Zeptomolar detection of 4-aminothiophenol by SERS using silver nanodendrites decorated with gold nanoparticles

2021 ◽  
Author(s):  
Manuel Ceballos ◽  
Israel López ◽  
Ana María Arizmendi-Morquecho ◽  
Margarita Sanchez-Dominguez
Keyword(s):  
Gold Nanoparticles ◽  
Hot Spots ◽  
Enhancement Factor ◽  
Intensity Increase ◽  
Sers Substrate ◽  
Raman Intensity ◽  
Gold Nanospheres ◽  
Chemical Factor ◽  
Dendritic Nanostructures ◽  
Silver Nanodendrites

Abstract In the present work we report a simple, fast, reproducible and cheap methodology for SERS substrate fabrication of silver dendritic nanostructures (prepared by electrodeposition) decorated with gold nanospheres by electrophoretic deposition. This is the first report where a metal dendritic nanostructure has been decorated with another type of metal nanoparticles by this technique. The decorated nanostructures were used directly as SERS substrate using 4-aminothiophenol (4-ATP) as analyte. The objective of the decoration is to create more hot-spots in order to detect the analyte in a lower concentration. Decorated nanodendrites had a detection limit one million times lower than bare silver nanodendrites and all the substrates showed an increase in the Raman intensity at concentrations below 1 nM; because this concentration corresponds to the threshold for the formation of a monolayer resulting in a triple mechanism of intensity increase, namely electric field, chemical factor and hot-spots. 4-ATP was detected in zeptomolar concentration, which is below 1 ppq, corresponding to an analytical enhancement factor (AEF) in the order of 1015.

Optical properties of nanostructured carbon and gold nanoparticle hybrids

2014 ◽  
Vol 1700 ◽  
pp. 79-82 ◽  
Author(s):  
Yuan Li ◽  
Nitin Chopra
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties ◽  
Hot Spots ◽  
Simulation Method ◽  
Dipole Approximation ◽  
Multilayer Graphene ◽  
Nanostructured Carbon ◽  
Near Surface ◽  
Scattering Effects ◽  
Dda Method

ABSTRACTWe report simulation of optical properties of hybrid geometry comprised of multilayer graphene shell encapsulated gold nanoparticles loaded with carbon nanotubes. The discrete dipole approximation (DDA) method was employed. The results indicated that the optical properties of encapsulated gold nanoparticles were not suppressed by the carbon material coating. Furthermore, low scattering effects were also observed. The simulation method helped visualize the near-surface normalized electric field, which is directly related to the intensity of hot spots on the surface of these hybrid nanoarchitectures.

scholarly journals Highly ordered arrays of hat-shaped hierarchical nanostructures with different curvatures for sensitive SERS and plasmon-driven catalysis

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chao Zhang ◽  
Zhaoxiang Li ◽  
Si Qiu ◽  
Weixi Lu ◽  
Mingrui Shao ◽  
...  
Keyword(s):  
Hot Spots ◽  
Hybrid Structure ◽  
Sers Substrate ◽  
Polystyrene Spheres ◽  
Hierarchical Nanostructures ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Narrow Gaps

Abstract Regulation of hot spots exhibits excellent potential in many applications including nanolasers, energy harvesting, sensing, and subwavelength imaging. Here, hat-shaped hierarchical nanostructures with different space curvatures have been proposed to enhance hot spots for facilitating surface-enhanced Raman scattering (SERS) and plasmon-driven catalysis applications. These novel nanostructures comprise two layers of metal nanoparticles separated by hat-shaped MoS2 films. The fabrication of this hybrid structure is based on the thermal annealing and thermal evaporation of self-assembled polystyrene spheres, which are convenient to control the metal particle size and the curvature of hat-shaped nanostructures. Based on the narrow gaps produced by the MoS2 films and the curvature of space, the constructed platform exhibits superior SERS capability and achieves ultrasensitive detection for toxic molecules. Furthermore, the surface catalytic conversion of p-nitrothiophenol (PNTP) to p, p′-dimercaptobenzene (DMAB) was in situ monitored by the SERS substrate. The mechanism governing this regulation of hot spots is also investigated via theoretical simulations.

scholarly journals Different distributions of gold nanoparticles on the tumor and calculation of dose enhancement factor by Monte Carlo simulation

