APR 16, 2020 9:38 AM PDT

A New Way to Quickly Test for COVID-19

WRITTEN BY: Carmen Leitch

PCR (polymerase chain reaction) is a fundamental tool used in many aspects of biological research. In the reaction, a specific piece of DNA can be identified and amplified using short strands of nucleotides called primers. These primers can amplify DNA of interest from very small quantities of template DNA in a sample. For example, a patient's blood can be tested for COVID-19 by using primers that are specific to the genetic material of SARS-CoV-2. If the virus is present, the primers will find it and will amplify it so it can be detected.

Identifying people who have the virus and testing their contacts will be the fastest way to get society functioning again. Unfortunately, however, huge numbers of these PCR-based tests would be needed to do that, and this massive demand may overwhelm the supply of PCR reagents. These tests can also be unreliable; there have been reports of false-positive and false-negative results.

To ease the strain on PCR reagents and the machines that are used to carry out the reactions, scientists have been looking for other ways to diagnose the virus, including CT scans and antibody tests. Researchers have now created a diagnostic test based on a concept called plasmonic photothermal sensing. The work has been reported in ACS Nano.

In this method (explained in the video), a beam of light hits a metallic surface, and that beam then bounces onto a detector. The metallic surface is a sensor chip, and the electrons inside get excited by the light beam hitting the surface; they resonate. In this case, the sensor chip holds probes that recognize sequences of SARS-CoV-2 RNA. These probes are linked to gold nanoparticles. When pieces of the viral genome are present in a sample, the viral RNA will link up with the probes, and by applying heat, false-positives are reduced.

When the researchers tested their method, the assay was very specific; it was able to tell the difference between SARS-CoV-2 and a close viral relative, SARS-CoV-1. One drawback of the diagnostic test, however, is that it requires intact viral RNA from patient samples.

Colorized scanning electron micrograph of an apoptotic cell (green) heavily infected with SARS-COV-2 virus particles (purple), isolated from a patient sample. Image captured and color-enhanced at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Maryland. / Credit: NIAID

Sources: AAAS/Eurekalert! via American Chemical Society, ACS Nano

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
MAY 09, 2021
Microbiology
Bacteria Can Read Genes Forwards or Backwards
MAY 09, 2021
Bacteria Can Read Genes Forwards or Backwards
One of the most basic processes in life in the creation of proteins from mRNA molecules, which are transcribed from DNA. ...
MAY 13, 2021
Genetics & Genomics
The Unique Caecilians of São Tomé Island
MAY 13, 2021
The Unique Caecilians of São Tomé Island
There are many islands that have unique flora and fauna, like these limbless creatures (Photo © Andrew Stanbridge) of Sã ...
MAY 24, 2021
Genetics & Genomics
Lead Exposure Can Lead to Epigenetic Changes
MAY 24, 2021
Lead Exposure Can Lead to Epigenetic Changes
In Brazil, automotive battery plants use lead to make their products, exposing workers to the element, which is abundant ...
JUN 05, 2021
Coronavirus
Newly-Named Coronavirus Variant Causes Concern
JUN 05, 2021
Newly-Named Coronavirus Variant Causes Concern
WHO has decided to create a new naming system for coronavirus variants for several reasons. The names will now be based ...
JUN 25, 2021
Genetics & Genomics
Towards More Efficient Plant Engineering with CRISPR-Cas9 Gene Drive
JUN 25, 2021
Towards More Efficient Plant Engineering with CRISPR-Cas9 Gene Drive
Many people in the world don't have access to enough food. And while humans might find ways to adapt to a changing world ...
JUN 27, 2021
Genetics & Genomics
How Colorful Geckos Can Teach Us About Biology
JUN 27, 2021
How Colorful Geckos Can Teach Us About Biology
A colony of Lemon Frost geckos was created by the reptile shop of Steve Sykes, which included Mr. Frosty, seen here cour ...
Loading Comments...