Device for COVID-19 testing

A study recently published in Cell shows a new fast and easy point-of-care device for SARS-CoV-2 testing.

Reducing SARS-Cov-2 transmission has proven difficult because pre-symptomatic, symptomatic, and asymptomatic individuals cannot be identified. Medical communities around the world have made efforts to develop effective treatments. Appropriate testing is required to contain the spread. Current problems with available SARS-Cov-2 tests are inaccessibility, expensive costs and long waiting times for results. A group of researchers successfully developed a sensitive, accurate, and fast portable point-of-care device for testing for SARS-Cov-2.

The current standard for SARS-Cov-2 tests is PCR. This technique measures the amount of DNA present in a sample in several costly steps and using specific laboratory equipment. Other testing methods include using CRISPR diagnosis. CRISPR was invented to change the DNA of an organism. This allows scientists to target DNA sequences that can then be removed, changed, or added to other DNA. The CRISPR-Cas9 system is the most widely used. Cas-9 is a protein that is responsible for cutting DNA. The researchers developed a new system called CRISPR-Cas13 that uses CRISPR-Cas gene editing technology. It works the same as other CRISPR-Cas systems, but their protein is Cas13, which targets RNA instead of DNA.

The study was conducted to test the effectiveness of CRISPR-Cas13 and a smartphone-based detector system. Pre-extracted nasal swab samples from SARS-Cov-2 positive patients were collected and passed through the test. The researchers developed the CRISPR-Cas13 system so that when the Cas13 protein binds to RNA, it cuts the sequence and attaches a fluorescent probe that can be captured by a smartphone camera. In this way, the researchers were able to determine exactly how much RNA virus was present. Measuring the number of viral particles (RNA load) within an individual is necessary to determine how infectious they are. The current Cas13 test procedure was able to detect only 30 virus particles per microliter of sample and up to 100 particles in 30 minutes. The CRISPR-Cas13 system was also able to accurately diagnose the set of pre-extracted patient RNA in just five minutes.

The new CRISPR-Cass13 system can deliver accurate SARS-CoV-2 test results with just one smartphone reader.

By eliminating the need to detect DNA, the CRISPR-Cas13 system is better than other CRISPR and PCR test methods. It avoids the need for expensive equipment, trained laboratory staff and long waiting times. More importantly, the test is sensitive to even the smallest amount of viral RNA present. By providing a quantitative measure (number of virus particles) compared to simply “positive” and “negative” results, clinicians can make more informed decisions about patient infectivity. This novel point-of-care instrument offers a quick and easy SARS-CoV-2 test system that enables better containment of virus transmission.

Written by Melody Sayrany

References:

CellPressNews. (n.d.). The researchers are adapting the cell phone camera for SARS-CoV-2 detection. Retrieved December 12, 2020 from https://www.eurekalert.org/pub_releases/2020-12/cp-rac120420.php

Fozouni, P., Sohn, S., Díaz de León Derby, M., Knott, GJ, Gray, CN, D & # 39; Ambrosio, MV, … Ott, M., Amplification-free detection of SARS-CoV-2 with CRISPR -Cas13a and mobile phone microscopy, Cell (2021), doi: https://doi.org/10.1016/ j.cell.2020.12.001.

Reference to get started: https://www.eurekalert.org/pub_releases/2020-12/cp-rac120420.php

Image by fernando zhiminaicela from Pixabay