A Theoretical Model of Pulmonary Surfactant Multilayer Collapse under Oscillating Area Conditions

Area of Science:

• Pulmonary surfactant
• Interface dynamics
• Surface tension

Background:

• Pulmonary surfactant monolayers exhibit collapse and respreading.
• These phenomena contribute to significant area hysteresis observed in pulsating bubble surfactometry.
• Standard models often focus solely on transport processes like diffusion, adsorption, and desorption.

Purpose of the Study:

• To develop an analytical model that incorporates monolayer collapse and respreading.
• To simulate a wide range of pulmonary surfactant behaviors, including large area hysteresis.
• To investigate the role of multilayer dynamics in achieving ultralow surface tensions.

Main Methods:

• Development of an analytical model integrating monolayer collapse and respreading with standard transport processes.
• Simulation of surfactant behavior under varying conditions.
• Comparison of model outputs with experimental data from pulsating bubble surfactometry.

Main Results:

• The model successfully mimics responses ranging from insoluble monolayers to significant area hysteresis.
• Incorporation of collapse and respreading mechanisms is crucial for accurate simulation.
• Multilayer dynamics appear essential for replicating the ultralow surface tensions characteristic of pulmonary surfactant.

Conclusions:

• The developed analytical model provides a robust framework for understanding pulmonary surfactant behavior.
• Monolayer collapse and respreading are key contributors to observed area hysteresis.
• Multilayer dynamics are critical for achieving the ultralow surface tensions necessary for lung function.