Abdur Rasheed1, Shubham Sharma1, Prasenjit Kabi2, Abhishek Saha3, Swetaprovo Chaudhuri4, Saptarshi Basu5. 1. Department of Mechanical Engineering, Indian Institute of Science, Bengaluru, KA 560012, India. 2. Interdisciplinary Centre for Energy Research, Indian Institute of Science, Bengaluru, KA 560012, India. 3. Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093, USA. 4. Institute for Aerospace Studies, University of Toronto, Toronto, Ontario M3H 5T6, Canada. 5. 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. Electronic address: sbasu@iisc.ac.in.
Abstract
HYPOTHESIS: 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. EXPERIMENTS: 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. FINDINGS: 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.
HYPOTHESIS: 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. EXPERIMENTS: 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. FINDINGS: 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.
Authors: Maurice D Walker; Jack C Vincent; Lee Benson; Corinne A Stone; Guy Harris; Rachael E Ambler; Pat Watts; Tom Slatter; Martín López-García; Marco-Felipe King; Catherine J Noakes; Richard J Thomas Journal: Viruses Date: 2022-05-15 Impact factor: 5.818