Face Mask Sensor Detects Covid-19 Virus

Covid-19 face mask diagnostic (Wyss Institute, Harvard Univ.)

29 June 2021. Engineers designed sensors made from bioactive materials integrated into fabrics, beginning with a face mask that detects the SARS-CoV-2 virus. Researchers from the Wyss Institute for Biologically Inspired Engineering at Harvard University and Massachusetts Institute of Technology describe these materials in yesterday’s issue of the journal Nature Biotechnology.

A team from the lab of biomedical engineering professor James Collins, affiliated with both Harvard and MIT, is seeking easy-to-use ways for measuring chemical changes in the body, including the presence of pathogens and toxins, with inexpensive sensor fabrics woven into clothing. These materials need to be chemically stable to last a long time, easy to form into threads, and safe for humans to wear for extended periods.

Researchers led by postdoctoral fellows Peter Ngyuen and Luis Soenksen based their bioactive fabrics on earlier Wyss Institute work with freeze drying biochemical compounds to improve their chemical stability. Freeze drying, for example, could enable vaccines to be shipped and stored for long periods at room temperature instead of constantly refrigerated. The freeze-dried materials include separate water-soluble pellets containing synthetic biological processes to create bioactive molecules from previously inert substances, when mixed with water.

These freeze-dried formulations can then be applied to common materials for portable diagnostics. As reported by Science & Enterprise in September 2020, Wyss Institute researchers developed a process for freeze-drying the gene-editing technique Crispr with bioactive molecules to detect Plasmodium parasites responsible for malaria. An extension of Crispr called Sherlock, short for specific high-sensitivity enzymatic reporter unlocking, uses Crispr editing enzymes that seek out specific genetic sequences in a specimen sample, and if detected in the sample, bind to and cut the RNA in nearby locations. The freeze-dried mix is then added to paper strips for point-of-care malaria testing in low-resource regions.

Breath captured and analyzed within the mask

The researchers extended the freeze-drying technology to fabrics for wearable sensors. In these applications, bioactive molecules change color or glow when Crispr editing enzymes interact with target molecules, by adding polymeric optic fibers made with fluorescent polymers. These fibers then illuminate when target molecules react.

The Covid-19 pandemic offered an opportunity to apply this technology to a face mask that detects the presence of SARS-CoV-2 viruses in the wearer’s breath. The team built the mask with a paper microfluidic pad to collect exhaled breath and a small reservoir of water to wet the freeze-dried mix by pushing a button on the mask. The mask has layers with fibers that amplify and convert RNA in the breath sample with reverse transcription–recombinase polymerase amplification, then analyze the amplified sample with Sherlock-Crispr to detect SARS-CoV-2 viruses. The fluorescent polymers illuminate if SARS-CoV-2 is detected.

Simulations with lung-airway models in the lab show a prototype face mask can detect SARS-CoV-2 viral RNA in breath samples and report results in 90 minutes, with performance comparable to standard RT-PCR tests usually requiring a clinician. “This work,” says Collins in a Wyss Institute statement, “shows that our freeze-dried, cell-free synthetic biology technology can be extended to wearables and harnessed for novel diagnostic applications, including the development of a face mask diagnostic.”

The authors believe the technology can be extended further into fabrics worn by civilian first responders or military personnel facing biological threats, and protective gear worn in medical labs. Moreover, conductive fibers can also be added to the fabrics enabling electronic signals to be transmitted to nearby electronic devices.

More from Science & Enterprise:

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• Low Cost Vaccine, Patch Device Produce Immune Responses
• Medical Devices to Reduce Military Travel Disorders
• Biomanufacturing Materials Company Issues $500M IPO
• Graphene Crispr Chip Detects Small Genetic Differences

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