Centro Galénico, Departamento Farmacia y Tecnología Farmacéutica, University of Navarra, Irunlarrea 1, 31080 Pamplona, Spain.
J Microencapsul. 2010;27(5):460-9. doi: 10.3109/02652041003638158.
A commercially available chitosan with a degree of deacetylation (DD) of 85% and a molecular weight (Mw) of 400 kDa was modified by acetylation with acetic anhydride to obtain a chitosan with a DD of 75%. Both polysaccharides were used to prepare DNA-chitosan nanoparticles by charge interactions with pDNA (coacervation process). Both resulting nanoparticles showed an almost total DNA loading efficiency (96%) and displayed similar physico-chemical properties with a size of approximately 200 nm and a zeta potential close to +20 mV. In order to study the effect of the DD on the properties of DNA-chitosan nanoparticles as gene delivery systems, the hydrodynamics-based procedure was used. The transgene expression was observed using either the green fluorescent protein (GFP) or the luciferase (Luc) as reporter genes. After the hydrodynamic injection, the DNA-chitosan nanoparticles were accumulated in the liver, where the transgene expression was mostly localized. Interestingly, the decrease of the DD affected the transgene expression, improving the initial burst effect and accelerating the DNA release. Both combined effects led to an increase in the transgene expression levels. In addition, the emitted bioluminescence could be detected over 105 days for all the formulations injected. The calculation of the kinetic parameters (C(max), AUC, Ke, t(1/2) Ke and MET) gave some interesting information regarding the abilities to control the DNA release of the two DNA-chitosan formulations tested and allowed narrower comparisons.
一种商业可得的脱乙酰度（DD）为 85%、分子量（Mw）为 400 kDa 的壳聚糖，通过与乙酸酐的乙酰化反应进行修饰，得到 DD 为 75%的壳聚糖。这两种多糖都通过与 pDNA（凝聚过程）的电荷相互作用用于制备 DNA-壳聚糖纳米粒子。两种得到的纳米粒子都显示出几乎完全的 DNA 负载效率（96%），并且具有相似的物理化学性质，粒径约为 200nm，zeta 电位接近+20mV。为了研究 DD 对 DNA-壳聚糖纳米粒子作为基因传递系统的性质的影响，采用了基于流体动力学的程序。使用绿色荧光蛋白（GFP）或荧光素酶（Luc）作为报告基因观察转染基因的表达。在流体动力学注射后，DNA-壳聚糖纳米粒子在肝脏中积累，转染基因的表达主要定位于此处。有趣的是，DD 的降低会影响转染基因的表达，改善初始爆发效应并加速 DNA 释放。这两种结合的效应导致转染基因表达水平的增加。此外，所有注射的制剂都可以在 105 天内检测到发出的生物发光。动力学参数（C(max)、AUC、Ke、t(1/2) Ke 和 MET）的计算为测试的两种 DNA-壳聚糖制剂的 DNA 释放控制能力提供了一些有趣的信息，并允许更窄的比较。
