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Interaction between chitosan and bovine lung extract surfactants
Ningxi Kang1, Zdenka Policova, Gelareh Bankian
1Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, Canada M5S 3E5.
Biochimica Et Biophysica Acta
|November 6, 2007
Summary
Chitosan addition to bovine lung extract surfactant (BLES) improves surface tension and elasticity at low ratios but causes collapse at high ratios. Electrostatic interactions between chitosan and anionic lipids in BLES are key to these effects.
Area of Science:
- Biophysics
- Materials Science
- Biochemistry
Background:
- Lung surfactant maintains alveolar stability by reducing surface tension.
- Exogenous bovine lung extract surfactant (BLES) is used therapeutically.
- Chitosan, a cationic polyelectrolyte, can interact with biological molecules.
Purpose of the Study:
- To investigate the interaction between chitosan and BLES.
- To determine the effect of chitosan on BLES surface activity.
- To elucidate the role of electrostatic interactions in BLES-chitosan mixtures.
Main Methods:
- Dynamic compression/expansion cycles in a Constrained Sessile Drop (CSD) device.
- Environmental chamber at 37°C and 100% relative humidity.
- Zeta potential measurements and surface tension analysis.
Main Results:
- Low chitosan:BLES ratios yielded low minimum surface tensions (<5 mJ/m²) and enhanced elasticity/stability.
- High chitosan:BLES ratios led to monolayer collapse at high minimum surface tensions (>15 mJ/m²).
- Chitosan binding to anionic lipids (phosphatidyl glycerols) in BLES was observed, correlating with surface activity changes and aggregate flocculation.
Conclusions:
- Chitosan's effect on BLES surface activity is dependent on its ratio to BLES.
- Electrostatic interactions between chitosan and anionic lipids are crucial for modulating BLES properties.
- The findings highlight the importance of electrostatic interactions in lung surfactant systems and suggest potential for chitosan in surfactant formulations.
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