Liquid Surface-Enhanced Raman Spectroscopy (SERS) Sensor-Based Au-Ag Colloidal Nanoparticles for Easy and Rapid Detection of Deltamethrin Pesticide in Brewed Tea

Deltamethrin pesticides can cause inflammation, nephrotoxicity and hepatotoxicity as well as affect the activity of antioxidant enzymes in tissues. As a result of this concern, there is a rising focus on the development of fast and reliable pesticide residue testing to minimise potential risks to humans. The goal of this study is to use Au-Ag colloid nanoparticles as liquid surface-enhanced Raman spectroscopy (SERS) to improve the Raman signal in the detection of deltamethrin pesticide in a brewed tea. The liquid SERS system is fascinating to study due to its ease of use and its unlikeliness to cause several phenomena, such as photo-bleaching, combustion, sublimation and even photo-catalysis, which can interfere with the Raman signal, as shown in the SERS substrate. Our liquid SERS system is simpler than previous liquid SERS systems that have been reported. We performed the detection of pesticide analyte directly on brewed tea, without diluting it with ethanol or centrifuging it. Femtosecond laser-induced photo-reduction was employed to synthesise the liquid SERS of Au, Au-Ag, and Ag colloidal nanoparticles. The SERS was utilised to detect deltamethrin pesticide in brewed tea. The result showed that liquid SERS-based Ag NPs significantly enhance the Raman signal of pesticides compared with liquid SERS-based Au NPs and Au-Ag Nanoalloys. The maximum residue limits (MRLs) in tea in Indonesia are set at 10 ppm. Therefore, this method was also utilised to detect and improve, to 0.01 ppm, the deltamethrin pesticide Limit of Detection (LOD).

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Cascaded microsphere-coupled surface-enhanced Raman spectroscopy (CMS-SERS) for ultrasensitive trace-detection

Nanophotonics ◽

10.1515/nanoph-2021-0620 ◽

2022 ◽

Vol 0 (0) ◽

Author(s):

Yanlin Mi ◽

Yinzhou Yan ◽

Mengyuan Wang ◽

Lixue Yang ◽

Jing He ◽

...

Keyword(s):

Raman Spectroscopy ◽

Limit Of Detection ◽

Surface Enhanced Raman Spectroscopy ◽

Sers Substrate ◽

Trace Detection ◽

Excitation Light ◽

Analytical Technique ◽

Nano Structures ◽

Surface Enhanced ◽

Surface Enhanced Raman

Abstract Surface-enhanced Raman spectroscopy (SERS) has been widely investigated and employed as a powerful optical analytical technique providing fingerprint vibrational information of molecules with high sensitivity and resolution. In addition to metallic nanostructure, dielectric micro-/nano-structures with extraordinary optical manipulation properties have demonstrated capability in enhanced Raman scattering with ultralow energy losses. Here we report a facile cascaded structure composed of a large microsphere (LMS) and a small microsphere array with Ag nanoparticles as a novel hybrid SERS substrate, for the first time. The cascaded microsphere-coupled SERS substrate provides a platform to increase the molecular concentration, boost the intensity of localized excitation light, and direct the far-field emission, for giant Raman enhancement. It demonstrates the maximum enhancement factor of Raman intensity greater than 108 for the limit of detection down to 10−11 M of 4-nitrothiphenol molecules in aqueous solution. The present work inspires a novel strategy to fabricate cascaded dielectric/metallic micro-/nano-structures superior to traditional SERS substrates towards practical applications in cost-effective and ultrahigh-sensitive trace-detection.

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Surface Enhanced Raman Spectroscopy for DNA Biosensors—How Far Are We?

