98-105 degrees Fahrenheit). Such a test would improve upon key limitations of currently available options for Zika detection, such as potential cross-reactivity with closely-related viruses and a lack of specialized skills or equipment to screen for the virus outside of large urban areas.
If proven successful in the field, "the test's low cost and minimal equipment also means that it can be used for monitoring the spread of illnesses across large populations of people, enabling us to monitor the pathogen as an outbreak is occurring," Collins says. "NGOs like the WHO can use this information to get ahead of an outbreak in order to contain it and save lives."
source: Cell Press