We study the mechanism of enhanced permeability of lipid bilayers induced by the adsorption of single chain nanoparticles(SCNP)with controlled hydrophobicity by coarse-grained Monte-Carlo simulations with explicit solvent.The simulation results reveal two transition points of the effects of SCNP on the membrane structure and permeability with the increasing of chain hydrophobicity.The first transition point occurs at moderate hydrophobicity region,at which the SCNP anchored stably on one side of the membrane,which causes significant disturbance of the lipids on the other side of the bilayer,facilitating the translocation of solvent molecules through the bilayer in the vicinity of the SCNP.Further increase of the hydrophobicity makes the SCNP fully embed into the membrane core,which decreases the membrane permeability due to the fact that the disturbance of the lipids is blocked with centralization of SCNP.When the hydrophobicity is high,a full coverage of the SCNP by the lipid molecules is observed.In this case,the SCNP is compressed and deformed,which enlarges the area in the xy plane and destabilizes the surrounding lipids,leading to an increase of permeability.