Face mask prototype can detect if the wearer has Covid-19

The masks are embedded with tiny, disposable sensors that can be fitted into other face masks and could also be adapted to detect other viruses.

The sensors are based on freeze-dried cellular machinery that the research team has previously developed for use in paper diagnostics for viruses such as the Ebola and Zika viruses. As well as face masks, the sensors could be incorporated into clothing such as lab coats, offering a new option for monitoring health care workers’ exposure to pathogens.

“We’ve demonstrated that we can freeze-dry a broad range of synthetic biology sensors to detect viral or bacterial nucleic acids, as well as toxic chemicals, including nerve toxins. We envision that this platform could enable next-generation wearable biosensors for first responders, health care personnel, and military personnel,” said Professor James Collins at MIT’s Institute for Medical Engineering and Science, senior author of the study.

The face mask sensors are designed so they can be activated by the wearer when they’re ready to perform the test, and the results are only displayed on the inside of the mask, for user privacy.

In 2014, Collins demonstrated that proteins and nucleic acids needed to create synthetic gene networks that react to specific target molecules could be embedded into paper, and he used this approach to create paper diagnostics for the Ebola and Zika viruses. He later developed another cell-free sensor system which is based on CRISPR enzymes and allows highly sensitive detection of nucleic acids.

These cell-free circuit components are freeze-dried and remain stable for many months, until they are rehydrated. When activated by water, they can interact with their target molecule, which can be any RNA or DNA sequence, as well as other types of molecules, and produce a signal such as a change in colour.

The researchers have also screened hundreds of different types of fabric, from cotton and polyester to wool and silk, to find out which might be compatible with this kind of sensor for use in a lab coat or other garment.

“We ended up identifying a couple that are very widely used in the fashion industry for making garments,” said MIT’s Luis Soenksen. “The one that was the best was a combination of polyester and other synthetic fibres.”

To make wearable sensors, the researchers embedded their freeze-dried components into a small section of this synthetic fabric, where they are surrounded by a ring of silicone elastomer to prevent it from evaporating or diffusing away from the sensor.

To demonstrate the technology, the researchers created a jacket embedded with about 30 of these sensors. They showed that a small splash of liquid containing viral particles, mimicking exposure to an infected patient, can hydrate the freeze-dried cell components and activate the sensor. The sensors can be designed to produce different types of signals, including a colour change that can be seen with the naked eye, or a fluorescent or luminescent signal, which can be read with a handheld spectrometer.

The researchers said the face mask is most likely the first application that could be made available as the technology is closer to commercialisation.