Face mask can detect viral exposure

Presented in the journal Matter, the mask can alert wearers via their mobile devices within ten minutes if targeted pathogens are present in the surrounding air. 

Respiratory pathogens that cause Covid-19 and H1N1 influenza spread through small droplets and aerosols released by people when they talk, cough and sneeze. These virus-containing molecules, especially tiny aerosols, can remain suspended in the air for a very long time.

Yin Fang, the study’s corresponding author and a material scientist at Shanghai Tongji University, tested the mask with his colleagues in an enclosed chamber by spraying the viral surface protein containing trace-level liquid and aerosols on the mask.

According to the team, the sensor responded to as little as 0.3 microlitres of liquid containing viral proteins. This is about 70 to 560 times less than the volume of liquid produced in one sneeze and much less than the volume produced by coughing or talking, Fang said.

The team designed a small sensor with aptamers, a type of synthetic molecule that can identify unique proteins of pathogens like antibodies. In their proof-of-concept design, researchers modified the multi-channel sensor with three types of aptamers, which can simultaneously recognise surface proteins on SARS-CoV-2, H5N1 and H1N1.

Once the aptamers bind to the target proteins in the air, the ion-gated transistor connected will amplify the signal and alert the wearers via their phones. An ion-gated transistor is a novel type of device that is highly sensitive, so the mask can detect even trace levels of pathogens within ten minutes, researchers confirmed.

“Our mask would work really well in spaces with poor ventilation, such as elevators or enclosed rooms, where the risk of getting infected is high,” said Fang. 

In the future, if a new respiratory virus emerges, Fang added that the sensor’s design could be easily updated to detect the novel pathogens. 

The team now hopes to shorten the detection time and further increase the sensor’s sensitivity by optimising the design of the polymers and transistors. They are also working on wearable devices for a variety of health conditions including cancers and cardiovascular diseases.

“Currently, doctors have been relying heavily on their experiences in diagnosing and treating diseases. But with richer data collected by wearable devices, disease diagnosis and treatment can become more precise,” Fang said.