Molecules ◽

10.3390/molecules24244423 ◽

2019 ◽

Vol 24 (24) ◽

pp. 4423 ◽

Cited By ~ 3

Author(s):

Edyta Pyrak ◽

Jan Krajczewski ◽

Artur Kowalik ◽

Andrzej Kudelski ◽

Aleksandra Jaworska

Keyword(s):

Raman Spectroscopy ◽

Limit Of Detection ◽

Surface Enhanced Raman Spectroscopy ◽

Diagnostic Tools ◽

Strong Increase ◽

Raman Signal ◽

Silver Nanostructures ◽

Dna Sensors ◽

Surface Enhanced ◽

Surface Enhanced Raman

A sensitive and accurate identification of specific DNA fragments (usually containing a mutation) can influence clinical decisions. Standard methods routinely used for this type of detection are PCR (Polymerase Chain Reaction, and its modifications), and, less commonly, NGS (Next Generation Sequencing). However, these methods are quite complicated, requiring time-consuming, multi-stage sample preparation, and specially trained staff. Usually, it takes weeks for patients to obtain their results. Therefore, different DNA sensors are being intensively developed by many groups. One technique often used to obtain an analytical signal from DNA sensors is Raman spectroscopy. Its modification, surface-enhanced Raman spectroscopy (SERS), is especially useful for practical analytical applications due to its extra low limit of detection. SERS takes advantage of the strong increase in the efficiency of Raman signal generation caused by a local electric field enhancement near plasmonic (typically gold and silver) nanostructures. In this condensed review, we describe the most important types of SERS-based nanosensors for genetic studies and comment on their potential for becoming diagnostic tools.

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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 ◽

10.3390/nano10122339 ◽

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.

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Genetic Algorithm-Driven Surface-Enhanced Raman Spectroscopy Substrate Optimization

Nanomaterials ◽

10.3390/nano11112905 ◽

2021 ◽

Vol 11 (11) ◽

pp. 2905

Author(s):

Buse Bilgin ◽

Cenk Yanik ◽

Hulya Torun ◽

Mehmet Cengiz Onbasli

Keyword(s):

Genetic Algorithm ◽

Raman Spectroscopy ◽

Strong Electric Field ◽

Surface Enhanced Raman Spectroscopy ◽

Raman Signal ◽

Sers Substrate ◽

Design Constraints ◽

Sers Substrates ◽

Surface Enhanced ◽

Surface Enhanced Raman

Surface-enhanced Raman spectroscopy (SERS) is a highly sensitive and molecule-specific detection technique that uses surface plasmon resonances to enhance Raman scattering from analytes. In SERS system design, the substrates must have minimal or no background at the incident laser wavelength and large Raman signal enhancement via plasmonic confinement and grating modes over large areas (i.e., squared millimeters). These requirements impose many competing design constraints that make exhaustive parametric computational optimization of SERS substrates prohibitively time consuming. Here, we demonstrate a genetic-algorithm (GA)-based optimization method for SERS substrates to achieve strong electric field localization over wide areas for reconfigurable and programmable photonic SERS sensors. We analyzed the GA parameters and tuned them for SERS substrate optimization in detail. We experimentally validated the model results by fabricating the predicted nanostructures using electron beam lithography. The experimental Raman spectrum signal enhancements of the optimized SERS substrates validated the model predictions and enabled the generation of a detailed Raman profile of methylene blue fluorescence dye. The GA and its optimization shown here could pave the way for photonic chips and components with arbitrary design constraints, wavelength bands, and performance targets.

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Rapid uropathogen identification using surface enhanced Raman spectroscopy active filters

Scientific Reports ◽

10.1038/s41598-021-88026-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Simon D. Dryden ◽

Salzitsa Anastasova ◽

Giovanni Satta ◽

Alex J. Thompson ◽

Daniel R. Leff ◽

...

Keyword(s):

Raman Spectroscopy ◽

Bacterial Infections ◽

Surface Enhanced Raman Spectroscopy ◽

Active Filters ◽

Raman Signal ◽

Rapid Diagnostics ◽

Bacterial Classification ◽

Surface Enhanced ◽

Surface Enhanced Raman

AbstractUrinary tract infection is one of the most common bacterial infections leading to increased morbidity, mortality and societal costs. Current diagnostics exacerbate this problem due to an inability to provide timely pathogen identification. Surface enhanced Raman spectroscopy (SERS) has the potential to overcome these issues by providing immediate bacterial classification. To date, achieving accurate classification has required technically complicated processes to capture pathogens, which has precluded the integration of SERS into rapid diagnostics. This work demonstrates that gold-coated membrane filters capture and aggregate bacteria, separating them from urine, while also providing Raman signal enhancement. An optimal gold coating thickness of 50 nm was demonstrated, and the diagnostic performance of the SERS-active filters was assessed using phantom urine infection samples at clinically relevant concentrations (105 CFU/ml). Infected and uninfected (control) samples were identified with an accuracy of 91.1%. Amongst infected samples only, classification of three bacteria (Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae) was achieved at a rate of 91.6%.

