siRNA为肿瘤治疗带来了希望。可是半衰期短、特异性分布差、易被血管壁和组织屏障及难被细胞摄取等问题限制了siRNA的临床应用，寻找适宜的siRNA载体成为研究热点。申请人曾用纳米金刚石将siRNA送入肿瘤细胞，并使基因沉默。为提高肿瘤靶向性，本项目将肿瘤可识别的RGDS与纳米金刚石（ND）共价结合，制备新型载体“NDCO-RGDS”，然后加载包括VEGF-siRNA在内的肿瘤新血管生成siRNA，构成全新的运载体系“siRNA/NDCO-RGDS”。利用电镜、红外、DSC表征其加载siRNA特性，检测这些粒子在促进siRNA细胞摄取过程中的分子机制，包括细胞膜结合、细胞内吞、胞浆释放动力学、转染效率及基因沉默效应。用荷瘤鼠评价肿瘤靶向性及抑制肿瘤新血管生成作用。完成本项目，预期可构建一个全新的siRNA运载系统，为siRNA肿瘤治疗奠定基础。

siRNA is clinically used for gene therapy in several pathological conditions including cancer, autoimmune, infection and neuronal disease. Due to negative-charge, water-solubility and high molecular weight a naked siRNA is unable to cross the cell membrane. In this study we prepared siRNA/NDCO-RGDS to transfer siRNA. We aimed to demonstrate that the carrier could efficiently deliver siRNA into cancer cells, induce significant gene silencing effects, and lead to regulate the related protein expression in cellular levels. The morphological structural features and gene transfection efficiency in vitro will be characterized. The gene silencing efficiency was investigated by RT-PCR, and the protein expression was detected by ELISA and Western blotting. The Migratory capacity was evaluated by HUVEC, and the cytotoxicity of the carrier was measured to prove the low cytotoxicity. To study the effect of genes in new vessels of implanted breast cancer，nude mice was used to be the model in vivo. The purpose of this study was to demonstrate the feasibility of NDCO-RGDS to be a promising delivery system for therapeutic applications.