title: Enhanced siRNA delivery and silencing gold-chitosan nanosystem with surface charge-reversal polymer assembly and good biocompatibility.
abstract: 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.
authors: CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China.
authors: Lu
authors: L
authors: Han
authors: Jing
authors: J
authors: Zhao
authors: Xu
authors: X
authors: Zhang
authors: Weipeng
authors: W
authors: Cao
authors: Xixue
authors: X
authors: Hu
authors: Guozhang
authors: G
authors: Zou
authors: Xianglin
authors: X
authors: Duan
authors: Xing-Jie
authors: XJ
authors: Liang
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis; D048271:Chitosan / Q000737:chemistry*; D020868:Gene Silencing; D018014:Gene Transfer Techniques; D006046:Gold / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D061986:MCF-7 Cells; D008422:Materials Testing; D053769:Nanocapsules / Q000737:chemistry* / Q000648:ultrastructure; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000737:chemistry*; D055672:Static Electricity
chemical_list: D001672:Biocompatible Materials; D053769:Nanocapsules; D034741:RNA, Small Interfering; D006046:Gold; D048271:Chitosan