Image credit: Harvard University
As the country begins to open up and more people go back to work and school, face masks are becoming our first line of defense against the novel Coronavirus. Many businesses won’t allow employees or customers to enter without a face mask to protect against the transmission of moisture droplets or aerosols that could contain the virus.
One challenge is that asymptomatic or pre-symptomatic people can transmit the COVID-19 virus unwittingly. Studies indicate that the rate of asymptomatic transmission could be as high as 40 percent. To help prevent the silent spread, scientists at Harvard University’s Wyss Institute and the Massachusetts Institute of Technology (MIT) have developed virus-detecting technology that can be embedded on materials that can be worn, such as a face mask.
Rather than testing for symptoms, such as an elevated temperature, the sensors detect the virus itself. They are activated by the moisture expelled when a person breathes, coughs, or sneezes; the sensor acts as a miniature test tube or lab that detects the virus with no additional lab equipment. The respiratory particles released in mucus, saliva, or vapor attach to and activate the instrument. Only a small sequence of the virus is needed to activate the sensor, and different strains of the virus can be detected.
The scientists use cell-free and synthetic biology technologies to design the sensors. To embed the COVID-19 virus on the sensor, the team uses genetic material from DNA and RNA, which bind to a virus. The genetic material is then adhered to the sensor via a freeze-drying process, which removes the moisture without killing the genetic material. The freeze-drying process allows the genetic material to remain stable at room temperature for several months, so the masks are shelf stable. Wearers cannot contract the virus from the sensor.
If the sensor detects COVID-19, it will emit a fluorescent signal within one to three hours. The fluorescent signal is not visible to the naked eye, so confirmation requires that the mask be scanned by a fluorimeter, a device that measures fluorescent light. The team of scientists has also experimented with color-changing sensors that would be visible to the naked eye. These sensors work the same way as the light-emitting sensors but would instead change color if the virus is indicated.
Imaged credit: The Wyss Institute
The cost of the sensor-enabled mask is estimated at less than $25, compared to about $100 or more for a current Coronavirus test. A handheld fluorimeter is inexpensive—far less than a testing lab—and could be deployed more easily in a variety of locations.
Similar to a thermal scanner use, people’s masks can be scanned by a fluorimeter before entering public spaces or public transportation. If COVID-19 is indicated, a person could be denied entry and sent for further medical attention. The turnaround time is hours rather than days, so infected people would know to self-quarantine earlier, thus stemming further spread of the virus.
The team at Harvard and MIT modified existing technology to create a COVID-19 sensor. The original virus-detecting sensor was embedded on paper and was designed to detect the Ebola virus. It proved to be successful during the Ebola virus outbreak in 2014 and was successfully adapted to combat the 2016 Zika virus outbreak. The sensors also can detect SARS, measles, influenza, hepatitis C, and West Nile.
Further research led the team to discover that the virus sensors are compatible with other materials, such as plastic, quartz, and cloth. This sparked the idea of embedding the sensors within face masks. The researchers are testing the masks now and considering whether to embed the sensor directly into the mask or to create a removable module that could be inserted into a pocket within a mask.