Developments in CRISPR technology for identifying ailments through a novel diagnostic method
In a significant breakthrough for rapid and inexpensive diagnostic tools, a team from the Broad Institute of MIT and Harvard, and MIT has enhanced the power of the CRISPR-based diagnostic tool, SHERLOCK. The researchers have developed a simple, paper-based test that allows results to be seen with the naked eye, without the need for expensive equipment.
SHERLOCK's new feature is analogous to pregnancy tests, featuring a paper strip that displays test results for a single genetic signature, courtesy of visual cues. After dipping the paper strip into a processed sample, a line appears, signaling whether the target molecule was detected or not.
The innovation opens up opportunities for field use, such as during an outbreak. Moreover, the team has boosted SHERLOCK's sensitivity and added the ability to quantify the amount of target in a sample and test for multiple targets simultaneously. These advancements have accelerated SHERLOCK's ability to quickly and accurately detect genetic signatures, including pathogens and tumor DNA, in samples.
Feng Zhang, a core institute member of the Broad Institute, an investigator at the McGovern Institute, and the James and Patricia Poitras '63 Professor in Neuroscience, commented on the development: "SHERLOCK provides an inexpensive, easy-to-use, and sensitive diagnostic method for detecting nucleic acid material, which can mean a virus, tumor DNA, and many other targets."
The researchers have previously demonstrated SHERLOCK's utility for various applications. In the new study, the team utilized SHERLOCK to detect cell-free tumor DNA in blood samples from lung cancer patients and detect synthetic Zika and Dengue virus simultaneously.
The new paper readout for SHERLOCK lets users see whether their target was present in the sample without the need for machinery. This development brings the technology much closer to a field-ready diagnostic. The technology's versatility in nucleic acid target detection promises potential applications in healthcare, industrial, and agricultural sectors.
The core of SHERLOCK's success lies in a CRISPR-associated protein called Cas13, which can be programmed to bind to a specific piece of RNA. Cas13 can bind to any genetic sequence, making it a powerful tool for diagnostics. To drive the enzyme to cascade cuts, the team engineered the system to be compatible with both DNA and RNA.
SHERLOCK's diagnostic potential relies on additional strands of synthetic RNA, which are used to create a signal after being cleaved. Cas13 will chop up the RNA after it hits its original target, releasing the signaling molecule, resulting in a readout that indicates the presence or absence of the target.
The updated SHERLOCK platform can now be adapted to test for multiple targets. While the initial version could only detect one nucleic acid sequence, the new one can give fluorescent signals for up to four different targets, meaning less sample is required to run through diagnostic panels. Additionally, SHERLOCK's second iteration uses an additional CRISPR-associated enzyme to amplify its detection signal, making the tool more sensitive than its predecessor.
The authors have made their reagents available to the academic community through Addgene, and their software tools can be accessed via the Zhang lab website and GitHub.
This study was supported in part by the National Institutes of Health and the Defense Threat Reduction Agency.
(Relevant details from the Enrichment Data: SHERLOCK's high sensitivity and specificity for RNA and DNA identification make it a potent tool for detecting various mutations, including cancer-related ones like BRAFV600E and EGFR-L858R. Additionally, broader trends in CRISPR-based diagnostics are focusing on developing user-friendly, low-cost methods for point-of-care diagnostics, such as SHERLOCK's paper test for naked-eye results. Ongoing research is also working on enhancing diagnostic tools for ease of use and multi-target detection.)
- The new SHERLOCK diagnostic tool, developed by MIT and Harvard's Broad Institute, features a paper-based test that enables users to see results with the naked eye, revolutionizing rapid and inexpensive diagnostic tools.
- SHERLOCK's latest iteration resembles a pregnancy test, with a paper strip displaying test results for a single genetic signature, visible via visual cues.
- The team has boosted SHERLOCK's sensitivity and added the ability to quantify the amount of target in a sample, as well as test for multiple targets simultaneously.
- Feng Zhang, a professor in Neuroscience, explained that SHERLOCK provides an inexpensive, easy-to-use, and sensitive diagnostic method for detecting nucleic acid material, such as viruses, tumor DNA, and various other targets.
- In the new study, SHERLOCK was used to detect cell-free tumor DNA in blood samples from lung cancer patients and to detect synthetic Zika and Dengue viruses simultaneously.
- The new paper readout for SHERLOCK allows users to determine whether their target was present in the sample without requiring machinery, bringing the technology much closer to a field-ready diagnostic.
- The versatility of SHERLOCK in nucleic acid target detection promises potential applications in healthcare, industrial, and agricultural sectors.
- The authors of the study have made SHERLOCK's reagents available to the academic community through Addgene and have shared their software tools via the Zhang lab website and GitHub. The work was supported in part by the National Institutes of Health and the Defense Threat Reduction Agency.
