Researchers from Simon Fraser University and the University of Victoria have discovered a method—using only visible light—to treat and safely sterilize non-woven polypropylene-fabrics, the material used to fabricate personal protective equipment (PPE).
Led by Tyler Cuthbert, a former SFU School of Engineering Science post-doctoral fellow, researchers tested a chemical insertion method developed by UVic chemistry professor Jeremy Wulff to attach a light-sensitive, zinc-based compound onto a non-woven polypropylene fabric.
SFU health sciences colleagues Siobhan Ennis and Masahiro Niikura placed a small measure of a known infectious virus—Influenza A—onto the treated fabric before exposing the fabric to high intensity visible light for approximately four hours. Following the light exposure, researchers found that the treated sheet had inactivated 99.99 per cent of Influenza A virus particles compared to a control.
Influenza A was chosen as the virus for this study to provide proof of concept because its enveloped structure and RNA genome are similar to SARS-CoV2, the virus responsible for the current global COVID-19 pandemic. As well, Influenza A itself is a pathogen that has high pandemic potential—indeed, a strain of Influenza A was responsible for the H1N1 swine flu pandemic in 2009-10.
“This work has the potential to decrease the environmental impact of a large industry producing billions of single-use PPE products per year that are not being recycled,” says Cuthbert, currently at the Eidgenössische Technische Hochschule in Zürich.
“Ideally, sterilization of PPE should be simple and accessible so that healthcare workers everywhere, including those in remote communities, are able to access safe and sterile PPE despite global shortages and supply chain disruptions.”
According to Wulff, covalent attachment approaches are ideal for use with PPE. “When the photosensitizing compound is applied to PPE fabrics using covalent attachment, it doesn’t leach out of the material, making it safer to use and longer-lasting,” he says. “This process also allows the compound to be integrated into the PPE fabric without adding bulkiness or otherwise affecting the existing properties of the material.”
Cuthbert hopes this proof of concept study will pave a potential path forward to developing PPE that can provide healthcare providers with greater protection against airborne pathogens, and the potential for elongated or re-use of devices, a feature particularly attractive to healthcare teams in low resource settings.
“PPE should not decrease or dictate the level of care that can be provided to patients,” he says. “By introducing a continuously sterilizing material the threat of pathogen transfer and infection can be ideally eliminated, which in turn has the potential to improve the overall care in hospitals especially in units that rely on, and require, PPE such as N95 respirators.”
The researchers plan to further investigate the limits of their new treated fabric by studying how the fabric performs against different types of pathogens, activates under different light-intensities, and responds to washing and detergents.