Smart face mask could detect coronavirus on other people’s breath

A prototype N95 face mask with a sensor built into the breath valve appears to be highly sensitive to virus proteins in early-stage tests

By Clare Wilson

19 September 2022

The virus-sensing face mask during a test

Matter/Wang et al. (CC BY-SA)

A face mask with an integrated virus sensor could detect tiny amounts of the coronavirus after a 10-minute conversation with someone who is infected.

The mask would then send a signal to the smartphone of the person wearing the face covering, letting them decide to leave an area where coronavirus is in the air – or take off their mask if they feel safe when there is no virus detected.

But the results so far are based on early-stage work. The mask hasn't yet been tested against whole viruses – just the coronavirus's surface proteins – and the technology is still in development, says Yin Fang at Tongji University in China.

Fang's team has developed a tight-fitting N95 type of face mask that detects outer proteins from three viruses: two flu strains, H5N1 and H1N1, and SARS-CoV-2, the virus that causes covid-19.

The sensor within the mask's breath valve contains aptamers, short strands of DNA or RNA that can be designed to bind to specific proteins. Aptamers are similar to antibodies, which are used to detect the coronavirus spike protein in lateral flow tests, but are smaller and more stable.

If the aptamers bind to their target proteins, their electrical charge changes and an integrated chip in the mask sends a signal to a designated smartphone.

The team tested the mask by putting it in a closed chamber and spraying it with tiny drops of liquid – similar to those produced when an infected person coughs or talks – containing the coronavirus spike protein or surface proteins from the two flu viruses. After 10 minutes, the system could detect as little as 0.1 femtograms (0.0000000000000001 grams) of protein per millilitre of fluid.

The mask could be useful for people who need to be in indoor spaces with poor ventilation, says Fang. "It's a new technique we can use to protect people." The system could also be updated with aptamers that recognise different pathogens, he says.

The team hasn't yet tested how often the mask wrongly gives an alert signal when it encounters surface proteins from other viruses.

Al Edwards at the University of Reading, UK, says the idea has potential, but needs further testing. "It's really hard to make things work in the real world," he says.

The principle of using highly sensitive aptamer-based tests could also be exploited in other settings, such as placing the sensors within ventilation units or in hospital wards, he says.

Matter DOI: 10.1016/j.matt.2022.08.020

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