Researchers at the City University of Hong Kong have developed a face mask containing laser-induced graphene that can kill bacteria and has demonstrated potential in deactivating coronaviruses. The graphene layer has antibacterial properties and can generate heat when exposed to sunlight, which may underlie its ability to deactivate coronaviruses. The researchers hope that such masks could help to reduce viral transmission and infection during the current COVID-19 pandemic.
Face masks are an important part of our arsenal in the fight against COVID-19, but if used incorrectly, they can pose an infection risk. Viral particles can settle on the mask and, if touched or disposed of inappropriately, could potentially infect someone. A mask that can deactivate viral particles or other pathogens on its surface would be very useful right now. Moreover, the sheer volume of masks currently being used, and the fact that many are not reusable, is an environmental issue. Reusable masks could help to make mask wearing a more sustainable activity.
To address these issues, the Hong Kong researchers have developed a mask made using laser-induced graphene. They produced the material by passing an infrared laser over a carbon-containing polyimide film, which results in a porous graphene layer. Graphene has antibacterial properties, which are not completely understood, but it can also generate heat when exposed to light, helping with decontamination.
Over 90% of the E. coli deposited on activated carbon fiber (fig c and d) and melt-blown fabrics (fig e and f) remained alive even after 8 hours. In contrast, most of the E. coli deposited on the graphene surface (fig a and b) were dead. (Photo source: DOI number: 10.1021/acsnano.0c05330)
So far, the researchers have made and tested masks that contain a layer of the laser-induced graphene, and have found that they demonstrate significant anti-bacterial effects, and may have potential against coronaviruses. In tests with two types of human coronavirus, the masks inactivated 90% of viral particles in sunlight within just 5 minutes, and 100% within 10 minutes.
The technique is also more environmentally friendly, as the masks are reusable if decontaminated correctly. Numerous carbon-containing materials, such as existing biodegradable biomaterials, can be converted to graphene using this technique.
“Laser-induced graphene masks are reusable. If biomaterials are used for producing graphene, it can help to resolve the problem of sourcing raw material for masks,” said Ye Ruquan, a researcher involved in the study. “And it can lessen the environmental impact caused by the non-biodegradable disposable masks.”