Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada.
School of Public Health, University of Alberta, Edmonton, AB, T6G 1H9, Canada.
Sci Rep. 2020 Aug 17;10(1):13875. doi: 10.1038/s41598-020-70623-9.
Respiratory protection is key in infection prevention of airborne diseases, as highlighted by the COVID-19 pandemic for instance. Conventional technologies have several drawbacks (i.e., cross-infection risk, filtration efficiency improvements limited by difficulty in breathing, and no safe reusability), which have yet to be addressed in a single device. Here, we report the development of a filter overcoming the major technical challenges of respiratory protective devices. Large-pore membranes, offering high breathability but low bacteria capture, were functionalized to have a uniform salt layer on the fibers. The salt-functionalized membranes achieved high filtration efficiency as opposed to the bare membrane, with differences of up to 48%, while maintaining high breathability (> 60% increase compared to commercial surgical masks even for the thickest salt filters tested). The salt-functionalized filters quickly killed Gram-positive and Gram-negative bacteria aerosols in vitro, with CFU reductions observed as early as within 5 min, and in vivo by causing structural damage due to salt recrystallization. The salt coatings retained the pathogen inactivation capability at harsh environmental conditions (37 °C and a relative humidity of 70%, 80% and 90%). Combination of these properties in one filter will lead to the production of an effective device, comprehensibly mitigating infection transmission globally.
呼吸防护在预防空气传播疾病方面至关重要，例如，新冠疫情就凸显了这一点。传统技术存在几个缺点（例如交叉感染风险、呼吸受限导致过滤效率提高有限以及无法安全重复使用），这些缺点尚未在单个设备中得到解决。在这里，我们报告了一种克服呼吸保护设备主要技术挑战的过滤器的开发。大孔径膜透气性高，但细菌捕获能力低，经过功能化处理后，纤维表面均匀覆盖一层盐。与裸膜相比，盐功能化膜的过滤效率更高，差异高达 48%，同时保持高透气性（与商业外科口罩相比，即使是最厚的盐过滤器也增加了>60%）。盐功能化过滤器能快速杀死革兰氏阳性和革兰氏阴性细菌气溶胶，在体外观察到的 CFU 减少早在 5 分钟内，在体内则由于盐再结晶而导致结构损伤。盐涂层在恶劣的环境条件（37°C 和相对湿度为 70%、80%和 90%）下保留了病原体灭活能力。在一个过滤器中结合这些特性将导致生产出一种有效的设备，全面减轻全球的感染传播。
