Preparation And Properties Of Triple Responsive Yolk-shell Structure Mesoporous Silicon Nanospheres

The magnetic nanomaterials of yolk-shell structure have unique magnetic properties which are easy to recover for reuse.After grafting other polymer materials,it has the properties of other polymer materials,and have a broad application prospect in the controllable release of stimulus response.As a result,the magnetic nanomaterials of yolk-shell structure have attracted more and more attention from researchers.Consequently,in this paper,we used magnetic mesoporous silicon nanoparticles as the matrix,combined the acid sensitivity of Schiff-base bond,and the temperature responsive of PNVCL to design the stimuli-responsive release system with the combination of magnetic,p H and temperature.The main research contents are described as follows:The Fe₃O₄ nanoparticles with superparamagnetic properties were synthesized by solvent heat method,the surface was then coated with a mesoporous silica shell by the sol-gel method.The yolk-shell structure Fe₃O₄@V-mSiO₂ nanoparticles were synthesized by etching the Fe₃O₄ nuclei partially with the HCl-ethanol solution,the saturation magnetization strength of Fe₃O₄@V-mSiO₂ was 37 emo/g,and the adsorption experiment of rhodamine B investigated its load capacity and application economy.The results showed that the adsorption amount of Fe₃O₄@V-mSiO₂ to rhodamine B was increased with the increasing concentration of rhodamine B.When the concentration of rhodamine B was 100μg/m L,the adsorption amount reached85.64 mg/g;After seven times repeated adsorption tests for rhodamine B,the equilibrium adsorption amount still remained above 74 mg/g.Aminidation modification and aldehyde modification were performed successively on the surface of Fe₃O₄@mSiO₂,and then reacted with the aminidation temperature-responsive polymer PNVCL to obtain Fe₃O₄@V-mSiO₂-PNVCL.The DOX-Fe₃O₄@V-mSiO₂-PNVCL was obtained by loading DOX into the nanoparticles through physical adsorption process.The results showed that the saturation magnetization strength of Fe₃O₄@V-mSiO₂-PNVCL was 21.01 emo/g,which still had good magnetic responsiveness;The loading amount of DOX was 9.39%higher than that of solid core-shell structure;The encapsulation effect of DOX at 37℃was better than 25℃,and the drug release rate of nanoparticles in the tumor acidic microenvironment（p H=5.0）was higher than in the normal tissue environment（p H=7.4）.In addition,drug-loaded nanoparticles could enter cells through endocytosis and released drugs to act on the nucleus;MTT experiments proved that nanoparticles had little toxicity to normal cells and had targeted and sustained release therapy effect on tumor cells under applied magnetic field.