Bilayer aggregate microstructure determines viscoelasticity of lung surfactant suspensions

Abstract

Premature infants are treated with replacement surfactants whose viscosity varies depending on the bilayer self-assembly in the dispersion, which determines how the material spreads from the trachea to the alveoli.

Sol-gel transition induced by alumina nanoparticles in a model pulmonary surfactant

“…These results disclose a Newtonian behavior for the 40 g L -1 sample and a slightly viscoelastic behavior for the 80 g L -1 . In contrast to Ciutara and Zasadzinski [34], no yield stress behavior was found in the Curosurf® samples studied here. Of note here, the data from cone-and-plate rheology show good agreement with those of MRS technique (Fig.…”

“…As a result, the concentration at which Curosurf® is formulated (80 g L -1 ) is associated with the volume fraction of 𝜙 = 0.42, suggesting that the vesicles are in a crowded environment. In support of this result, it should be noted that Lu et al had found volume fractions of vesicles in the order of 60% for Infasurf, another surfactant substitute [33] and more recently Ciutara and Zasadzinski reported values in the range 40-50% for Curosurf® and Survanta [34], in good agreement with our results. The 𝜙(𝑐)-relationship will be further useful to express the measured viscosity as a function of volume fraction and to compare it to rheological models of colloids.…”

“…Such a process is indeed dependent on the surface tension and on the viscosity of the fluid. Surprisingly, there are currently few rheology measurements of endo-or exogenous pulmonary surfactant [26,33,34]. As a vesicle dispersion, pulmonary surfactant is expected to behave as a viscous liquid under physiological conditions, i.e.…”

Comment on “Bilayer aggregate microstructure determines viscoelasticity of lung surfactant suspensions” by C. O. Ciutara and J. A. Zasadzinski, Soft Matter, 2021, 17, 5170–5182

“…Comparison of rheological data from Ciutara et al 21 and Thai et al 25 : Fig. 1 compares the results obtained by the two groups in dynamical frequency sweeps for 𝐺 ′ (𝜔) and 𝐺 ′′ (𝜔) and at 40 and 80 g L -1 .…”

“…[22][23][24] In 𝜂(𝜎)flow curves, where 𝜂(𝜎) is the shear viscosity at the applied shear stress 𝜎, the existence of a threshold stress is seen by a sharp decrease in viscosity at 𝜎 = 𝜎 𝑦 (Figure 2 from Ref. 21 ). The yield stress values obtained were on the order of 𝜎 𝑦 = 0.02 Pa for Infasurf® and Curosurf®, and 𝜎 𝑦 = 1 Pa for Survanta®.…”