Department of Mechanical Engineering, Indian Institute of Science, Bengaluru, KA 560012, India.
Interdisciplinary Centre for Energy Research, Indian Institute of Science, Bengaluru, KA 560012, India.
J Colloid Interface Sci. 2021 Oct 15;600:1-13. doi: 10.1016/j.jcis.2021.04.128. Epub 2021 Apr 28.
The droplets ejected from an infected host during expiratory events can get deposited as fomites on everyday use surfaces. Recognizing that these fomites can be a secondary route for disease transmission, exploring the deposition pattern of such sessile respiratory droplets on daily-use substrates thus becomes crucial.
The used surrogate respiratory fluid is composed of a water-based salt-protein solution, and its precipitation dynamics is studied on four different substrates (glass, ceramic, steel, and PET). For tracking the final deposition of viruses in these droplets, 100 nm virus emulating particles (VEP) are used and their distribution in dried-out patterns is identified using fluorescence and SEM imaging techniques.
The final precipitation pattern and VEP deposition strongly depend on the interfacial transport processes, edge evaporation, and crystallization dynamics. A constant contact radius mode of evaporation with a mixture of capillary and Marangoni flows results in spatio-temporally varying edge deposits. Dendritic and cruciform-shaped crystals are majorly seen in all substrates except on steel, where regular cubical crystals are formed. The VEP deposition is higher near the three-phase contact line and crystal surfaces. The results showed the role of interfacial processes in determining the initiation of fomite-type infection pathways in the context of COVID-19.
感染宿主在呼气事件中喷出的飞沫可能会作为污染物沉积在日常使用的表面上。鉴于这些污染物可能是疾病传播的次要途径，因此探索这些固定呼吸飞沫在日常使用的基质上的沉积模式变得至关重要。
所使用的替代呼吸液由基于水的盐-蛋白溶液组成，研究了其在四种不同基质（玻璃、陶瓷、钢和 PET）上的沉淀动力学。为了追踪这些飞沫中病毒的最终沉积，使用了 100nm 病毒模拟颗粒（VEP），并使用荧光和 SEM 成像技术来识别其在干燥图案中的分布。
最终的沉淀模式和 VEP 沉积强烈依赖于界面传输过程、边缘蒸发和结晶动力学。具有毛细和 Marangoni 流混合的恒定接触半径蒸发模式导致边缘沉积物随时间和空间变化。除了钢之外，所有基质中都主要形成了树枝状和十字形晶体，而在钢中则形成了规则的立方晶体。VEP 沉积在三相接触线和晶面附近较高。结果表明，在 COVID-19 背景下，界面过程在确定污染物型感染途径的起始中起重要作用。
