Browse
Submit Data
Databases
API
Help

Dataset Information

26 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Au@Ag Core@Shell Nanoparticles Synthesized with Rumex hymenosepalus as Antimicrobial Agent.

ABSTRACT: In this work, we used a sequential method of synthesis for gold-silver bimetallic nanoparticles with core@shell structure (Au@AgNPs). Rumex hymenosepalus root extract (Rh), which presents high content in catechins and stilbenes, was used as reductor agent in nanoparticles synthesis. Size distribution obtained by Transmission Electron Microscopy (TEM) gives a mean diameter of 36 ± 11 nm for Au@AgNPs, 24 ± 4 nm for gold nanoparticles (AuNPs), and 13 ± 3 nm for silver nanoparticles (AgNPs). The geometrical shapes of NPs were principally quasi-spherical. The thickness of the silver shell over AuNPs is around 6 nm and covered by active biomolecules onto the surface. Nanoparticles characterization included high angle annular dark field images (HAADF) recorded with a scanning transmission electron microscope (STEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-Ray Diffraction (XRD), UV-Vis Spectroscopy, Zeta Potential, and Dynamic Light Scattering (DLS). Fourier Transform Infrared Spectrometer (FTIR), and X-ray Photoelectron Spectroscopy (XPS) show that nanoparticles are stabilized by extract molecules. A growth kinetics study was performed using the Gompertz model for microorganisms exposed to nanomaterials. The results indicate that AgNPs and Au@AgNPs affect the lag phase and growth rate of Escherichia coli and Candida albicans in a dose-dependent manner, with a better response for Au@AgNPs.

SUBMITTER: Villalobos-Noriega JMA

PROVIDER: S-EPMC8298724 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Tailored Engineering of Bimetallic Plasmonic Au@Ag Core@Shell Nanoparticles.

Project description:A distinctive synthetic method for the efficient synthesis of multifunctional bimetallic plasmonic Au@Ag core@shell nanoparticles (NPs) with tunable size, morphology, and localized surface plasmon resonance (LSPR) using Triton X-100/hexanol-1/deionized water/cyclohexane-based water-in-oil (W/O) microemulsion (ME) is described. The W/O ME acted as a "true nanoreactor" for the synthesis of Au@Ag core@shell NPs by providing a confined and controlled environment and suppressing the nucleation, growth, agglomeration, and aggregation of the NPs. High-resolution transmission electron microscopic analysis of the synthesized Au@Ag core@shell NPs revealed an "unusual core@shell" contrast, and the selected area electron diffraction and Moiré patterns showed that Au layers are paralleled to Ag layers, thus indicating the formation of Au@Ag core@shell NPs. Interestingly, the UV-visible spectrum of the Au@Ag core@shell NPs exhibited enthralling plasmonic properties by introducing a high-frequency quadrupolar LSPR mode originated from the isolated Au@Ag NPs along with a low-frequency dipolar LSPR mode originated from the coupled Au@Ag NPs. The effective plasmonic enhancement of the Au@Ag core@shell NPs is attributed to the extreme enhancement of the localized electromagnetic field by coupling of the localized surface plasmons of the Au core and Ag shell. The mechanisms for the nucleation and growth of Au@Ag core@shell NPs in W/O ME have been proposed. A unique electron transfer phenomenon between the Au core and Ag shell is elucidated for better understanding and manipulation of the electronic properties, which evinced the development of Au@Ag core@shell NPs through suppression of the galvanic replacement reaction.

| S-EPMC6843713 | biostudies-literature

Core-shell Au@Pd nanoparticles with enhanced catalytic activity for oxygen reduction reaction via core-shell Au@Ag/Pd constructions.

Project description:Core-shell nanoparticles often exhibit improved catalytic properties due to the lattice strain created in these core-shell particles. Herein, we demonstrate the synthesis of core-shell Au@Pd nanoparticles from their core-shell Au@Ag/Pd parents. This strategy begins with the preparation of core-shell Au@Ag nanoparticles in an organic solvent. Then, the pure Ag shells are converted into the shells made of Ag/Pd alloy by galvanic replacement reaction between the Ag shells and Pd(2+) precursors. Subsequently, the Ag component is removed from the alloy shell using saturated NaCl solution to form core-shell Au@Pd nanoparticles with an Au core and a Pd shell. In comparison with the core-shell Au@Pd nanoparticles upon directly depositing Pd shell on the Au seeds and commercial Pd/C catalysts, the core-shell Au@Pd nanoparticles via their core-shell Au@Ag/Pd templates display superior activity and durability in catalyzing oxygen reduction reaction, mainly due to the larger lattice tensile effect in Pd shell induced by the Au core and Ag removal.

| S-EPMC4491719 | biostudies-literature

Experimental High-Resolution Observation of the Truncated Double-Icosahedron Structure: A Stable Twinned Shell in Alloyed Au-Ag Core@Shell Nanoparticles.

