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Surface-enhanced Raman spectroscopy (SERS) has gained increasing attention for sensing chemicals and molecules at low concentrations. Localized surface plasmons (LSPs) that occur on metal nanostructures can be used to enhance small Raman signals while maintaining the non-destructivity of Raman spectroscopy. SERS can be used to detect consumer chemical products that effect on the human body through the ecosystem. In addition, there is increasing demand for its use in personal disease-monitoring systems. SERS materials can be made in various forms using metal nanoparticles (NPs) that can produce LSPs. Recently, nanotechnology has been used to fabricate SERS materials with high selectivity for target materials by finely controlling the structure. Since the structure affects the enhancement of Raman signals, research into various nanostructures is important for next-generation SERS sensors. Herein, we first discuss various fabrication of SERS dispersions and substrates using plasmonic metal NPs. Afterward, we summarize the enhancement factor (EF) and limit of detection (LOD) values of SERS materials prepared via various fabrication methods. [ABSTRACT FROM AUTHOR]

AbstractIn this study, the surface-enhanced Raman spectroscopy spectra of dimethyl methyl phosphonate, which serves as a surrogate for the chemical warfare agent sarin, were modeled using density functional theory calculations. In addition, the fundamental mechanisms underlying the enhancement of surface-enhanced Raman spectroscopy are investigated. A comprehensive examination was conducted of the adsorption behavior and Surface-Enhanced Raman Spectroscopy enhancement effects resulting from the interaction between dimethyl methylphosphonate and silver clusters. Moreover, a comparison was made between the findings of the present study and the results of previous experiments in order to ascertain the optimal positions for the adsorption of silver clusters on dimethyl methylphosphonate molecules. In this article, the kinetics of the interaction between dimethyl methylphosphonate and silver clusters were theoretically explored through six different adsorption configurations. It was found that the configuration involving the dimethyl methylphosphonate structure and silver clusters containing three silver atoms exhibited the highest stability. By integrating Raman spectroscopic data with our theoretical insights, the vibrational modes, Raman spectra, and surface-enhanced Raman spectra of dimethyl methylphosphonate molecules were systematically correlated using Gaussian 09 and GaussView 5.0.8 software for detailed image-based analysis. [ABSTRACT FROM AUTHOR]

Abstract With the growing global challenge of drug abuse, there is an urgent need for rapid, accurate, and cost-effective drug detection methods. This study introduces an innovative approach to drug abuse screening by quickly detecting ephedrine (EPH) in tears using drop coating deposition-surface enhanced Raman spectroscopy (DCD-SERS) combined with machine learning (ML). Using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), the average concentration of EPH in tear fluid of Sprague-Dawley (SD) rats, measured over 3 h post-injection, was 1235 ng/mL. DCD-SERS effectively identified EPH in tear samples, with distinct Raman peaks observed at 1001 cm−1 and 1242 cm−1. To enable rapid analysis of complex SERS data, three ML algorithms—linear discriminant analysis (LDA), partial least squares discriminant analysis (PLS-DA), and random forest (RF)—were employed. These algorithms achieved over 90% accuracy in distinguishing between EPH-injected and non-injected SD rats, with area under the ROC curve (AUC) values ranging from 0.9821 to 0.9911. This approach offers significant potential for law enforcement by being easily accessible, non-invasive and ethically appropriate for examinees, while being rapid, accurate, and affordable for examiners.

ABSTRACT: Surface enhanced Raman spectroscopy (SERS) offers many advantages for the fast and sensitive detection of specific compounds, metal ions or pathogens in foods, motivating to its increasing utilization in food safety. SERS-tags, typically constructed using signal enhanced substrate, Raman reporter molecules, a biocompatible protective layer and a specific recognition element, provide a powerful tool for the analysis of food hazards. This article reviews recent progress in the development of SERS-tags for food safety assessment covering SERS-tags with characteristic peaks in the “fingerprint” region (800–1 800 cm–1) and the “biological-silent” region (1 800–2 800 cm–1). Following a brief description of SERS substrates, the design, synthesis and applications of SERS-tag are explored in detail. The application of SERS-tags technology for the detection of microorganisms, pesticides and antibiotics are then investigated. Finally, the prospects of using SERS-tag in real-world food safety analysis are critically discussed.

