Physicochemical properties of respiratory droplets and their role in COVID-19 pandemics: a critical review
Ting Ge, Shengfeng Cheng
Table 1 List of representative nonaqueous components in a respiratory droplet
Nonaqueous components Brief description
Salt and lactate Soluble, present as charged ions
Cholesterol Insoluble, non-polar (except for the hydroxyl group at one end)
Proteins and enzymes Amphiphilic, net charge depends on the sequence of amino acids and pH
Lung surfactants Amphiphilic mixture of phospholipids and proteins
Cell debris Organic waste from epithelial and immune system cells
Bacteria Most bacterial cell walls carry negative charges
Viruses pH-dependent surface charges