CLF study to investigate transmission of viruses

STFC's Central Laser Facility (CLF) is to investigate how viruses are transmitted from person-to-person and how this changes in different settings and environments.

The new study, funded by the UK government under the PROTECT COVID-19 National Core Study, will use an intricate laser trapping technique to help reveal how viruses hitch-hike on airborne droplets.

The collaboration, led by Manchester University’s Professor Neil Bourne, will involve teams from the CLF, Diamond Light Source, Public Health England and the Health and Safety Executive with advice from Dstl.

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One possible source of transmission of COVID-19 is through the air, carried by aerosol droplets expelled by the host through actions such as sneezing, coughing, or by speaking.

According to STFC, the team will focus on aerosol-based transmissions, mapping the behaviour of particles and inactivated viruses within a droplet. These inactivated viruses exhibit the same physical properties as the ‘real’ virus but is non-infectious and safe to study.

The team aims to determine the fate of those viruses through the lifetime of the droplet, including deliberately placing the droplets on different surfaces including the material in a facemask.

To achieve these goals, CLF’s Dr Andy Ward will use techniques available at the CLF’s Octopus Imaging Facility, one of which involves levitating a droplet containing inactivated virus particles in mid-air using laser beams.

Optical trapping with these laser tweezers will allow him to study the virus inside droplets before they can interact with any surfaces.

In a statement Dr Ward said: “In the past, we have combined our expertise in droplet studies with the fluorescent microscopy and spectroscopy techniques at the CLF Octopus facility to learn more about respiratory therapy, pollution and cloud chemistry.

"Our combination of techniques will allow us to follow the behaviour of 100nm particles and viruses within a droplet. We also aim to see where the virus comes to rest when the droplet, for example, evaporates. This will help us to gain a greater insight into how virus interacts with the world around us.”