2019 ◽  
Vol 5 (4) ◽  
pp. 361-371 ◽  
Author(s):  
Sajad Keshavarz ◽  
Dariush Sardari
Keyword(s):  
Gold Nanoparticles ◽  
Uniform Distribution ◽  
Enhancement Factor ◽  
Radiation Energy ◽  
Distribution Model ◽  
Distribution Models ◽  
Dose Enhancement ◽  
X Ray ◽  
Nanoparticle Distribution ◽  
Nanoparticle Sizes

Gold nanoparticles can be used to increase the dose of the tumor due to its high atomic number as well as being free from apparent toxicity. The aim of this study is to evaluate the effect of distribution of gold nanoparticles models, as well as changes in nanoparticle sizes and spectrum of radiation energy along with the effects of nanoparticle penetration into surrounding tissues in dose enhancement factor DEF. Three mathematical models were considered for distribution of gold nanoparticles in the tumor, such as 1-uniform, 2- non-uniform distribution with no penetration margin and 3- non-uniform distribution with penetration margin of 2.7 mm of gold nanoparticles. For this purpose, a cube-shaped water phantom of 50 cm size in each side and a cube with 1 cm side placed at depth of 2 cm below the upper surface of the cubic phantom as the tumor was defined, and then 3 models of nanoparticle distribution were modeled. MCNPX code was used to simulate 3 distribution models. DEF was evaluated for sizes of 20, 25, 30, 50, 70, 90 and 100 nm of gold nanoparticles, and 50, 95, 250 keV and 4 MeV photon energies. In uniform distribution model the maximum DEF was observed at 100 nm and 50 keV being equal to 2.90, in non-uniform distribution with no penetration margin, the maximum DEF was measured at 100 nm and 50 keV being 1.69, and in non-uniform distribution with penetration margin of 2.7 mm, the maximum DEF was measured at 100 nm and 50 keV as 1.38, and the results have been showed that the dose was increased by injecting nanoparticles into the tumor. It is concluded that the highest DEF could be achieved in low energy photons and larger sizes of nanoparticles. Non-uniform distribution of gold nanoparticles can increase the dose and also decrease the DEF in comparison with the uniform distribution. The non-uniform distribution of nanoparticles with penetration margin showed a lower DEF than the non-uniform distribution without any margin and uniform distribution. Meanwhile, utilization of the real X-ray spectrum brought about a smaller DEF in comparison to mono-energetic X-ray photons.

scholarly journals Commercial Gold Nanoparticles on Untreated Aluminum Foil: Versatile, Sensitive, and Cost-Effective SERS Substrate

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Kristina Gudun ◽  
Zarina Elemessova ◽  
Laura Khamkhash ◽  
Ekaterina Ralchenko ◽  
Rostislav Bukasov
Keyword(s):  
Gold Nanoparticles ◽  
Low Cost ◽  
Aluminum Foil ◽  
Cost Effective ◽  
Sers Substrate ◽  
Au Film ◽  
Response Range ◽  
Sers Detection ◽  
Film Substrate ◽  
Linear Response Range

We introduce low-cost, tunable, hybrid SERS substrate of commercial gold nanoparticles on untreated aluminum foil (AuNPs@AlF). Two or three AuNP centrifugation/resuspension cycles are proven to be critical in the assay preparation. The limits of detection (LODs) for 4-nitrobenzenethiol (NBT) and crystal violet (CV) on this substrate are about 0.12 nM and 0.19 nM, respectively, while maximum analytical SERS enhancement factors (AEFs) are about 107. In comparative assays LODs for CV measured on AuNPs@Au film and AuNPs@glass are about 0.35 nM and 2 nM, respectively. The LOD for melamine detected on AuNPs@ Al foil is 27 ppb with 3 orders of magnitude for linear response range. Overall, AuNPs@AlF demonstrated competitive performance in comparison with AuNPs@ Au film substrate in SERS detection of CV, NBT, and melamine. To check the versatility of the AuNPs@AlF substrate we also detected KNO3 with LODs of 0.7 mM and SERS EF around 2 × 103, which is on the same order with SERS EF reported for this compound in the literature.