Umesh Chandra Garnaik,1 Anshuman Chandra,1 Vijay Kumar Goel,1 Balázs Gulyás,2 Parasuraman Padmanabhan,2 Shilpi Agarwal1 1School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India; 2Cognitive Neuroimaging Centre, Nanyang Technological University (NTU), Singapore, SingaporeCorrespondence: Shilpi Agarwal, Optics and Photonics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi, 110067, India, Email shilpiagarwal@mail.jnu.ac.in Parasuraman Padmanabhan, Cognitive Neuroimaging Centre, Nanyang Technological University (NTU), Singapore, 636921, Singapore, Email ppadmanabhan@ntu.edu.sgPurpose: Development of SERS-based Raman nanoprobes can detect the misfolding of Amyloid beta (Aβ) 42 peptides, making them a viable diagnostic technique for Alzheimer’s disease (AD). The detection and imaging of amyloid peptides and fibrils are expected to help in the early identification of AD.Methods: Here, we propose a fast, easy-to-use, and simple scheme based on the selective adsorption of Aβ 42 molecules on SERS active gold nanoprobe (RB-AuNPs) of diameter 29 ± 3 nm for Detection of Alzheimer’s Disease Biomarkers. Binding with the peptides results in a spectrum shift, which correlates with the target peptide. We also demonstrated the possibility of using silver nanoparticles (AgNPs) as precursors for the preparation of a SERS active nanoprobe with carbocyanine (CC) dye and AgNPs known as silver nanoprobe (CC-AgNPs) of diameter 25 ± 4 nm.Results: RB-AuNPs probe binding with the peptides results in a spectrum shift, which correlates with the target peptide. Arginine peak appears after the conjugation confirms the binding of Aβ 42 with the nanoprobe. Tyrosine peaks appear after conjugated Aβ 42 with CC-AgNPs providing binding of the peptide with the probe. The nanoprobe produced a strong, stable SERS signal. Further molecular docking was utilized to analyse the interaction and propose a structural hypothesis for the process of binding the nanoprobe to Aβ 42 and Tau protein.Conclusion: This peptide–probe interaction provides a general enhancement factor and the molecular structure of the misfolded peptides. Secondary structural information may be obtained at the molecular level for specific residues owing to isotope shifts in the Raman spectra. Conjugation of the nanoprobe with Aβ 42 selectively detected AD in bodily fluids. The proposed nanoprobes can be easily applied to the detection of Aβ plaques in blood, saliva, and sweat samples.Keywords: Alzheimer’s disease, nanoparticles, amyloid beta, surface enhanced Raman spectroscopy

A composite comprising a silver nanoparticles‐loaded poly(amidoamine) (PAMAM) dendrimer crosslinked with glutaraldehyde (PAMAM/AgNPs) is synthesized using a one‐step method under vortex at room temperature. The structure of glutaraldehyde‐crosslinked PAMAM dendrimer is characterized using FTIR and high‐resolution magic angle spinning–carbon 13 nuclear magnetic resonance (HRMAS 13C NMR) spectroscopy. The crosslinking structure ensures the uniformity and stability of the Ag nanoparticles, and the flexibility of the PAMAM/AgNPs composite. X‐ray diffraction (XRD) analysis and energy dispersive spectroscopy (EDS) confirm the formation of Ag nanoparticles in the PAMAM/AgNPs composite. Scanning electron microscopy (SEM) and three‐dimensional (3D) micro‐Raman images reveal the coarsely porous 3D micro‐structure of the PAMAM/AgNPs composite. This unique micro‐3D architecture provides the PAMAM/AgNPs composite with spongy flexibility and a swab‐like nature, which is advantageous for the rapid and effective absorption of liquid samples on the surfaces of objects. Surface enhanced Raman spectroscopy (SERS) indicates that the detection limits of both rhodamine 6G (R6G) and thiram are 1.0 × 10−5 mol L−1, and the SERS enhancement factor of R6G is determined to be 1.35 × 104. The spongy flexible PAMAM/AgNPs SERS substrate therefore has potential for use in Raman active compound detection. [ABSTRACT FROM AUTHOR]

