Features Partner Sites Information LinkXpress hp
Sign In
Advertise with Us

Download Mobile App





Virus-Like Probes Could Help Make Rapid COVID-19 Testing More Accurate and Reliable

By LabMedica International staff writers
Posted on 02 Dec 2020
A team of nanoengineers has developed new and improved probes, known as positive controls, that could make it easier to validate rapid, point-of-care diagnostic tests for COVID-19 across the globe.

The positive controls, made from virus-like particles by nanoengineers at the University of California San Diego (La Jolla, CA, USA), are stable and easy to manufacture. More...
Researchers say the controls have the potential to improve the accuracy of new COVID-19 tests that are simpler, faster and cheaper, making it possible to expand testing outside the lab.

Positive controls are a staple in the lab - they are used to verify that a test or experiment indeed works. The positive controls that are primarily used to validate today’s COVID-19 tests are naked synthetic RNAs, plasmids or RNA samples from infected patients. But the issue is RNA and plasmids are not stable like viral particles. They can degrade easily and require refrigeration, making them inconvenient and costly to ship around the world or store for long periods of time.

By packaging segments of RNA from the SARS-CoV-2 virus into virus-like particles, the researchers have shown that they can create positive controls for COVID-19 tests that are stable - they can be stored for a week at temperatures up to 40 C (104 F), and retain 70% of their activity even after one month of storage - and can pass detection as the novel coronavirus without being infectious. The team developed two different controls: one made from plant virus nanoparticles, the other from bacteriophage nanoparticles. The controls are run and analyzed right alongside a patient sample, providing a reliable benchmark for what a positive test result should look like.

To make the plant virus-based controls, the researchers use the cowpea chlorotic mottle virus, which infects black-eyed pea plants. They essentially open the virus, remove its RNA contents, replace them with a synthesized RNA template containing specific sequences from the SARS-CoV-2 virus, then close everything back up. The process to make the bacteriophage-based controls starts with plasmids, which are rings of DNA. Inserted into these plasmids are the gene sequences of interest from the SARS-CoV-2 virus, as well as genes coding for surface proteins of the bacteriophage Qbeta. These plasmids are then taken up by bacteria. This process reprograms the bacteria to produce virus-like particles with SARS-CoV-2 RNA sequences on the inside and Qbeta bacteriophage proteins on the outside.

Both controls were validated with clinical samples. A big advantage, the researchers point out, is that unlike the positive controls used today, these can be used in all steps of a COVID-19 test. So far, the researchers have adapted their controls for use in the CDC-authorized RT-PCR test. While this is currently the gold standard for COVID-19 testing, it is expensive, complex, and can take days to return results due to the logistics of sending samples off to a lab with PCR capability. The researchers are now working on adapting the controls for use in less complex diagnostic tests like the RT-LAMP test that can be done on the spot, out of the lab and provide results right away.

“Our goal is to make an impact not necessarily in the hospital, where you have state-of-the-art facilities, but in low-resource, underserved areas that may not have the sophisticated infrastructure or trained personnel,” said Nicole Steinmetz, a professor of nanoengineering at the UC San Diego Jacobs School of Engineering. “It’s a relatively simple nanotechnology approach to make low-tech assays more accurate. This could help break down some of the barriers to mass testing of underserved populations in the U.S. and across the world.”

Related Links:
University of California San Diego


Gold Member
SARS-CoV-2 Reactive & Non-Reactive Controls
Qnostics SARS-CoV-2 Typing
Portable Electronic Pipette
Mini 96
New
Autoimmune Liver Diseases Assay
Microblot-Array Liver Profile Kit
New
Sperm Quality Analyis Kit
QwikCheck Beads Precision and Linearity Kit
Read the full article by registering today, it's FREE! It's Free!
Register now for FREE to LabMedica.com and get access to news and events that shape the world of Clinical Laboratory Medicine.
  • Free digital version edition of LabMedica International sent by email on regular basis
  • Free print version of LabMedica International magazine (available only outside USA and Canada).
  • Free and unlimited access to back issues of LabMedica International in digital format
  • Free LabMedica International Newsletter sent every week containing the latest news
  • Free breaking news sent via email
  • Free access to Events Calendar
  • Free access to LinkXpress new product services
  • REGISTRATION IS FREE AND EASY!
Click here to Register








Channels

Hematology

view channel
Image: New research points to protecting blood during radiation therapy (Photo courtesy of 123RF)

Pioneering Model Measures Radiation Exposure in Blood for Precise Cancer Treatments

Scientists have long focused on protecting organs near tumors during radiotherapy, but blood — a vital, circulating tissue — has largely been excluded from dose calculations. Each blood cell passing through... Read more

Immunology

view channel
Image: The VENTANA HER2 (4B5) test is now CE-IVDR approved (Photo courtesy of Roche)

Companion Diagnostic Test Identifies HER2-Ultralow Breast Cancer and Biliary Tract Cancer Patients

Breast cancer is the most common cancer in Europe, with more than 564,000 new cases and 145,000 deaths annually. Metastatic breast cancer is rising in younger populations and remains the leading cause... Read more

Technology

view channel
Image: Conceptual design of the CORAL capsule for microbial sampling in the small intestine (H. Mohammed et al., Device (2025). DOI: 10.1016/j.device.2025.100904)

Coral-Inspired Capsule Samples Hidden Bacteria from Small Intestine

The gut microbiome has been linked to conditions ranging from immune disorders to mental health, yet conventional stool tests often fail to capture bacterial populations in the small intestine.... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.