Researchers 3D print ‘invisible threads’ to measure mask leakage

The tiny strands could be used for all sorts of health applications, including combatting COVID-19.

UV light sterilization of face mask to disinfect and reuse. COVID-19 prevention concept. Close up at...

The University of Cambridge has announced that a team of researchers has created barely-there electronic fibers that can monitor health. The fibers act as sensors and were demoed for respiratory purposes, but the technology could be applied to a number of applications. The 3D-printed fibers are inexpensive to produce, easy to use, and wearable. The research was published in Science Advances and one of the first use cases is measuring the leakage from face masks, the new fashion essential of 2020, and one that's set to be a necessary accessory for months, or even years, to come. But not all masks are created equal, so checking their relative efficacy could help separate the life-saving wheat from the fashionable but ineffectual chaff.

Invisible threads — The fibers are made from silver and / or semiconducting polymers — not unlike electrical wires, just on a smaller scale. Each fiber is 100 times thinner than a human hair. They can be added to phones to collect data on breath patterns, along with sound and even imagery, which could help users with impairments get a sense of their surroundings. One of the paper's authors, Andy Wang, used the fibers to test the moisture leakage from his face mask, and they outperformed traditional sensors significantly.

Close-ups of the incredibly small fibers, imperceptible to the human eye.University of Cambridge/Science Advances

The researchers hope to use this 3D-printing technique to create multi-functional sensors and advance wearable health technology. The fibers could also change medical procedures; the team can already make biocompatible versions that can guide cells into patterns, and they’re so cheap and thin that they could help revolutionize another vibrant avenue of COVID-19-related research: at-home rapid testing kits.

What does this mean for the coronavirus? — The fibers are hypersensitive, but they cannot detect viral particles. Where they can be effective, however, is in measuring the effectiveness of face coverings and alerting wearers or (eventually) manufacturers to weak coverage spots or other design flaws.

“Sensors made from small conducting fibres [sic] are especially useful for volumetric sensing of fluid and gas in 3D, compared to conventional thin-film techniques, but so far, it has been challenging to print and incorporate them into devices, and to manufacture them at scale,” Dr. Yan Yan Shery Huang, research lead from Cambridge’s Department of Engineering, said in a statement.

The team found that tight-fitting N-95 masks leaked from the top or sides while cloth or surgical masks leaked from the front. In all cases, the masks helped weaken exhaled breath flow, valuable information as the CDC has finally begun publicly saying that SARS-CoV-2 is primarily transmitted through the air.