Interdisciplinary Initiatives Program Round 2 – 2002

Peter Kao, Medicine
Gerald Fuller, Chemical Engineering

Lung surfactant, a mixture of phospholipids and proteins, is essential for lowering surface tension and adjusting interfacial rheology to facilitate breathing. Lungs filled with fluid can be expanded with minimal pressure. When lungs are filled with air, the surface tension arising from intermolecular attraction between water molecules at the air-water interface contributes very substantially to lung recoil, increasing the work of breathing.

Natural lung surfactant demonstrates greater surface tension-lowering effects at small surface pressures (5 dynes/cm) than at large surface pressures (50 dynes/cm). This important property of variable surface tension prevents small alveoli from collapsing into larger ones at the end of expiration. Cycles of alveolar collapse (atelectasis) followed by reexpansion would contribute to alveolar injury and a tendency toward respiratory failure.

We have formed a unique Bio-X collaborative effort between Chemical Engineering (Professor Gerald Fuller) and Pulmonary Medicine (Dr. Peter Kao) to study the biophysical properties of natural and semisynthetic lung surfactants using advanced methods of interfacial rheology. New discoveries from this research may influence the design of replacement surfactants for treatment of lung diseases.