Self-disinfecting mask that inactivates viruses

Whether made of cellulose or fabric, protective masks have become an indispensable part of our everyday lives. In today's models, their protective effect is based on the filtering of aerosols or additionally on the passive inactivation of viruses by means of charged surfaces, for example by silver cations. For the masks to provide reliable protection, they must be worn correctly and replaced or professionally washed in good time. A protective mask that can be sterilized at any time at the touch of a button would have decisive advantages. This is where the ZHAW and the company Osmotex from Thalwil come in: Using a novel electrochemical technology, viruses and other pathogens can be rendered harmless not only passively, but also actively in addition. A prototype of this mask is currently being optimized by three research groups at the ZHAW Institute of Chemistry and Biotechnology in Wädenswil. The researchers have been able to demonstrate that the new mask is safe and poses no health risks. It should be ready for the market by spring 2021 at the latest.  

First mask with electrochemical technology

According to Osmotex chief technologist Trond Heldal, the results so far are promising. "Our Sterilizer Mask would be the first mask in the world that can be sterilized electrochemically - and quickly and reliably. We have already patented the corresponding process," Heldal explains. "Thanks to ZHAW's scientific know-how, we were able to optimize the mask and bring it to market within a short time." The project, initiated jointly by ZHAW chemist Chahan Yeretzian and Osmotex, is supported by the federal funding agency Innosuisse with 902,000 Swiss francs and has a budget of 1.7 million Swiss francs. While Chahan Yeretzian's team is dedicated to the safety of the mask, ZHAW microbiologist Martin Sievers' team is responsible for the efficiency and that of ZHAW chemist Christian Adlhart for the material. "After documenting the effectiveness of the electrochemical technology with a study in the summer of 2020, we are now working on optimising this technology for sterile protective masks and making it suitable for everyday use," says Yeretzian.

Sterilization at the touch of a button

The novel mask consists of a multilayer special material as well as electrodes and a voltage source. An insulating membrane lies between two conductive layers. Thanks to an integrated battery that can be recharged via a USB connection, an electrical voltage of a few volts is applied at the touch of a button. This generates reactive oxygen molecules that reliably inactivate viruses and bacteria. In this way, the surface of the mask can be sterilized in a few minutes - and even while it is being worn. The applied voltage and the generated reactive oxygen molecules are minimal and absolutely harmless to humans.

Which reactive oxygen molecules are produced and how efficiently they inactivate pathogens depends on the voltage and materials used. The ZHAW researchers are currently searching for the optimal mixture in the laboratory. "Depending on the tension and structure of the textile, we can achieve virus inactivation of over 99 percent, under much higher requirements and in less time than recommended for antiviral textiles," says ZHAW project leader Sebastian Opitz. The sterilization efficiency could therefore be specifically adapted depending on the area of application.

Potential for further applications

The great potential of Osmotex's electrochemical process has already been demonstrated earlier in the development of "smart" sports textiles that actively transport sweat to the outside. As part of the Innosuisse project, Osmotex and the ZHAW researchers therefore want to extend this technology to other applications, such as seat covers and other textiles in the public sector. The list of potential applications is long: hospitals, rescue teams, hotels, public transport, offices and workplaces. This could replace expensive as well as potentially dangerous chemical substances or UV systems. "Electrochemical sterilization could even be an answer to the growing problem of multi-resistant hospital germs," says Chahan Yeretzian. However, everyday applications are also conceivable. For example, a handbag could be used for the simple sterilization of objects such as keys, mobile phones or coins.

Contact:
Prof. Dr. Chahan Yeretzian, Institute of Chemistry and Biotechnology, ZHAW Department of Life Sciences and Facility Management, Tel. 058 934 55 26, e-mail chahan.yeretzian@zhaw.ch