Theory Study Of The Interaction Between Nanoparticles And Biomembranes

In modern tumor treatment,anti-cancer drugs are often encapsulated in some nano drug carriers for better therapeutic effects.Nanoparticles can accumulate drugs in the focal region and control their release through passive,active and physicochemical stimulated targeting ways.Therefore,nanocarriers are often modified to have targeted groups on their surface.Based on the elastic theory of biomembranes proposed by Prof.Helfrich and Ouyang Zhongcan and combined with the mean field theory and the model of flexible polymer chain,this paper establishes two theoretical models about the interaction between nanoparticles and biofilms considering whether nanoparticles are modified with polymer chains.The membrane is regarded as a vesicle formed by amphipathic molecules.Using the surface variational technique,a new shape equation of the membrane is derived taking account of the interaction potential of membrane/polymer,polymer/solvents and membrane/nanoparticles.By numerically solving the shape equations of coordinate transformation,Different shapes of vesicle and the free energy of the system are obtained under different conditions(distance between the drug-loaded particles and vesicles,the different effect of each component,the internal and external pressure,the vesicle surface tension,and the vesicle bending stiffness).The simulation results show that the final shape of the vesicle is determined by the balance among the elastic properties,the surface tension energy and the interaction of the various components with the vesicle.When the nanoparticles are modified by Gaussian chains,the disturbance of the nanoparticles to the membrane is more obvious.When the nanoparticles and the membrane repel each other and the modified chain and the membrane attract each other,the shape of the vesicle is calculated to be the most favorable shape for encapsulating the nanoparticles.However,when the density of the modified chain is too large,it is not conducive for the nanoparticles to be enveloped by the membrane.The nanoparticles do not require too much energy from the outside while they are approaching to the vesicle if the modified chain and the membrane attract each other.In addition,the membrane's properties are also important factors that affect its deformability.For example,the larger the bending stiffness of the membrane,the smaller the deformability.