This figure depicts the particle trajectory inside the cyclone sampler during air sampling. The Washington University team used computational fluid dynamics (CFD) simulations to gain insight into the size-dependent collection efficiency of aerosols inside the wet cyclone.
(Image: Joseph Puthussery)
‘The idea with this device is that you can know essentially in real time, or every 5 minutes, if there is a live virus in the air.’
John Cirrito
Now that the emergency phase of the COVID-19 pandemic has ended, scientists are looking at ways to surveil indoor environments in real time for viruses. By combining recent advances in aerosol sampling technology and an ultrasensitive biosensing technique, researchers at Washington University in St. Louis have created a real-time monitor that can detect any of the SARS-CoV-2 virus variants in a room in about 5 minutes.
The inexpensive, proof-of-concept device could be used in hospitals and health care facilities, schools and public places to help detect CoV-2 and potentially monitor for other respiratory virus aerosols, such as influenza and respiratory syncytial virus (RSV). Results of their work on the monitor, which they say is the most sensitive detector available, are published July 10 in Nature Communications.
The interdisciplinary team of researchers from the McKelvey School of Engineering and the School of Medicine consists of Rajan Chakrabarty, the Harold D. Jolley Career Development Associate Professor of energy, environmental & chemical engineering in McKelvey Engineering; Joseph Puthussery, a postdoctoral research associate in Chakrabarty’s lab; John Cirrito, a professor of neurology at the School of Medicine; and Carla Yuede, an associate professor of psychiatry at the School of Medicine.
“There is nothing at the moment that tells us how safe a room is,” Cirrito said. “If you are in a room with 100 people, you don’t want to find out five days later whether you could be sick or not. The idea with this device is that you can know essentially in real time, or every 5 minutes, if there is a live virus in the air.”
Cirrito and Yuede had previously developed a micro-immunoelectrode (MIE) biosensor that detects amyloid beta as a biomarker for Alzheimer’s disease and wondered if it could be converted into a detector for SARS-CoV-2. They reached out to Chakrabarty, who assembled a team that included Puthussery, who had expertise in building real-time instruments to measure the toxicity of air.
To convert the biosensor from detecting amyloid beta to coronavirus, the researchers exchanged the antibody that recognizes amyloid beta for a nanobody from llamas that recognizes the spike protein from the SARS-CoV-2 virus. David Brody, MD, PhD, a former faculty member in the Department of Neurology at the School of Medicine and an author on the paper, developed the nanobody in his lab at the National Institutes of Health (NIH). The nanobody is small, easy to reproduce and modify and inexpensive to make, the researchers said.
“The nanobody-based electrochemical approach is faster at detecting the virus because it doesn’t need a reagent or a lot of processing steps,” Yuede said. “SARS-CoV-2 binds to the nanobodies on the surface, and we can induce oxidation of tyrosines on the surface of the virus using a technique called square wave voltammetry to get a measurement of the amount of virus in the sample.”
Chakrabarty and Puthussery integrated the biosensor into an air sampler that operates based on the wet cyclone technology. Air enters the sampler at very high velocities and gets mixed centrifugally with the fluid that lines the walls of the sampler to create a surface vortex, thereby trapping the virus aerosols. The wet cyclone sampler has an automated pump that collects the fluid and sends it to the biosensor for seamless detection of the virus using electrochemistry.
“The challenge with airborne aerosol detectors is that the level of virus in the indoor air is so diluted that it even pushes toward the limit of detection of polymerase chain reaction (PCR) and is like finding a needle in a haystack,” Chakrabarty said. “The high virus recovery by the wet cyclone can be attributed to its extremely high flow rate, which allows it to sample a larger volume of air over a 5-minute sample collection compared with commercially available samplers.”
Most commercial bioaerosol samplers operate at relatively low flow rates, Puthussery said, while the team’s monitor has a flow rate of about 1,000 liters per minute, making it one of the highest flow-rate devices available. It is also compact at about 1 foot wide and 10 inches tall and lights up when a virus is detected, alerting administrators to increase airflow or circulation in the room.
The team tested the monitor in the apartments of two COVID-positive patients. The real-time PCR results of air samples from the bedrooms were compared with air samples collected from a virus-free control room. The devices detected RNA of the virus in the air samples from the bedrooms but did not detect any in the control air samples.
In laboratory experiments that aerosolized SARS-CoV-2 into a room-sized chamber, the wet cyclone and biosensor were able to detect varying levels of airborne virus concentrations after only a few minutes of sampling.
“We are starting with SARS-CoV-2, but there are plans to also measure influenza, RSV, rhinovirus and other top pathogens that routinely infect people,” Cirrito said. “In a hospital setting, the monitor could be used to measure for staph or strep, which cause all kinds of complications for patients. This could really have a major impact on people’s health.”
The team is working to commercialize the air quality monitor.
Original Article: Air monitor can detect COVID-19 virus variants in about 5 minutes
More from: McKelvey School of Engineering | Washington University School of Medicine
The Latest Updates from Bing News
Go deeper with Bing News on:
Virus detector
- Is my antivirus sufficient? Not really | It’s Geek to Me
Viruses have been such a pernicious threat that Microsoft decided to just add antivirus capability directly in the operating system itself.
- Bird found with West Nile Virus in Concord
A dead bird in Concord has tested positive for West Nile virus. The Contra Costa Mosquito and Vector Control District said Friday an American crow was picked up with the virus April 9. It’s the first ...
- Multiple agencies issue alerts on 'highly pathogenic avian flu' after detection in milk
The World Health Organization urged the public not to consume raw milk, and the FDA said although they're not common, sporadic human infections have occurred.
- One in Five Milk Samples Has Bird Flu Virus Fragments, Suggesting Cow Infections Are More Widespread Than Thought
The research has not yet found evidence that milk contains infectious virus, and the FDA says the commercial milk supply is safe ...
- How bird flu virus fragments get into milk sold in stores, and what the spread of H5N1 in cows means for the dairy industry and milk drinkers
The discovery of viral fragments of avian flu virus in milk sold in U.S. stores suggests that the H5N1 virus may be more widespread in U.S. dairy cattle than previously realized.
Go deeper with Bing News on:
Real-time virus detector
- Securing the Digital Realm: Navigating the Cyber Threat Landscape
Digital realm, encompassing everything from personal data to critical infrastructure, is constantly under threat ...
- H5N1 avian flu infects Colorado dairy cows as global experts weigh in on virus changes
For example, the global experts said a novel H5N1 reassortant seen in poultry in Cambodia, Laos, and Vietnam over the past 2 years has now been detected in humans, one from Cambodia and the other from ...
- Remnants of bird flu virus found in pasteurized milk, FDA says
The U.S. Food and Drug Administration said Tuesday that samples of pasteurized milk had tested positive for remnants of the bird flu virus that has infected dairy ... Tune in to WBAL NewsRadio for ...
- Miggo Unfurls Real-Time Application Detection and Response Platform
The platform analyzes application interactions to identify cyberattacks and applies mitigations to limit the attack's impact.
- Malvertising Slips Through: Boosting Digital PR And Ad Safety Is Vital
Discover the critical need for improved ad safety and digital PR to safeguard against the rising threat of malvertising.