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Search for "gold Nanoparticles" in Full Text gives 224 result(s) in Beilstein Journal of Nanotechnology. Showing first 200.
Mammalian cell growth on gold nanoparticle-decorated substrates is influenced by the nanoparticle coating
Beilstein J. Nanotechnol. 2014, 5, 2479–2488, doi:10.3762/bjnano.5.257
- ; gold; nanoparticles; Introduction Over the last decade, the biomedical applications for gold nanoparticles have become increasingly diverse due to their small size and plasmonic nature [1]. The plasmon resonance wavelength of the nanoparticle, which exhibits strong light scattering and absorption, can
- be controlled by synthesis conditions [2] in order to match the “optical window” of biological tissue in the wavelength region of 650–900 nm [3]. Therefore, gold nanoparticles can be used, for example, as biosensors [4][5], as delivery systems [6][7], as contrast agents in imaging [8][9], and as
- special functionality), this study is focused on the impact of basolateral exposure of gold nanoparticles on epithelial cells. Here, epithelial cells were exposed to nanoparticles adsorbed onto a surface. Since MDCK II cells exhibit caveolae only basolaterally, it is conceivable that internalization is
Interaction of dermatologically relevant nanoparticles with skin cells and skin
Beilstein J. Nanotechnol. 2014, 5, 2363–2373, doi:10.3762/bjnano.5.245
- in vivo over time [12]. On the other hand, hair follicles were found to be excretion pathways for injected gold nanoparticles [15]. Raman microscopy is another technique with high spatial resolution which permits such studies. While we gathered first own results on skin with the in vivo detection of
Inorganic Janus particles for biomedical applications
Beilstein J. Nanotechnol. 2014, 5, 2346–2362, doi:10.3762/bjnano.5.244
- the control over the size was much more precise performing a synthesis of hydrophobic gold nanoparticles using tert-butylamine borane complex as reducing agent [74]. The size of the oleylamine-capped particles is varied between 2 and 8 nm by changing the reaction temperature or in a subsequent growth
- ], the gold nanoparticles were functionalized with 1-octadecanethiol to suppress multiple nucleation of manganese oxide on different crystal facets or surface defects. This surface functionalization was proved not to be necessary for Au@Fe3O4 heterodimers. The morphology as well as the sizes of the metal
- . attributed this broadening and damping to the tunnelling of conduction band electrons of the Au nanoparticles into the projected density of states of the Fe3O4 domains, the so-called “interface decay channel” [56]. As a metal oxide starts to nucleate heterogeneously on the gold nanoparticles, the induced
Liquid-phase exfoliated graphene: functionalization, characterization, and applications
Beilstein J. Nanotechnol. 2014, 5, 2328–2338, doi:10.3762/bjnano.5.242
- to pure DMF. In this process, carbon nanofibers (CNFs) are formed revealing the occurrence of chemical reactions. During the ultrasonication process, graphene sheets were cut close to the edges, producing small fragments which later aggregate into CNFs. To verify the mechanism of CNF formation, gold
- nanoparticles (Au NPs) were introduced as contrast markers. Tiopronin and its fragments are well-known stabilizers for Au NPs. The analysis by transmission electron microscopy (TEM) showed Au NPs mostly resided on the nanofibers, thus supporting the proposed mechanism as shown in Figure 2. This methodology
Localized surface plasmon resonances in nanostructures to enhance nonlinear vibrational spectroscopies: towards an astonishing molecular sensitivity
Beilstein J. Nanotechnol. 2014, 5, 2275–2292, doi:10.3762/bjnano.5.237
- observed and correspond to the nonlinear wave mixing: SFG, SHG (second harmonic generation) and CARS signals. Interestingly, coupling nano-objects, i.e., tuning the distance between gold nanoparticles until they get in contact [60], shifts the frequency of the LSPR. For an optimal distance, i.e., when LSPR
- signature of thiophenol-functionalized gold nanoparticles (17 nm of diameter) grafted on flat silicon could be detected at a surface coverage as low as about 1% [70][71]. The SFG spectra displayed a single mode corresponding to the CH groups of the aromatic core of thiophenol at 3055 cm−1 (Figure 6). The Au
