Theoretical Simulation Of Nano-Drug Encapsulation And Release In Functional Polymer Vesicles

In recent decades,drug delivery systems(DDSs)composed of nano-scale polymers have received much attention in the field of pharmaceutical science,and can be used for the initial diagnosis and precise treatment of many diseases.Due to considerable progress in the fields of medical science and materials science,experts have developed many nanocarriers with different sizes,structures and surface properties for DDSs,such as inorganic nanoparticles,metal block organic frameworks,liposomes,polymers micelles and polymer vesicles.Block copolymers and nanoparticles can be assembled together to obtain rich aggregate morphologies,such as disk-like micelles,sphere-like micelles,spherical vesicles,composite micelles,and multi-cavity polymer vesicles.Among them,since the morphology of block polymer vesicles is similar to various microbial cells and viral capsid membranes,the self-assembly of nanoscale polymer vesicles has received extensive attention in the field of biomedicine in recent years.We used dissipative particle dynamics(DPD)to study the co-assembly of amphiphilic diblock copolymers(AB),nanodrugs(D)and functional nanoparticles(P)in solution,and explored the parameter conditions required for drug loading and release of the functional polymer vesicles produced by co-assembly.The main contents and conclusions of this article are as follows:Study on the use of block copolymers and nanoparticles to assemble drug-loaded functional vesicles.In the simulation,by controlling the interaction parameters between the hydrophobic block / solvent and the functional nanoparticles,the length of the hydrophobic block,and the size and concentration of the drugs and functional nanoparticles,we obtained different self-assembly aggregate structures,such as disk-like micelles,sphere-like micelles,spherical vesicles and multi-cavity vesicles.Analysis of the self-assembled structural changes brought about by the change of the interaction force between the particles,and we found that when the repulsive force of the functional nanoparticles with the solvent and the hydrophobic block is not too large(a BP = a PS = 40),it is easier to form the spherical vesicle that the functional nanoparticles dispersed uniformly on the outer surface of the vesicle,while the drugs are dispersed and encapsulated in the vesicle.While increasing the length of the hydrophobic block,the self-assembled morphologies gradually changed from vesicles to micelles,and the aggregate wall thickness increased,the hydrophilic cavity gradually decreased,but the outer diameter did not change much.When the length of the hydrophobic block is short,the cavity of the hydrophilic layer formed by the vesicle is the largest.The concentration of functional nanoparticles has little effect on the overall form of self-assembly,but its size change has a great influence on the distribution of functional nanoparticles in vesicles.The concentration and size of drugs have a very important effect on the self-assembled form.When the size of the drugs is large(RD ≥ 2.00),as the concentration of drugs increases,the self-assembled form will change from vesicle to disk then to form sphere-like micelles.Based on the exploration,we obtained the functional vesicles encapsulated with drugs by self-assembly.Study on drug release in functional polymer vesicles.In the current exploration of drug release in the field of biology and polymers,targeted release of drugs from vesicles can be achieved through functional blocks,but the drug release percentage is basically 60%,and there is a phenomenon of inefficiency and waste.Based on the above investigations,we use the obtained drug-loaded functional polymer vesicles to conduct a series of investigations on drug release based on theoretical simulations.We found that the drug loaded in the functional vesicles can gradually release into the solvent when reducing the interaction force between the drug and the solvent.The greater the concentration of drugs,the faster the drug release rate.The drugs are gradually released into the solvent over time until they are almost completely released.This will also have a guiding significance for improving the release rate of drugs in vesicles in actual experiments.