Plant pathogens, including viruses, bacteria, and fungi, cause massive crop losses around the world. Abiotic stresses, such as drought, salinity and nutritional deficiencies are even more detrimental. Timely diagnostics of plant diseases and abiotic stresses can be used to provide site- and doze-specific treatment of plants. In addition to the direct economic impact, this "smart agriculture" can help minimizing the effect of farming on the environment. Mounting evidence demonstrates that vibrational spectroscopy, which includes Raman (RS) and infrared spectroscopies (IR), can be used to detect and identify biotic and abiotic stresses in plants. These findings indicate that RS and IR can be used for in-field surveillance of the plant health. Surface-enhanced RS (SERS) has also been used for direct detection of plant stressors, offering advantages over traditional spectroscopies. Finally, all three of these technologies have applications in phenotyping and studying composition of crops. Such noninvasive, non-destructive, and chemical-free diagnostics is set to revolutionize crop agriculture globally. This review critically discusses the most recent findings of RS-based sensing of biotic and abiotic stresses, as well as the use of RS for nutritional analysis of foods. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work reports on the development of an analyte sampling strategy on a plasmonic substrate to amplify the detection capability of a dual analytical system, paper spray ionization–mass spectrometry (PSI-MS) and surface-enhanced Raman spectroscopy (SERS). While simply applying only an analyte solution to the plasmonic paper results in a limited degree of SERS enhancement, the introduction of plasmonic gold nanoparticles (AuNPs) greatly improves the SERS signals without sacrificing PSI-MS sensitivity. It is initially revealed that the concentration of AuNPs and the type of analytes highly influence the SERS signals and their variations due to the "coffee ring effect" flow mechanism induced during sampling and the degree of the interfacial interactions (e.g., van der Waals, electrostatic, covalent) between the plasmonic substrate and analyte. Subsequent PSI treatment at high voltage conditions further impacts the overall SERS responses, where the signal sensitivity and homogeneity significantly increase throughout the entire substrate, suggesting the ready migration of adsorbed analytes regardless of their interfacial attractive forces. The PSI-induced notable SERS enhancements are presumably associated with creating unique conditions for local aggregation of the AuNPs to induce effective plasmonic couplings and hot spots (i.e., electromagnetic effect) and for repositioning analytes in close proximity to a plasmonic surface to increase polarizability (i.e., chemical effect). The optimized sampling and PSI conditions are also applicable to multi-analyte analysis by SERS and MS, with greatly enhanced detection capability and signal uniformity. [ABSTRACT FROM AUTHOR]

ObjectiveTo develop a rapid and quantitative method for the detection of enrofloxacin in chicken and pork using magnetic solid phase extraction （MSPE） combined with surface enhanced Raman spectroscopy （SERS）.MethodsMagnetic Fe3O4@ covalent organic framework （COF） nanocomposites were synthesized and applied as absorbent to separate and enrich enrofloxacin. The SERS spectra of enrofloxacin were collected by a portable Raman spectrometer with Ag nanoparticles as enhancing substrate. The characteristic SERS signals of enrofloxacin were used to realize its quantification.ResultsIntensities of SERS signals at 745.77 cm-1 and the logarithmic values of the concentrations of enrofloxacin in the range of 5.0×10-7 to 1.0×10-5 mol/L displayed a good linear relationship with a coefficient of determination of 0.962. The limit of detection and limit of quantitation were 0.07 and 0.23 µg/g respectively. The recoveries of enrofloxacin in chicken and pork were 80.97%~100.98% with relative standard deviations of 1.6%~4.6%.ConclusionThe developed method has the advantages of simple in operate， short in time， high in sensitivity and stability， which provides a new method for the rapid detection and on-site detection of enrofloxacin.

