Controlled Formation of Smaller Gold Nanoparticles by the Use of Four-Chained Disulfide Stabilizer

Yonezawa, Tetsu; Yasui, Kanji; Kimizuka, Nobuo

doi:10.1021/la001247c

Cited by 142 publications

(97 citation statements)

References 29 publications

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“…To identify the optimal conjugates in terms of transfection efficiency, they were prepared at three different PEI2͞Au molar ratios. The resultant ratios in the purified conjugates were proportional to the initial ones (see Experimental Procedures), as observed with other ligands (41,42). All the conjugates exhibited the plasmon band of GNPs with max Ϸ 500 nm (Fig.…”

Section: Resultssupporting

confidence: 66%

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Conjugation to gold nanoparticles enhances polyethylenimine's transfer of plasmid DNA into mammalian cells

Thomas

Klibanov

2003

Proc. Natl. Acad. Sci. U.S.A.

521

322

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Branched polyethylenimine (PEI) chains with an average molecular mass of 2 kDa (PEI2) have been covalently attached to gold nanoparticles (GNPs), and the potency of the resulting PEI2-GNPs conjugates as vectors for the delivery of plasmid DNA into monkey kidney (COS-7) cells in the presence of serum in vitro has been systematically investigated. The transfection efficiencies vary as a function of the PEI͞gold molar ratio in the conjugates, with the best one (PEI2-GNPII) being 12 times more potent than the unmodified polycation. This potency can be further doubled by adding amphiphilic N-dodecyl-PEI2 during complex formation with DNA. The resulting ternary complexes are at least 1 order of magnitude more efficient than the 25-kDa PEI, one of the premier polycationic gene-delivery vectors. Importantly, although unmodified PEI2 transfects just 4% of the cells, PEI2-GNPII transfects 25%, and the PEI2-GNPII͞dodecyl-PEI2 ternary complex transfects 50% of the cells. The intracellular trafficking of the DNA complexes of these vectors, monitored by transmission electron microscopy, has detected the complexes in the nucleus <1 h after transfection.G ene therapy holds great promise for treating diseases ranging from inherited disorders to acquired conditions and cancer (1-4). The most common vectors (carriers) in current clinical trials are recombinant viruses, wherein the gene of interest is covalently inserted into the viral genome. Unfortunately, such severe side reactions encountered in patients as immune response and insertional mutagenesis leading to death, carcinogenesis, or germ-cell-line alterations pose serious concerns about the clinical application of viral vectors (5-7) and have prompted development of nonviral delivery systems (8-10). Unlike viral vectors, nonviral ones rely on the formation of noncovalent assemblies between DNA (a polyanion) and cationic polymers or liposomes. Vectors based on cationic polymers (polycations) are particularly attractive because of their synthetic maneuverability, allowing incorporation of multiple functional elements within the same molecule without compromising DNA-binding ability (11)(12)(13). And yet, available polycations are handicapped by their low potencies (14, 15), prompting the search for new ones with better transfection efficiencies (16)(17)(18)(19)(20). It is likely that major improvements may be brought about by elucidating the mechanism of gene delivery by those vectors already relatively competent, followed by their targeted chemical derivatization to overcome extra-and͞or intracellular barriers to nonviral gene delivery (10). For these reasons, polyethylenimine (PEI), a synthetic ''proton-sponge'' polycation (21-24) introduced for transfection a few years ago, is an ideal candidate for such a quest.The transfection efficiency and toxicity of PEI correlate strongly with its molecular mass. For example, PEI2 is some 2 orders of magnitude less efficient than its 25-kDa counterpart (PEI25) at the same concentration, presumably because of its inability to condense...

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Section: Resultssupporting

confidence: 66%

“…PEI2-GNP conjugates were synthesized by reducing hydrogen tetrachloroaurate with sodium borohydride (39)(40)(41)(42) in the presence of the thiol-modified PEI2 (Fig. 1).…”

Section: Resultsmentioning

confidence: 99%

Conjugation to gold nanoparticles enhances polyethylenimine's transfer of plasmid DNA into mammalian cells

Thomas

Klibanov

2003

Proc. Natl. Acad. Sci. U.S.A.

521

322

View full text Add to dashboard Cite

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“…6,7 However, these nanoparticles have been synthesized as small: less than 10 nm. [8][9][10] The techniques cannot be applied when larger nanoparticles are required for applications such as light-scattering experiments. 5,[11][12][13] On the other hand, several research groups have revealed that Au nanoparticles synthesized using a citrate-reduction method are strongly adsorbed onto a glass surface coated with bifunctional-organosilanes.…”

Section: Introductionmentioning

confidence: 99%

Gold Nanoparticle Monolayer Formation on a Chemically Modified Glass Surface

2009

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Physicochemical analyses of Au nanoparticle monolayer formation on a glass surface functionalized with 3-aminopropyltrimethoxysilane (APTMS) and ethyltrimethoxysilane (ETMS) were performed for fabricating a nanoarchitecture of metal nanoparticles using self-assembly. The Au nanoparticle surface density on the functionalized glass surface correlated linearly with the optical response because of Au-nanoparticle localized surface plasmon resonance (LSPR). This relation enabled assessment of the Au nanoparticle deposition. A Frumkin isotherm showed the deposition of Au nanoparticles on the APTMS or APTMS/ETMS functionalized glass surface. For an APTMS-derivatized surface, the affinity between the Au nanoparticles and the surface decreased with the lowering of the APTMS surface coverage. The interaction parameter exhibited attractive interaction of 30-nm-diameter Au nanoparticles; 12 nm particles were repulsive. Adsorption isotherm experiments using Au nanoparticles on glass surfaces with an APTMS and ETMS mixed layer suggest that hydrophobic interaction between Au nanoparticles' bare gold surfaces caused the attractive interaction among 30-nm-diameter nanoparticles.

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“…In the analysis of the monolayers generated by the deposit of our derivatives on gold surface we considered the compounds anchored by two sulfur atoms as the literature data [34,35,36,37] suggest for disulfides. The anchorage of the compounds on the gold surface by disulfides is more efficient than the fixation on gold in the case of the compounds anchored by only one sulfur atom (e.g.…”

Section: 13mentioning

confidence: 99%

Synthesis, stereochemistry and adsorption studies of new spiranes and polyspiranes containing 1,2‐dithiolane units

Gropeanu

Tintas

Pilon

et al. 2007

Journal of Heterocyclic Chem

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S SGold Substrate where R 1 , R 2 = H, methyl, phenyl, 1-naphthyl, or R 1 -R 2 = (un)substituted cyclohexylThe synthesis and stereochemistry of a series of new cyclic disulfides containing (poly)spirane 1,2-dithiolane units are reported. Also included is a study of the self-assembled monolayers (SAMs) of these compounds on a gold surface. The characteristics of the resultant SAMs were determined by IR spectroscopy using molecular mechanics calculations.

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Controlled Formation of Smaller Gold Nanoparticles by the Use of Four-Chained Disulfide Stabilizer

Cited by 142 publications

References 29 publications

Conjugation to gold nanoparticles enhances polyethylenimine's transfer of plasmid DNA into mammalian cells

Conjugation to gold nanoparticles enhances polyethylenimine's transfer of plasmid DNA into mammalian cells

Gold Nanoparticle Monolayer Formation on a Chemically Modified Glass Surface

Synthesis, stereochemistry and adsorption studies of new spiranes and polyspiranes containing 1,2‐dithiolane units

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