Studies On The Interaction Mechanisms Between MoS₂ Nanosheet And Biomolecules Based On Molecular Dynamics Simulation

With the rapidly research on two-dimensional?2D?nanomaterials in recent years,many 2D nanomaterials have shown great application potential in the field of biomedicine due to their unique physical and chemical properties.However,it is very important and urgent to evaluate the biocompatibility and toxicity of these nanomaterials before widely applied them in the biomedical field.Therefore,we need to fully understand the interaction between these 2D nanomaterials and various biological molecules,so as to successfully utilize these nanomaterials.Molybdenum disulfide?MoS₂?,as a representative material of transitional metal dichalcogenides,has shown a good application prospect in biological antibacterial,drug carrier,biosensor,biological imaging and other biomedical fields.But there are still few studies on its biosafety and biocompatibility.In order to better apply these nanomaterials in the field of biomedicine in the future,our topic is committed to the study of the interaction between MoS₂ and different biomolecules.Based on the method of molecular dynamics simulation,the interactions between monolayer MoS₂nanosheet and the bacterial cell membrane as well as the islet amyloid polypeptides were studied.The main results of this research are as follows:1.Molecular mechanisms of the interaction between MoS₂ nanosheet and bacterial membrane.Here,we investigated the interaction between MoS₂ nanosheet and the bacterial membrane by using both theoretical and experimental methods.Molecular dynamics simulation presented that MoS₂ nanosheet can disrupt the structure of the lipid membrane by making dents on its surface and extract phospholipid molecules to reduce the integrity of the membrane.This is attributed to the combination of the dispersion interaction of lipid tails with S atoms and the electrostatic interactions of the lipid head groups with the Mo and S atoms in the lateral edges of MoS₂ nanosheet.At the same time,scanning electron microscopy and transmission electron microscopy confirmed the dents and the membrane destruction,which would lead to the loss of cytoplasm and the death of bacteria.It should be noted that the phenomenon that MoS₂ induces dents is different from the direct insertion of graphene-based nanomaterials,which might be due to the thicker and stiffer structure of MoS₂.Therefore,we believe that the molecular interactions of 2D nanomaterials with bacterial membranes should be highly correlated with their structural characteristics.2.Studies on the interaction between different shape MoS₂ nanosheet and bacterial membrane.A triangular MoS₂ nanosheet was constructed and its interaction with bacterial membrane was studied by molecular dynamics simulation.The results show that the triangular MoS₂ nanosheet is very easy to adhere to the lipid membrane when there is no position limit.It is mainly driven by the electrostatic force and van der Waals force between MoS₂ nanosheet and phospholipid molecules.And this phenomenon is similar to that of graphene nanosheet,so it may also be related to the hydrophobic properties of these two materials.3.Effect of MoS₂ nanosheet on the structure of hIAPP_1-37-37 oligomers.The interaction between MoS₂ nanosheet and hIAPP_1-37-37 monomer and dimer was studied by molecular dynamics simulation.It was found that due to the electrostatic force and van der Waals force generated between the MoS₂ nanosheet and polypeptide molecules,the hIAPP_1-37-37 monomer are easily adsorb onto the surface of the MoS₂nanosheet,and the secondary structure are destroyed.As for the dimer of hIAPP_1-37,it will also adhere to the surface of the nanosheet,however it accompany with a slightly changes of the secondary structure,which may be due to the strong interaction of the intra-polypeptide molecules,so that the impact of MoS₂ nanosheet on the structure of the hIAPP_1-37-37 dimer is reduced.