Scientists develop paper test tool to diagnose cancer, virus

An American team from the Broad Institute of Massachusetts Institute of Technology (MIT) has developed a paper test tool that allows people's genetic signatures to be seen in a paper strip with the naked eyes, like what is like in pregnancy tests.
The study, published on Thursday in the journal Science, is paving the way for an rapid, inexpensive and highly sensitive diagnostic tool to identify virus or cancer.
Researchers led by Zhang Feng, the core institute member at the Broad Institute, unveiled the power of tool called SHERLOCK in the study.
After dipping the paper strip into a processed sample, a line appears, indicating whether the target molecule was detected or not.
SHERLOCK, a shorthand for Specific High-sensitivity Enzymatic Reporter unLOCKing, is based on the powerful genome-editing technology CRISPR.
It can be used to detect cell-free tumor DNA in blood samples from lung cancer patients and to detect synthetic Zika and Dengue virus simultaneously, without instrumentation.
The team envisions a wide range of uses for SHERLOCK, due to its versatility in nucleic acid target detection.
"The technology demonstrates potential for many healthcare applications, including diagnosing infections in patients and detecting mutations that confer drug resistance or cause cancer, but it can also be used for industrial and agricultural applications where monitoring steps along the supply chain can reduce waste and improve safety," said Zhang.
Also, the SHERLOCK platform can be adapted to test for multiple targets. Initially, it could only detect one nucleic acid sequence at a time, but now one analysis can give fluorescent signals for up to four different targets at once.
It means that less sample is required to run through diagnostic panels.
For example, the new version of SHERLOCK can determine in a single reaction whether a sample contains Zika or dengue virus particles, which both cause similar symptoms in patients, according to the researchers.
"With the original SHERLOCK, we were detecting a single molecule in a microliter, but now we can achieve 100-fold greater sensitivity," explained co-first author Omar Abudayyeh, a MIT graduate student in Zhang's lab at Broad.
"That's especially important for applications like detecting cell-free tumor DNA in blood samples, where the concentration of your target might be extremely low," Zhang said.