Project description:Given the binary nature of nanoalloy systems, their properties are dependent on their size, shape, structure, composition, and chemical ordering. When energy and entropic factors for shapes and structure variations are considered in nanoparticle growth, the spectra of shapes become so vast that even metastable arrangements have been reported under ambient conditions. Experimental and theoretical variations of multiply twinned particles have been observed, from the Ino and Marks decahedra to polyicosahedra and polydecahedra with comparable energetic stability among them. Herein, we report the experimental production of a stable doubly truncated double-icosahedron structure (TdIh) in Au-Ag nanoparticles, in which a twinned Ag-rich alloyed shell is reconstructed on a Au-Ag alloyed Ino-decahedral core. The structure, chemical composition, and growth pathway are proposed on the basis of high-angle annular dark-field scanning transmission electron microscopy analysis and excess energy calculations, while its structural stability is estimated by large-scale atomic molecular dynamics simulations. This novel nanostructure differs from other structures previously reported.

| S-EPMC11010228 | biostudies-literature

The characteristic Ag(core)Au(shell) nanoparticles as SERS substrates in detecting dopamine molecules at various pH ranges.

Project description:AgcoreAushell nanoparticles (NPs) are a promising surface-enhanced Raman scattering (SERS) substrate, which can offer a high enhancement factor through the combined effect of the high SERS activity of the Ag core and the biocompatibility of the Au shell. In this study, AgcoreAushell NPs were examined as SERS substrates for the sensitive detection of dopamine (DA) molecules in an aqueous solution. The SERS activity of the AgcoreAushell NPs was strongly dependent on the pH of the solution. When the pH of the solution was acidic (pH <5) or basic (pH >9), the AgcoreAushell NPs exhibited negligible SERS activity toward the DA molecules, due to the weakened interactions (or repulsive forces) between the DA molecules and the core-shell NPs. On the other hand, the AgcoreAushell NPs exhibited a high SERS activity in the intermediate pH ranges (pH 7-9), due to the molecular bridging effect of DA molecules, which allows probe molecules to be located at the interstitial junctions (so-called hot spots) between the core-shell NPs. The results of this study highlight the importance of probe-induced clustering of core-shell NPs in the SERS measurements at physiological pH.

| S-EPMC4554420 | biostudies-literature

Understanding metal-enhanced fluorescence and structural properties in Au@Ag core-shell nanocubes.

Project description:Au@Ag core-shell structures have received particular interest due to their localized surface plasmon resonance properties and great potential as oxygen reduction reaction catalysts and building blocks for self-assembly. In this study, Au@Ag core-shell nanocubes (Au@AgNCs) were fabricated in a facile manner via stepwise Ag reduction on Au nanoparticles (AuNPs). The size of the Au@AgNCs and their optical properties can be simply modulated by changing the Ag shell thickness. Structural characterization has been carried out by TEM, SAED, and XRD. The metal-induced fluorescence properties of probe molecules near the Au@AgNCs were measured during sedimentation of the Au@AgNCs. The unique ring-like building block of Au@AgNCs has dual optical functions as a fluorescence quencher or fluorescence enhancement medium depending on the assembled regions.

| S-EPMC9071844 | biostudies-literature

Plasmonic enhancements of photocatalytic activity of Pt/n-Si/Ag photodiodes using Au/Ag core/shell nanorods.

Project description:We report the plasmonic enhancement of the photocatalytic properties of Pt/n-Si/Ag photodiode photocatalysts using Au/Ag core/shell nanorods. We show that Au/Ag core/shell nanorods can be synthesized with tunable plasmon resonance frequencies and then conjugated onto Pt/n-Si/Ag photodiodes using well-defined chemistry. Photocatalytic studies showed that the conjugation with Au/Ag core/shell nanorods can significantly enhance the photocatalytic activity by more than a factor of 3. Spectral dependence studies further revealed that the photocatalytic enhancement is strongly correlated with the plasmonic absorption spectra of the Au/Ag core/shell nanorods, unambiguously demonstrating the plasmonic enhancement effect.

| S-EPMC3236240 | biostudies-literature

Au@Ag core-shell nanocubes with finely tuned and well-controlled sizes, shell thicknesses, and optical properties.

