The Synthesis And Drug Controlled Release Of The Multifunctional Mesoporous Silica Nanoparticles

Great concern has been focused on mesoporous silica nanoparticles as drug carrier in cancer treatment because of its characteristics of good biocompatibility and easy surface functional. In this paper, we choose fluorescent monodisperse mesoporous silica as the drug carrier, in order to evaluate the drug loading and release behavior we choose DOX as model drug. The biocompatibility of blank carrier co-cultured with cancer cells and the antitumor effect of drug carrier are estimated by invitro cytotoxicity test. The distribution of nanoparticles in cells is observed by confocal laser scanning microscopy and the endocytic efficiency is analysised quantitatively by flow cytometry.In order to reduce the damage to normal tissue caused by drug whole body diffusion, we graft control release group and target moleculars into the surface of carrier to increase the deposition efficiency of the carrier in the lesion and enhance the therapeutic effect. The microenvironment of tumor is acidic compared with normal tissue, so control-release drug deliver systerm can be triggered by the change of p H. The acid-labile groups ATU is grafted into the surface of nanoparticles through the amide bond which formed between carboxyl on nanoparticles and amino on ATU by EDC/NHS. Folic acid is also grafted into the surface of nanoparticles by EDC/NHS, it not only can be used targeting moleculars increase the deposition efficiency but also be used plugging agent to block the the mesoporous channels preventing the leakage of drug molecules. Once the carrier arrive at the tumor site, the acid-labile groups start to hydrolytic leading to folic acid molecules cleavage from the mesoporous channels and the drug release from the carriers.The hollow nanostructure synthesized through the selective etching method can be used a ideal candidate to achieve the targets of synergistic therapeutic and inhibition tumor cell drug-resistance because it possess big space to load large molecule drugs and gene. Different types of silicon source are used to form the "sandwich" structure which the core and outer layer is-Si-O-Si- dense network structure condensed by TEOS and the middle layer is-R-Si-O-Si- incomplete network structure condensed by TEOS and organic silane. We choose HF as etchant to etching middle layer to form hollow structure.