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As the virus that causes COVID-19 began to spread from person to person in communities (community transmission), scientists needed to track the disease and try to slow its spread. Fast and reliable tests for the new coronavirus are urgently needed to bring the pandemic under control as soon as possible.
Most SARS-CoV-2 detection assays require a sample to be collected and sent to a lab for detection of viral genetic signatures or associated antigens. Most laboratories use a molecular method called reverse transcription polymerase chain reaction, or RT-PCR for short, to detect viruses in respiratory infections. This is well established and can detect even tiny amount of viruses — but at the same time it can be time consuming and prone to error.
Depending on whether amplification of genetic material is required, results are available on time scales ranging from 10s of minutes to days. While generally offering required specificity, processing times are too slow to be of use for atmospheric sampling. Direct identification from air (specifically, aerosol samples) would be ideal, but such detection has not been very successful due to the difficulty in sample collection and the extremely low pathogen concentration found in aerosol samples.
Environmental monitoring for pathogens has historically been, and continues to be, an extremely challenging area of study. Techniques explored to date have included spectral techniques, affinity techniques, and sampling and assay techniques. Driven by small and variable signals available from the virus and dynamic and complex backgrounds, achieving desired performance characteristics using a single measurement technique is a formidable challenge.
Current air-breathing environmental sensors using optical techniques offer fast detection times but limited ability to discriminate between benign and pathogenic material, such as the SARS-CoV-2 virus.
In general, current methods are not suitable for room-sized, indoor environmental monitoring and lack practical combinations of sensitivity, specificity (precision and recall), acceptable false positive rates, and speed and/or have substantial barriers to scaling due to cost or size, weight, and/or power requirements. The COVID-19 pandemic has highlighted the need for improved environmental sensing of pathogens.
Program
DARPA launched SenSARS project in Nov 2020 for Sensing SARS-CoV-2 virus in the air with high sensitivity and specificity that could provide a new mechanism for public health monitoring, enabling safer conditions for a wide range of basic activities including work, travel, and school.
Recent developments in radiofrequency vibrometry, improvements in terahertz sources and sensors, improvements in mass spectrometric techniques, emerging immunosensing techniques, electrochemical detection methods, and advances in signal analysis using machine learning approaches could potentially surmount these challenges.
The continually expanding knowledge base regarding the virus provides much needed data to allow for signature development for these and other detection modalities. These approaches have the potential to enable sample agnostic detection of low viral concentrations within seconds to minutes, characteristics that are paramount for real-time aerosol detection. Improvements in portability of traditional methods of detection – immunoassays and nucleic acid-based assays – out of the lab setting may enable onsite confirmation of results.
SenSARS aims to identify SARSCoV-2 signatures suitable for rapid indoor air monitoring and use these signatures to develop and demonstrate a technology readiness level (TRL) 4 prototype sensor. The SenSARS program is structured in two phases. The 9-month Phase 1 focuses on determining environmental SARS-CoV-2 signature feasibility. The 9-month Phase 2 option seeks to refine signatures and produce and demonstrate a TRL 4 prototype sensor. Selection for the Phase 2 option depends on Phase 1 results and funding availability.
Proposals submitted in response to this DO must be UNCLASSIFIED and must address two independent and sequential project phases (a Phase 1 Feasibility Study (base) and a Phase 2 Proof of Concept (option)). The periods of performance for these phases are 9 months for the
Phase 1 base effort and 9 months for the Phase 2 option effort. Combined Phase 1 base and Phase 2 option efforts for this DO must not exceed 18 months. The Phase 1 (base) award value is limited to $500,000. The Phase 2 (option) award value is limited to $500,000. The Phase 1 and Phase 2 limits each include performer cost share, if required or if proposed. As previously stated, the total award value for the combined Phase 1 base and Phase 2 option is limited to $1,000,000. This total award value includes Government funding and performer cost share, if required.
The ultimate goal of SenSARS is to develop a prototype sensor that can detect SARS-CoV-2 in the air with enough sensitivity, specificity, and speed to enable practical concepts of operation to be employed before infection can occur within an indoor environment. Three potential use cases of interest are an office of 50 m3 , a conference room or classroom of 300 m3 , and central monitoring of buildings up to 10 stories through the heating, ventilation, and air conditioning (HVAC) system.
Army scientists team with DARPA to build COVID-19 air detector, reported in Feb 2021
Army scientists have teamed with the Defense Advanced Research Projects Agency and others to build a monitor that would detect COVID-19 proteins in the air. The team of researchers includes Army scientists with the U.S. Army Combat Capabilities Development Command, Georgia Tech Research Institute, Cardea Bio and the University of Georgia, according to an Army statement.
The prototype sensor the group is developing would help detect the virus with enough speed and accuracy that users could prevent infection from spreading. “Monitoring pathogens in the environment remains a challenging area of study,” said Dr. Matthew Coppock, Army chemist and team leader. “(Army Research Laboratory) has a unique capability to design and synthesize selective biosensor recognition elements using short synthetic peptides. …”
Those peptides, short chains of amino acids linked by peptide bonds, mimic the way antibodies attach to the COVID-19 virus. The team is taking the receptors produced during the past year of COVID response work. If successful the sensor could allow for a new way to monitor public health beyond the Department of Defense, such as monitoring for COVID at work sites, travel points and schools.
But the foundational work of what’s come together so far should have applications far beyond the COVID-19 virus. That’s because, with minimal variations, scientists anticipate they will be able to use the peptides, known as protein-catalyzed capture agents, for other diseases.
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“This capture component ideally can be incorporated into any biological detection device, such as test strips or graphene-based detectors, like the one being developed,” Coppock said. The PCCs can be used to rapidly address new biological threats. The use of PCC bio-detection technology was introduced by the Jim Heath Laboratory at the California Institute of Technology for a project with ARL, according to the statement.
Military Times reported in July that DARPA studies also monitored the airflow in various types of military aircraft to determine which posed the lowest threat of infection from coronavirus patients. The work measured the flow of coronavirus-sized particles to determine risk factors f
or those platforms and which aircraft would be preferable if needed for virus-laden transport.
DARPA spokesman Jared Adams told Military Times in an email response that the testing looked at six aircraft: C-17, KC-135, C-130J, C-5, KC-46 and KC-10. “DARPA concluded that the aircraft with the most favorable airflow circulation was the KC-10, which provided complete protection to the front compartments through the use of directed airflow and smoke barriers,” Adams told Military Times
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