低分子量聚乙烯亚胺/金纳米棒纳米载体的制备及毒性研究

Synthesization and Toxicity of Low-molecular-weight PEI/Gold Nanords Nanosystem

以表面修饰巯基十一烷酸的金纳米棒(GNRs/MUA)为骨架,将低分子量的聚乙烯亚胺(PEI)连接到GNRs/MUA表面,构建GNRs/MUA/PEI纳米载体。首先采用MUA对GNRs进行表面修饰,减少由于GNRs表面的十六烷基三甲基溴化铵(CTAB)所造成的生物毒性。然后采用低分子量PEI进一步修饰,同时利用GNRs巨大的比表面积进一步放大PEI的携带基因能力,这样既能够降低阳离子聚合物的毒性,又能够提高整个体系的转染效率。利用透射电子显微镜(TEM)、紫外可见吸收光谱(UV-Vis)、Zeta电位等对纳米载体进行了表征。结果显示,MUA与PEI已成功修饰到GNRs表面,并很好地保留了GNRs的光学性质,其表面电位发生正负交替变化。采用噻唑蓝(MTT)比色法对纳米载体进行细胞毒性研究,结果显示GNRs/MUA/PEI(1.8 k Da)非病毒纳米载体,细胞存活率在控制聚合物浓度为300μg/m L时仍然稳定在75%以上,明显高于商品化的PEI(25 k Da)。

Based on the gold nanorods modified by 11-mercaptopropanic acid ( MUA) as the skele-ton, the low molecular weight polyethylenimine PEI was conjugated to the surface of GNRs/MUA to form GNRs/MUA/PEI nanocomplexes. Firstly, surface modification of gold nanorods was carried out by using MUA to reduce the toxicity of gold nanorods caused by CTAB surfactants, and then further modified by low molecular weight PEI. The large surface area of gold nanorods allows them to carry more genes, which can simultaneously reduce the toxicity of cationic polymer and improve the trans-fection efficiency of the whole system. GNRs/MUA/PEI were characterized by transmission electron microscopy ( TEM) , UV-Vis absorption spectra, and Zeta potential. The results show that MUA and PEI are conjugated to GNRs successfully which cause charge reversal on the surface of GNRs, and the optical properties of GNRs are well preserved. In vitro cytotoxic effects of GNRs/MUA/PEI (1. 8 kDa) are quantified by MTT assay, and the results suggest that the cell viability is above 75%at the concentration of 300 μg/mL, much higher than the commercialized PEI(25 kDa) .