Manuela Callari
Researchers from the Wyss Institute for Biologically Inspired Engineering at Harvard University and the Massachusetts Institute of Technology have found a way to embed synthetic biology reactions into fabrics that can detect viral pathogens such as SARS-CoV2.
The team has integrated these biosensors into standard face masks that can detect the presence of SARS-CoV2 in a person’s breath. The mechanism is activated by the push of a button; it gives results within 90 minutes with an accuracy comparable to standard laboratory tests. The discovery was reported in Nature Biotechnology.
Biosensors have been incorporated into bench-top diagnostics in the past. But these have used living engineered bacteria to trigger the biological reactions that identify the presence of a pathogen. But the difficulty of sustaining living organisms for extended periods have limited the application of these devices.
The Harvard and MIT researchers have extracted and freeze-dried the necessary biological elements from cells. The freeze-drying process involves freezing the biological machinery and extracting the water under a vacuum. The result is shelf-stable biological machinery that can be reactivated by simply adding water to them.
The team has designed a biosensor using this freeze-dried biological machinery, a CRISPR-based genetically engineered circuit and fluorescent molecules. The biosensor can produce a detectable signal in response to the presence of a target molecule.
The final product consists of three different biological reactions that are sequentially activated when the push of a button releases water.
The first reaction cuts open the SARS-CoV-2 membrane to expose its RNA. The second reaction makes numerous copies of the gene that encodes the coronavirus spike protein from the RNA. In the final reaction, the CRISPR-based circuits detect the spike gene and, in response, activate the fluorescent molecule, which can be observed on a lateral flow assay strip, similar to an at-home pregnancy test.
“Our mask technology could allow us to greatly increase the testing frequency, enabling potentially daily testing by having a diagnostic that is easy to use for the general population without the need of a laboratory,” says Dr Peter Nguyen, a research scientist at the Wyss Institute and one of the authors of the study.
The technology has some limitations. The biosensors are single-use and don’t function in high humidity conditions. But their low costs means that they can potentially be manufactured on a large scale.
“The device was constructed as an add-on to any mask, which could make the whole system very affordable across the globe, hopefully within the US$1–2 (approx. AUD1.35–2.70) range after design for manufacturing,” says Dr Luis R Soenksen, a research scientist at MIT and co-author of the study.
“We envision such diagnostic masks could be available at any pharmacy,” says Nguyen. “That would allow a sick person to easily diagnose if they have influenza versus the common cold, for example.”
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