[Preparation and feasibility of superparamagnetic dextran iron oxide nanoparticles as gene carrier].

Background & Objective: Application of magnetic nano- particles as gene carrier in gene therapy of tumor has developed quickly. To obtain a new type non-viral gene introduction and therapy system,which is convenient,and can drive target gene to express highly and stably,this study was designed to explore the preparation of superparamagnetic dextran iron oxide nanoparticles(SDION),and the feasibility of SDION used as gene carrier in vitro.

Methods: SDION were prepared by chemical co-precipitation,separated by gel filtration chromatography on Sephacryl S-300HR,and centrifugation techniques,characterized by transmission electron microscopy,laser scattering system,and vibrating sample magnetometer signal processor. The green fluorescent protein-C2 (GFP-C2) plasmid was used as target gene. SDION-GFP- C2 compounds were synthesized by oxidation-reduction reaction. The connection rate of SDION and GFP-C2 was analyzed by agarose electrophoresis,and evaluated by measuring concentration of GFP in the supernatant after centrifugation. Liposome transfection was used as control,the efficiencies of SDION and liposome in transferring GFP gene into human bladder cancer BIU-87 cells were evaluated under fluorescence microscope in vitro.

Results: The diameter of SDION ranged from 3 nm to 8 nm, the effective diameter was 59.2 nm, and the saturation magnetization was 0.23 emu/g. After oxidized by sodium periodate of 10 mmol/L,and deoxidized by sodium hydride boron of 0.5 mol/L, SDION could connect with GFP in maximum degree,the transfection efficiency of SDION as gene carrier was about 45%, even higher than that of liposome (about 30%).

Conclusion: SDION could connect with GFP plasmid by oxidation- reduction reaction,and success to transfer GFP gene into human bladder cancer BIU-87 cells in vitro.