- was studied by Tourillon et al. [74], for which the SFG spectroscopy was performed on a dense gold nanoparticles monolayer (11 nm) on a quartz prism surface. The interface was probed in the total internal reflection (TIR) configuration, in ppp polarization, with the visible frequency matching the LSPR
Influence of stabilising agents and pH on the size of SnO2 nanoparticles
Beilstein J. Nanotechnol. 2014, 5, 2192–2201, doi:10.3762/bjnano.5.228
- stabilising agents significantly affect the size, shape and surface properties of nanomaterials synthesised in their presence [18]. In 1718, Helcher applied a natural polymer (starch) to stabilise gold nanoparticles [19]. Today, synthetic polymers are commonly used to stabilise different types of
Properties of plasmonic arrays produced by pulsed-laser nanostructuring of thin Au films
Beilstein J. Nanotechnol. 2014, 5, 2102–2112, doi:10.3762/bjnano.5.219
- theory with the temperature gradients both lateral and normal to the film surface taken into account [8][9][10]. The gold nanoparticles produced from thin Au films on Si and indium tin oxide (ITO) substrates using a 532 nm laser operated in a single-pulse regime were studied in detail by Ruffino et al
Effect of silver nanoparticles on human mesenchymal stem cell differentiation
Beilstein J. Nanotechnol. 2014, 5, 2058–2069, doi:10.3762/bjnano.5.214
- within the endo-lysosomes after 24 h. Fröhlich et al. [36] have reported that access to other organelles depends on the particle size. Similarly, as suggested by Berry et al., the uptake of nanoparticles is constrained by the dimensions of the nuclear pore because gold nanoparticles (Au-NP) with a size
- was impaired at subtoxic concentrations of Ag-NP and Ag+ ions, whereas chondrogenic differentiation was not influenced by the presence of silver. Similar results were observed by Fan et al. when using gold nanoparticles [46]. These nanoparticles, with a size of 30 nm, led to decreases in the
PVP-coated, negatively charged silver nanoparticles: A multi-center study of their physicochemical characteristics, cell culture and in vivo experiments
Beilstein J. Nanotechnol. 2014, 5, 1944–1965, doi:10.3762/bjnano.5.205
- ]. Specifically, we have addressed the effect of a PVP coating around the metallic surface of silver and, for comparison, gold nanoparticles, on the adsorption/desorption equilibrium of serum albumin molecules – an established model protein [57][59][60][61][62]. To quantify this equilibrium, we have used circular
- containing PVP-coated silver nanoparticles at various concentrations as well as the corresponding analytical plot. Equilibrium constants for the adsorption of albumin to silver and gold nanoparticles with and without a PVP coating were determined, revealing the influence of the polymer coating on the ability
- localization of silver in the perinuclear region was observed (Figure 5A). In none of the investigated cells an indication for uptake into the nucleus was found, which is in agreement with a quantitative TEM analysis of citrate- or polyethylene glycol (PEG)-stabilized gold nanoparticles, in which no particles
Towards bottom-up nanopatterning of Prussian blue analogues
Beilstein J. Nanotechnol. 2014, 5, 1933–1943, doi:10.3762/bjnano.5.204
- deposition, whatever the deposition time, the silicon substrate is completely and homogeneously covered by gold nanoparticles (as expected for sputtering deposition). But, the size of the particles depends on the deposition time. The gold layers obtained with 30 s, 60 s and 150 s deposition time are composed
- of gold nanoparticles of 10 nm, 15 nm and 40 nm in diameter, respectively. The roughness is 0.27 nm for the silicon substrate, 0.44 nm for the 10 nm thick gold layer, 0.48 nm for the 20 nm thick gold layer and 1.01 nm for the 50 nm thick one. After the gold deposition, the surfaces exhibit a small
High speed e-beam lithography for gold nanoarray fabrication and use in nanotechnology
Beilstein J. Nanotechnol. 2014, 5, 1918–1925, doi:10.3762/bjnano.5.202
- ) is used as a top electrode and the gold nanocrystals act as bottom electrodes. Within a single CAFM image it is possible to get statistics on thousands of molecular junctions which allowed us, in particular, to evidence the presence of 2 phases of organization on alkyl-thiolated gold nanoparticles
