School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47906, USA.
Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN, 47906, USA.
Sci Rep. 2022 Jun 1;12(1):9109. doi: 10.1038/s41598-022-13316-9.
The COVID-19 pandemic has caused a multi-scale impact on the world population that started from a nano-scale respiratory virus and led to the shutdown of macro-scale economies. Direct transmission of SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) and its variants through aerosolized droplets is a major contributor towards increasing cases of this infection. To curb the spread, one of the best engineered solutions is the use of face masks to prevent the passage of infectious saliva micro-droplets from an infected person to a healthy person. The commercially available masks are single use, passive face-piece filters. These become difficult to breathe in during strenuous activities. Also, they need to be disposed regularly due to accumulation of unwanted particulate and pathogens over time. Frequent disposal of these masks is unsustainable for the environment. In this study, we have proposed a novel design for a filter for enhanced virus filtration, better breathability, and virus inactivation over time. The filter is called Hy-Cu named after its (Hy) drophobic properties and another significant layer comprises of copper (Cu). The breathability (pressure drop across filter) of Hy-Cu is tested and compared with widely used surgical masks and KN95 masks, both experimentally and numerically. The results show that the Hy-Cu filter offers at least 10% less air resistance as compared to commercially available masks. The experimental results on virus filtration and inactivation tests using MS2 bacteriophage (a similar protein structure as SARS-CoV-2) show that the novel filter has 90% filtering efficiency and 99% virus inactivation over a period of 2 h. This makes the Hy-Cu filter reusable and a judicious substitute to the single use masks.
新冠疫情以一种多尺度的方式影响着全球人口，它始于一种纳米级别的呼吸道病毒，导致了宏观经济的停摆。SARS-CoV-2（严重急性呼吸综合征冠状病毒 2）及其变体通过气溶胶化飞沫的直接传播是导致这种感染病例增加的主要原因之一。为了遏制其传播，最好的工程解决方案之一是使用口罩来防止感染的人将传染性唾液微滴传递给健康的人。市售的口罩是一次性、被动的面罩过滤器。在剧烈运动时，这些口罩会让人呼吸困难。此外，随着时间的推移，口罩会逐渐积累不需要的颗粒和病原体，因此需要定期更换。频繁更换这些口罩对环境来说是不可持续的。在这项研究中，我们提出了一种用于增强病毒过滤、改善透气性和随时间灭活病毒的新型过滤器设计。该过滤器被称为 Hy-Cu，得名于其（Hy）疏水性和另一个重要的铜（Cu）层。我们对 Hy-Cu 的透气性（过滤器两侧的压差）进行了测试，并与广泛使用的手术口罩和 KN95 口罩进行了实验和数值比较。结果表明，与市售口罩相比，Hy-Cu 过滤器的空气阻力至少降低了 10%。使用 MS2 噬菌体（与 SARS-CoV-2 具有相似蛋白结构的噬菌体）进行病毒过滤和失活动力学实验的结果表明，新型过滤器在 2 小时内的过滤效率达到 90%，病毒灭活率达到 99%。这使得 Hy-Cu 过滤器具有可重复使用性，是一次性口罩的明智替代品。
