Permeation of nanocrystals across lipid membranes

Biological membranes are one of the major structural elements of cells, and play a key role as a selective barrier and substrate for many proteins that facilitate transport and signaling processes. Understanding the structural and mechanical properties of lipid membranes during permeation of nanomaterials is of prime importance in determining the toxicity of nanomaterials to living cells. It has been shown that the interaction between lipid membranes and nanomaterials and the disruption of lipid membranes are often determined by physicochemical properties of nanomaterials, such as size, shape and surface composition. In this work, molecular dynamic simulations were carried out using various sizes of nanocrystals as a probe to explore the transport of nanomaterials across dipalmitoylphosphatidylcholine (DPPC) bilayers and the changes in the structural and mechanical properties of DPPC bilayers during the permeation. A coarse-grained model was used to provide insight at large time and length scales. In this work, an external driving force helps the nanocrystals across the lipid bilayer. The minimum forces needed to penetrate the model membrane and the interaction of nanocrystals and lipid bilayers were investigated in simulations. The elastic and dynamic properties of lipid bilayers, including the local and bulk properties during the permeation of the nanocrystals, which are of considerable fundamental interest, were also studied. The findings described will lead to better understanding of nanomaterial-lipid membrane interactions and the mechanical and dynamic properties of lipid membranes under permeation.