PMC:7723248 / 26557-28998
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{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/7723248","sourcedb":"PMC","sourceid":"7723248","source_url":"https://www.ncbi.nlm.nih.gov/pmc/7723248","text":"pH\nOur results demonstrate that pH affects the stability of MS2 and Φ6 differently in droplets. MS2 survived equally well in acidic, pH-neutral, and basic droplets, whereas Φ6 survived best in pH-neutral droplets and decayed more in acidic or basic droplets. Previous studies have reported that viruses in bulk solutions are sensitive to pH [57, 58]. Both non-enveloped and enveloped viruses are generally more susceptible in acidic and basic solutions than in pH-neutral solutions [57]. At extreme pHs, viruses decay due to the denaturing of surface proteins and the hydrolysis of the viral genome [48, 59]. However, MS2 appears to be insensitive to pH. In a previous study, a moderate decay rate of ~0.5 log10 unit per day was observed for MS2 in bulk solutions at pH values of 4 and 10, and MS2 retained its viability when the solution was pH-neutral. The effect of pH on the viability of enveloped viruses is generally more noticeable than its effect on non-enveloped viruses [57], consistent with our observation of pronounced decay of Φ6 in acidic solutions across all RH levels. Besides the protein denaturing effect, the fusion of enveloped viruses’ membrane structure caused by extreme pH also leads to inactivation [48]. Low-pH treatment is widely used in monoclonal antibody purification processes to inactivate viruses because of its reliable performance (e.g., \u003e 4 log10 decay) on enveloped viruses [60].\nIn addition to the inactivation effect induced by pH, the dynamic change in pH of evaporating droplets can also affect virus survival. Although the pH of all virus suspensions was adjusted to the target pH at the beginning of experiments, the pH is likely to change as droplets evaporate. The loss of water will enrich ions, such as H3O+ and OH-, which may create pH-gradients inside droplets [46]. Additionally, since droplets were exposed to ambient air, the uptake of CO2 and formation of carbonic acid may lower the pH of droplets, but determining the extent of this process in evaporating droplets is challenging. Therefore, the pH of droplets is not expected to remain constant at its initial value throughout the experiment. The dynamic change in the pH of evaporating droplets introduces uncertainties in understanding its effect on the survival of viruses. Tools to monitor the real-time pH in evaporating droplets are necessary to fully explain the effect of pH on the viability of viruses in this complex system.","divisions":[{"label":"title","span":{"begin":0,"end":2}},{"label":"p","span":{"begin":3,"end":1417}}],"tracks":[]}