Ion concentration effect (Na+ and Cl−) on lipid vesicle formation

Essentials in saline pharmacology for nasal or respiratory hygiene in times of COVID-19

“…The effect was also sustained in the presence of surfactants and polysaccharides (dextrans), although the particle count was slightly enhanced by the latter substances: it was moreover found that surface tension was not the determinant factor, but rather the conductivity and viscosity [30]. In the mono-, bi-, or multilayer vesicle technology, saline has been shown to supress the vesicle formation, to induce aggregation of vesicles, and to lead to faster vesicle deposition on surface substrates: the ionic nature makes it more easily to be captured by the substrate layer, while vice versa, as a result, droplets are more difficult to detach from the resulting salt-integrating surface substrate [31,32]. Saline thus leads to much less bio-aerosol while remaining droplets may average larger sizes, as was shown by Edwards [23][24][25]: this will affect deposition indirectly in 2 ways: (1) faster deposition of droplets following coughing in the vicinity of the spreader (due to higher gravity and inertia of the larger droplets) [33]; (2) faster deposition of incidentally inhaled droplets in the nose and upper airways, as they are too large to penetrate into the bronchioles and lungs [34].…”

“…Charge shielding of mucin or mucin-like macromolecules that consequently undergo gelation, stabilizing ALF/air interface and reducing its breakup, resulting in a reduced tendency of the ALF to disintegrate into very small droplets Saline droplets (emulsion) [31] Mechanistic study of NaCl droplets ± surfactant Added to nanoemulsions, NaCl makes finer micellar droplets "aggregate", making the droplet size distribution to move to a bigger size range (so will lead to faster deposition), while surfactant in contrast breaks up the droplets to smaller sizes Saline phospholipid droplets [32] Mechanistic study of effect of NaCl on phospholipid vesicles and bilayers -Na + and Cl − binds with the lipid head and induces strong hydrophobic repulsion on the lipid tail -This leads to enhanced hydrophobic repulsion on lipids and so forces lipids to attach firmly on the surface substrate Much larger external energy is needed for vesicle formation in salt solutions than in pure water Sodium chloride aerosol [35] Mechanistic study of NaCl and corn oil (bio)aerosol on filtration by face mask materials (FFP1, N95, P100, and elastomeric half-mask respirators)…”

Formation of Giant Lipid Vesicles in the Presence of Nonelectrolytes—Glucose, Sucrose, Sorbitol and Ethanol

“…Figure 3 shows the fluorescence results of lipid hydration in solutions with different concentrations of sucrose and those when the sucrose coexisted with 50 mM sodium chloride (the NaCl/water molar ratio is 0.09%). As shown in Figure 3a, the presence of sucrose promoted the swelling and detachment of the lipid membranes, thus promoting the GLV formation, which was opposite to the effect of sodium chloride [14]. At high sucrose concentrations, the supported lipid membranes and GLVs were dragged by the water flow generated by adding aqueous solution and moved with it (indicated by the arrows in Figure 3a), and they were even detached from the substrate and dispersed in the solutions, which made the GLVs difficult to count.…”

“…In 2017, in order to figure out how the presence of salt suppressed GLV formation, we designed and fabricated a miniaturized chip, and based on the miniaturized chip we investigated the effect of sodium chloride on the processes and results of lipid hydration [14]. We found that the presence of sodium chloride suppressed GLV formation mainly because the swelling and detachment of the lipid membranes were suppressed under a stronger hydrophobic repulsion.…”

“…In this work, using the same method as that in reference [14], we investigated how the lipid hydration and GLV formation would be influenced by the presence of several nonelectrolytes that commonly appeared in physiological conditions and laboratories, including sucrose, glucose, sorbitol and ethanol. These molecules also play important roles in life activities.…”