Optical properties and catalytic activity of bimetallic gold-silver nanoparticles

Feng, Lili; Gao, Guo; Huang, Peng; Wang, Kan; Wang, Xiansong; Luo, Teng; Zhang, Chunlei

doi:10.5101/nbe.v2i4.p258-267

Cited by 56 publications

(39 citation statements)

References 84 publications

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“…Alloy formation of Ag-Au NPs caused a plasmon maximum in the UV-vis spectrum between the absorption maximum of Ag and Au that varies with respect to composition distribution. The plasmon peak position was red-shifted due to the continuous change of the d-band energy level that contributes to the interband transition term in the dielectric function as a result of an increase in Au composition, and a damping of the absorbance maxima is seen attributed to the higher electron scattering by foreign atoms upon alloying and the gold d-sp interband transition [24,26,28].…”

Section: Au-ag Alloy Np Systemsmentioning

confidence: 94%

Effect of gold alloying on stability of silver nanoparticles and control of silver ion release from vapor-deposited Ag–Au/polytetrafluoroethylene nanocomposites

et al. 2012

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In the present study, nanocomposites containing Ag-Au alloy nanoparticle ensembles with various compositions on polytetrafluoroethylene were prepared by physical vapor deposition. After a certain time of immersion of the samples in water, oxidation and dissolution of the Ag nanoparticles (AgNPs) occurred, and changes in the morphology, optical properties and composition of the nanocomposites were examined using transmission electron microscopy, ultraviolet-visible spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. The composition-dependence and the time-dependence of the silver ion release were studied, and the concentration of the silver ions in water was detected using inductively coupled plasma mass spectrometry. The results indicate that with increasing gold fraction in the AuAg alloy nanoparticles, a strong improvement of the oxidation resistance of the AgNPs occurs. The dissolution of Ag is rapid at the first contact of the sample with water until a saturation state is reached. XPS synchrotron measurements with different excitation energies show that the depletion of Ag from the nanoparticles does not lead to the formation of a Au-rich shell and that the atomic mobility is high enough in the small nanoparticles of about 5 nm average size to equilibrate any concentration gradient.

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Section: Au-ag Alloy Np Systemsmentioning

confidence: 94%

Effect of gold alloying on stability of silver nanoparticles and control of silver ion release from vapor-deposited Ag–Au/polytetrafluoroethylene nanocomposites

et al. 2012

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“…Further control of electromagnetic properties can also be afforded with bimetallic systems that offer unique combinations of optical, photothermal, catalytic and biological properties[30]. Bimetallic gold-silver nanoparticles reported in the literature include binary alloys[31-33], segmented heterometallic nanorods[34], and core-shell structures[35, 36].…”

Section: Introductionmentioning

confidence: 99%

Bacterial Killing by Light‐Triggered Release of Silver from Biomimetic Metal Nanorods

Black

Sileika

et al. 2013

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Illumination of noble metal nanoparticles at the plasmon resonance causes substantial heat generation, and the transient and highly localized temperature increases that result from this energy conversion can be exploited for photothermal therapy by plasmonically heating gold nanorods (NRs) bound to cell surfaces. Here, we report the first use of plasmonic heating to locally release silver from gold core/silver shell (Au@Ag) NRs targeted to bacterial cell walls. A novel biomimetic method of preparing Au@Ag core-shell NRs was employed, involving deposition of a thin organic polydopamine (PD) primer onto Au NR surfaces, followed by spontaneous electroless silver metallization, and conjugation of antibacterial antibodies and passivating polymers for targeting to gram-negative and gram-positive bacteria. Dramatic cytotoxicity of S. epidermidis and E. coli cells targeted with Au@Ag NRs was observed upon exposure to light as a result of the combined antibacterial effects of plasmonic heating and silver release. The antibacterial effect was much greater than with either plasmonic heating or silver alone, implying a strong therapeutic synergy between cell-targeted plasmonic heating and the associated silver release upon irradiation. Our findings suggest a potential antibacterial use of Au@Ag NRs when coupled with light irradiation, which was not previously described.

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“…Up to date, Au NPs-based SERS is emerging as a new theranostic platform for tumor boundary identification, exhibiting the following advantages: 1) minimization of photobleaching and peak overlapping; 2) high spectral specificity; 3) low signal-to-noise ratio in complex biological systems; and 4) enhanced SERS signal. Au nanoparticles-based SERS enables the detection of very low concentration of analytes, even single molecule with high sensitivity and specificity [33][34][35]. Up to date, few report is closely associated with gold nanorod-based SERS for detection and imaging of analytes.…”

Section: Introductionmentioning

confidence: 99%

EGFR Antibody Conjugated Bimetallic Au@Ag Nanorods for Enhanced SERS-Based Tumor Boundary Identification, Targeted Photoacoustic Imaging and Photothermal Therapy

Chen¹,

Zhang²,

Yang³

et al. 2016

Nano BioMed ENG

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The development of multifunctional nanoprobes for simultaneous targeted imaging, tumor boundary identification and photothermal therapy of gastric cancer has become a great challenge. Herein, EGFR monoclonal antibody-conjugated Au@Ag nanorods decorated with DTNB nanoprobes (5,5'-Dithiobis-(2-nitrobenzoic acid)) (EGFR-Au@Ag NR nanotags) were prepared and characterized. Their biocompatibility was analyzed by MTT assay. In vitro studies show that EGFR-Au@Ag NR nanotags own good biocompatibility and capability of targeting and entering into gastric cancer MGC803 cells, silver nano-film layer on the surface of gold nanorods remarkably enhance surfaceenhanced rama spectra (SERS) signal, enhanced photoacoustic imaging efficacy and photothermal conversion efficiency of gold nanorods. In vivo studies show that prepared nanotags could target actively gastric cancer cells at 2 h post-injection, and distributed in the tumor site, exhibited enhanced SERS signals to display clearly tumor boundary, enhanced photoacoustic imaging to display clearly tumor boundary. Under 1 w/cm 2 laser irradiation, tumor growth was remarkably inhibited by local photothermal therapy. In conclusion, high performance EGFR-antibody conjugated Au@Ag nanorod-DTNB nanoprobes exhibit great potential in applications such as targeted photoacoustic imaging, simultaneous tumor boundary identification and selective photothermal therapy of gastric cancer in the near future.

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Optical properties and catalytic activity of bimetallic gold-silver nanoparticles

Cited by 56 publications

References 84 publications

Effect of gold alloying on stability of silver nanoparticles and control of silver ion release from vapor-deposited Ag–Au/polytetrafluoroethylene nanocomposites

Effect of gold alloying on stability of silver nanoparticles and control of silver ion release from vapor-deposited Ag–Au/polytetrafluoroethylene nanocomposites

Bacterial Killing by Light‐Triggered Release of Silver from Biomimetic Metal Nanorods

EGFR Antibody Conjugated Bimetallic Au@Ag Nanorods for Enhanced SERS-Based Tumor Boundary Identification, Targeted Photoacoustic Imaging and Photothermal Therapy

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