| As a ubiquitous biological phenomenon in vivo and vitro, the transport of a polymer through a nanopore is a representative nonequilibrium process. These processes include the translocation of DNA and RNA through nuclear pores, the transport of protein across kinds of organelle membranes, the virus injecting into the host cell and so on. From the perspective of experiment, theory and simulation, the polymer translocation attract more and more attention due to its significantly potential application in sequencing of DNA rapidly and cheaply, the drug controlled release and the gene expression. The polymer translocation through the nanopore along with a number of molecular chain conformation greatly reduced, so this is a process to overcome a lot of obstacles entropy, so the study of the driving mechanism is important to understand the polymer translocation. Throughout the polymer translocation the past two decades the development of the subject, we found that the main driving force of perforations applied electric field strength, chemical potential difference, the adsorption of molecular motors and holes where the membrane surface, etc. In this paper, by using three-dimensional (3D) Langevin dynamics simulations, we investigate the dynamics of a flexible polymer chain translocation through a nanopore induced by the selective adsorption of translocated segments onto the trans-side of the membrane. In addition, we also study the effect of the membrane on the polymer translocation.By using a simple flexible chain model, we first investigated the effect of the adsorption strength on the dynamic of the polymer translocation. We confirmed that the adsorption can be the driven force for the polymer translocation, and we showed that the translocation success rate increases with increasing the adsorption energy. It confirmed that the adsorption is facilitated for the translocation. Further from the simulation results, we found that the mean translocation time shows a minimum as a function of the adsorption energy. We analyzed this phenomenon from the perspective of the theory and gave out the reasonable explanation.By changing the LJ diameter asp, we changed the membrane’s surface roughness. The smaller asp means the rougher surface. We found the mean translocation time as well as the scaling exponent a between the translocation time and the polymer chain length decrease with increasing σsp. We can explain this from the view of the diffusion coefficient of a polymer moving on the absorb surface. The diffusion coefficient increases with surface becoming smoother, it will accelerate the translocation. As the adsorption strength becomes too strong, the polymer chain is absorbed tightly on the surface like a "pancake". So the translocation is very slow because the chain particles block around the pore.In the last, we reported the effects of the surface adsorption strength and the surface roughness on the probability distribution of the mean translocation time. We showed that a nearly Gaussian distribution of the translocation time is observed only for the smoothest surface we studied. |
