The Delivery Of Peptides Through Carbon Nanotubes Under Electric Fields:A Molecular Dynamics Simulation Study

The research of molecular dynamics of carbon nanotubes is currently a research hotspot,especially in the role of carbon nanotubes as a transport channel.The research of molecular dynamics used in this microcosmic transfer process has important implications for the application of carbon nanotubes for drug transport in the medical field.In this paper,the molecular dynamics simulation method was used to simulate the structure and dynamic behavior of peptide(R8)in the course of passing through carbon nanotubes under an external electric field.We examined the effects of various factors on this transport process.For example,by adjusting the presence or absence of carbon nanotubes,we can observe whether the presence of carbon nanotubes is beneficial to the transport of the peptide;Whether or not the presence of an external electric field is observed to facilitate the transport of peptide by adding an external electric field;By adjusting the intensity of the applied electric field,the effect of field strength with different intensities on the movement of peptide through carbon nanotubes was investigated.By changing the type of carbon nanotubes,the process of transporting peptide by single-walled and double-walled carbon nanotubes was investigated and compared.By analyzing the physical quantities such as Lennard-Jones potential energy,PMF free energy,and RMSD rms variance in the simulation results,the entire motion process is analyzed in detail,and the influence of these factors on the operation of the transmission is qualitatively described.Simulation results show that carbon nanotubes can indeed accelerate the movement of peptides under certain conditions;Peptides cannot spontaneously enter carbon nanotubes without an external electric field;The external electric field can significantly increase the efficiency of peptides passing through the carbon nanotubes,and with the increase of electric field strength,the transport efficiency increases;Compared with double-walled carbon nanotubes,single-walled carbon nanotubes are more suitable for the delivery of peptides and they are more efficient transport systems.The simulation results also gave us a clearer understanding of the entire motion of the peptides through nanotubes at a microscopic scale.During the whole process of the peptides penetrating through carbon nanotubes,the Lennard-Jones potential energy between nanotubes and peptides outside the tube is always higher than that inside the tube,indicating that the carbon nanotubes always keep attracting the peptides once the peptides enter into the nanotubes.The PMF profile for the peptide penetrating through the nanotube has a peak at the CNT nozzle,which indicates that there exists an energy barrier that prevents the movement of the peptide into and out of the CNT.The change in the RMSD value of the peptides indicates that there is a change in the configuration of the peptides during their-entering and leaving the CNT.In this article,we investigate the transport of peptides through carbon nanotubes under external electric fields via molecular dynamics simulations.We examine the effects of different parameters on the transport efficiency,qualitatively analyse the entire transport process of peptides and describe the movements on the microscopic level in order to better understand the role of electric fields on the transport of the peptides and the corresponding mechanisms.