Enhanced siRNA Delivery and Silencing Gold鈥揅hitosan Nanosystem with Surface Charge-Reversal Polymer Assembly and Good Biocompatibility
详细信息 查看全文
- 作者：Lu Han ; Jing Zhao ; Xu Zhang ; Weipeng Cao ; Xixue Hu ; Guozhang Zou ; Xianglin Duan ; Xing-Jie Liang
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：August 28, 2012
- 年：2012
- 卷：6
- 期：8
- 页码：7340-7351
- 全文大小：854K
- 年卷期：v.6,no.8(August 28, 2012)
- ISSN：1936-086X
文摘
A simple nanocarrier coated with chitosan and the pH-responsive charge-reversible polymer, PAH-Cit, was constructed using layer-by-layer assembly to deliver siRNA. Gold nanoparticles (AuNPs) were di-rectly reduced and stabilized by chitosan (CS), forming a positively charged AuNP-CS core. Charge-reversible PAH-Cit and polyethylenimine (PEI) were sequentially deposited onto the surface of AuNP-CS through electrostatic interaction, forming a PEI/PAH-Cit/AuNP-CS shell/core structure. After loading siRNA, the cytotoxicity of siRNA/PEI/PAH-Cit/AuNP-CS against HeLa and MCF-7R cells was negligible. This vehicle completely protected siRNA against enzymatic degradation at vector/RNA mass ratios of 2.5:1 and above. An in vitro release profile demonstrated an efficient siRNA release (79%) from siRNA/PEI/PAH-Cit/AuNP-CS at pH 5.5, suggesting a pH-induced charge-reversing action of PAH-Cit. This mechanism also worked in vivo and facilitated the escape of siRNA from endosomes. Using this carrier, the uptake of cy5-siRNA by HeLa cells was significantly increased compared to PEI, an efficient polycationic transfection reagent. In drug-resistant MCF-7 cells, specific gene silencing effectively reduced expression of MDR1, the gene encoding the drug exporter P-gp, and consequently promoted the uptake of doxorubicin. This simple charge-reversal polymer assembly nanosystem has three essential benefits (protection, efficient uptake, and facilitated escape) and provides a safe strategy with good biocompatibility for enhanced siRNA delivery and silencing.