A ToF-SIMS study of the lateral organization of lipids and proteins in pulmonary surfactant systems

► ToF-SIMS is suitable in studies of lateral organization of surfactant films. ► Saturated phospholipids (PLs) and cholesterol are found in LC domains. ► Unsaturated PLs and miniB are found in LE phase. ► Distribution of PLs and peptide not affected by cholesterol addition. ► ToF-SIMS identifies differences in organization of normal and dysfunctional PS.