Laboratory of Pharmaceutical Technology, University of Liège, 1 Bld du Rectorat, Liège 4000, Belgium.
Biomaterials. 2010 Mar;31(7):1839-49. doi: 10.1016/j.biomaterials.2009.11.028. Epub 2009 Nov 30.
RNA interference-based therapies are dependent on intracellular delivery of siRNA. The release of siRNA from the endosomal compartment may be a rate limiting step in the transfection process. The purpose of this study was to produce pH-responsive nanocarriers made of trimethylchitosan (TMC). To this end, pH-sensitive methacrylic acid (MAA) copolymer was added to TMC-siRNA formulations. Four different TMCs associated or not with MAA were evaluated as siRNA carriers. Nanoparticles were characterized in terms of size, surface charge, morphology and interaction with siRNA. A swelling behaviour due to a decrease in pH was observed and was found to be dependent on MAA content in the complexes. In vitro experiments aimed at evaluating how the capacity of the nanocarriers to transfect siRNA in L929 cells was affected by MAA content. Confocal microscopy experiments showed that fluorescent MAA-containing particles exhibit a different distribution pattern inside the cells comparing to their counterpart without this pH-sensitive polymer. Transfection efficiency was investigated by RhoA mRNA expression inhibition. MAA-TMC-siRNA complexes were able to transfect L929 cells with greater efficiency than corresponding TMC-siRNA complexes. This study gives an insight into the opportunity of pH-sensitive nanocarriers for siRNA delivery. Such formulations may represent an attractive strategy to improve endosomal escape of siRNA.
RNA 干扰疗法依赖于 siRNA 的细胞内递呈。siRNA 从内体区室的释放可能是转染过程中的限速步骤。本研究的目的是制备由三甲基壳聚糖（TMC）制成的 pH 响应性纳米载体。为此，将 pH 敏感的甲基丙烯酸（MAA）共聚物添加到 TMC-siRNA 制剂中。评估了四种不同的 TMC 是否与 MAA 相关作为 siRNA 载体。从大小、表面电荷、形态和与 siRNA 的相互作用等方面对纳米颗粒进行了表征。观察到由于 pH 值降低而引起的溶胀行为，并且发现该行为取决于复合物中的 MAA 含量。体外实验旨在评估纳米载体向 L929 细胞转染 siRNA 的能力如何受到 MAA 含量的影响。共焦显微镜实验表明，与不含这种 pH 敏感聚合物的相应颗粒相比，含有荧光 MAA 的颗粒在细胞内呈现出不同的分布模式。通过 RhoA mRNA 表达抑制来研究转染效率。与相应的 TMC-siRNA 复合物相比，MAA-TMC-siRNA 复合物能够更有效地转染 L929 细胞。本研究深入了解了 pH 敏感纳米载体在 siRNA 递送上的机会。这种制剂可能代表了提高 siRNA 内体逃逸的有吸引力的策略。
