title: Gene silencing by gold nanoshell-mediated delivery and laser-triggered release of antisense oligonucleotide and siRNA.
abstract: RNA interference (RNAi)--using antisense DNA or RNA oligonucleotides to silence activity of a specific pathogenic gene transcript and reduce expression of the encoded protein--is very useful in dissecting genetic function and holds significant promise as a molecular therapeutic. A major obstacle in achieving gene silencing with RNAi technology is the systemic delivery of therapeutic oligonucleotides. Here we demonstrate an engineered gold nanoshell (NS)-based therapeutic oligonucleotide delivery vehicle, designed to release its cargo on demand upon illumination with a near-infrared (NIR) laser. A poly-L-lysine peptide (PLL) epilayer covalently attached to the NS surface (NS-PLL) is used to capture intact, single-stranded antisense DNA oligonucleotides, or alternatively, double-stranded short-interfering RNA (siRNA) molecules. Controlled release of the captured therapeutic oligonucleotides in each case is accomplished by continuous wave NIR laser irradiation at 800 nm, near the resonance wavelength of the nanoshell. Fluorescently tagged oligonucleotides were used to monitor the time-dependent release process and light-triggered endosomal release. A green fluorescent protein (GFP)-expressing human lung cancer H1299 cell line was used to determine cellular uptake and gene silencing mediated by the NS-PLL carrying GFP gene-specific single-stranded DNA antisense oligonucleotide (AON-GFP), or a double-stranded siRNA (siRNA-GFP), in vitro. Light-triggered delivery resulted in ~47% and ~49% downregulation of the targeted GFP expression by AON-GFP and siRNA-GFP, respectively. Cytotoxicity induced by both the NS-PLL delivery vector and by laser irradiation is minimal, as demonstrated by a XTT cell proliferation assay.
authors.affiliation: Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States.
authors.forename: Ryan
authors.initials: R
authors.lastname: Huschka
authors.forename: Aoune
authors.initials: A
authors.lastname: Barhoumi
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.forename: Jack A
authors.initials: JA
authors.lastname: Roth
authors.forename: Lin
authors.initials: L
authors.lastname: Ji
authors.forename: Naomi J
authors.initials: NJ
authors.lastname: Halas
mesh_terms: D045744:Cell Line, Tumor; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000138:chemical synthesis; D020868:Gene Silencing / Q000528:radiation effects*; D006046:Gold / Q000737:chemistry; D006801:Humans; D007834:Lasers; D008175:Lung Neoplasms / Q000235:genetics* / Q000378:metabolism; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry; D053769:Nanocapsules / Q000737:chemistry* / Q000648:ultrastructure*; D020319:Oligodeoxyribonucleotides, Antisense / Q000008:administration & dosage / Q000235:genetics* / Q000493:pharmacokinetics; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000235:genetics* / Q000493:pharmacokinetics; D014162:Transfection / Q000379:methods
chemical_list: D003692:Delayed-Action Preparations; D053769:Nanocapsules; D020319:Oligodeoxyribonucleotides, Antisense; D034741:RNA, Small Interfering; D006046:Gold