Cooperative Transmembrane Penetration Of Nanoparticles

Dissipative particle dynamics (DPD) simulations are applied to study the penetration of nanoparticle through a lipid membrane by two pathways (i.e., physical penetration and internalization). For the physical penetration, we find that the translocation of nanoparticles through the membrane occurs in a cooperative manner, where the quantity and surface chemistry of the nanoparticles regulate the cooperative function. For nanoparticles with a hydrophilic surface, the increase of nanoparticle quantity facilitates penetration, while for nanoparticles with a partly or totally hydrophobic surface, the opposite holds. Interesting phenomena, such as aggregation, aggregation-dispersion, or even aggregation-dispersion-reaggregation of the nanoparticles, are observed during the penetration process. For the internalization of a nanoparticle by a lipid membrane, influence of receptor structure (e.g., the length of receptor and the number of chains that compose the receptor) on the wrapping process is investigated. It is found that these structural factors of the receptor have a strong effect on the wrapping behavior of the membrane. Under the similar simulation conditions, the nanoparticle can adhere on the membrane surface, or be wrapped by the membrane. Furthermore, the rupture of the lipid membrane is possibly observed in some cases. All these phenomena are tightly associated with the change of receptor structure. These results provide people fundamental understanding in the underlying mechanisms of interaction between lipid membrane and nanoparticle, and shed light on the nanoparticle-aided drug and gene delivery.