COVID-19 Research: New technologies in air filtration, disinfection, remote symptom detection

Since COVID-19 emerged on the world scene, Ryerson physics professor Alexandre (Sasha) Douplik has been busier than ever. His Photonics Group currently has multiple projects on the go in the global research effort and has been conducting them in his labs on Ryerson campus and at the Institute for Biomedical Engineering, Science and Technology (iBEST) at St. Michael’s Hospital, a site of Unity Health Toronto.

Prior to, the team had already been working steadily on various biomedical applications using light and electronics. During the pandemic, parallel applications became apparent. The lab quickly pivoted their existing base technologies into three new pandemic mitigation tools:

• smartphone accessory that reads cardio-respiratory parameters on the skin as early signs of infection
• ultrasensitive, nano-based sensing platform to trap virus particles and determine viral concentrations in the air
• UV/blue light disinfection system to kill airborne virus particles
  

Beyond COVID-19, the innovations could eventually provide quicker, more effective means to contain and manage similar disease outbreaks in the future.  

Contactless symptom detection by smartphone
Body temperature is a widely used but non-reliable screening parameter for a possible COVID-19 infection. To develop an alternative, Douplik’s lab is working with healthcare technology company Swift Medical (external link) . They’ve innovated a smartphone optical accessory that provides touchless readings of three parameters: respiratory rate (RR), heart rate (HR) and heart rate variability (HRV).

“When the immune system is in good working order, HRV fluctuates. When there’s trouble, variability drops, and HR and RR also tend to rise,” Douplik explains. “All of that is actually reflected in tiny motions on the body’s surface. With our smartphone accessory, we can remotely detect the waves on exposed skin. Through some complex math transformations, the software then derives the cardio-respiratory parameters. With proper optics, you can even observe these signs on people from quite a distance.”

Front-facing cameras can be used for self-assessment; rear-facing cameras for screening another person. If abnormal HR, RR or HRV is detected, the device triggers an alarm for further diagnostics. The technology may provide faster, more effective early symptom detection for use in healthcare units, airports and other areas requiring COVID-19 screening.

Ultra-sensitive airborne pathogen detection
Identifying contaminants on hard surfaces or human tissue, such as the mouth or nose, is relatively easy. Doing so in the air is much more difficult, especially on a continual basis. The Photonics Group’s second COVID-19 research project involves a highly sensitive platform that grabs, preserves and detects airborne pathogens and organic compounds at the level of just a few molecules — even single DNA, RNA and protein molecules.

Douplik explains: “With our system, you place the porous, 3D matrix in a room. Virus particles circulating in the air come into contact with the material and become trapped inside. Then, with the attached fibre-optic probe, we can identify the particles and determine the concentration of the virus in the room.”

The system is based on nanotechnology and Raman spectroscopy, a chemical analysis technique that identifies molecules by their “chemical bonds fingerprint”. Douplik’s lab is partnering with Tornado Spectral Systems (external link) , a global provider of chemical analysis and measurement systems for Raman spectroscopy. Their technology expedites the Raman signalling process, reducing it from a few minutes down to only a few seconds. If virus concentrations surpass a given threshold, attendants can block off a room and purify the air before allowing people to re-enter. The system allows for continuous, high-accuracy air quality sample analysis and monitoring.

UVC/blue light air disinfection
Beyond simply detecting airborne pathogens, Douplik’s third project involves optical technology to actively kill them too. The work is part of a larger, five-year project to revolutionize air travel comfort, led by Ryerson Aerospace Engineering professor Dr. Fengfeng (Jeff) Xi in partnership with Bombardier (external link) .

Ultraviolet and blue light have long been used as disinfectants for air and water. Douplik’s and Xi’s labs are currently determining the best wavelength, or light colour, for use against airborne virus particles. Since UV light also emits toxic ozone, the purification system must also degrade any ozone produced before circulating the air back into the passenger cabin. Beyond aircraft, such a system may also be fitted inside air ducts for ventilation systems as part of COVID-19 air filtration strategies.

^{Research and development of the above technologies continues, with projects extending into 2022. Funding for the projects was provided by the involved industry partners, Ryerson University and Natural Sciences and Engineering Research Council of Canada (NSERC) Alliance program.}