Fabrication Of The Nano-drug Delivery System Based On Silica And Its Biological Applications

An ideal carrier-drug system has advantages,such as safe excretion from the biological system after functioning and controllable release.In this paper,mesoporous silicananomaterials are used as the scaffold.Decomposable carrier materials and multi-condition controlled-release drug systems were prepared.The contents of this paper are as follows:(1)This paper reports a new kind of pH-responsive silica/anticancer drug hybrid drug delivery system(MSNPs-1),which was prepared through improved Stober method with anti-cancer drug doxorubicin(DOX)and silica.The structure of MSNPs-1 was characterized by scanning transmission electron microscopy.The drug release behaviors of DOX under different pH condition were studied by UV-vis spectroscopy.The structure changes during release processes were monitored by transmission electron microscopy.It is verified that the carrier of MSNPs-1 decomposed simultaneously with drug release in acidic or alkaline solution.The results of cellular experiments confirm that MSNPs-1 could control slow and steady release of drug in 7721 cells and provide the theoretical basis for the study of MSNPs-1 in the treatment of tumor field.(2)The other silicabased drug delivery system is a novel andintelligent nano-container(MSNPs-2)with pH and UV light dual-responsive character.The preparation process is devided into three major steps:1)modifying surface of MCM-41 with functional molecular chains containing recognition sites of hydrazone bond and azobenzene derivative,2)DOX loading,3)a-cyclodextrin(a-CD)capping.4-(Hydrazomethyl)Azobenzene was synthesized,as guest molecules and a-cyclodextrin as host molecules were mixed in water to self-assemble into complexes.The self-complexation behavior was studied under different light condition.The outer surface of MSNs was linked with aldehyde triethoxysilane,then the scaffold MSNs was connected with 4-(Hydrazomethyl)Azobenzene to form hydrazone bond.The modified MSNs was loaded with DOX and capped with a-CD.The release behaviors of the DOX under acidic and UV condition were studied by the UV-vis spectroscopy.It was verified that MSNPs-2 displayed advanced features of pH-light dual stimuli-responsiveness.The results of MCF-7 cellular experiments proved the hypotoxicity of carrier,and MSNPs-2 could release the drug quickly in the cells under UV irradiation condition.MSNPs-2 shows great potential in the biomedical field.