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

While extensive research has focused on understanding the degradation mechanisms of Poly(vinyl acetate) (PVAC) paint under different environmental conditions, limited attention has been paid to the long-term stability of PVAC-based white glues, especially when used in artworks. This study investigates the accelerated degradation, under simulated photoaging, and isothermal treatment of a commercial PVAC-based white glue considered representative of this class of materials used in contemporary artworks to predict its durability and assess its behavior in art objects. Through accelerated aging experiments and comparison with natural aging observed in artworks, the study reveals the formation of chromophores and the release of plasticizers as key processes; in particular, the progressive darkening was considered an early indicator of degradation processes, before structural changes could be detected by FTIR or NMR spectroscopies. The plasticizer loss induces an increase in glass transition temperature, from 7 °C to temperatures higher than room temperature, affecting the adhesive's cohesive strength and contributing to the detachment of materials in artworks. The findings underscore the importance of preventive conservation measures to mitigate degradation issues in PVAC-based artworks. [ABSTRACT FROM AUTHOR]

Determination of antibiotic residues using surface enhanced Raman spectroscopy (SERS) based methods is simple to operate and time-efficient, but susceptible to the interference of the sample matrix. In this study, 4-MBN which has characteristic signal in the biological samples Raman signal silent region is used as the signal molecule to construct the SERS probe.Fe3O4 nanoparticles functionalized with aptamer (Apt) are used as the capture probe. And the SERS probe and the capture probe are used to assemble a composite probe through the hybridization of the complementary DNA (cDNA) in the SERS probe and Apt in the capture probe. In the presence of enrofloxacin, the aptamer in the composite probe binds specifically to enrofloxacin, leading to the release of the SERS probe.The intensity of the characteristic SERS signal of 4-MBN at the Raman shift of 2 227 cm-1 shows a good linear correlation with the logarithm value of enrofloxacin concentration in the range of 1～500 nM,with a determination coefficient of 0.99 and a detection limit of 0.07 nM.The recovery rate of enrofloxacin detection in fish and pork is between 84.0%～109.0%,and the relative standard deviation is varied in 0.2%～0.8%.The results provide a new method for the rapid detection of enrofloxacin in complex matrices. [ABSTRACT FROM AUTHOR]

Recent progress of surface-enhanced Raman spectroscopy (SERS) in malignant tumors is reviewed. Firstly, the development status of SERS detection technology was briefly introduced, and the advantages of SERS detection technology were put forward. Secondly, the development status of SERS technology in multi-system malignant tumor species was reviewed. Finally, the application of SERS in the diagnosis of multi-system malignant tumors was summarized and analyzed, and the prospect was put forward. [ABSTRACT FROM AUTHOR]

Surface enhanced resonance Raman (SERS) is a powerful optical technique, which can help enhance the sensitivity of Raman spectroscopy aided by noble metal nanoparticles (NPs). However, current SERS‐NPs are often suboptimal, which can aggregate under physiological conditions with much reduced SERS enhancement. Herein, a robust one‐pot method has been developed to synthesize SERS‐NPs with more uniform core diameters of 50 nm, which is applicable to both non‐resonant and resonant Raman dyes. The resulting SERS‐NPs are colloidally stable and bright, enabling NP detection with low‐femtomolar sensitivity. An algorithm has been established, which can accurately unmix multiple types of SERS‐NPs enabling potential multiplex detection. Furthermore, a new liposome‐based approach has been developed to install a targeting carbohydrate ligand, i.e., hyaluronan, onto the SERS‐NPs bestowing significantly enhanced binding affinity to its biological receptor CD44 overexpressed on tumor cell surface. The liposomal hyaluronan (HA)‐SERS‐NPs enabled visualization of spontaneously developed breast cancer in mice in real time guiding complete surgical removal of the tumor, highlighting the translational potential of these new glyco‐SERS‐NPs. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Research into extracellular vesicles (EVs) has grown significantly over the last few decades with EVs being widely regarded as a source of biomarkers for human health and disease with massive clinical potential. Secreted by every cell type in the body, EVs report on the internal cellular conditions across all tissue types. Their presence in readily accessible biofluids makes the potential of EV biosensing highly attractive as a noninvasive diagnostic platform via liquid biopsies. However, their small size (50-250 nm), inherent heterogeneity, and the complexity of the native biofluids introduce challenges for effective characterization, thus, limiting their clinical utility. This has led to a surge in the development of various novel EV biosensing techniques, with capabilities beyond those of conventional methods that have been directly transferred from cell biology. In this review, key detection principles used for EV biosensing are summarized, with a focus on some of the most recent and fundamental developments in the field over the last 5 years. This article is categorized under: Diagnostic Tools > Biosensing Diagnostic Tools > In Vitro Nanoparticle-Based Sensing.

