CRISPR is a powerful piece of gene-editing technology. By highjacking the ability of E. coli to destroy the genetic material of viruses, scientists can selectively delete parts of DNA or paste in new parts. There are many implications, such as being able to edit out diseases or engineer new types of plants and animals. It turns out that it has another useful application— it can be used in cheap and fast tests for pathogens. CRISPR can be used to detect the Zika virus, along with antibiotic resistance and even cancer mutations.

A pathogen sleuth

Most tests for pathogens compromise speed, simplicity, price, or sensitivity. This new method with CRISPR combines the best of all four. It can be used to test blood, urine or saliva samples easily. The researchers at the Broad Institute in Cambridge, Massachusetts who invented it, and clearly like acronyms, called it SHERLOCK. It stands for Specific High Sensitivity Enzymatic Reporter Unlocking.

There’s a new SHERLOCK in town. Image credits: Public Domain Pictures.

SHERLOCK snoops out pathogens by first making RNA copies of DNA and then using CRISPR to look for particular genetic sequences. An enzyme creates fluorescence once it has found a target sequence. If you specify a virus, bacteria, or mutation, then you would get fluorescence if it is detected.


The research group tested just a few of many potential uses for this pathogen test. The first use is, of course, using it to detect harmful viruses and bacteria, such as the Zika and Dengue virus. Additionally, they were able to detect antibiotic resistance in one type of bacteria. With increasing antibiotic resistance, this information is important to know.

SHERLOCK can find the difference even between genetic sequences that differ by only one base pair. Therefore it can be used for quick human genotyping to find gene variants that are important for health. For example, someone could be screened for heritable diseases. The researchers also used SHERLOCK to identify two cancer mutations. The test can be adapted to detect different diseases and mutations; the possibilities are endless!

Wonder if you have Zika? This simple test could tell you. Image credits: James Gathany.

There are some very convincing pros when comparing this test with existing pathogen tests. SHERLOCK could screen people quickly when there is an epidemic outbreak. It can detect down to single molecules of samples, so it has been shown to be very accurate so far. The test can be completed in just an hour, so you don’t have to wait long for results. As if that wasn’t good enough, a paper test costs only 61 cents to design and make. The test can also be stored for a long time. it just needs to be tested with patients on a larger scale.

SHERLOCK, the agent of CRISPR, has countless possible applications when it comes to health and disease monitoring.

Journal reference: Gootenberg, J.S. 2017. Nucleic acid detection with CRISPR-Cas13a/C2c2, Science.

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