scholarly journals Modification of Ag SERS-active surface to promote charged analytes adsorption

2021 ◽  
Author(s):  
Bahdan V Ranishenka ◽  
Andrei Yu Panarin ◽  
Irina A Chelnokova ◽  
Sergei N Terekhov ◽  
Peter Mojzes ◽  
...  
Keyword(s):  
Surface Charge ◽  
Copper Ions ◽  
Substrate Surface ◽  
Active Surface ◽  
Sers Spectrum ◽  
Sers Substrate ◽  
Ag Nps ◽  
Sers Signal ◽  
Surface Enhanced Raman ◽  
The Impact

This work aims at the impact of the electrostatic interaction between analyte molecules and silver nanoparticles (Ag NPs) on the surface enhanced Raman scattering (SERS) performance. For this, we fabricated nanostructured plasmonic films by immobilization of Ag NPs on glass plates and functionalized them by a set of differently charged hydrophilic thiols (sodium 2-mercaptoethyl sulfonate, mercaptopropionic acid, 2-mercaptoethanol, 2-(dimethylamino) ethanethiol hydrochloride and thiocholine) to vary the surface charge of the SERS-substrate. We used two oppositely charged porphyrins, cationic Cu(II)-tetrakis(4-N-methylpyridyl) porphine (CuTMpyP4) and anionic Cu(II)-5,10,15,20-tetrakis(4-sulphonatophenyl) porphine (CuTSPP4), with equal charge value and similar structure as model analytes to probe SERS signal. Our results indicate that the SERS spectrum intensity strongly, up to complete signal disappearance, correlates with the substrate’s surface charge that tends to be negative. Using the data obtained and our model SERS-system, we analyzed modification of Ag surface by different reagents (lithium chloride, polyethyleneimine, polyhexamethylene guanidine and multicharged metal ions). Finally, all those surface modifications were tested using a negatively charged oligonucleotide labeled with Black Hole Quencher (BHQ1) dye. Only addition of copper ions into the analyte solution allowed to get a good SERS signal. Considering strong interaction of copper ions with the DNA molecule, we suppose that the analyte charge inversion played the key role in that case, instead of the recharging of the substrate surface. Analyte recharging could be a promising way to get intensive SERS spectra of negatively charged molecules on Ag SERS-active supports.

scholarly journals Modification of a SERS-active Ag surface to promote adsorption of charged analytes: effect of Cu2+ ions

2021 ◽  
Vol 12 ◽  
pp. 902-912
Author(s):  
Bahdan V Ranishenka ◽  
Andrei Yu Panarin ◽  
Irina A Chelnokova ◽  
Sergei N Terekhov ◽  
Peter Mojzes ◽  
...  
Keyword(s):  
Surface Charge ◽  
Copper Ions ◽  
Substrate Surface ◽  
Sers Spectrum ◽  
Sers Substrate ◽  
Ag Nps ◽  
Sers Signal ◽  
Surface Enhanced Raman ◽  
Analyte Solution ◽  
The Impact

This work studies the impact of the electrostatic interaction between analyte molecules and silver nanoparticles (Ag NPs) on the intensity of surface-enhanced Raman scattering (SERS). For this, we fabricated nanostructured plasmonic films by immobilization of Ag NPs on glass plates and functionalized them by a set of differently charged hydrophilic thiols (sodium 2-mercaptoethyl sulfonate, mercaptopropionic acid, 2-mercaptoethanol, 2-(dimethylamino)ethanethiol hydrochloride, and thiocholine) to vary the surface charge of the SERS substrate. We used two oppositely charged porphyrins, cationic copper(II) tetrakis(4-N-methylpyridyl) porphine (CuTMpyP4) and anionic copper(II) 5,10,15,20-tetrakis(4-sulfonatophenyl)porphine (CuTSPP4), with equal charge value and similar structure as model analytes to probe the SERS signal. Our results indicate that the SERS spectrum intensity strongly, up to complete signal disappearance, correlates with the surface charge of the substrate, which tends to be negative. Using the data obtained and our model SERS system, we analyzed the modification of the Ag surface by different reagents (lithium chloride, polyethylenimine, polyhexamethylene guanidine, and multicharged metal ions). Finally, all those surface modifications were tested using a negatively charged oligonucleotide labeled with Black Hole Quencher dye. Only the addition of copper ions into the analyte solution yielded a good SERS signal. Considering the strong interaction of copper ions with the oligonucleotide molecules, we suppose that inversion of the analyte charge played a key role in this case, instead of a change of charge of the substrate surface. Changing the charge of analytes could be a promising way to get clear SERS spectra of negatively charged molecules on Ag SERS-active supports.

