scholarly journals Seed-Mediated Electroless Deposition of Gold Nanoparticles for Highly Uniform and Efficient SERS Enhancement

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 185 ◽  
Author(s):  
Junqi Tang ◽  
Quanhong Ou ◽  
Haichun Zhou ◽  
Limin Qi ◽  
Shiqing Man
Keyword(s):  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
Electroless Deposition ◽  
Trisodium Citrate ◽  
Mixed Solution ◽  
Large Area ◽  
Reaction Conditions ◽  
Au Nps ◽  
Sers Enhancement ◽  
Seed Mediated

A seed-mediated electroless deposition (SMED) approach for fabrication of large-area and uniform gold nanoparticle films as efficient and reproducible as surface-enhanced Raman scattering (SERS) substrates was presented. This approach involved a seeding pretreatment procedure and a subsequent growth step. The former referred to activation of polylysine-coated glass slides in gold seed solution, and the latter required a careful control of the reactant concentration and reaction time. With the aid of gold seeds and appropriate reaction conditions, a large-area and uniform nanofilm with evenly distributed gold nanoparticles (Au NPs) was formed on the surface of the substrates after adding a mixed solution containing ascorbic acid and trisodium citrate. The morphology of the Au nanofilm was examined by scanning electron microscopy. The size evolution of Au NPs on the surface of the substrates was analyzed in detail. The nanofilm substrate was prepared by reaction conditions of the seeded activation process: 10 mL ascorbic acid and trisodium citrate mixture and 30 min of soaking time, which exhibited an excellent uniformity and reproducibility of SERS enhancement with relative standard deviation (RSD) values of less than 8% (particularly, a RSD value of 3% can be reached for the optimized measurement). Compared to the common electroless deposition, the seed-mediated electroless deposition possessed inherent advantages in controllability, reproducibility, and economic benefit.

Synthesis and Characterization of Silver Nanoplates by a Seed-mediated Method

2019 ◽  
Vol 29 (3) ◽  
Author(s):  
Mai Ngọc Tuan Anh
Keyword(s):  
Hydrogen Peroxide ◽  
Silver Nanoparticles ◽  
Ascorbic Acid ◽  
Silver Nitrate ◽  
Sodium Borohydride ◽  
Trisodium Citrate ◽  
Synthesis And Characterization ◽  
Silver Nanoplates ◽  
Seed Mediated

Silver nanoplates (SNPs) having different size were synthesized by a seed-mediated method. The seeds -silver nanoparticles with 4 – 6 nm diameters were synthesized first by reducing silver nitrate with sodium borohydride in the present of Trisodium Citrate and Hydrogen peroxide. Then these seeds were developed by continue reducing Ag\(^+\) ions with various amount of L-Ascorbic acid to form SNPs. Our analysis showed that the concentratrion of L-Ascorbic acid, a secondary reducing agent, played an important role to form SNPs. In addition, the size and in-plane dipole plasmon resonance wavelenght of silver nanoplates were increased when the concentration of added silver nitrate increased. The characterization of SNPs were studied by UV-Vis, FE-SEM, EDS and TEM methods.

Preparation of Cellulose Acetate Ultra-Fine Fibers Containing Quasi-Spherical Gold Nanoparticles by Electrospinning Method

2011 ◽  
Vol 391-392 ◽  
pp. 400-403
Author(s):  
Dong Mei Zhao ◽  
Li Guo Sun ◽  
Li Li Lv ◽  
Jian Li
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Cellulose Acetate ◽  
Trisodium Citrate ◽  
X Ray Diffraction ◽  
Au Nps ◽  
Transmission Electron ◽  
Electrospinning Method ◽  
Before And After ◽  
Spherical Gold Nanoparticles

Quasi-spherical gold nanoparticles(Au NPs) prepared by trisodium citrate reduction of HAuCl4were dispersed into cellulose acetate(CA) ultra-fine fibers by electrospinning. The optical properties of Au NPs before and after electrospinning were measured by UV-vis spectrometer. The morphology and distribution of Au NPs in CA ultra-fine fibers were observed by transmission electron microscopy (TEM). The morphology and diameter of Au NPs/CA fibers were studied by scanning electron microscopy (SEM). The crystallinity change of CA fiber before and after adding Au NPs was characterized by X-ray diffraction (XRD).

scholarly journals Seed-Mediated Growth of Gold Nanorods: Limits of Length to Diameter Ratio Control

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Christopher J. Ward ◽  
Robert Tronndorf ◽  
Alicia S. Eustes ◽  
Maria L. Auad ◽  
Edward W. Davis
Keyword(s):  
Ascorbic Acid ◽  
Aspect Ratio ◽  
Gold Nanorods ◽  
Reducing Agent ◽  
Gold Content ◽  
Reaction Conditions ◽  
Growth Solution ◽  
Transmission Electron ◽  
Seed Mediated

