Biophysical function of pulmonary surfactant in liquid ventilation

Area of Science:

• Biophysics
• Respiratory Physiology
• Biomaterials Science

Background:

• Liquid ventilation uses perfluorocarbon (PFC) liquids instead of air for mechanical ventilation.
• Pulmonary surfactant is essential for lung compliance due to high PFC-water interfacial tension, but its role in liquid ventilation is unclear.
• PFC-water interfacial tension is high (59 mN/m), necessitating surfactant action.

Purpose of the Study:

• To investigate the adsorption and dynamic surface activity of Infasurf at the PFC-water interface.
• To understand the biophysical function of pulmonary surfactant in the context of liquid ventilation.
• To simulate the intra-alveolar microenvironment of liquid ventilation.

Main Methods:

• Constrained drop surfactometry to simulate liquid ventilation conditions.
• Atomic force microscopy to analyze surfactant structure at the interface.
• Dynamic compression-expansion cycles to mimic physiological conditions.

Main Results:

• Infasurf rapidly reduced PFC-water interfacial tension from 59 mN/m to 9 mN/m.
• Adsorbed Infasurf formed multilayered structures (10-20 nm thickness) at the PFC-water interface.
• The Infasurf film dynamically regulated interfacial tension between ~1-12 mN/m during simulated ventilation.

Conclusions:

• Pulmonary surfactant plays a vital role in modulating interfacial tension in liquid ventilation.
• These findings enhance understanding of surfactant function at the PFC-water interface.
• The results offer translational insights for developing liquid ventilation and liquid breathing techniques.