RAPID: Silver and Copper-based Nanowire Structures for Antiviral Applications

非技术摘要：当前的COVID-19大流行已经确定了美国应对国家生物灾难战略准备的关键问题。其中之一是N95呼吸机短缺，这种呼吸机为治疗受感染患者的医务人员提供关键保护。这个问题是这些N95净化器的一次性使用性质的直接后果;聚合物纤维过滤器，包括N95和HEPA过滤器，捕获和积累活病原体，因此具有生物危害性。在所提出的工作中，金属纳米线燕窝和静电纺丝纤维被提出作为解决这些问题的方法，从而改进呼吸器。多孔金属纳米线鸟巢允许空气通过，类似于聚合物纤维过滤器，但金属表面具有抗菌和抗病毒特性。因此，在鸟巢中捕获的病原体被灭活，改善了对医务工作者的保护，并延长了呼吸器的有效性。同样的金属纳米线也将被整合到自由表面静电纺丝装置中，从而产生具有抗菌/抗病毒纳米线的聚合物纤维。静电纺丝机可以在内部熔化并重新纺成新的纺丝机。这一回收步骤允许制冷机连续重复使用，消除了不断重新储存的需要。这些努力一起可以解决当前流行病中的过滤器短缺问题，并提供具有生物活性成分的上级过滤器产品。技术摘要：这项工作旨在为N95过滤器开发可重复使用的生物活性过滤材料。目前的过滤材料是一次性使用的，并积累活病原体，使其本质上是不卫生的。我们建议使用两种方法来应对这些问题。在第一种方法中，将使用Ag和Cu纳米线制备冷冻铸造金属纳米线鸟巢。鸟巢的多孔结构允许空气通过，类似于传统的过滤器，而Ag和Cu已被证明具有抗菌和抗病毒的纳米颗粒特性。纳米线由于其刺穿细胞和病毒膜的能力而可能对病原体具有更高的功效。在第二种方法中，静电纺丝聚丙烯纤维垫将被制备为传统的空气吹制聚合物过滤器的替代品。电纺织物可以生长到定制适合操作者的面部，提供用作呼吸器的特殊密封。使用过的消毒剂可以就地熔化（熔化温度210 - 280 ° C）并重新纺丝，以制备新的卫生消毒剂。将纳米线分散到熔融聚丙烯中将产生具有精细金属纳米线毛发的聚合物纤维。和以前一样，金属纳米线将赋予抗菌和抗病毒的特性。鸟巢、静电纺丝过滤器和混合纺织品的功效将使用细菌和噬菌体（感染细菌的病毒）的悬浮液和气溶胶进行快速测试。大肠埃希菌和枯草芽孢杆菌将分别作为革兰氏阴性和革兰氏阳性细菌病原体的非致病性替代物。囊病毒科中的一种有包膜噬菌体将作为SARS-CoV-2的非致病性替代物。拟议的研究将调查纳米线作为抗菌和抗病毒剂的可行性，开发一种新的纳米结构过滤材料，并探索一种替代的制造方法，该奖项反映了NSF的法定使命，并通过利用基金会的知识价值和更广泛的知识价值进行评估，被认为值得支持。影响审查标准。

Non-Technical Abstract: The current COVID-19 pandemic has identified key problems in the US strategic preparedness for a national biological disaster. One of those is a shortage of N95 respirators, which provide critical protection to medical personnel as they treat infected patients. This issue is a direct consequence of the one-time-use nature of these N95 respirators; polymer fiber filters, including N95 and HEPA filters, capture and accumulate live pathogens, and so become biohazardous. In the proposed work, metallic nanowire bird’s nests and electrospun fibers are presented as approaches to resolve these problems, resulting in an improved respirator. The porous metallic nanowire bird’s nests allow air to pass through, similar to a polymer fiber filter, but the metallic surfaces possess antibacterial and antiviral qualities. As a consequence, pathogens captured in the bird’s nest are inactivated, improving the protection to medical workers and prolonging the usefulness of the respirator. The same metallic nanowires will also be integrated into a free surface electrospinning device, resulting in polymer fibers which are hairy with the antibacterial/antiviral nanowires. Electrospun respirators can be melted down in-house and re-spun into new respirators. This recycling step allows for respirators to be continuously re-used, removing the need to constantly re-stock. These efforts together may resolve the shortages of respirators in the current pandemic and present a superior filter product with bioactive components. Technical Abstract: This work seeks to develop reusable, bioactive filter materials for N95 respirators. Current filter materials are one-time-use and accumulate live pathogens, making them intrinsically unsanitary. We propose to respond to these problems using two approaches. In the first approach, freeze-cast metallic nanowire bird’s nests will be prepared using Ag and Cu nanowires. The porous structure of the bird’s nest allows air to pass, similar to a traditional filter, while Ag and Cu have been shown to have antibacterial and antiviral qualities as nanoparticles. Nanowires may present higher efficacy against pathogens due to their ability to puncture the cell and viral membranes. In the second approach, electrospun polypropylene fiber mats will be prepared as an alternative to traditional air-blown polymer filters. The electrospun textiles can be grown to custom fit operator’s faces providing an exceptional seal for use as a respirator. Used respirators can be melted on-site (melting temperature 210-280 °C) and re-spun, to prepare new, sanitary respirators. Incorporating nanowires into the molten polypropylene will result in polymer fibers with fine metallic nanowire hairs. As before, the metallic nanowires will confer antibacterial and antiviral qualities. The efficacy of the bird’s nest, the electrospun filter, and hybrid textile will be rapidly tested using suspensions and aerosols of bacteria and bacteriophages (viruses that infect bacteria). Escherichia coli and Bacillus subtilis will serve as non-pathogenic surrogates for Gram-negative and Gram-positive bacterial pathogens, respectively. An enveloped bacteriophage in family Cystoviridae will serve as a non-pathogenic surrogate of SARS-CoV-2. The proposed research will investigate the feasibility of nanowires as antibacterial and antiviral agents, develop a new, nanostructured filter material, and explore an alternative fabrication methodology, resulting in new materials and techniques with direct consequences to the US preparedness for biological disasters.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.