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Rapid compression transforms interfacial monolayers of pulmonary surfactant
1Departments of Biochemistry and Molecular Biology, Medicine, and Physiology and Pharmacology, Oregon Health Sciences University, Portland, Oregon 97201-3098, USA.
Biophysical Journal
|March 22, 2001
Summary
Rapid compression transforms pulmonary surfactant films, enabling them to maintain high surface pressures in the lungs. This discovery impacts understanding of lung mechanics and surfactant function.
Area of Science:
- Pulmonary physiology
- Surface chemistry
- Biophysics
Background:
- Pulmonary surfactant films are metastable, collapsing easily at equilibrium spreading pressures.
- In vitro compression often leads to surfactant film collapse, unlike in vivo lung conditions.
Purpose of the Study:
- To investigate the effect of compression rate on the stability of pulmonary surfactant monolayers.
- To determine if rapid compression can prevent surfactant film collapse at high surface pressures.
Main Methods:
- Utilized captive bubble surfactometry at 37°C with extracted calf surfactant and dimyristoyl phosphatidylcholine.
- Varied compression rates from 3%/min to over 32%/s.
- Measured surface pressure maintenance after rapid compression and subsequent expansion.
Main Results:
- Increasing compression rate to >32%/s allowed monolayers to reach surface pressures exceeding 68 mN/m.
- Films compressed rapidly remained stable at high pressures, even after expansion.
- Similar results were observed with dimyristoyl phosphatidylcholine, indicating broad applicability.
Conclusions:
- Compression rate is a critical factor in pulmonary surfactant film stability.
- Lung-like compression rates can transform surfactant monolayers into a metastable state, preventing collapse.
- Surfactant film transformation and stability can be achieved without compositional changes.