Enhanced Gene Delivery and siRNA Silencing by Gold Nanoparticles Coated with Charge-Reversal Polyelectrolyte

Abstract

Charge-reversal functional gold nanoparticles first prepared by layer-by-layer technique were employed to deliver small interfering RNA (siRNA) and plasmid DNA into cancer cells. Polyacrylamide gel electrophoresis measurements of siRNA confirmed the occurrence of the charge-reversal property of functional gold nanoparticles. The expression efficiency of enhanced green fluorescent protein (EGFP) was improved by adjuvant transfection with charge-reversal functional gold nanoparticles, which also had much lower toxicity to cell proliferation. Lamin A/ C, an important nuclear envelope protein, was effectively silenced by lamin A/C-siRNA delivered by charge-reversal functional gold nanoparticles, whose knockdown efficiency was better than that of commercial Lipofectamine 2000. Confocal laser scanning microscopic images indicated that there was more cy5-siRNA distributed throughout the cytoplasm for cyanine 5-siRNA/ polyethyleneimine/cis-aconitic anhydride-functionalized poly(allylamine)/polyethyleneimine/11-mercaptoundecanoic acid-gold nanoparticle (cy5-siRNA/PEI/PAH-Cit/PEI/MUA-AuNP) complexes. These results demonstrate the feasibility of using charge-reversal functional gold nanoparticles as a means of improving the nucleic acid delivery efficiency.Keywords gold nanoparticles; charge-reversal polyelectrolyte; drug delivery; layer-by-layer assembly; siRNA delivery Over the past decade, due to good biocompatibility, easy synthesis, monodispersity, and ready functionalization, gold nanoparticles have emerged as an attractive candidate for delivery of various payloads into cells, such as small drug molecules or large biomolecules, 1-5 such as DNA and siRNA. [6][7][8][9][10][11][12][13] The intracellular release could be triggered by glutathione (GSH), 3 pH, or external (e.g., light) stimuli. 1,4,[14][15][16][17] siRNA has emerged recently as a promising method for biological research and holds great potential for treatment of human * Address correspondence to liangxj@nanoctr.cn. ⊥ These authors contributed equally to this work. Supporting Information Available:Preparation process of charge-reversal polyelectrolyte-coated gold nanoparticles using layer-bylayer technique; TEM images of colloidal AuNPs after the coating steps; fluorescence microscope image of 293T cells transfected with DNA/PEI/PAH-Cit/PEI/MUA-AuNP complexes; and cell viability of HeLa cells treated with PEI/PAH-Cit/PEI/MUA-AuNPs and nucleic acid complexes by MTT assay. This material is available free of charge via the Internet at http://pubs.acs.org. [18][19][20] Nucleic acid was mostly loaded by gold nanoparticles through thiol linkages or electrostatic interaction with cationic gold nanoparticles. [6][7][8][9][10][11][12][13]21,22 Elbakry et al. first developed the PEI/siRNA/PEI-AuNP system to deliver siRNA into cells and knockdown the expression of target gene based on the self-assembly layer-by-layer technology. 11 PEI, which has strong escape capacity from the endosome due to its so-called "proton sponge" effect and is usually a gold standa...

15 years on siRNA delivery: Beyond the State-of-the-Art on inorganic nanoparticles for RNAi therapeutics

“…Copyright 2015, Nature Publishing Group. [29,[44][45][46]. However, almost all nanoconjugates using siRNA have exclusively been tested in cell cultures and targeting only reporter genes (i.e.…”

“…Lately, a new kind of polymer named "chargereversal" has appeared, whose main property is the ability to change their charge as a function of pH, being positive at neutral pH and negative in acidic conditions. One of the best examples is PAH-Cit, which is also effective in reducing the possible cytotoxicity induced by highly positive species [29,108,109].…”

“…Many examples of silencing have used luciferase activity as an indicator of success [25,29,38,45,46].…”

Multifunctional Gold Nanocarriers for Cancer Theranostics: From Bench to Bedside and Back Again?

“…Several other studies using engineered NPs modified with siRNA have demonstrated a cytoplasmic delivery system of siRNA and efficient gene silencing using AuNPs (Giljohann et al, 2009;Lee et al, 2009;Guo et al, 2010;Lee et al, 2008). However, almost all nanoconjugates using siRNA have exclusively been tested in cell cultures targeting only reporter genes.…”

Multimodal Magnetic Core–Shell Nanoparticles for Effective Stem‐Cell Differentiation and Imaging

“…[14] These non-water-soluble ZnFe 2 O 4 @Au nanoparticles were then rendered water-soluble by exchanging their surface oleylamine moieties with 11-mercaptoundecanoic acid (MUA). [15] Initial characterization was performed to confirm that the water-soluble MCNPs ( Figure 1A) retained their magnetic properties ( Figure 2D) and showed a distinct pink coloration, which resembles a gold colloidal solution ( Figure 2E), due to the surface plasmon resonance (SPR) properties of the outer Au shell.…”