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 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 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 ◽  
Sers Substrate ◽  
Structure Property ◽  
Contrast Imaging ◽  
Structure Property Relationships ◽  
High Contrast Imaging ◽  
Surface Enhanced Raman ◽  
Versatile Tool ◽  
Background Continuum

Abstract 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. To address this limitation, we show the distinct correlation of the ever-present but often neglected broad SERS background continuum with the SERS signal intensity of the analyte and how to exploit this correlation for an easy-to-handle, automatable and more reliable SERS measurement. First, fast and high-contrast imaging of the SERS substrate is performed for hot spot localisation utilizing the SERS background. Subsequently, highly enhanced SERS spectra are recorded at the centre of these spots. Furthermore, we correlate our SERS background imaging with other optical imaging modalities and electron microscopy to assess structure-property relationships. Monte Carlo simulations based on actual measurements illustrate the sampling error of a conventional SERS experiment and the advantages our method provides.

scholarly journals SERS background imaging – A versatile tool towards more reliable SERS analytics

2021 ◽  
Author(s):  
Paul Ebersbach ◽  
Ute Münchberg ◽  
Erik Freier
Keyword(s):  
Sampling Error ◽  
Hot Spot ◽  
Sers Substrate ◽  
Structure Property ◽  
Contrast Imaging ◽  
Structure Property Relationships ◽  
High Contrast Imaging ◽  
Surface Enhanced Raman ◽  
Versatile Tool ◽  
Background Continuum

Abstract 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. To address this limitation, we show the distinct correlation of the ever-present but often neglected broad SERS background continuum with the SERS signal intensity of the analyte and how to exploit this correlation for an easy-to-handle, automatable and more reliable SERS measurement. First, fast and high-contrast imaging of the SERS substrate is performed for hot spot localisation utilizing the SERS background. Subsequently, highly enhanced SERS spectra are recorded at the centre of these spots. Furthermore, we correlate our SERS background imaging with other optical imaging modalities and electron microscopy to assess structure-property relationships. Monte Carlo simulations based on actual measurements illustrate the sampling error of a conventional SERS experiment and the advantages our method provides.

scholarly journals Three-Dimensional Hierarchical Reticular Nanostructure of Fulfora candelaria Wing Decorated by Ag Nanoislands as Practical SERS-Active Substrates

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 905 ◽  
Author(s):  
Mingli Wang ◽  
Yuhong Wang ◽  
Xiaoya Yan ◽  
Xin Sun ◽  
Guochao Shi ◽  
...  
Keyword(s):  
Hot Spot ◽  
Three Dimensional ◽  
Fdtd Simulation ◽  
Raman Signal ◽  
Sers Substrate ◽  
Practical Applications ◽  
Recognition Ability ◽  
Surface Enhanced Raman ◽  
Signal Sensitivity ◽  
Biological Substrates

Although surface-enhanced Raman scattering (SERS) technology has been widely explored nowadays in various fields, the fabrication of practical SERS-active substrates with prominent recognition ability for various analyte molecules is still defective. Natural Fulfora candelaria wing (FCW) with three-dimensional (3D) hierarchical reticular nanostructure was selected as a new bioscaffold for rough silver (Ag) nanoislands to be assembled on to prepare a practical SERS substrate (Ag/FCW substrate). By adjusting the sputtering time of metal Ag, the morphology of the substrates could be easily tuned to control the formation and distribution of “hot spots”. Three-dimensional finite-difference time-domain (3D-FDTD) simulation indicated that the excellent SERS performance under optimal morphology was ascribed to the local enhanced electric field in rough Ag surface and effective “hot spot” areas. The SERS measurement results show that the optimal Ag/FCW substrates had high SERS performance in terms of Raman signal sensitivity, reproducibility, uniformity and recognition ability for various analyte molecules. Coupled with flexibility of the biological substrates and the cost effectiveness, the sensitive SERS detection of varied analytes based on Ag/FCW substrates offered great potential for practical applications.

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 Quantitative SERS by hot spot normalization – surface enhanced Rayleigh band intensity as an alternative evaluation parameter for SERS substrate performance

2017 ◽  
Vol 205 ◽  
pp. 491-504 ◽  
Author(s):  
Haoran Wei ◽  
Alexis McCarthy ◽  
Junyeob Song ◽  
Wei Zhou ◽  
Peter J. Vikesland
Keyword(s):  
Hot Spot ◽  
Surface Enhanced Raman Spectroscopy ◽  
Sers Substrate ◽  
Alternative Evaluation ◽  
Plasmonic Nanoparticle ◽  
Sers Substrates ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Excitation Volume ◽  
Quantitative Sers

