Browsing by Author "Poon, Leo L. M."

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    SARS-CoV-2 virus transfers to skin through contact with contaminated solids
    Behzadinasab, Saeed; Chin, Alex W. H.; Hosseini, Mohsen; Poon, Leo L. M.; Ducker, William A. (2021-11-24)
    Transfer of SARS-CoV-2 from solids to fingers is one step in infection via contaminated solids, and the possibility of infection from this route has driven calls for increased frequency of handwashing during the COVID-19 pandemic. To analyze this route of infection, we measured the percentage of SARS-CoV-2 that was transferred from a solid to an artificial finger. A droplet of SARS-CoV-2 suspension (1 mu L) was placed on a solid, and then artificial skin was briefly pressed against the solid with a light force (3 N). Transfer from a variety of solids was detected, and transfer from the non-porous solids, glass, stainless steel, and Teflon, was substantial when the droplet was still wet. The viral titer for the finger was 13-16% or 0.8-0.9 log less than for the input droplet. Transfer still occurred after the droplet evaporated, but was smaller, 3-9%. We found a lower level of transfer from porous solids but did not find a significant effect of solid wettability for non-porous solids.
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    Transparent and Sprayable Surface Coatings that Kill Drug-Resistant Bacteria within Minutes and Inactivate SARS-CoV-2 Virus
    Behzadinasab, Saeed; Williams, Myra D.; Hosseini, Mohsen; Poon, Leo L. M.; Chin, Alex W. H.; Falkinham, Joseph O. III; Ducker, William A. (American Chemical Society, 2021-11-24)
    Antimicrobial coatings are one method to reduce the spread of microbial diseases. Transparent coatings preserve the visual properties of surfaces and are strictly necessary for applications such as antimicrobial cell phone screens. This work describes transparent coatings that inactivate microbes within minutes. The coatings are based on a polydopamine (PDA) adhesive, which has the useful property that the monomer can be sprayed, and then the monomer polymerizes in a conformal film at room temperature. Two coatings are described (1) a coating where PDA is deposited first and then a thin layer of copper is grown on the PDA by electroless deposition (PDA/Cu) and (2) a coating where a suspension of Cu2O particles in a PDA solution is deposited in a single step (PDA/Cu2O). In the second coating, PDA menisci bind Cu2O particles to the solid surface. Both coatings are transparent and are highly efficient in inactivating microbes. PDA/Cu kills >99.99% of Pseudomonas aeruginosa and 99.18% of methicillin-resistant Staphylococcus aureus (MRSA) in only 10 min and inactivates 99.98% of SARS-CoV-2 virus in 1 h. PDA/Cu2O kills 99.94% of P. aeruginosa and 96.82% of MRSA within 10 min and inactivates 99.88% of SARS-CoV-2 in 1 h.