Development and Evaluation of A CRISPR-based Diagnostic 2 For 2019-novel Coronavirus (Hou et al., 2020)
Discussion:
The CRISPR-nCoV assay is convenient and greatly needed in the laboratory and in the clinical setting. Because the CRISPR-nCoV assay does not require thermal cyclers, the time of the testing is decreased, and this assay can operate in a setting with minimal resources. Presently, there is a demand for more testing of the 2019-nCoV virus. In some states and counties testing is limited. Also, the current tests take a long time to produce results. The fastidious and rapid diagnosis of 2019-nCoV may help many quarantine earlier before the symptoms become too intense. The CRISPR-nCoV is exceptional because less instruments as thermocyclers are required, which could help transfer the CRISPR-nCoV into the clinical setting. However, mNGS, a metagenomic test, is still needed to track any signs of genetic drift in the 2019-nCoV viral genome.
CRISPR detection of 2019-nCoV is an extremely promising assay with much potential because it can provide tests with high sensitivity and specificity. The inclusion of CRISPR technology increases and produces test results for 2019-nCoV with higher specificity because Cas13a can directly target and cleave RNA, using crRNA as guide RNAs. The 2019-nCoV is a single strand RNA virus, so the synthesized guide RNAs can bind to and guide the Cas13a nuclease to that specific RNA sequence for cleavage.The CRISPR-nCoV assay detected RNA sequences of 2019-nCoV, fluorescent signals were produced, and then collected. The sensitivity of CRISPR detection of 2019-nCov was extremely sensitive during serial dilutions at many different nucleic acid concentrations.
The results of the sensitivity tests determined that 7.5 copies of 2019-nCoC were detected in all 10 replicates, 2.5 copies were found in 6 out 10 replicates, and 1.25 copies were in 2 out of 10 replicates. Specificity tests for CRISPR-nCoV were tested against DNA from human cells, microbes, human coronaviruses, and other respiratory viruses where none triggered false positive results. From ROC analysis 100% sensitivity and specificity results of the curves were produced from the positive 2019-nCoV test results. The ROC results are important for use of CRISPR-nCoV in the clinical setting where highly sensitive and specific tests are required. No false positives were detected from all 62 cases.
What are a few issues that may affect the effective diagnostics of CRISPR-nCoV assays?
Hi,
You can go through this link. It looks interesting.
Thank you.
https://www.nature.com/articles/d41586-020-01362-0?WT.ec_id=NATURE-20200514&utm_source=nature_etoc&utm_medium=email&utm_campaign=20200514&sap-outbound-id=6E287FDB11FF724D598EEAA28629C3A8FA8ADFCB
Hello,
The CRISPR-nCoV is a very good method for the diagnosis of Sars-cov2, but if the target sequence has a mutation, for example, a deletion can CRISPR identify the virus?
I think that the 2019-nCoV viral genome is highly conserved without many mutations. I need to double check.
Here’s a link discussing the evolution of SARS-CoV-2.
https://www.centerforhealthsecurity.org/resources/COVID-19/COVID-19-fact-sheets/200128-nCoV-whitepaper.pdf