scholarly journals Stabilizing Ag Nanoparticles Using Anatase TiO2 and Cu on Al Surface

2020 ◽  
pp. 22-30
Author(s):  
Masayoshi Kaneko
Keyword(s):  
Ag Nanoparticles ◽  
Au Nanoparticles ◽  
Active Surface ◽  
Anatase Tio2 ◽  
Sers Substrate ◽  
Ag Nps ◽  
Au Nps ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Chemical adsorption of anatase TiO2, silver nanoparticles (Ag NPs), and Cu particles (Cu Ps) on aluminum (Al) surface yielded an active surface-enhanced Raman scattering (SERS) substrate. TiO2 is known to reduce both silver (Ag) and copper (Cu). In an oxidizing environment, Ag NPs remain unoxidized since Cu has a more negative redox potential than Ag. Ag is therefore protected by Cu from getting oxidized. Although Ag NPs exhibit better SERS activity than Au NPs, Ag is relatively easier to oxidize, limiting the development of Ag-based nanomaterials. Therefore, despite the poor SERS activity of Au nanoparticles than that of Ag nanoparticles, Au nanoparticles have been widely used. Herein, the stabilization of Ag nanoparticles by incorporating a reductive process using anatase TiO2 is reported. The fabricated substrates bearing anatase, Ag NPs, and Cu Ps were stable, as seen by Raman spectra, and remained unchanged for more than 2 months.

scholarly journals SERS Background Imaging – a Versatile Tool Towards More Reliable SERS Analytics

2020 ◽  
Author(s):  
Paul Ebersbach ◽  
Ute Münchberg ◽  
Erik Freier
Keyword(s):  
Sampling Error ◽  
Hot Spot ◽  
Measurement Procedure ◽  
Sers Spectrum ◽  
Sers Substrate ◽  
Structure Property ◽  
Contrast Imaging ◽  
High Contrast Imaging ◽  
Surface Enhanced Raman ◽  
Versatile Tool

<div>Surface-enhanced Raman scattering (SERS) is a highly selective and sensitive straightforward analytical method, which is however not yet established in routine analysis due to a lack of reliability and reproducibility. Here we utilise the broad SERS continuum background (SERS-BG) accompanying every SERS measurement as a versatile tool towards more reliable SERS analytics. We apply a heterogeneous gold SERS substrate immersed with an adenosine triphosphate solution to show that the integrated SERS-BG distinctly correlates with the intensity of the analyte signals in the SERS spectrum. Based on this relationship we introduce an easy-to-handle, automatable and more reliable SERS measurement procedure starting with fast and high-contrast imaging of the SERS substrate followed by hot spot localisation and recording of highly enhanced SERS spectra at the centre of the diffraction-limited spot. We further demonstrate the applicability of SERS-BG imaging by combining it with other optical modalities and electron microscopy to assess structure-property relationships. Additionally, we perform Monte-Carlo simulations to evaluate the sampling error in SERS experiments highlighting the advantages of our method over conventional SERS experiments.</div>

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.

Rapid fabrication of self-assembled interfacial film decorated filter paper as an excellent surface-enhanced Raman scattering substrate

2014 ◽  
Vol 6 (24) ◽  
pp. 9547-9553 ◽  
Author(s):  
Wu-Li-Ji Hasi ◽  
Shuang Lin ◽  
Xiang Lin ◽  
Xiu-Tao Lou ◽  
Fang Yang ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Filter Paper ◽  
Surface Enhanced Raman Scattering ◽  
Sers Substrate ◽  
Ag Nps ◽  
Interfacial Film ◽  
Rapid Fabrication ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

The fabrication of this paper-based SERS substrate is facile and rapid (<10 min). The coverage rate of Ag NPs is relatively high.

scholarly journals Highly Sensitive Surface Enhanced Raman Spectroscopy from Ag Nanoparticles Decorated Graphene Sheet

