INSTM National Interuniversity Consortium of Materials Science and Technology, Research Unit of University of Trieste, 34127 Trieste, Italy.
Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy.
Int J Environ Res Public Health. 2022 Oct 23;19(21):13790. doi: 10.3390/ijerph192113790.
Standardized methods for testing Viral Filtration Efficiency (VFE) of tissues and devices are lacking and few studies are available on aerosolizing, sampling and assessing infectivity of SARS-CoV-2 in controlled laboratory settings. NanoAg-coated endonasal filters appear a promising aid for lowering viable virus inhalation in both adult and younger populations (e.g., adolescents).
to provide an adequate method for testing SARS-CoV-2 bioaerosol VFE of bio-gel Ag nanoparticles endonasal filters, by a model system, assessing residual infectivity as cytopathic effect and viral proliferation on in vitro cell cultures.
A SARS-CoV-2 aerosol transmission chamber fed by a BLAM aerosol generator produces challenges (from very high viral loads (10 PFU/mL) to lower ones) for endonasal filters positioned in a Y shape sampling port connected to a Biosampler. An aerosol generator, chamber and sampler are contained in a class II cabinet in a BSL3 facility. Residual infectivity is assessed from aliquots of liquid collecting bioaerosol, sampled without and with endonasal filters. Cytopathic effect as plaque formation and viral proliferation assessed by qRT-PCR on Vero E6 cells are determined up to 7 days post inoculum.
Each experimental setting is replicated three times and basic statistics are calculated. Efficiency of aerosolization is determined as difference between viral load in the nebulizer and in the Biosampler at the first day of experiment. Efficiency of virus filtration is calculated as RNA viral load ratio in collected bioaerosol with and without endonasal filters at the day of the experiment. Presence of infectious virus is assessed by plaque forming unit assay and RNA viral load variations.
A procedure and apparatus for assessing SARS-CoV-2 VFE for endonasal filters is proposed. The apparatus can be implemented for more sophisticated studies on contaminated aerosols.
缺乏测试组织和设备病毒过滤效率（VFE）的标准化方法，关于在受控实验室环境中雾化、采样和评估 SARS-CoV-2 感染性的研究也很少。纳米银涂层鼻内过滤器似乎是降低成人和年轻人群（例如青少年）吸入活病毒的有希望的辅助手段。
通过模型系统，提供一种充分的方法来测试生物凝胶 Ag 纳米颗粒鼻内过滤器的 SARS-CoV-2 生物气溶胶 VFE，评估细胞培养物中的细胞病变效应和病毒增殖作为残余感染性。
通过 BLAM 气溶胶发生器为 SARS-CoV-2 气溶胶传输室供料，为位于与 Biosampler 相连的 Y 型采样端口的鼻内过滤器带来挑战（从非常高的病毒载量（10 PFU/mL）到较低的病毒载量）。气溶胶发生器、室和采样器都包含在 BSL3 设施中的 II 级机柜中。通过 qRT-PCR 在 Vero E6 细胞上评估来自收集生物气溶胶的等分试样的残余感染性，评估有无鼻内过滤器时的生物气溶胶。接种后 7 天内测定细胞病变效应（形成噬菌斑）和病毒增殖。
每个实验设置重复三次，并计算基本统计数据。气溶胶化效率是通过实验第一天雾化器和 Biosampler 中病毒载量之间的差异来确定的。病毒过滤效率是通过实验当天收集的生物气溶胶中有无鼻内过滤器的 RNA 病毒载量比来计算的。通过噬菌斑形成单位测定法和 RNA 病毒载量变化来评估传染性病毒的存在。
提出了一种评估鼻内过滤器对 SARS-CoV-2 VFE 的程序和设备。该设备可用于更复杂的污染气溶胶研究。