- application, chemical characterization of self-assembled monolayer coated gold nanoparticles is of prime importance, but it could not be achieved in [4][8] because a 1 cm2 nanoarray is required for comfortable XPS analysis. Whereas it would have required almost one full week of writing, we have written such
- contrast provided by the 8 nm thick gold nanoparticles, these arrays are indicated by pink squares. a) Plot of the estimated writing times per gold nanoarray area for each of the four different methods using an e-beam current of 10 nA and a pitch of 100 nm. Black points correspond to measured values. The
In vitro and in vivo interactions of selected nanoparticles with rodent serum proteins and their consequences in biokinetics
Beilstein J. Nanotechnol. 2014, 5, 1699–1711, doi:10.3762/bjnano.5.180
- dynamical change during AuNP translocation in fluids and across membranes within the organism. Keywords: biokinetics; gold nanoparticles; protein corona; protein–nanoparticle conjugate; serum protein binding; surface modification; Introduction Like any foreign material that enters into the organism
The influence of molecular mobility on the properties of networks of gold nanoparticles and organic ligands
Beilstein J. Nanotechnol. 2014, 5, 1664–1674, doi:10.3762/bjnano.5.177
- UMR 7504, 23 Rue du Loess, 67034 Strasbourg, France 10.3762/bjnano.5.177 Abstract We prepare and investigate two-dimensional (2D) single-layer arrays and multilayered networks of gold nanoparticles derivatized with conjugated hetero-aromatic molecules, i.e., S-(4-{[2,6-bipyrazol-1-yl)pyrid-4-yl
- gold nanoparticles through Au–S bonds is found, with no evidence for the formation of N–Au bonds between the pyridine or pyrazole groups of BPP and the gold surface. Subtle, but significant shifts with temperature of specific Raman S-BPP modes are also observed. We attribute these to dynamic changes in
- that dynamic changes in the molecular layers effectively lower the molecular tunnel barrier for BPP-based arrays at higher temperatures. Keywords: aromatic capping ligands; gold nanoparticles; molecular charge transport; self-assembly; surface enhanced Raman spectroscopy; Introduction Inspired by
Silica nanoparticles are less toxic to human lung cells when deposited at the air–liquid interface compared to conventional submerged exposure
Beilstein J. Nanotechnol. 2014, 5, 1590–1602, doi:10.3762/bjnano.5.171
- and the concentrations of particles to induce the lowest observed effect levels were reduced [38]. Moreover, gold nanoparticles were deposited with the previous system but, in contrast to some other submerged studies, did not induce adverse effects [39]. Also a mono-culture of bronchial 16HBE14o cells
Current state of laser synthesis of metal and alloy nanoparticles as ligand-free reference materials for nano-toxicological assays
Beilstein J. Nanotechnol. 2014, 5, 1523–1541, doi:10.3762/bjnano.5.165
- -generated nanoparticles without artificial ligands In order to review nanoparticle size control strategies, gold nanoparticles were chosen as they are an excellent reference material for toxicological studies. Due to their exceptionally high stability concerning surface oxidation, gold nanoparticles do not
- release ions under physiological conditions. Hence, in contrast to gold atom clusters [33], gold nanoparticles are known to have a comparably low toxicity [34][35]. Hence, all adverse effects probably originate from the nanoscopic dimensions of the material, e.g., causing the formation of reactive oxygen
- species [33][36], and cannot originate from the material itself, like the ion release from nanoparticles composed of less noble materials. The fabrication of gold nanoparticles by PLAL has been extensively examined in numerous studies, while ablation may be performed in aqueous media [37][38][39] as well
A sonochemical approach to the direct surface functionalization of superparamagnetic iron oxide nanoparticles with (3-aminopropyl)triethoxysilane
Beilstein J. Nanotechnol. 2014, 5, 1472–1476, doi:10.3762/bjnano.5.160
- used as linker in the synthesis of composite or hybrid nanoparticles consisting of SPION and other inorganic materials such as gold nanoparticles [5][6]. More importantly, for targeting and delivery purposes the functional amine moiety can further be modified with other functional groups, such as
