Yiannis Kaznessis, Principal Investigator

Computer Simulations of Model Lung Surfactants

Pulmonary surfactant (PS) is a surface active phospholipid-protein material that lines the alveolar epithelium. It reduces the surface tension at the air/water interface, stabilizing the alveoli during expiration. Deficiency of pulmonary surfactant results in the respiratory distress syndrome (RDS) in premature infants. Since supplies of human lung surfactant are extremely limited, a typical treatment of RDS involves the use of animal surfactants as a replacement for human PS. However, animal sources carry the danger of viral infection or immunological response. Thus, the problem of a synthetic lung surfactant is an important research goal.

The main phospholipids and principal tensoactive components of PS are phosphatidylcholine (PC) and phosphatidylglycerol (PG). PC and PG reduce the surface tension throughout the lung and contribute significantly to the lung’s compliance. The surfactant proteins SP-B and SP-C also enhance the surface properties of the surfactant. As a first step toward understanding how surfactant function is affected by the component interactions, this research group is investigating the morphology of monolayer films of dipalmitoylphosphatidycholine (DPPC), dipalmitoylphosphatidylglycerol (DPPG) and SP-B(1-25) at the air/water interface. These model systems have been extensively investigated with experimental techniques and are thought to adequately describe in vivo surfactant function phenomena. This research uses charmm (Chemistry at Harvard Macromolecular Mechanics) on the SGI Origin 3800.