An innovative air quality monitor capable of detecting the live SARS-CoV-2 virus in indoor environments has been developed by a collaborative team from the McKelvey School of Engineering and the School of Medicine. This monitor integrates an air sampler, utilizing wet cyclone technology, with a biosensor composed of nanobodies. Image courtesy of Joseph Puthussery.
The device, still in the proof-of-concept stage, can also identify flu, RSV, and other respiratory viruses. In the post-emergency phase of the COVID-19 pandemic, there is a growing need for real-time surveillance of indoor spaces for viral presence. To answer this need, Washington University researchers in St. Louis have devised this monitor, which can detect any variant of the SARS-CoV-2 virus in a room within approximately 5 minutes.
The cost-effective device is an excellent candidate for use in medical facilities, schools, and public areas to detect CoV-2 and potentially other respiratory viral aerosols, such as influenza and respiratory syncytial virus (RSV). The monitor, hailed as the most sensitive detector currently available, has been detailed in an article published today (July 10) in Nature Communications.
The diverse team of researchers includes Rajan Chakrabarty, Joseph Puthussery, John Cirrito, and Carla Yuede from the McKelvey School of Engineering and the School of Medicine. Their joint expertise spans energy, environmental & chemical engineering, neurology, psychiatry, and the development of real-time instruments for air toxicity measurement.
The researchers utilized a micro-immunoelectrode (MIE) biosensor, previously created by Cirrito and Yuede for Alzheimer’s disease biomarker detection, and repurposed it for SARS-CoV-2 detection. To achieve this, they replaced the antibody recognizing amyloid beta with a llama-derived nanobody that recognizes the SARS-CoV-2 spike protein. This nanobody, which is small, easily modifiable, and cheap to produce, was developed by David Brody, MD, PhD, at the National Institutes of Health (NIH).
The unique nanobody-based electrochemical approach expedites virus detection by eliminating the need for a reagent or extensive processing steps. As Yuede explains, the SARS-CoV-2 virus binds to the nanobodies on the surface, allowing oxidation of tyrosines on the virus’s surface. Using a technique called square wave voltammetry, a measure of the viral quantity in the sample can be obtained.
Chakrabarty and Puthussery incorporated this biosensor into an air sampler, based on wet cyclone technology, which captures virus aerosols by creating a surface vortex with high-speed air and a lining fluid. This device boasts a high flow rate, enabling a large volume of air to be sampled within 5 minutes – an advantage over commercially available samplers.
The device was tested in the residences of two COVID-positive patients, and the air samples collected were compared with a control room’s samples. The device successfully detected the virus’s RNA in the patient’s bedrooms but found none in the control room’s samples.
Though the initial focus is on SARS-CoV-2, there are plans to expand the device’s capabilities to detect other common pathogens like influenza, RSV, and rhinovirus. In a hospital setting, the monitor could be used to detect staph or strep, helping prevent complications for patients.
The researchers are now exploring options for commercializing the air quality monitor.
Citation: “Real-time environmental surveillance of SARS-CoV-2 aerosols” 10 July 2023, Nature Communications. DOI: 10.1038/s41467-023-39419-z
Funding for this research was provided by the National Institutes of Health (NIH) RADx-Rad program (U01 AA029331, U01 AA029331-S1), the NIH National Institute of Neurological Disorders and Stroke Intramural Research Program, the SARS-CoV-2 Assessment of Viral Evolution (SAVE) Program, and the WashU-IITB Joint Master’s Program.
Frequently Asked Questions (FAQs) about Real-time air monitor
What is the purpose of the new air quality monitor developed by researchers at the McKelvey School of Engineering and the School of Medicine?
The air quality monitor has been developed to detect live SARS-CoV-2 virus, along with other respiratory viruses like the flu and RSV, in real-time within indoor environments.
What sets the nanobody-based electrochemical approach apart?
The nanobody-based electrochemical approach expedites virus detection because it doesn’t require a reagent or many processing steps. It allows for quick oxidation of tyrosines on the virus’s surface, facilitating a rapid measurement of the viral quantity in the sample.
What are the advantages of this air monitor over commercially available samplers?
The air monitor has a high flow rate, enabling a larger volume of air to be sampled within a 5-minute period. This is a significant advantage over commercially available samplers, which often have lower flow rates.
How was the monitor tested?
The device was tested in the residences of two COVID-positive patients. The air samples collected from the patients’ bedrooms were compared with samples collected from a virus-free control room. The device successfully detected the RNA of the virus in the bedrooms but not in the control room’s samples.
Are there plans to expand the capabilities of the device?
Yes, while the initial focus is on SARS-CoV-2, there are plans to extend the device’s detection capabilities to other common pathogens like influenza, RSV, rhinovirus, and even bacteria such as staph and strep in a hospital setting.
More about Real-time air monitor
- McKelvey School of Engineering
- School of Medicine
- Nature Communications Journal
- National Institutes of Health (NIH)
- SARS-CoV-2 Assessment of Viral Evolution (SAVE) Program
- WashU-IITB Joint Master’s Program