Department of Atmospheric and Oceanic Sciences, Canada.
Department of Chemistry McGill University, 801 Sherbrooke St. W., Montreal, QC, H2A 0B8, Canada.
Environ Sci Process Impacts. 2024 Nov 13;26(11):2010-2019. doi: 10.1039/d4em00411f.
Ice nucleation processes in the earth's atmosphere are critical for cloud formation, radiation, precipitation, and climate change. We investigated the physicochemical properties and ice nucleation potential of selected viral aerosols, including their RNA and proteins, using advanced techniques such as scanning-transmission electron microscopy (S/TEM), small angle X-ray scattering (SAXS), particle analyzers, and a peltier chamber. The experiments revealed that RNA particles obtained from MS2 bacteriophage had a mean freezing point of -13.9 ± 0.3 °C, comparable to the average ice nucleation temperature of global dust particles, which is approximatively -15 °C. RNA from MS2, Influenza, SARS-CoV-1 and SARS-CoV-2 demonstrated average ice nucleation temperatures of -13.9 ± 0.3 °C, -13.7 ± 0.3 °C, -13.7 ± 0.3 °C, and -15.9 ± 0.4 °C, respectively. SAXS analysis indicated a high local crystallinity value of 0.5 of MS2 RNA particles, hinting that high crystalline nature may contribute to their effectiveness as ice nuclei. Dilution experiments show that viral RNA consistently catalyzes ice nucleation. The addition of dust-containing particles, such as FeO, CuO, and TiO, to MS2 bacteriophage droplets enhanced ice nucleation, as did UV radiation. We herein discuss the implications of this work on ice nucleation and freezing processes.
地球大气中的冰核形成过程对于云的形成、辐射、降水和气候变化至关重要。我们使用扫描透射电子显微镜 (S/TEM)、小角 X 射线散射 (SAXS)、颗粒分析仪和珀耳帖室等先进技术，研究了选定病毒气溶胶的物理化学性质和冰核形成潜力，包括它们的 RNA 和蛋白质。实验表明，从 MS2 噬菌体获得的 RNA 颗粒的平均冰点为-13.9 ± 0.3°C，与全球尘埃颗粒的平均冰核形成温度（约-15°C）相当。MS2、流感、SARS-CoV-1 和 SARS-CoV-2 的 RNA 的平均冰核形成温度分别为-13.9 ± 0.3°C、-13.7 ± 0.3°C、-13.7 ± 0.3°C 和-15.9 ± 0.4°C。SAXS 分析表明 MS2 RNA 颗粒具有 0.5 的高局部结晶度值，这表明高结晶度可能有助于其作为冰核的有效性。稀释实验表明，病毒 RNA 始终催化冰核形成。向 MS2 噬菌体液滴中添加含有尘埃的颗粒，如 FeO、CuO 和 TiO，以及紫外线辐射，都会增强冰核形成。我们在此讨论这项工作对冰核形成和冻结过程的影响。