The effects of the seed reaction conditions on the two-step seed-mediated growth of gold nanorods and the effect of gold and reducing agent content in the growth solution were evaluated. Results indicate that the reaction conditions used to produce the seeds have a significant impact on the aspect ratio of the gold nanorods produced. Increasing the concentration of gold or the reaction temperature in the seed production step results in lower length to diameter (aspect ratio) gold rods. In addition, the amount of prepared seed added to the growth solution impacts the rod aspect ratio, with increasing amounts of seed reducing the aspect ratio. The effects of reducing agent, ascorbic acid (AA), and gold content of the growth solution on the aspect ratio of the produced rods are strongly interrelated. There exists a minimum ascorbic acid to gold concentration below which rods will not form; however, increasing the ratio above this minimum results in shorter rods being formed. Characterization of nanorod growth is performed by UV-vis-NIR spectrophotometry and transmission electron microscopy (TEM).

Ascorbic acid functionalized gold nanoparticles as a probe for colorimetric and visual read-out determination of dichlorvos in environmental samples

2014 ◽  
Vol 6 (22) ◽  
pp. 9007-9014 ◽  
Author(s):  
Stephanie L. D'souza ◽  
Ranjan Kumar Pati ◽  
Suresh Kumar Kailasa
Keyword(s):  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
Environmental Samples ◽  
Schematic Representation ◽  
Au Nps ◽  
Colorimetric Probe ◽  
Analytical Process ◽  
Functionalized Gold Nanoparticles

Schematic representation of the analytical process for detecting dichlorvos using AA–Au NPs as a colorimetric probe.

scholarly journals Synthesis and Characterization of Gold Nanoparticles Using Trisodium Citrate as a Reductant

2020 ◽  
Vol 2 (1) ◽  
pp. 10-16
Author(s):  
Astriana Dewi ◽  
Suriati Eka Putri ◽  
Pince Salempa
Keyword(s):  
Gold Nanoparticles ◽  
Trisodium Citrate ◽  
Morphological Characterization ◽  
Reducing Agent ◽  
Face Centered Cubic ◽  
Au Nps ◽  
Time Variations ◽  
Face Centered

This research is an experimental study that aims to determine the characteristics of gold nanoparticles (Au-NPs) synthesized using trisodium citrate as a reducing agent. 0.4 mM HAuCl4 solution was synthesized using Na3C6H5O7 to convert Au3+ to Au0 with several variations of the reducing agent concentration, 3.5%; 5%; 6.5% and 8%. Determination of reaction time was measured using a UV-Vis spectrophotometer with time variations of 1, 5, 15, 30 and 45 minutes. Characterization of the size and lattice of Au-NPs crystals using X-Ray Difraction (XRD) and morphological characterization using Scanning Electron Microscopy (SEM). The results of the characterization, Au-NPs were produced blackish brown in color, and yields were 66.13%, 89%, 59.63% and 50.30% respectively for trisodium citrate reductant concentrations of 3.5%; 5%; 6.5% and 8%, with an average Au-NPs size of 46.97; 19.06; 50.03 and 39.68 nm, Face Centered Cubic (FCC) Crystal lattice and have a homogeneous morphology.

Seed-mediated synthesis and PEG coating of gold nanoparticles for controlling morphology and sizes

MRS Advances ◽  
2020 ◽  
Vol 5 (63) ◽  
pp. 3353-3360
Author(s):  
Susana Helena Arellano Ramírez ◽  
Perla García Casillas ◽  
Christian Chapa González
Keyword(s):  
Gold Nanoparticles ◽  
Polyethylene Glycol ◽  
Room Temperature ◽  
Colloidal Stability ◽  
Infrared Spectrometry ◽  
Ammonium Bromide ◽  
Chloroauric Acid ◽  
Vis Spectroscopy ◽  
Seed Mediated ◽  
Peg Coating

AbstractA significant area of research is biomedical applications of nanoparticles which involves efforts to control the physicochemical properties through simple and scalable processes. Gold nanoparticles have received considerable attention due to their unique properties that they exhibit based on their morphology. Gold nanospheres (AuNSs) and nanorods (AuNRs) were prepared with a seed-mediated method followed of polyethylene glycol (PEG)-coating. The seeds were prepared with 0.1 M cetyltrimethyl-ammonium bromide (CTAB), 0.005 M chloroauric acid (HAuCl4), and 0.01 M sodium borohydride (NaBH4) solution. Gold nanoparticles with spherical morphology was achieved by growth by aggregation at room temperature, while to achieve the rod morphology 0.1 M silver nitrate (AgNO3) and 0.1 M ascorbic acid solution were added. The gold nanoparticles obtained by the seed-mediated synthesis have spherical or rod shapes, depending on the experimental conditions, and a uniform particle size. Surface functionalization was developed using polyethylene glycol. Morphology, and size distribution of AuNPs were evaluated by Field Emission Scanning Electron Microscopy. The average size of AuNSs, and AuNRs was 7.85nm and 7.96 x 31.47nm respectively. Fourier transform infrared spectrometry was performed to corroborate the presence of PEG in the AuNPs surface. Additionally, suspensions of AuNSs and AuNRs were evaluated by UV-Vis spectroscopy. Gold nanoparticles were stored for several days at room temperature and it was observed that the colloidal stability increased once gold nanoparticles were coated with PEG due to the shield formed in the surface of the NPs and the increase in size which were 9.65±1.90 nm of diameter for AuNSs and for AuNRs were 29.03±5.88 and 8.39±1.02 nm for length and transverse axis, respectively.

