Carbon air-filter design could capture and destroy Covid-19 particles

Created by scientists and engineers from Cambridge in the UK and Ma’alot-Tarshiha in Israel, the ‘active virus filter’ - in the form of a thin carbon nanotube mat ('TorStran') - has the filtration and air permeability properties that allow it to capture free virus molecules and those contained in airborne aerosolised droplets.

According to its developers, both filtration and virus disruption take place at the same time, allowing the filter to reduce the risk of infection by removing contamination from the air. The team envisage it being particularly useful in confined situations such as emergency vehicles, hospitals, transportation, waiting areas and wards.

In the UK, the project team behind the filter was led by Q-Flo, who manufacture and develop advanced carbon-based materials. Martin Pick, the COO of Q-Flo, said: “Our challenge now is to turn our membrane [TorStran] into an effective active virus filter module.”

Meanwhile in Israel, development and manufacturing efforts are being led by Meir Hefetz, the CTO of Israeli R&D start-up Tortech, who develop nanofibres. “We are throwing our full resources behind the project,” Hefetz said. “We are meeting the initial challenges of achieving the correct properties in order to move on to practical scale-up issues.”

James Elliott, a professor in the Department of Materials Science at Cambridge added: “I’m very excited that this new application of carbon-based filter materials developed initially within our lab can be rapidly prototyped and tested to help with shortages of PPE protective equipment due to the coronavirus pandemic.”

Professor Alan Windle, one of the inventors of the process to make the nanotube material at Cambridge University said that the original objective of the process was to make ultra-strong conductive fibres for a wide range of applications. “The fact that the nanotubes compressed into an otherwise randomly oriented mat makes an excellent filter for virus-bearing airborne particles of moisture are suddenly very important as the world faces its current Covid-19-crisis,” he added.

Meanwhile, Adam Boies, a reader in Nanomaterials and Aerosol Engineering in the Department of Engineering, expressed that the unique capability of the active virus filter to both effectively filter and destroy the virus opens up new possibilities for reducing airborne viral loading. “Ultimately, it will also allow for extended filter lifetimes or reusable filtration media which do not degrade with successive cleaning,” he said.

According to Ian Goodfellow, a professor of Virology in the Department of Pathology at Cambridge, their application showed that low power to the active virus filter has the ability to completely inactivate trapped animal coronaviruses, adding that the ability to incorporate this type of technology into PPE and air handling systems “is an exciting opportunity to provide an additional tool to protect people against Covid-19”.

Dr Shuki Yeshurun, joint CEO of Q-Flo and Tortech summed up progress and points the way to the future deployment of what the team have described as a potentially life-saving product. “Our teams in Israel and the UK, including colleagues at Cambridge University, have worked flat out over the past few weeks to demonstrate the effectiveness of the TorStran active virus filter in catching and ‘killing’ the virus.”

He added they are now looking for partners to bring these units into service.