Computer simulation of the inclusion of hydrophobic nanoparticles into a lipid bilayer

Understanding influences of nanoparticle (NP) inclusions into a lipid membrane is important in a variety of areas including biological systems and pharmacology. However, the inhomogeneous nature of lipid bilayers on a nanometer length scale complicates experimental studies of membrane inclusion. Here, we have performed coarse-grained molecular dynamics simulations aimed at the influence of the hydrophobic NPs inclusion into the lipid bilayer (dipalmitoylphosphatidylcholine or DPPC bilayer). The immersion of a nanoparticle into the hydrophobic core of the membrane has been observed in the simulation. To gain more insight in the inclusion, we have obtained free energy, entropy, enthalpy, and heat capacity profiles based on umbrella sampling calculations. These results show the inclusion process is driven by the co-action of entropy and enthalpy, which is consistent with some experimental and theoretical observations. Those results could be applied in the design of specific nanoparticles for various biomedical applications.