The team that first unveiled the rapid, inexpensive, highly sensitive CRISPR-based diagnostic tool called SHERLOCK has greatly enhanced the tool’s power, and has developed a miniature paper test that allows results to be seen with the naked eye — without the need for expensive equipment.
The work, led by researchers from the Broad Institute of MIT and Harvard and from MIT, has the potential for a transformative effect on research and global public health.
The SHERLOCK team developed a simple paper strip to display test results for a single genetic signature, borrowing from the visual cues common in pregnancy tests. After dipping the paper strip into a processed sample, a line appears, indicating whether the target molecule was detected or not.
The team has also increased the sensitivity of SHERLOCK and added the capacity to accurately quantify the amount of target in a sample and test for multiple targets at once.
The researchers previously showcased SHERLOCK’s utility for a range of applications. In the new study, the team uses SHERLOCK to detect cell-free tumor DNA in blood samples from lung cancer patients and to detect synthetic Zika and Dengue virus simultaneously, in addition to other demonstrations.
At the core of SHERLOCK’s success is a CRISPR-associated protein called Cas13, which can be programmed to bind to a specific piece of RNA.
SHERLOCK’s diagnostic potential relies on additional strands of synthetic RNA that are used to create a signal after being cleaved. Cas13 will chop up this RNA after it hits its original target, releasing the signaling molecule, which results in a readout that indicates the presence or absence of the target.
The SHERLOCK platform can now be adapted to test for multiple targets. SHERLOCK initially 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 — meaning less sample is required to run through diagnostic panels.
News Source: http://news.mit.edu/2018/researchers-advance-crispr-based-tool-diagnosing-disease-0215
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