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Combining vancomycin-modified gold nanorod arrays and colloidal nanoparticles as the sandwich model for discrimination of gram-positive bacteria and their detection via surface-enhanced Raman spectroscopy (SERS)

The Analyst ◽

10.1039/d1an00321f ◽

2021 ◽

Author(s):

Araz Norouz Dizaji ◽

Nihal Simsek Ozek ◽

Ferhunde Aysin ◽

Ayfer Calis ◽

Asli Yilmaz ◽

...

Keyword(s):

Raman Spectroscopy ◽

Surface Enhanced Raman Spectroscopy ◽

Colloidal Nanoparticles ◽

Nanorod Arrays ◽

Gram Positive ◽

Gram Positive Bacteria ◽

Sensor Platform ◽

Highly Sensitive ◽

Surface Enhanced ◽

Surface Enhanced Raman

This study reports the development of a highly sensitive antibiotic-based discrimination and sensor platform for the detection of gram-positive bacteria through surface-enhanced Raman spectroscopy (SERS). Herein, the combination of gold...

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Fabrication-friendly polarization-sensitive plasmonic grating for optimal surface-enhanced Raman spectroscopy

Journal of the European Optical Society Rapid Publications ◽

10.1186/s41476-020-00144-5 ◽

2020 ◽

Vol 16 (1) ◽

Author(s):

Arpan Dutta ◽

Tarmo Nuutinen ◽

Khairul Alam ◽

Antti Matikainen ◽

Peng Li ◽

...

Keyword(s):

Raman Spectroscopy ◽

Fill Factor ◽

Surface Enhanced Raman Spectroscopy ◽

Transverse Magnetic ◽

Raman Signal ◽

Optical Resonance ◽

Excitation Light ◽

Surface Enhanced ◽

Surface Enhanced Raman ◽

Plasmonic Gratings

Abstract Plasmonic nanostructures are widely utilized in surface-enhanced Raman spectroscopy (SERS) from ultraviolet to near-infrared applications. Periodic nanoplasmonic systems such as plasmonic gratings are of great interest as SERS-active substrates due to their strong polarization dependence and ease of fabrication. In this work, we modelled a silver grating that manifests a subradiant plasmonic resonance as a dip in its reflectivity with significant near-field enhancement only for transverse-magnetic (TM) polarization of light. We investigated the role of its fill factor, commonly defined as a ratio between the width of the grating groove and the grating period, on the SERS enhancement. We designed multiple gratings having different fill factors using finite-difference time-domain (FDTD) simulations to incorporate different degrees of spectral detunings in their reflection dips from our Raman excitation (488 nm). Our numerical studies suggested that by tuning the spectral position of the optical resonance of the grating, via modifying their fill factor, we could optimize the achievable SERS enhancement. Moreover, by changing the polarization of the excitation light from transverse-magnetic to transverse-electric, we can disable the optical resonance of the gratings resulting in negligible SERS performance. To verify this, we fabricated and optically characterized the modelled gratings and ensured the presence of the desired detunings in their optical responses. Our Raman analysis on riboflavin confirmed that the higher overlap between the grating resonance and the intended Raman excitation yields stronger Raman enhancement only for TM polarized light. Our findings provide insight on the development of fabrication-friendly plasmonic gratings for optimal intensification of the Raman signal with an extra degree of control through the polarization of the excitation light. This feature enables studying Raman signal of exactly the same molecules with and without electromagnetic SERS enhancements, just by changing the polarization of the excitation, and thereby permits detailed studies on the selection rules and the chemical enhancements possibly involved in SERS.