Protein-coated pH-responsive gold nanoparticles: Microwave-assisted synthesis and surface charge-dependent anticancer activity
Beilstein J. Nanotechnol. 2014, 5, 1452–1462, doi:10.3762/bjnano.5.158
- ), Gwangju 500-712, South Korea Institute of Medical System Engineering, Gwangju Institute of Science & Technology (GIST), Gwangju 500-712, South Korea 10.3762/bjnano.5.158 Abstract The biocompatibility and ease of functionalization of gold nanoparticles underlie significant potential in biotechnology and
- biomedicine. Eight different proteins were examined in the preparation of gold nanoparticles (AuNPs) in aqueous medium under microwave irradiation. Six of the proteins resulted in the formation of AuNPs. The intrinsic pH of the proteins played an important role in AuNPs with strong surface plasmon bands. The
- AuNPs are internalized by the cells to a greater level than the negatively charged AuNPs. These AuNPs synthesized with protein coating holds promise as anticancer agents and would help in providing a new paradigm in area of nanoparticles. Keywords: anticancer; cytotoxicity; gold Nanoparticles; pH
Near-field photochemical and radiation-induced chemical fabrication of nanopatterns of a self-assembled silane monolayer
Beilstein J. Nanotechnol. 2014, 5, 1441–1449, doi:10.3762/bjnano.5.156
- ], self-assembled block-copolymer structures [17], block-copolymer micelle nanolithography [18] as well as polymer blend lithography [19]. Moreover, gold nanoparticles with functional groups have been arranged in many different approaches to form chemical nanopatterns [14]. With parallel lithographic
- nanoparticles, which was performed to increase the topographical contrast for detection by means of AFM. By binding 1.4 nm negatively charged gold nanoparticles to the positively charged APTES SAM nanopattern it could be demonstrated that the pattern transfer was successful even for 0.22 µm masks (Figure 3c
- the order of 200 nm. Alternatively, a UV–ozone treatment is applied in process 3. After removal of the gold mask, the resulting APTES SAM nanopattern is decorated by binding of negatively charged gold nanoparticles or fluorescent molecules to the amino groups of APTES. The results of nanopatterns
Purification of ethanol for highly sensitive self-assembly experiments
Beilstein J. Nanotechnol. 2014, 5, 1254–1260, doi:10.3762/bjnano.5.139
- with the desired thiolates for surface sites. Here we present that gold nanoparticles deposited onto zeolite X can be used to remove these contaminants by chemisorption. This nanoparticle-impregnated zeolite does not only show high capacities for surface-active contaminants, such as thiols, but can be
- fully regenerated via a simple pyrolysis protocol. Keywords: ethanol; gold nanoparticles; purification; self-assembled monolayers; solvent; Introduction Thirty years after their introduction [1][2][3], self-assembled monolayers (SAMs) of organothiolates have matured to an established tool for surface
- using copper, presumably due to slight differences in the reactivity of gold and copper towards these compounds. We therefore decided to use gold nanoparticles (NPs), which have a very high surface/weight ratio, to obtain purified ethanol. For this, the NPs were immobilized onto an inert, porous support
Model systems for studying cell adhesion and biomimetic actin networks
Beilstein J. Nanotechnol. 2014, 5, 1193–1202, doi:10.3762/bjnano.5.131
- increased by the presence of divalent ions such as manganese or calcium [16]. Cellular adhesion strength is mostly controlled by the intermolecular spacing of the adhesion receptors rather than by their density [17]. This result was obtained from different studies using highly ordered gold nanoparticles
- , which were functionalised with RGD peptides. The adhesive gold nanoparticles had a diameter below 8 nm, which allowed the binding of one integrin molecule per RGD-functionalised nanoparticle [18]. If the distance between adjacent integrin-binding gold nanoparticles was less than 70 nm, cell adhesion was
Integration of ZnO and CuO nanowires into a thermoelectric module
Beilstein J. Nanotechnol. 2014, 5, 927–936, doi:10.3762/bjnano.5.106
