磁性白蛋白纳米球作为基因载体的研究

目的 制备载基因的磁性白蛋白纳米球，评估磁性白蛋白纳米球作为基因载体的可行性及体外的磁靶向性。方法 采用去溶剂化-交联法制备载基因磁性白蛋白纳米球，分别运用透射电镜（TEM）、动态光散射分析（DLS）对其形态、粒径进行表征。应用绿色荧光蛋白基因系统（pGFP），观察载基因磁性白蛋白纳米球体外释放基因速率的情况及转染细胞的情况。运用普鲁士蓝染色法观察磁性纳米球的体外磁靶向性。结果 载基因磁性纳米球在TEM检测下为球形，大小均匀，并且在载基因磁性纳米球中明显地观察到在电子密度较低的白蛋白纳米球中包裹着电子密度较高的磁性纳米粒。DLS显示载基因免疫磁性纳米球的水合粒径约为209nm。体外动态释放基因速率，计算其累积释放率显示，该材料13h释放基因为95.25%，曲线平缓；转染实验结果显示载基因磁性纳米球能够有效转染SMMC-7721细胞，且转染效率高于载基因纳米球。普鲁士蓝染色实验结果显示磁靶向组细胞内的铁颗粒明显多于非靶向组。结论 成功制备了载基因磁性白蛋白纳米球，具有缓释基因的作用，并且能高效转染人肝癌细胞SMMC-7721。磁性白蛋白纳米球基因载体具有体外靶向性，有望作为一种潜在的靶向基因载体应用到生物医学领域。

Research of Magnetic Albumin Nanoparticles as Gene Vector

Objective To study the preparation of gene-loaded magnetic albumin nanospheres, to evaluate the feasibility of magnetic albumin nanoparticles as gene vector and its magnetic targeting in vitro.Methods Gene-loaded magnetic albumin nanospheres were prepared by desolvation-crosslinking method. TEM and DLS were used to characterize the shape and particle size of the nanospheres. Plasmid release rate in vitro was dynamically evaluated. The transfection efficiency of gene-loaded magnetic albumin nanospheres was observed by using it transfect the SMMC-7721 cells. We observed the magnetic targeting of the magnetic albumin nanospheres through prussian blue staining.Results TEM analysis showed that gene-loaded magnetic albumin nanospheres were approximately spherical and uniform in size. It was clearly demonstrated that the magnetite materials with high electron density were well-incorporated in the core of albumin nanospheres. DLS showed the hydrated particle size of the gene-loaded magnetic albumin nanospheres was about 209nm. The nanospheres cumulative release rate was 95.25% by calculating dynamic release rate of thirteen hours in vitro and the curve was flat. The gene-loaded magnetic albumin nanospheres can carry the plasmid to SMMC-7721 cells and its transfection efficiency was higher than the gene-loaded albumin nanospheres. Prussian blue staining demonstrated that after the magnetic targeting group incubated with SMMC-7721 cells, more blue-stained iron particles were observed in the cells than in the cells of the non-targeting group.Conclusion Gene-loaded magnetic albumin nanospheres were prepared successfully, the gene-loaded magnetic albumin nanospheres can transfect SMMC-7721 cells with high efficiency and slowly release the plasmid. The gene vector have magnetic targeting and could be a promising targeting gene vector supplied in biomedicine field.