Penetration of C₆₀ into lung surfactant membranes: Molecular dynamics simulation studies

We performed molecular dynamics simulations of the systems consisting of C₆₀ molecules and dipalmitoylphosphatidylcholine (DPPC) monolayer membranes to study the penetration of C₆₀ into lung surfactant (LS) membranes. The potential of mean force of the C₆₀ penetration through the LS membrane was calculated as a function of the distance of a C₆₀ molecule from the DPPC monolayer membrane. The free energy minimum of around 43 kcal/mol is located in the DPPC tail region, indicating that the C₆₀ molecules can accumulate in the LS membrane region. The energy decomposition shows the main driving force of the C₆₀ accumulation in the lipid tail region is the van der Waals interaction with the hydrocarbon tails of DPPC lipids. Finally, we observed that the water evaporation rate can be significantly enhanced by the accumulation of C₆₀ molecules in the membrane tail region.