- dried with synthetic air. Gold nanoparticles have been deposited by RF magnetron sputtering (70 W Ar plasma for 5 s at room temperature, pressure 5 × 10−3 mbar) on the substrate, as they will act as catalyst for the nanowire growth. This technique was very easy and straightforward to use and allowed a
- , it is possible to use focused ion beam (FIB) lithography to deposit actively each gold nanoparticles, but it is very time consuming and there is no demonstration of improved performances of the device. The ability to control the size and dispersion of the catalyst is a key parameter to control both
Gas sensing with gold-decorated vertically aligned carbon nanotubes
Beilstein J. Nanotechnol. 2014, 5, 910–918, doi:10.3762/bjnano.5.104
- decorated with gold nanoparticles were investigated as gas sensitive materials for detecting nitrogen dioxide (NO2) at room temperature. Gold nanoparticles of about 6 nm in diameter were sputtered on the top surface of the carbon nanotube forests to enhance the sensitivity to the pollutant gas. We showed
- corners and edges of particles, particularly abundant on the nanometer-sized particles [19][20]. Accordingly, the loading of gold nanoparticles has been reported to strongly influence CNT sensor sensitivity [17][21][22]. In this work we study the influence of the length of aligned CNTs decorated with gold
- particles in the gas sensing applications. We investigated the sensing response of VA-CNTs with different lengths (150, 300 and 500 µm), decorated with gold nanoparticles, to a NO2 atmosphere at room temperature. Moreover, the effect of humidity from dry to 50% R.H. on the gas sensing was also studied. The
Nanostructure sensitization of transition metal oxides for visible-light photocatalysis
Beilstein J. Nanotechnol. 2014, 5, 696–710, doi:10.3762/bjnano.5.82
- loaded with gold and silver nanoparticles exhibited anodic photocurrents in response to visible light irradiation [75]. Based on this finding, they proposed a charge transfer mechanism to explain the phenomenon. More specifically, due to the plasmon resonance effect, gold nanoparticles can be
- photoexcited to generate hot electrons, which are injected from the surface of the gold nanoparticles to the CB of TiO2. Meanwhile, the compensative electrons can be transferred from a certain type of donor in the solution to the gold nanoparticles [76]. The proposed charge transfer mechanism is shown in
- spectra between transition metal oxides and gold nanoparticles. Due to N-doping and N- and F-impurities generated in the anodization process, the N-doped TiO2 nanoparticles and TiO2 nanotubes have absorption spectra in the visible range and show an overlap with that of gold nanoparticles. Therefore, when
Injection of ligand-free gold and silver nanoparticles into murine embryos does not impact pre-implantation development
Beilstein J. Nanotechnol. 2014, 5, 677–688, doi:10.3762/bjnano.5.80
- control groups (gold nanoparticles: 67.3%, silver nanoparticles: 61.5%, sham: 66.2%, handling control: 79.4%). Real-time PCR analysis of six developmentally important genes (BAX, BCL2L2, TP53, OCT4, NANOG, DNMT3A) did not reveal an influence on gene expression in blastocysts. Contrary to silver
- ][40][41]. However, while AgNP remained embryotoxic even up to a size of 100 nm albeit in higher concentrations [13][40], AuNP only appear to be toxic if they are <2 nm [15][41], a size range at which gold nanoparticles consist of atom clusters. In this work, AuNP and AgNP were chosen for testing. AuNP
- on embryos [49]. However, the injection into 2-cell-stage embryos allows for an internal control. This provides the opportunity to also detect sublethal effects, for instance, the interference with cell division mechanisms, a toxic effect already documented for gold nanoparticles [50]. There are
In vitro toxicity and bioimaging studies of gold nanorods formulations coated with biofunctional thiol-PEG molecules and Pluronic block copolymers
Beilstein J. Nanotechnol. 2014, 5, 546–553, doi:10.3762/bjnano.5.64
- gold nanoparticles formulation will be affected and this may impact their applications in sensing, imaging and targeted delivery. Thus, it is essential for the nanoparticle community to understand the effects of functionalizing PEG-SH or PEO–PPO–PEO molecules on the AuNRs surface and their
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