Can CO2 snow cleaning remove the Covid-19 virus from surfaces or masks?
Honesty, we do not know. Testing is required! We are not an experts in biology and can’t pass judgement on the work cited below. What follows are opinions and a brief summary of past published work on biological samples.
Past publications on CO2 snow removal of bacteria (not viruses) based contamination on Si wafers by Jang et al. showed promising results, though one older study by Buss et al. showed negative results. As for a virus, we do not know of any studies. Peptides on silica have been studied, and they can remain on a surface if deposited with a covalent bond. Excess peptides have been removed. DNA not properly bound to a surface can be removed, but no one has studied DNA properly bound. A paper by Singh et al. showed protein removal, including one with a covalent bond.
A key aspect of surface removal is how a specie is bound to the surface. The basic premise for CO2 snow cleaning is that it can remove physically bound (van der Waals) specie, but can’t remove any chemically bound specie. Any covalent, ionic, or metallic bound material should stay though Singh et al. demonstrated otherwise for a certain protein. We do not understand what bonds the virus form. However, it must form a strong of some kind that allows for transfer of genetic material. A paper by Wrapp et al. on the spikes of the Covid-19 virus spikes highlights the structural complexity and binding issues.
Masks are porous and porous samples are not good candidates for CO2 snow cleaning.
CO2 snow is cold, and it is unclear if the cold will deactivate the virus. Furthermore, the virus on a surface may stay warmer than the dry ice due to the thermal “mass” of the surface.
We will continue selling CO2 snow jets to companies not involved in studying the epidemic. We will sell to companies that are studying the epidemic if they certify that they will test and have the means to test effectiveness. This excludes small cleaning companies. Selling equipment of uncertain effectiveness is professionally unprincipled.
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