Simulation Study Of Several Influencing Factors On DNA Sequencing Of Molybdenum Disulfide Nanopores

In recent years,gene sequencing has shown great application potential in disease prediction and treatment.It is of great significance to develop the efficient gene sequencing technology.At present,solid-state nanopore sequencing is considered to be the most promising next-generation sequencing method.Fortunately,the two-dimensional monolayer molybdenum disulfide with single-atom thickness has attracted much attention.It has been considered as a promising nanomaterial due to its excellent electronic properties and mechanical properties.In this thesis,molecular dynamics(MD)simulation method was used to evaluate the single nucleotide distinguish resolution of Mo S2 nanopore.Firstly,the adsorption behavior of DNA molecule on the surface of molybdenum disulfide was explored.Secondly,the effects of many key factors including applied voltage,nanopore diameter,and surface charge on the DNA sequencing of molybdenum disulfide nanopores were further evaluated.These simulation could provide useful guidance for the experiments.The conclusions of this thesis are as follows:1.The adsorption behavior of DNA with different initial orientations on the surface of molybdenum disulfide was studied at the molecular level.The results show that horizontal and vertical DNA systems tend to adsorb on the surface of molybdenum disulfide vertically.Due to strong electrostatic repulsion between the phosphate groups of DNA and the sulfur atom in the molybdenum disulfide.The DNA molecule tends to adsorb on the surface of molybdenum disulfide through residue at the end under the effect of van der Waals force.In addtion,our simulation demonstrated that the adsorption of DNA on the surface of molybdenum sulfide is not affected by the sequence and length of the double-strands DNA.In this part,it has been proved that the adsorption orientation behavior of DNA is conducive to DNA sequencing of molybdenum disulfide nanopores.2.Based on the study of DNA orientation,the effect of applied voltage and nanopore diameter on the DNA sequencing by molybdenum disulfide nanopore was explored in this thesis.The results show that the translocation time of DNA chain passing through the molybdenum disulfide nanopore decreases with the increases of applied voltage,and the translocation time of single base passing through the nanopore also decreases with the increases of voltage.In addition,the probability of DNA passing through the molybdenum disulfide nanopore increases with the increases of pore size.It shows us that the applied voltage and nanopore size could significantly affect the DNA sequencing resolution of nanopore.3.Finally,the effects of the traction and atomic charge distribution of molybdenum disulfide on DNA sequencing was also explored in this thesis.This study shows that the single base resolution of molybdenum disulfide nanopore sequencing decreases with the increases of traction.At the same time,the resolution of sequencing decreases with the increases of the atomic charge of molybdenum disulfide.Based on the optimal external factor of molybdenum disulfide model,nanopore can effectively distinguish four different types of bases and obtain high-resolution single-base sequencing.