How X-rays Could Make Reliable, Rapid COVID-19 Tests a Reality

An imaging technique pioneered by Berkeley Lab is helping reveal the best antibodies for COVID-19 detection
Lawrence Berkeley National Laboratory

Newswise — Vaccines are turning the tide in the pandemic, but the risk of infection is still present in some situations. If you want to visit a friend, get on a plane, or go see a movie, there is no highly accurate, instant test that can tell you right then and there whether or not you have a SARS-CoV-2 infection. But new research from Lawrence Berkeley National Laboratory (Berkeley Lab) could help get reliable instant tests on the market. 

A study led by Michal Hammel and Curtis D. Hodge suggests that a highly sensitive lateral flow assay – the same type of device used in home pregnancy tests – could be developed using pairs of rigid antibodies that bind to the SARS-CoV-2 nucleocapsid protein. Such a test would only require a small drop of mucus or saliva, could give results in 15 minutes, and could detect a COVID-19 infection one day before the onset of symptoms. Their work was published in the journal mABs.

The current gold standard tests for COVID-19 use a form of polymerase chain reaction (PCR) to identify the presence of SARS-CoV-2 nucleic acid (RNA) rather than a viral protein. They are quite accurate, with false negative rates ranging less then 5%  (depending primarily on the sampling site, sample type, and stage of infection). However, PCR tests must be sent away for analysis at an accredited lab. 

Rapid antigen tests use antibodies to detect specific parts of the viral particle itself. Current antigen tests have a very low rate of false positives, but are plagued by high false negative rates, and therefore can’t replace PCR tests for definitive COVID-19 diagnosis. If a more accurate antigen test was brought to market, it could serve as a helpful initial screening tool similar to how home pregnancy tests work. In the case of a positive result, the user would need to begin appropriate precautionary measures (isolation and other transmission-prevention behaviors) and then have the diagnosis confirmed by an official test at a health clinic. 

“As we move toward gaining normalcy and reopening economies worldwide, there is continued demand for rapid, low-cost tests that can be self-administered without the need for a trained professional,” said Hammel, a biophysicist in Berkeley Lab’s Biosciences Area. “Currently used COVID-19 PCR tests are expensive, at about $100 per test, and on average, U.S. labs are performing one million tests per day. An accurate rapid antigen test could cost $1 each and eliminate the wait time.”

Hammel, Hodge, and their colleagues used small angle X-ray scattering (SAXS) performed at Berkeley Lab’s Advanced Light Source (ALS) to examine about 20 antibody-antigen interactions. Their data showed that a particular pair of monoclonal antibodies bound to the nucleocapsid protein very strongly and stably, in part due to the antibodies’ rigidity. All antibodies vary in their degree of rigidity based on the amino acid sequence of their “arms,” which are the part of the Y-shaped molecules that bind to antigens. “The combination of the two rigid antibodies was also observed to increase networking – a process in which multiple antibodies bound to the same antigen at different sites form larger clumps or ‘networks,’” explained Hodge, a postdoctoral researcher and first author on the study. 

Antibody networking and high binding stability are known to improve the sensitivity of lateral flow assays, and researchers have long speculated that antibody flexibility plays a role in both properties. But studying the physical dynamics of antibody-antigen pairs to find the most effective antibodies is very difficult with traditional imaging techniques, which require the molecules to be stabilized or crystallized. The SAXS technique developed by Hammel and his colleagues allows scientists to examine antibodies and antigens in their natural state, i.e. when moving freely in a liquid. 

“We showed that we can rapidly identify new antibody-antigen pairs that result in a more sensitive detection assay,” said Hammel. “This technique could be applied to hundreds of antibodies in a short amount of time to identify the most suitable antibodies to achieve as-of-yet unattained sensitivity of antibody-based diagnostics, which are key for early diagnosis of SARS-CoV-2 as well as other pathogens.” 

The team is now investigating methods of improving test sensitivity even further.

 

# # #

This work was funded through the National Virtual Biotechnology Laboratory (NVBL), a consortium of DOE National laboratories with core capabilities relevant to the threats posed by COVID-19, and funded under the Coronavirus Aid, Relief, and Economic Security (CARES) Act. The ALS is an Office of Science User Facility. 

Founded in 1931 on the belief that the biggest scientific challenges are best addressed by teams, Lawrence Berkeley National Laboratory and its scientists have been recognized with 14 Nobel Prizes. Today, Berkeley Lab researchers develop sustainable energy and environmental solutions, create useful new materials, advance the frontiers of computing, and probe the mysteries of life, matter, and the universe. Scientists from around the world rely on the Lab’s facilities for their own discovery science. Berkeley Lab is a multiprogram national laboratory, managed by the University of California for the U.S. Department of Energy's Office of Science.   DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science.

