Fabrication of microplastic-free biomass-based masks: Enhanced multi-functionality with all-natural fibers

With the coronavirus-2019 epidemic, disposable surgical masks have become a common personal protective necessity. However, off-the-shelf masks have low filtration efficiency and short service life and can only physically isolate pathogens, easily leading to secondary infection and cross-infection between users. Additionally, they produce debris and microplastics, which can be inhaled by the human body and cause serious diseases. To address this, this study introduced a brand-new, microplastic-free, long-life, biodegradable, self-disinfecting, and gas-sensitive mask made of basal dialdehyde-chitosan crosslinked animal-collagen/plant composite fibers (CP-Mask) with an asymmetric bilayer structure using scalable paper-processing technology. The CP-Mask demonstrated outstanding filtration performance (95.9 %) for particulate matter with various sizes and constantly maintained filtration efficiency even after 20 friction cycles. The CP-Mask also exhibited stable and lasting antibacterial properties, with significant inhibition rates of 99.21 % for Staphylococcus aureus and 98.86 % for Escherichia coli and could effectively filter bacterial aerosols. In addition, CP-Mask realized the real-time detection of respiratory ammonia concentration and timely identified the ammonia level. The average response value was 68.26 %, and the average response time was 159.3 s, presenting good circulatory stability and is suitable for early diagnosis of ammonia-related diseases. Breakthrough, the origin of natural ingredients, fundamentally makes CP-Mask less likely to emit microplastics than commercially available masks and endows it with complete biodegradability in soil within three months, eliminating the risk of microplastic inhalation from the source. The proposed CP-Mask provides a new idea to facilitate personal health monitoring and portability of medical protection equipment regarding biocompatibility, biodegradability, self-disinfection, and ammonia sensing ability.