Abstract

Lung surfactant is a complex mixture of phospholipids and membrane proteins that is located on the surface of alveoli within our lungs. Lung surfactant reduces the work associated with respiration and prevents the collapse of the alveoli sacs during , breathing. The function of lung surfactant depends on lipid and membrane protein biophysical interactions which may be affected by the quality of air an individual inhales. Presently there exists extensive data concerning the chemical changes ozone, a major oxidant in photochemical smog, induces within exposed lung surfactant components. There is however little research focused on the biophysical impacts of lung surfactant oxidation. This research examines the surface activity, film morphology and rheological changes induced in model lung surfactant films by ozone exposure. These experiments will use monolayers as a model system to investigate film oxidation changes. The results of this research show that both unsaturated lipids and membrane proteins are ozone sensitive. The ozonolysis of films comprised of pure lipids and lipid-protein mixtures exhibit changes to surface activity, film organization and rheology. However, when membrane proteins are present the changes to film rheology after ozone exposure are not measurable. This thesis examines the molecular interactions that lead to these film property changes and relates them to lung surfactant physiological behavior.