 

SEE ORIGINAL STUDY



Filters close

Showing results

110 of 5862
Released: 23-Jun-2021 3:55 PM EDT
Cooperative Extension grant aims to vaccinate NYS’ vulnerable
Cornell University

A two-year, $200,000 grant from the USDA and the Extension Foundation to Cornell University researchers aims to help promote vaccine confidence and uptake in vulnerable communities in eight New York counties, both upstate and downstate.

Released: 23-Jun-2021 12:10 PM EDT
Phone swabs can accurately detect COVID-19
University College London

An accurate, non-invasive, and low-cost method of testing for COVID-19 using samples taken from the screens of mobile phones has been developed by a team led by UCL researchers at Diagnosis Biotech.

Newswise: NIH study suggests COVID-19 prevalence far exceeded early pandemic cases
Released: 23-Jun-2021 11:35 AM EDT
NIH study suggests COVID-19 prevalence far exceeded early pandemic cases
National Institute of Biomedical Imaging and Bioengineering

In a new study, NIH researchers report that the prevalence of COVID-19 in the United States during spring and summer of 2020 far exceeded the known number of cases and that infection affected the country unevenly.

Released: 23-Jun-2021 11:25 AM EDT
Half of young adults with covid-19 have persistent symptoms 6 months after
University of Bergen

A paper published in the prestigious journal Nature Medicine on long-COVID, describes persistent symptoms six months after acute COVID-19, even in young home isolated people.

Newswise:Video Embedded covid-19-vaccine-hesitancy-dr-vin-gupta-narrates-new-american-thoracic-society-video
VIDEO
Released: 23-Jun-2021 9:40 AM EDT
COVID-19 Vaccine Hesitancy: Dr. Vin Gupta Narrates New American Thoracic Society Video
American Thoracic Society (ATS)

The American Thoracic Society rolls out a new video to address vaccine hesitancy and answer common questions amid the COVID-19 pandemic.

18-Jun-2021 11:00 AM EDT
Had COVID-19? One Vaccine Dose Enough; Boosters For All, Study Says
American Chemical Society (ACS)

A new study in ACS Nano supports increasing evidence that people who had COVID-19 need only one vaccine dose, and that boosters could be necessary for everyone in the future.

Released: 22-Jun-2021 5:10 PM EDT
Tecnología de inteligencia artificial y ECG puede rápidamente descartar infección por COVID-19
Mayo Clinic

La inteligencia artificial puede ofrecer un manera de determinar con exactitud que una persona no está infectada con la COVID-19. Un estudio internacional y retrospectivo descubrió que la infección por SARS-CoV-2, el virus que causa la COVID-19, provoca sutiles cambios eléctricos en el corazón. Un electrocardiograma (ECG) mediado por inteligencia artificial detecta estos cambios y puede servir como una prueba rápida y confiable para descartar la infección por COVID-19.

Released: 22-Jun-2021 4:45 PM EDT
Penn Medicine to Use $1M from City of Philadelphia for Additional Community Vaccination Clinics
Perelman School of Medicine at the University of Pennsylvania

Penn Medicine will continue its collaboration with the West and Southwest Philadelphia communities to operate a series of COVID-19 vaccine clinics in partnership with community organizations, faith-based institutions, restaurants, barbershops, and even professional sports teams thanks to $1 million in funding from the City of Philadelphia, in partnership with PMHCC.

Released: 22-Jun-2021 12:30 PM EDT
Political Variables Carried More Weight Than Healthcare in Government Response to COVID-19
Binghamton University, State University of New York

Political institutions such as the timing of elections and presidentialism had a larger influence on COVID-19 strategies than the institutions organizing national healthcare, according to a research team led by a professor at Binghamton University, State University of New York.

22-Jun-2021 12:00 PM EDT
Study Testing How Well COVID-19 Vaccine Prevents Infection and Spread of SARS-CoV-2 Among University Students Now Expands to Include Young Adults Beyond the University Setting
Covid-19 Prevention Network (CoVPN)

The Prevent COVID U study, which launched in late March 2021 to evaluate SARS-CoV-2 infection and transmission among university students vaccinated with the Moderna COVID-19 Vaccine, has expanded beyond the university setting to enroll young adults ages 18 through 29 years and will now also include people in this age group who choose not to receive a vaccine.


Showing results

110 of 5862

close
1.58183