Cellulose Dialysis Membrane Tubing doped with Gold Nanoparticles as SERS Substrate

2022 ◽  
pp. 131718
Author(s):  
L.F. Gomez –Caballero ◽  
J.L. Pichardo-Molina ◽  
G. Basurto-Islas
Keyword(s):  
Gold Nanoparticles ◽  
Sers Substrate ◽  
Dialysis Membrane

A disulfur ligand stabilization approach to construct a silver(i)-cluster-based porous framework as a sensitive SERS substrate

Nanoscale ◽  
2019 ◽  
Vol 11 (35) ◽  
pp. 16293-16298 ◽  
Author(s):  
Tong Wu ◽  
Di Yin ◽  
Xun Hu ◽  
Bo Yang ◽  
Hong Liu ◽  
...  
Keyword(s):  
Hot Spots ◽  
Sers Substrate ◽  
Porosity Structure ◽  
Porous Framework ◽  
Highly Sensitive ◽  
Ligand Stabilization

An atomic-precise silver(i)-cluster-based MOF (UJN-1) stabilized by disulfur ligand has been demonstrated. Its reduced derivative exhibits highly sensitive SERS activity that can be ascribed to abundant hot spots sites and porosity structure.

scholarly journals Preparation of Hydrophobic Film by Electrospinning for Rapid SERS Detection of Trace Triazophos

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4120
Author(s):  
Fei Shao ◽  
Jiaying Cao ◽  
Ye Ying ◽  
Ying Liu ◽  
Dan Wang ◽  
...  
Keyword(s):  
Hot Spots ◽  
Large Scale ◽  
Limit Of Detection ◽  
Small Region ◽  
Sers Substrate ◽  
Ag Nps ◽  
Electrospinning Technique ◽  
Heterocyclic Molecules ◽  
Surface Enhanced Raman ◽  
Sers Detection

For real application, it is an urgent demand to fabricate stable and flexible surface-enhanced Raman scattering (SERS) substrates with high enhancement factors in a large-scale and facile way. Herein, by using the electrospinning technique, a hydrophobic and flexible poly(styrene-co-butadiene) (SB) fibrous membrane is obtained, which is beneficial for modification of silver nanoparticles (Ag NPs) colloid in a small region and then formation of more “hot spots” by drying; the final SERS substrate is designated as Ag/SB. Hydrophobic Ag/SB can efficiently capture heterocyclic molecules into the vicinity of hot spots of Ag NPs. Such Ag/SB films are used to quantitatively detect trace triazophos residue on fruit peels or in the juice, and the limit of detection (LOD) of 2.5 × 10−8 M is achieved. Ag/SB films possess a capability to resist heat. As a case, 6-mercaptopurine (6MP) that just barely dissolves in 90 °C water is picked for conducting Ag/SB-film-based experiments.

Estimation of microscopic dose enhancement factor around gold nanoparticles by Monte Carlo calculations

2010 ◽  
Vol 37 (7Part1) ◽  
pp. 3809-3816 ◽  
Author(s):  
Bernard L. Jones ◽  
Sunil Krishnan ◽  
Sang Hyun Cho
Keyword(s):  
Gold Nanoparticles ◽  
Monte Carlo ◽  
Enhancement Factor ◽  
Dose Enhancement ◽  
Monte Carlo Calculations

scholarly journals Porous carbon nanowire array for surface-enhanced Raman spectroscopy

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Nan Chen ◽  
Ting-Hui Xiao ◽  
Zhenyi Luo ◽  
Yasutaka Kitahama ◽  
Kotaro Hiramatsu ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Porous Carbon ◽  
Hot Spots ◽  
Strong Dependence ◽  
Nanowire Array ◽  
Surface Enhanced Raman Spectroscopy ◽  
Localized Surface Plasmon ◽  
Sers Substrate ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

Abstract Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for vibrational spectroscopy as it provides several orders of magnitude higher sensitivity than inherently weak spontaneous Raman scattering by exciting localized surface plasmon resonance (LSPR) on metal substrates. However, SERS can be unreliable for biomedical use since it sacrifices reproducibility, uniformity, biocompatibility, and durability due to its strong dependence on “hot spots”, large photothermal heat generation, and easy oxidization. Here, we demonstrate the design, fabrication, and use of a metal-free (i.e., LSPR-free), topologically tailored nanostructure composed of porous carbon nanowires in an array as a SERS substrate to overcome all these problems. Specifically, it offers not only high signal enhancement (~106) due to its strong broadband charge-transfer resonance, but also extraordinarily high reproducibility due to the absence of hot spots, high durability due to no oxidization, and high compatibility to biomolecules due to its fluorescence quenching capability.

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