Anion starch nanoparticle (StNP) with a diameter of 50 nm was prepared in wa-ter-in-oil microemulsion, with soluble starch as raw materials and POCl3 as crosslinking agent. PLL-StNP was prepared by linking poly-L-lysine (PLL) on the surface of StNP. At the same time, the size of PLL-StNP and its stability in aqueous solution were checked by AFM. The analysis of plasmid DNA binding, DNase I enzymatic degradation, toxicity and transfection were done. We discovered that PLL-StNP may be used as non-virus nanoparticle gene carrier. And we devel-oped the method of preparing PLL-StNP gene carrier and used it in cell transfection. As non-virus gene carrier, PLL-StNP has some advantages, such as large load of DNA, high transfection effi-ciency, low cell toxicity and biodegradability.

To research whether poly-L-lysine-starch nanoparticle (PLL-StNP) could protect DNA from ultrasound damage or not, a series experiments were carried out: plasmid DNA-PLL-StNP complexes were treated with ultrasound for diverse times; the electrophoresis result proved that DNA bound to the complexes all the same. To investigate whether the conjugated DNA was completely protected or not, cDNA fragments bound to PLL-StNP were treated with ultrasound, and matched molecular beacons (MBs) were added. The cDNA-MB-PLL-StNP complexes exhibited dramatically increasing fluorescence, and had the same intensity as that of those MBs that were hybridized with free cDNA fragments. After being treated by ultrasound, the pIRGFP plasmid DNA-PLL-StNP complexes were transferred into COS-7 cells mediated by ultrasound. Green fluorescence protein expressed in most of the cells. Those results indicated that PLL-StNP could completely protect DNA from ultrasound damage. Furthermore, the DNA kept the same function as untreated one.

The electrochemical behavior of breast cancer cells was studied on a graphite electrode by cyclic voltammetry (CV) and potentiometric stripping analysis (PSA). In both cases, only one oxidative peak at approximately +0.75V was observed. The peak area in PSA was used to study the growth of the cells and the effect of diosgenin on MCF-7 cells. The results showed that diosgenin can effectively inhibit the viability and proliferation of the breast cancer cells.

报道了多聚赖氨酸淀粉纳米颗粒（PLL-StNP）在超声波介导下作基因载体的研究，实验发现：DNA-PLL-StNPs 复合物经过超声波处理不同的时间后的电泳分析显示，结合的DNA受到保护，其生物学性质没有改变；将pIRGFP质粒DNA-PLL-StNPs复合物与COS 27细胞混合，在120W和40kHz的超声波强度下处理2min，细胞表达绿色荧光蛋白的比率最大，达到70%。这种基于超声波下淀粉纳米颗粒作载体的基因转导方法可被广泛应用于动物转基因技术和人类基因治疗，同样可被广泛应用于植物转基因技术。

以可溶性淀粉为原料，利用反向微乳液法，加入交联剂三氯氧磷，制备了直径为50nm左右带负电荷的交联淀粉纳米颗粒。以该纳米颗粒为内核，经多聚赖氨酸修饰，得到了多聚赖氨酸淀粉纳米颗粒（PLL-StNP）。对PLL-StNP进行了颗粒粒度、稳定性和电性的表征，并通过颗粒的体外细胞毒性检测、颗粒与DNA结合能力及细胞转染等方面的分析，发现多聚赖氨酸淀粉纳米颗粒（PLL-StNP）有可能作为基因载体，在此基础上发展了多聚赖氨酸淀粉纳米颗粒基因载体的构建与基因转染技术。作为非病毒基因载体，赖氨酸淀粉纳米颗粒具有基因装载量大、转染率高、细胞毒性低以及可生物降解等优点。