Covid-19: NZ-made breath test may pick up virus 'within minutes'

The vaccine rollout is aiming to reach 2 million Kiwis within four months with people at higher risk if they catch Covid-19 being the next in line behind border and healthcare workers.

A Kiwi-designed breath test may be able to detect Covid-19 in as little as five minutes.

Although other such breath-based Covid-19 tests have been designed around the world, New Zealand researchers say their solution could be as accurate as current lab sampling.

The work, led by researchers from Canterbury University, Callaghan Innovation and MacDiarmid Institute researchers from Massey University, has been described in a just-published study.

"We've developed a new approach to detecting Covid-19 viral proteins that is sensitive and accurate enough to directly detect coronavirus particles at biologically relevant levels, specifically in breath or saliva samples," said study co-author and Canterbury biochemist Associate Professor Deborah Crittenden.

Last year, Crittenden brought together a team with expertise in sensing measurements, biochemical analysis and making the Sars-Cov-2 virus' target protein.

The result was a proof-of-principle for a new test that could dramatically decrease turn-around times for testing, and increase the volume of tests that can be performed.

"Unlike other proposed Covid breath-testing technologies, this test directly detects the Covid spike protein antigen and so is expected to be as accurate as the gold standard lab-based approach," she said.

The research was motivated and made possible by the pandemic, as it allowed resource that would have been allocated elsewhere to be directed to the study, after the national lockdown in March and April.

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"Over lockdown, we started brainstorming how we could adapt existing biomolecular sensing approaches to detecting Covid," Crittenden explained.

"The key insight is that you need a 'recognition element' that specifically and selectively binds to part of the virus – in our case, the spike protein.

"The first thing we tried was part of the ACE2 receptor to which the virus is known to bind but it was too hard to make enough of it.

"We then discovered a paper in the literature about non-helical DNA sequences that were evolved to bind to the spike protein, and then built them into a range of different sensing systems, and tested how well they worked."

If developed and commercialised, she said New Zealand could have "near-immediate point of use" testing.

"One could imagine having these devices at all border facilities, such as airports, ports, and MIQ facilities, for example," she said.

"We will continue developing this as a 'platform technology' for other sensing applications, for example, rapid detection of other pathogens or environmental pollutants.

"In future, if other pathogens emerge, it would be really useful to be able to use what we have learned to roll out real-time sensors and diagnostics a lot more quickly."

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