Project description:This paper describes a facile method for generating Au@Ag core-shell nanocubes with edge lengths controllable in the range of 13.4-50 nm. The synthesis involved the use of single-crystal, spherical Au nanocrystals of 11 nm in size as the seeds in an aqueous system, with ascorbic acid serving as the reductant and cetyltrimethylammonium chloride (CTAC) as the capping agent. The thickness of the Ag shells could be finely tuned from 1.2 to 20 nm by varying the ratio of AgNO(3) precursor to Au seeds. We also investigated the growth mechanism by examining the effects of seeds (capped by CTAC or cetyltrimethylammonium bromide(CTAB)) and capping agent (CTAC vs CTAB) on both size and shape of the resultant core-shell nanocrystals. Our results clearly indicate that CTAC worked much better than CTAB as a capping agent in both the syntheses of Au seeds and Au@Ag core-shell nanocubes. We further studied the localized surface plasmon resonance properties of the Au@Ag nanocubes as a function of the Ag shell thickness. By comparing with the extinction spectra obtained from theoretical calculations, we derived a critical value of ca. 3 nm for the shell thickness at which the plasmon excitation of the Au cores would be completely screened by the Ag shells. Moreover, these Au@Ag core-shell nanocubes could be converted into Au-based hollow nanostructures containing the original Au seeds in the interiors through a galvanic replacement reaction.

| S-EPMC2997519 | biostudies-literature

BaTiO3-core Au-shell nanoparticles for photothermal therapy and bimodal imaging.

Project description:We report sub-100?nm metal-shell (Au) dielectric-core (BaTiO3) nanoparticles with bimodal imaging abilities and enhanced photothermal effects. The nanoparticles efficiently absorb light in the near infrared range of the spectrum and convert it to heat to ablate tumors. Their BaTiO3 core, a highly ordered non-centrosymmetric material, can be imaged by second harmonic generation, and their Au shell generates two-photon luminescence. The intrinsic dual imaging capability allows investigating the distribution of the nanoparticles in relation to the tumor vasculature morphology during photothermal ablation. Our design enabled in vivo real-time tracking of the BT-Au-NPs and observation of their thermally-induced effect on tumor vessels. STATEMENT OF SIGNIFICANCE:Photothermal therapy induced by plasmonic nanoparticles has emerged as a promising approach to treating cancer. However, the study of the role of intratumoral nanoparticle distribution in mediating tumoricidal activity has been hampered by the lack of suitable imaging techniques. This work describes metal-shell (Au) dielectric-core (BaTiO3) nanoparticles (abbreviated as BT-Au-NP) for photothermal therapy and bimodal imaging. We demonstrated that sub-100?nm BT-Au-NP can efficiently absorb near infrared light and convert it to heat to ablate tumors. The intrinsic dual imaging capability allowed us to investigate the distribution of the nanoparticles in relation to the tumor vasculature morphology during photothermal ablation, enabling in vivo real-time tracking of the BT-Au-NPs and observation of their thermally-induced effect on tumor vessels.

| S-EPMC5938150 | biostudies-literature

SERS spectral evolution of azo-reactions mediated by plasmonic Au@Ag core-shell nanorods.

Project description:The mechanism and application of localized surface plasmon resonance induced photocatalytic reactions remain an issue of interest. In this work, we used Au@Ag core-shell nanorods as a platform for plasmon-driven photocatalysis, which was in situ investigated by surface-enhanced Raman scattering (SERS) spectroscopy. The para-aminothiophenol (PATP) and para-nitrothiophenol (PNTP) adsorbed on the nanorods were irradiated with different excitation wavelengths (633 nm, 785 nm) and transformed into 4,4'-dimercaptoazobenzene (DMAB) as evidenced by the emerging Raman peaks at 1142 cm-1, 1390 cm-1, 1440 cm-1, and 1477 cm-1, corresponding to hot carrier dominated oxidation of PATP and reduction of PNTP. Preliminary azo-reaction kinetics and in situ SERS measurements were conducted by comparing the relative intensity ratio of SERS peaks at 1440 cm-1 (DMAB stretching of N[double bond, length as m-dash]N) and 1080 cm-1 (C-S stretching of PATP and PNTP). These results indicate that the catalytic efficiency was dominated by the excitation wavelength as well as the resonance condition between the plasmon band of the nanorods and the excitation line. As a proof of concept, the Au@Ag core-shell nanorods were used to catalyze 4-nitrophenol molecules, and 4-hydroxyazobenzene molecules as the product were confirmed by in situ SERS spectra as well theoretical predictions, showing potential in plasmon driven catalysis and degradation of organic molecules.

| S-EPMC9642349 | biostudies-literature

DNA origami based Au-Ag-core-shell nanoparticle dimers with single-molecule SERS sensitivity.

Project description:DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 10(10), which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled.

| S-EPMC4778414 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data