Study On The Driving Magnetic Field For The Movement Of Magnetic Nanocapsules Across Cell Membrane

Due to the physiological characteristics of the body,the drug delivery system needs to overcome multiple pathological and physiological barriers from the drug delivery to the target.The dense tumor extracellular matrix and blood-brain barrier have greatly hindered the drug from entering the deep disease source.As a new and effective tool,magnetic nanocapsules play an increasingly important role in practical applications.The magnetic nanocapsules formed by coating magnetic nanoparticles in the nanocapsules not only have low toxicity and high biocompatibility,but also have magnetic response characteristics,so nanocapsule is a perfect drug carrier material.Under the guidance of external magnetic field,the drug can be transported to the cell or specific area,which can effectively improve the drug transport efficiency.However,the development cycle of drug carriers is long and the price is expensive,meanwhile nanoparticles have potential risks remains to be verified.With the development of computer technology,molecular dynamics simulation has become a new research method.In this study,two kinds of carbon nanocapsules(fullerene and carbon nanotube)were simulated by molecular dynamics simulation in the background of magnetic nanocapsules crossing the blood-brain barrier.The transfer function between the force of the nanocapsule and the speed of the nanocapsule was identified by the method of system identification;the analytical model of magnetic nanoparticles in magnetic field is derived by using electromagnetic field equation;combined with the method of system identification and analytical model,the external magnetic field needed for magnetic nanocapsules to penetrate the membrane was solved.In addition,the feasibility of the experiment was verified theoretically by MRI.In this study,the work completed is as follows: 1.Using the molecular visualization software VMD,two kinds of molecular models with the same volume nanocapsules and cell membranes have been constructed.2.Molecular dynamics software GROMACS has been used to simulate the process of two kinds of nanocapsules passing through the cell membrane,and the stress of two kinds of nanocapsules passing through the cell membrane have been compared.3.According to the simulation results,the system identification method has been used to complete the system identification of the process of nanocapsules penetration,and the prediction of the force in different process of penetration speed has also been completed.4.The analytical model of magnetic nanoparticles in magnetic field has been established,and the optimal magnetic field range of magnetic nanocapsules has been calculated based on the results of system identification.5.According to the range of magnetic field,the gradient field intensity needed for the magnetic nanocapsules to penetrate the membrane in the static magnetic field was deduced.In this paper,a systematic recognition model of the process of nanocapsules passing through the cell membrane has been presented,which can be used to predict the forces on the process of magnetic nanocapsules passing through the membrane and provide a theoretical reference for the design of the external magnetic field during the process of magnetic nanocapsules passing through the membrane.The results show that the external magnetic field provided by the magnetic field generator,such as MRI,can control the magnetic nanocapsules to cross the cell membrane and realize the drug transport across the membrane.