Respirators for Switzerland

Swiss researchers are moving together in the Corona crisis. To ensure Switzerland's needs for protective materials, researchers from Empa, ETH Zurich, EPFL and Spiez Laboratory, together with a large number of partners from healthcare and industry, have the project "ReMask" was launched. The objectives of ReMask are to develop technologies for reuse of existing masks, domestic production of efficient protective equipment and development of alternative masks with new properties to bind and kill viruses.

ReMask's findings supported the recently formed National COVID-19 Science Task Force, whose experts advise the Federal Office of Public Health (FOPH), the crisis management team, and other federal agencies on pandemic response. One of the high-priority Task Force tasks is the effort led by Peter Wick (Empa), Sarah Tschudin Sutter (Uni Basel) and Andreas Mortensen (EPFL) to facilitate projects for the production and reuse of protective masks.

With ReMask, this multidisciplinary approach is now being implemented. The expert group "Masks" of the Science Task Force has now made a recommendation for minimum quality requirements for so-called "community masks" for the population. Based on these recommendations Empa will temporarily investigate such community masks during the current crisis situation until the relevant know-how can be transferred to an independent body.

Photos: Unsplash/istock

Surgical masks (right) are designed to prevent larger droplets containing pathogens from being secreted by the wearer. They therefore protect the wearer less, since small particles can pass inside and the mask does not fit tightly to the face. On the other hand, they protect the environment from virus-containing droplets from an infected wearer.

The FFP-2 respirators are different: FFP-2 masks (left) are designed to protect the wearer from pollutants and pathogens in the air. The smallest particles that can be trapped are around 600 nanometers in size. Both types of masks are currently intended for single use only.

Third are the so-called community masks or hygiene masks, which do not fall under the certified standards of the other two mask types. The use of community masks is - as the name suggests - intended for the general population as a way to minimize the risk of transmission and thus protect the environment.

Empa researcher Luzia Wiesli and mechanic Jörg Gschwend have already started with the test setups for the ReMask project. Photo: Empa

Research projects have already been launched in the Empa laboratories to bridge short-term bottlenecks and enable the reuse of masks. This also ensures more sustainable use of material resources in the long term. Among other things, it must be clarified how the masks can be sterilized in a non-destructive manner, how they can be stored in a durable manner and how their effectiveness can be proven beyond doubt even after multiple uses.

To avoid having to use dangerous viruses for these experiments, the researchers are working with non-infectious particles that simulate what happens on the inside and outside of a mask in terms of droplet infection. "We are currently developing apparatus to achieve these simulations," says Empa researcher René Rossi from the "Laboratory for Biomimetic Membranes and Textiles" in St. Gallen.

Likewise, other properties of the masks such as air permeability (<60 Pa/cm²), splash resistance (impermeable to splash water) or filtration efficiency against small particles (filtration efficiency of 70 % for particles with a size of 1 micrometer) will be studied. The test protocols that will be developed in this process will be distributed widely to companies that manufacture masks, filters and protective equipment. "It's about a timely, nationwide effort," Rossi said. That's why they're not working with a single industry partner, but have brought the entire industry on board.

For the ReMask project, experts from research, healthcare and industry have joined forces to provide urgently needed products, concepts and technologies to combat COVID-19 in a timely manner. At Empa, these are "Laboratory for Biomimetic Membranes and Textiles.", the "Particles-Biology Interactions Lab., the "Transport at Nanoscale Interfaces Laboratory", the "Center for X-ray Analytics. and the "Biointerfaces. Laboratory involved.
Partner: ETH Zurich, EPFL, Spiez Laboratory, University Hospital Zurich, Inselspital Bern, "Centre hospitalier universitaire vaudois" (CHUV), "Hôpitaux Universitaires de Genève" (HUG), Kantonsspital Wintertur, Spital Wallis, Regio 144 AG, Indema AG as well as 200 companies of the trade association Swiss Textiles (https://subitex.empa.ch)

ReMask's medium- and long-term goals also include the development and production of novel masks and mask components. For example, additional layers on the inside and outside of conventional masks are to improve their durability and functionality. On the inside of the masks, a water-binding layer is to bind moisture from the wearer's breath. On the outside, on the other hand, the corona virus is to be specifically blocked. It is already known that the crown-like pathogen shell is negatively charged electrically. "A coating of fibers or membranes that is positively charged would electrostatically bind the virus on the outside of the mask and thus block it," Rossi explains. The researchers also want to develop textiles with virus-killing properties. Says Rossi, "We are pursuing several approaches that can inactivate coronaviruses that land on the textile."

This builds on the knowledge acquired in the course of a previous project. Within this project of the Empa and the EPFLA mouthguard equipped with a new type of filter foil has been developed for this purpose. These new, more robust and efficient masks must also withstand the test procedures that are already being implemented for used masks.

Swiss companies will be involved in the production and functionalization of protective masks. Thus, in addition to being a research project, ReMask is also an economic development project that ensures orders for Swiss companies during the Corona crisis.

In recent years, more than half of all Swiss "deep tech" start-ups have emerged from institutions of the ETH Domain, creating new technologies, services and jobs. To ensure that the innovative and economy-boosting performance of start-ups in Switzerland is not jeopardized by the Corona crisis, the ETH Domain has recently launched a new initiative in which Empa is also involved. The "COVID-19 Start-up Task Force" is intended to support highly qualified young companies in the current crisis situation. It also uses synergies and contacts with the business experts of the "National COVID-19 Science Task Force" as well as the most important stakeholders in the Swiss start-up ecosystem.