Molecularly Imprinted Sensor for Ascorbic Acid Based on Gold Nanoparticles and Multiwalled Carbon Nanotubes

2020 ◽  
Vol 16 (7) ◽  
pp. 905-913
Author(s):  
Youyuan Peng ◽  
Qingshan Miao
Keyword(s):  
Carbon Nanotubes ◽  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
Multiwalled Carbon Nanotubes ◽  
Ph Value ◽  
Biological Fluids ◽  
Water Soluble ◽  
Multiwalled Carbon ◽  
Experimental Conditions ◽  
Molecularly Imprinted

Background: L-Ascorbic acid (AA) is a kind of water soluble vitamin, which is mainly present in fruits, vegetables and biological fluids. As a low cost antioxidant and effective scavenger of free radicals, AA may help to prevent diseases such as cancer and Parkinson’s disease. Owing to its role in the biological metabolism, AA has also been utilized for the therapy of mental illness, common cold and for improving the immunity. Therefore, it is very necessary and urgent to develop a simple, rapid and selective strategy for the detection of AA in various samples. Methods: The molecularly imprinted poly(o-phenylenediamine) (PoPD) film was prepared for the analysis of L-ascorbic acid (AA) on gold nanoparticles (AuNPs) - multiwalled carbon nanotubes (MWCNTs) modified glass carbon electrode (GCE) by electropolymerization of o-phenylenediamine (oPD) and AA. Experimental parameters including pH value of running buffer and scan rates were optimized. Scanning electron microscope (SEM), fourier-transform infrared (FTIR) spectra, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were utilized for the characterization of the imprinted polymer film. Results: Under the selected experimental conditions, the DPV peak currents of AA exhibit two distinct linear responses ranging from 0.01 to 2 μmol L-1 and 2 to 100 μmol L-1 towards the concentrations of AA, and the detection limit was 2 nmol L-1 (S/N=3). Conclusion: The proposed electrochemical sensor possesses excellent selectivity for AA, along with good reproducibility and stability. The results obtained from the analysis of AA in real samples demonstrated the applicability of the proposed sensor to practical analysis.

Amperometric assay of vitamin C using an ascorbate oxidase enzyme electrode

1979 ◽  
Vol 44 (11) ◽  
pp. 3395-3404 ◽  
Author(s):  
Pavel Posádka ◽  
Lumír Macholán
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Oxygen Electrode ◽  
Ascorbate Oxidase ◽  
Current Response ◽  
Reaction Conditions ◽  
Long Term Storage ◽  
Oxidase Enzyme ◽  
Optimal Reaction

An oxygen electrode of the Clark type, coated by a thin, active layer of chemically insolubilized ascorbate oxidase from squash peelings specifically detects by measuring oxygen uptake 10 to 400 μg of ascorbic acid in 3 ml of phosphate buffer. The record of current response to substrate addition lasts 1-2 min. The ascorbic acid values determined in various samples of fruit juices are in good agreement with the data obtained by titration and polarography. The suitable composition of the membrane and its lifetime and stability during long-term storage are described; optimal reaction conditions of vitamin C determination and the possibilities of interference of other compounds are also examined. Of the 35 phenols, aromatic amines and acids tested chlorogenic acid only can cause a positive error provided that the enzyme membrane has been prepared from ascorbate oxidase of high purity.

scholarly journals Easy and fast in-situ functionalization of exfoliated 2D black phosphorus with gold nanoparticles

2021 ◽  
Author(s):  
Salvatore Moschetto ◽  
Andrea Ienco ◽  
Gabriele Manca ◽  
Manuel Serrano-Ruiz ◽  
Maurizio Peruzzini ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Black Phosphorus ◽  
Au Nps ◽  
In Situ Functionalization

Heterostructures of single- and few-layer black phosphorus (2D bP) functionalized with gold nanoparticles (Au NPs) have been recently reported in the literature, exploiting their intriguing properties and biocompatibility for catalytic,...

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