The performance of surface-enhanced Raman spectroscopy (SERS) substrates is typically evaluated by calculating an enhancement factor (EF). However, it is challenging to accurately calculate EF values since the calculation often requires the use of model analytes and requires assumptions about the number of analyte molecules within the laser excitation volume. Furthermore, the measured EF values are target analyte dependent and thus it is challenging to compare substrates with EF values obtained using different analytes. In this study, we propose an alternative evaluation parameter for SERS substrate performance that is based on the intensity of the surface plasmon enhanced Rayleigh band (IRayleigh) that originates from the amplified spontaneous emission (ASE) of the laser. Compared to the EF, IRayleigh reflects the enhancing capability of the substrate itself, is easy to measure without the use of any analytes, and is universally applicable for the comparison of SERS substrates. Six SERS substrates with different states (solid, suspended in liquid, and hydrogel), different plasmonic nanoparticle identities (silver and gold), as well as different nanoparticle sizes and shapes were used to support our hypothesis. The results show that there are excellent correlations between the measured SERS intensities and IRayleigh as well as between the SERS homogeneity and the variation of IRayleigh acquired with the six SERS substrates. These results suggest that IRayleigh can be used as an evaluation parameter for both SERS substrate efficiency and reproducibility.

scholarly journals Quantizing single-molecule surface-enhanced Raman scattering with DNA origami metamolecules

2019 ◽  
Vol 5 (9) ◽  
pp. eaau4506 ◽  
Author(s):  
Weina Fang ◽  
Sisi Jia ◽  
Jie Chao ◽  
Liqian Wang ◽  
Xiaoyang Duan ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Single Molecule ◽  
Hot Spot ◽  
Surface Enhanced Raman Scattering ◽  
Dna Origami ◽  
Sers Spectrum ◽  
Metal Nanoclusters ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Tailored metal nanoclusters have been actively developed to manipulate light at the subwavelength scale for nanophotonic applications. Nevertheless, precise arrangement of molecules in a hot spot with fixed numbers and positions remains challenging. Here, we show that DNA origami metamolecules with Fano resonances (DMFR) can precisely localize single dye molecules and produce quantified surface-enhanced Raman scattering (SERS) responses. To enable tailored plasmonic permutations, we develop a general and programmable method for anchoring a set of large gold nanoparticles (L-AuNPs) on prescribed n-tuple docking sites of super-origami DNA frameworks. A tetrameric nanocluster with four spatially organized 80-nm L-AuNPs exhibits peak-and-dip Fano characteristics. The drastic enhancement at the wavelength of the Fano minimum allows the collection of prominent SERS spectrum for even a single dye molecule. We expect that DMFR provides physical insights into single-molecule SERS and opens new opportunities for developing plasmonic nanodevices for ultrasensitive sensing, nanocircuits, and nanophotonic lasers.

Synthesis of Silver Nanoparticles through the Soft Template Method and their Applications to Surface-Enhanced Raman Scattering

2013 ◽  
Vol 395-396 ◽  
pp. 158-161 ◽  
Author(s):  
Yu Dong Lu ◽  
Xia Xia Chen ◽  
Li Hui Chen
Keyword(s):  
Silver Nanoparticles ◽  
Raman Scattering ◽  
Carboxymethyl Cellulose ◽  
Surface Enhanced Raman Scattering ◽  
Soft Template ◽  
Sers Spectrum ◽  
Sers Substrate ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Silver Nanoparticles has been prepared using the complex of carboxymethyl cellulose (CMC) and Polyvinylpyrrolidone (PVP) as a template and used as SERS substrate. The effect of the ratio of CMC to PVP on silver nanoparticles was discussed. Silver Nanoparticles were characterized by UV-visible spectroscopy, transmission electron microscopy and Raman spectroscopy. The results show that the ratio of CMC to PVP plays a crucial role in the performance of nanoparticles. TEM studies reveal that particles are mostly near-spherical in shape with an average size of 60-70 nm. The SERS enhancement of these silver nanoparticles was tested by using Rhodamine 6G (R6G) as a probe molecule. The silver nanoparticles prepared with the complex of CMC and PVP as a template have been shown to provide strong enhancements in the SERS spectrum of R6G. Keywords: Carboxymethyl cellulose; Polyvinylpyrrolidone; Surface-enhanced Raman scattering; silver; Template

scholarly journals Tannin-furanic foams used as biomaterial substrates for SERS sensing in possible wastewater filter applications

2021 ◽  
Vol 8 (11) ◽  
pp. 115404
Author(s):  
Gebhard Sabathi ◽  
Andreas Reyer ◽  
Nicola Cefarin ◽  
Thomas Sepperer ◽  
Jonas Eckardt ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Hot Spot ◽  
Surface Enhanced Raman Spectroscopy ◽  
Silver Layer ◽  
Sers Substrate ◽  
Malachite Green Dye ◽  
Relative Standard ◽  
Surface Enhanced Raman ◽  
Potential Applications ◽  
Cost Efficient

Abstract Simple substrates for surface enhanced Raman spectroscopy (SERS), producible in a cost-efficient way, are of growing interest both for scientific and for environmental applications. In this study, we demonstrate the use of three types of bio-based tannin-furanic rigid foams as precursor materials for SERS substrates. Coated with a silver layer, these substrates allowed the detection of several well-known analytes in the mM regime by Raman spectroscopy. Specific optimization of the standard tannin-furanic foam morphology by tuning the chemical synthesis led to a smaller and more homogeneously distributed pore structure, supplying more active hot spot areas. Thus, we obtained a significant increase and a lower relative standard deviation (RSD) of the SERS signal recorded over the mapped SERS substrate area, for several analytes, in particular for Malachite Green dye. This work represents a feasibility study opening several potential applications of this biopolymers in fields such as the detection of water pollutants, virtually combining filtration and SERS capabilities driven by a controlled porosity.

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