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Hui Song ◽  
Xin Li ◽  
Sweejiang Yoo ◽  
Yuan Wu ◽  
Weihua Liu ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Size Distribution ◽  
Ag Nanoparticles ◽  
Surface Enhanced Raman Spectroscopy ◽  
Sers Substrate ◽  
Ag Nps ◽  
Sers Enhancement ◽  
Surface Enhanced ◽  
Enhancement Factors ◽  
Surface Enhanced Raman

Surface enhanced Raman spectroscopy (SERS) is a powerful analytical technique and has been most intensively studied. In this work, electroless deposition is proposed for Ag nanoparticles (NPs) decorated on chemical vapor deposition (CVD) growth graphene sheets (GS) to create hybrid SERS substrate. From three aspects of size distribution, morphology, and coverage, Ag NPs controllable decoration on GS and SERS enhancement factors of the hybrid SERS substrate is investigated. 200–300 times enhanced SERS intensities are detected from the Ag NPs on GS hybrid as compared to pure GS. Controllable decoration is crucial for improving SERS enhancement factorsβEF, becauseβEFfrom quasi cubic Ag NPs on GS is 6.53 times stronger than that from spheric one; 1.6 timesβEFis detected while the Ag NPs size distribution is reduced to half, and when the coverage is doubled,βEFis nearly doubled. This controllable Ag NPs/GS hybrid is capable of serving as a high performance SERS substrate for efficient chemical and biological sensing applications.

scholarly journals Versatile Silver Nanoparticles-Based SERS Substrate with High Sensitivity and Stability

Applied Nano ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 242-256
Author(s):  
Mimi Liu ◽  
Anjuli Bhandari ◽  
Mujtaba Ali Haqqani Mohammed ◽  
Daniela R. Radu ◽  
Cheng-Yu Lai
Keyword(s):  
Silver Nanoparticles ◽  
Design Patterns ◽  
Field Enhancement ◽  
High Sensitivity ◽  
Sers Substrate ◽  
Ag Nps ◽  
Particle Spacing ◽  
Analytical Technique ◽  
Nanomolar Detection ◽  
Surface Enhanced Raman

Surface-enhanced Raman scattering has developed into a mature analytical technique useful in various applications; however, the reproducible fabrication of a portable SERS substrate with high sensitivity and good uniformity is still an ongoing pursuit. Reported herein is a rapid fabrication method of an inexpensive SERS substrate that enables sub-nanomolar detection of molecular analytes. The SERS substrate is obtained by application of silver nanoparticles (Ag NPs)-based ink in precisely design patterns with the aid of an in-house assembled printer equipped with a user-fillable pen. Finite-difference time-domain (FDTD) simulations show a 155-times Ag NP electric field enhancement for Ag nanoparticle pairs with particle spacing of 2 nm. By comparing the SERS performance of SERS substrate made with different support matrices and fabrication methods, the PET-printed substrate shows optimal performance, with an estimated sensitivity enhancement factor of 107. The quantitative analysis of rhodamine 6G absorbed on optimized SERS substrate exhibits a good linear relationship, with a correlation coefficient (R2) of 0.9998, between the SERS intensity at 610 cm−1 and the concentration in the range of 0.1 nM—1μM. The practical low limit detection of R6G is 10 pM. The optimized SERS substrates show good stability (at least one month) and have been effectively tested in the detection of cancer drugs, including doxorubicin and metvan.

scholarly journals Comparative Performance of Citrate, Borohydride, Hydroxylamine and β-Cyclodextrin Silver Sols for Detecting Ibuprofen and Caffeine Pollutants by Means of Surface-Enhanced Raman Spectroscopy

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2339
Author(s):  
Michele Lemos de Souza ◽  
Juan Carlos Otero ◽  
Isabel López-Tocón
Keyword(s):  
Raman Spectroscopy ◽  
Emerging Contaminants ◽  
Limit Of Detection ◽  
Surface Enhanced Raman Spectroscopy ◽  
Molar Ratio ◽  
Sers Substrate ◽  
Comparative Performance ◽  
Sers Signal ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

