A personal protection equipment (PPE) mask made from a membrane of titanium oxide nanowires could provide a safe and environmentally sound alternative to disposable paper masks that trap pathogens but do not destroy them. Developed by researchers at École Polytechnique Fédérale de Lausanne (EPFL), the membrane for the new mask prototype is similar in appearance to filter paper, but with antipathogen properties. It uses the photocatalytic properties of titanium dioxide to kill viruses and bacteria. When exposed to ultraviolet radiation, the fibers in the titanate nanowire membrane convert resident moisture into oxidizing agents such as hydrogen peroxide, which have the ability to destroy pathogens. “Since our filter is exceptionally good at absorbing moisture, it can trap droplets that carry viruses and bacteria,” professor László Forró said. “This creates a favorable environment for the oxidation process, which is triggered by light.” Filter 'paper' made from titanium oxide nanowires is capable of trapping pathogens and destroying them with light. This discovery by an EPFL laboratory could be put to use in personal protective equipment, as well as in ventilation and air-conditioning systems. Courtesy of Swoxid SA/Endre Horváth. In experiments, the researchers demonstrated the membrane’s ability to destroy E. coli and DNA strands in just seconds. Based on these results, the researchers believe that the membrane could be successful on a wide range of viruses, including SARS-CoV-2 — although this remains to be demonstrated experimentally. Manufacturing the membranes on a large scale is feasible, the researchers said. The EPFL lab alone is capable of producing up to 200 sq m of filter paper per week, or enough for up to 80,000 masks per month. The manufacturing process, which involves calcining the titanite nanowires, makes the mask stable and prevents the risk of nanoparticles being inhaled by the user. The titanate nanowire masks can be sterilized and reused up to a thousand times. This could alleviate shortages and reduce the amount of waste created by disposable surgical masks. A startup named Swoxid is now preparing to move the mask membrane technology out of the lab. “The membranes could also be used in air-treatment applications such as ventilation and air-conditioning systems as well as in personal protective equipment,” researcher Endre Horváth, co-founder of Swoxid, said. The research was published in Advanced Functional Materials (www.doi.org/10.1002/adfm.202004615).