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Detection of Triphenylmethane Drugs in Fish Muscle by Surface-Enhanced Raman Spectroscopy Coupled with Au-Ag Core-Shell Nanoparticles

Journal of Nanomaterials ◽

10.1155/2014/730915 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 18

Author(s):

Lu Pei ◽

Yiqun Huang ◽

Chunying Li ◽

Yuanyuan Zhang ◽

Barbara A. Rasco ◽

...

Keyword(s):

Raman Spectroscopy ◽

Malachite Green ◽

Crystal Violet ◽

Bimetallic Nanoparticles ◽

Limit Of Detection ◽

Fish Muscle ◽

Surface Enhanced Raman Spectroscopy ◽

Vis Spectroscopy ◽

Surface Enhanced ◽

Surface Enhanced Raman

Silver-coated gold bimetallic nanoparticles were synthesized and used as substrates for surface-enhanced Raman spectroscopy (SERS) in detecting prohibited triphenylmethane drugs (including crystal violet and malachite green) in fish muscle. The optical properties and physical properties of bimetallic nanospheres were characterized by UV-Vis spectroscopy and transmission electron microscopy. The optimal nanospheres selected had relatively uniform size (diameter: 33 ± 3 nm) with a silver layer coated on the surface of gold seed (diameter: 18 ± 2 nm). For both crystal violet and malachite green, characteristic SERS spectral features could be identified at concentration as low as 0.1 μg/L with these bimetallic nanospheres. Crystal violet and malachite green residues in fish muscle could also be detected at levels as low as 0.1 ng/g, which could meet the most restricted regulatory requirements for the limit of detection in terms of analytical methods for crystal violet or malachite green in fish muscle. This study provides a basis for applying SERS technology with bimetallic nanoparticles to the identification of trace amounts of prohibited substances in aquatic food products, and the methodology could be extended to analyses of other hazardous chemicals in complex food matrices like vegetables and meats.

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Detection and Differentiation of Avian Mycoplasmas by Surface-Enhanced Raman Spectroscopy Based on a Silver Nanorod Array

Applied and Environmental Microbiology ◽

10.1128/aem.07419-11 ◽

2011 ◽

Vol 78 (6) ◽

pp. 1930-1935 ◽

Cited By ~ 23

Author(s):

Suzanne L. Hennigan ◽

Jeremy D. Driskell ◽

Naola Ferguson-Noel ◽

Richard A. Dluhy ◽

Yiping Zhao ◽

...

Keyword(s):

Raman Spectroscopy ◽

Sensitivity And Specificity ◽

Limit Of Detection ◽

Direct Detection ◽

Nanorod Array ◽

Surface Enhanced Raman Spectroscopy ◽

Mycoplasma Species ◽

Content Type ◽

Surface Enhanced ◽

Surface Enhanced Raman

ABSTRACTMycoplasma gallisepticumis a bacterial pathogen of poultry that is estimated to cause annual losses exceeding $780 million. The National Poultry Improvement Plan guidelines recommend regular surveillance and intervention strategies to containM. gallisepticuminfections and ensure mycoplasma-free avian stocks, but several factors make detection ofM. gallisepticumand diagnosis ofM. gallisepticuminfection a major challenge. Current techniques are laborious, require special expertise, and are typically plagued by false results. In this study, we describe a novel detection strategy which uses silver nanorod array–surface-enhanced Raman spectroscopy (NA-SERS) for direct detection of avian mycoplasmas. As a proof of concept for use in avian diagnostics, we used NA-SERS to detect and differentiate multiple strains of avian mycoplasma species, includingAcholeplasma laidlawii,Mycoplasma gallinarum,Mycoplasma gallinaceum,Mycoplasma synoviae, andM. gallisepticum, including vaccine strains 6/85, F, and ts-11. Chemometric multivariate analysis of spectral data was used to classify these species rapidly and accurately, with >93% sensitivity and specificity. Furthermore, NA-SERS had a lower limit of detection that was 100-fold greater than that of standard PCR and comparable to that of real-time quantitative PCR. Detection ofM. gallisepticumin choanal cleft swabs from experimentally infected birds yielded good sensitivity and specificity, suggesting that NA-SERS is applicable for clinical detection.

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