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The masks include 3D-printed components designed using photos taken with smartphones which map the wearer's face.
Scentists say their technique could be cheaper and more sustainable than single-use masks - which do not always fit properly and were in short supply during the first wave of the Covid pandemic.
The Edinburgh University team - which includes plastic surgeons, speech therapists, and virologists - designed the system to use 3D scanners and printers already available in hospitals.
Study leader Dr Adam Stokes, of Edinburgh's School of Engineering, said: "This project lays the groundwork for reusable PPE products that reduce the environmental impact from masks going to landfill, that enable resilience in the UK supply chain, and that meet the highest FFP3 standards as required by front line healthcare workers."
The research team carried out a pilot trial with 66 volunteer health workers from NHS Lothian.
They generated 3D images of participants' faces using either a precision scanner or three pictures taken with a smartphone.
Using a computer programme, this information was then used to create moulds that precisely matched the contours of individuals' faces.
The moulds were 3D-printed and used to make mask components made of silicone. The team assembled the final product using additional plastic parts and a filter section.
While masks could be made using scanners or smartphone images, being able to capture pictures remotely would be beneficial during a pandemic when social distancing and remote working is commonplace, the team says.
Researchers found that their masks provided the same level of protection as available single-use versions. Bespoke masks also tended to fit better, with almost 90 per cent of volunteers wearing them passing a face fit test, compared with only 76 per cent of those using single-use masks.
Further tests showed that the reusable facemasks could be safely decontaminated using common household detergents - such as washing-up liquid - and cleaning materials used routinely in hospitals.
The trial was funded by the Chief Scientist Office (CSO)'s Rapid Research in Covid-19 programme.
Dr Stokes added: "With this funding from the CSO, our team was able to design a new custom-fit and reusable facemask, to conduct a clinical trial, and to run virology assays for disinfection protocols.
"This team drew on our expertise from engineering, clinical practice, and the private sector and we have developed, rapidly, a proven technology that could prove vital in saving lives and protecting the planet."