Nobel Prize Winner's New Technology: 5 Minutes to Detect Novel Coronavirus

China Science News, October 12th, a research team led by Jennifer Doudna, a professor at the University of California, Berkeley and winner of the 2020 Nobel Prize in Chemistry, used CRISPR gene editing technology to propose a novel coronavirus that can be detected in just 5 minutes method. The test method does not require expensive laboratory equipment to run, and can be used in doctor's offices, schools, and office buildings. Related results were published on the preprint platform medRxiv.

Max Wilson, a molecular biologist at the University of California, Santa Barbara, said this looks like an absolutely reliable test.

In May of this year, two research teams reported a CRISPR-based new coronavirus detection method, which can detect the virus in about 1 hour, much faster than the 24 hours required by traditional detection methods. The newly proposed detection method is currently the fastest diagnostic method based on CRISPR.

The working principle of CRISPR detection is to recognize an RNA sequence of about 20 bases, which is a unique base sequence of the new coronavirus. They created a "guide" RNA complementary to the target RNA sequence and combined with the target RNA sequence in solution. When the "guide" RNA binds to the target RNA, the Cas13 "scissors" enzyme of the CRISPR tool will start and cut the nearby single-stranded RNA. Moreover, shearing will release individual fluorescent particles into the test solution. When the sample is irradiated with a laser, the released fluorescent particles will glow, indicating the presence of the virus.

The original CRISPR detection method requires researchers to first amplify viral RNA, and then perform detection and diagnosis, which undoubtedly increases the complexity, cost and time of detection. This new CRISPR diagnostic method does not require amplification of new coronavirus RNA.

The team also spent several months testing hundreds of "guide" RNAs to find multiple "guide" RNAs that can work together to improve detection sensitivity. Researchers report that using a single "guide" RNA, 100,000 viruses can be detected per microliter of solution. If they add a second "guide" RNA, they can detect 100 viruses per microliter.

Melanie Ott, a virologist at the University of California, San Francisco, who co-led the research, said that the method is still not as good as the traditional new coronavirus diagnostic device, which uses expensive laboratory machines to track the virus and can track one virus per microliter. However, she said that the new diagnostic method can accurately identify a batch of 5 positive clinical samples, and each test takes only 5 minutes, while the standard test takes 1 day or more to get results.

Wilson said that the new detection method has another key advantage: it can quantify the number of viruses in a sample. When traditional tests use the amplification of genetic material to achieve the purpose of detection, it will change the amount of the existing genetic material, making it impossible to determine the number of viruses in the sample. In contrast, the intensity of the fluorescent signal detected by the new detection method is directly proportional to the number of viruses in the sample. This not only reveals whether the sample is positive, but also how much virus the patient carries. Wilson said that this information can help doctors make treatment plans based on each patient's condition.