The detection of emerging contaminants in the aquatic environment, such as ibuprofen and caffeine, was studied by means of surface-enhanced Raman spectroscopy (SERS) using Ag nanoparticles (AgNPs) synthesized with β-cyclodextrin (βCD) as a reducing agent. The effect on the SERS signal of different molar ratios of Ag+/βCD in the synthesis route and the aging process of AgNPs were investigated by using trans-cinnamic as a test molecule. The SERS effectiveness of these β-cyclodextrin colloids (Ag@βCD) was also checked and compared with that of other silver sols usually employed in SERS synthesized by using other reducing agents such as citrate, borohydride and hydroxylamine. All the synthesized SERS substrates were characterized by different techniques. The experimental results indicate that Ag@βCD with the more diluted Ag+/βCD molar ratio showed the best SERS signal, enabling detection at trace concentrations of 0.5 µM in the case of trans-cinnamic acid. The Ag@βCD sols also showed the best sensitivity for detecting ibuprofen and caffeine, reaching the lowest limit of detection (0.1 mM). The proposed synthetic route for Ag@βCD sols provides an improved SERS substrate for detecting organic pollutants with better performance than other standard silver sols.

scholarly journals Using Si/MoS2 Core-Shell Nanopillar Arrays Enhances SERS Signal

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 733
Author(s):  
Tsung-Shine Ko ◽  
Han-Yuan Liu ◽  
Jiann Shieh ◽  
De Shieh ◽  
Szu-Hung Chen ◽  
...  
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Detection Efficiency ◽  
Core Shell ◽  
Sers Substrate ◽  
Sers Signal ◽  
Sers Substrates ◽  
Surface Enhanced Raman ◽  
Signal Peak ◽  
Enhanced Raman Scattering

Two-dimensional layered material Molybdenum disulfide (MoS2) exhibits a flat surface without dangling bonds and is expected to be a suitable surface-enhanced Raman scattering (SERS) substrate for the detection of organic molecules. However, further fabrication of nanostructures for enhancement of SERS is necessary because of the low detection efficiency of MoS2. In this paper, period-distribution Si/MoS2 core/shell nanopillar (NP) arrays were fabricated for SERS. The MoS2 thin films were formed on the surface of Si NPs by sulfurizing the MoO3 thin films coated on the Si NP arrays. Scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy were performed to characterize Si/MoS2 core-shell nanostructure. In comparison with a bare Si substrate and MoS2 thin film, the use of Si/MoS2 core-shell NP arrays as SERS substrates enhances the intensity of each SERS signal peak for Rhodamine 6G (R6G) molecules, and especially exhibits about 75-fold and 7-fold enhancements in the 1361 cm−1 peak signal, respectively. We suggest that the Si/MoS2 core-shell NP arrays with larger area could absorb more R6G molecules and provide larger interfaces between MoS2 and R6G molecules, leading to higher opportunity of charge transfer process and exciton transitions. Therefore, the Si/MoS2 core/shell NP arrays could effectively enhance SERS signal and serve as excellent SERS substrates in biomedical detection.

scholarly journals Facilely Flexible Imprinted Hemispherical Cavity Array for Effective Plasmonic Coupling as SERS Substrate

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3196
Author(s):  
Jihua Xu ◽  
Jinmeng Li ◽  
Guangxu Guo ◽  
Xiaofei Zhao ◽  
Zhen Li ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Mechanical Stability ◽  
Coupling Effect ◽  
Low Cost ◽  
Flexible Substrate ◽  
Localized Surface Plasmon ◽  
Sers Substrate ◽  
Ag Nps ◽  
Surface Enhanced Raman ◽  
Sers Detection

The focusing field effect excited by the cavity mode has a positive coupling effect with the metal localized surface plasmon resonance (LSPR) effect, which can stimulate a stronger local electromagnetic field. Therefore, we combined the self-organizing process for component and array manufacturing with imprinting technology to construct a cheap and reproducible flexible polyvinyl alcohol (PVA) nanocavity array decorating with the silver nanoparticles (Ag NPs). The distribution of the local electromagnetic field was simulated theoretically, and the surface-enhanced Raman scattering (SERS) performance of the substrate was evaluated experimentally. The substrate shows excellent mechanical stability in bending experiments. It was proved theoretically and experimentally that the substrate still provides a stable signal when the excited light is incident from different angles. This flexible substrate can achieve low-cost, highly sensitive, uniform and conducive SERS detection, especially in situ detection, which shows a promising application prospect in food safety and biomedicine.

Sign in / Sign up

Export Citation Format

Share Document