A paper-based rapid test for the Zika virus has been introduced by a consortium of research groups, according to The New York Times. The core of the test kit is a piece of paper covered with yellow dots that turn purple in the presence of Zika virus RNA.
Although the test is relatively fast and simple, it requires preliminary heating to amplify a sample’s RNA, which can be performed in most laboratories.
The test, which gives results in two to three hours, “is much faster and cheaper than the PCR tests used now,” said James J. Collins, a bioengineer at the Massachusetts Institute of Technology who is one of the test designers.
It should cost less than $1 per test, said Keith Pardee, a University of Toronto biochemist and another test designer. Dr. Collins took a cell’s normal reproductive “machinery”– including proteins, nucleic acids and ribosomes–and freeze-dried it on paper.
The work was described in the journal Cell. The color change can be read by the eye or by an extra-sensitive scanner that may eventually be able to measure viral loads in the blood sample. The test has worked on Zika-infected monkey blood, which was used because human samples were hard to obtain in time.
Now, Dr. Collins said, “we’re talking with groups in Colombia and Brazil about testing it in the field.” All components of the diagnostic system can be freeze-dried for storage and transport while retaining their efficacy.
“In response to an emerging outbreak, we envision a custom-tailored diagnostic system could be ready for use within one week’s time,” said Collins. The ability to recapitulate the genetic machinery of living cells in ordinary freeze-dried paper provides a way to develop revolutionary sensors and diagnostics in a fraction of the time and with higher sensitivity and specificity than conventional assays.
These inexpensive paper-based tests also can be easily transported out of the laboratory and distributed virtually anywhere in the world. “The potential for applications in health and environmental screening, particularly in low-resource areas, is huge,” said Donald Ingber, director of Harvard’s Wyss Institute.
The collaboration also included scientists from the Broad Institute, Cornell University, Arizona State University, and Boston University. The work was also supported by the Defense Threat Reduction Agency and the National Institutes of Health.
Separately, studies from three different teams of scientists offered proof that Zika can reach and destroy brain cells in the fetuses of pregnant mice, findings that solidify the link between the mosquito-borne virus and birth defects.
In February, the World Health Organization declared Zika a global health emergency based on its association with thousands of cases in Brazil of microcephaly, a birth defect marked by small head size that can cause severe developmental problems.
The studies in pregnant mice, published in the journals Nature, Cell and Cell Stem Cell, showed Zika invading brain cells in fetal mice, demonstrating convincingly that Zika can attack fetal brain tissue and cause significant damage.
Monday, May 16, 2016 / Vol. 24 / No. 19