The Raman effect originates from spontaneous inelastic scattering of photons by matter. These photons provide a characteristic fingerprint of this matter, and are extensively utilized for chemical and biological sensing. The probability of generation, and hence the detection of these Raman scattered photons, is very low; hence, it is difficult to use this directly for sensing in complex matrices. To amplify this signal, surface-enhanced Raman spectroscopy (SERS) has been extensively investigated and has emerged as a powerful analytical tool for sensing diverse analytes, including ions, small molecules, inorganics, organics, radionucleotides, and cells. Plasmonic nanoparticles, called hotspots, exhibit localized surface plasmon resonance (LSPR). This amplifies the Raman signal and may offer up to a 10 10-fold SERS signal enhancement. The development of SERS active substrates requires further consideration and optimization of several critical features such as surface periodicity, hotspot density, mitigation of sample or surface autofluorescence, tuning of surface hydrophilicities, use of specific (bio) recognition elements with suitable linkers and bioconjugation chemistries, and use of appropriate optics to obtain relevant sensing outcomes in terms of sensitivity, cross-sensitivity, limit of detection, signal-to-noise ratio (SNR), stability, shelf-life, and disposability. This article details the optimization of the aforementioned considerations in the use of disposable materials such as commercial grades of paper, textiles, glasses, polymers, and some specific substrates such as blue-ray digital versatile discs (DVDs) for use as SERS-active substrates for point-of-use (POU) sensing applications. The advancements in these technologies have been reviewed and critiqued for analyte detection in resource-limited settings, highlighting the prospects of applications ranging from single-molecule to single-cell detection.

The purpose of the study was to analyze the structural characteristics of flagellin FliC (FliCEcN) of Escherichia coli Nissle 1917 and its stimulating effect on Caco-2 cells. FliCEcN protein was expressed by Escherichia coli BL21 (DE3), purified by NTA column and verified by SDS-PAGE and Western-blot. The structure model of FliCEcN protein was predicted by SOPMA and Alphold2, and the structure of FliCEcN protein was analyzed by surface enhanced Raman spectroscopy and circular dichroism spectroscopy. The secretion level of immune related factors was detected after stimulating Caco-2 cells with FliCEcN protein. The results showed that the size of FliCEcN protein was 64 kDa, which could be specifically recognized by anti-His monoclonal antibody. The amino and carboxyl terminals of FliCEcN protein were mainly composed of α-helix, and the intermediate domain is mainly composed of β-fold. The maximum absorption peaks of amide Ⅰ region of FliCEcN protein were all located at 1 656 cm-1, and the main secondary structures were α-helix and β-fold. FliCEcN's α-helix accounts for 44.4%, β-fold accounts for 23.4%, β-rotation angle accounts for 13.5%, and irregular curl accounts for 19.0%. The FliCEcN protein could effectively stimulate the secretion of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) in Caco-2 cells. With the increase of stimulation time, the secretion level of IL-6 decreased, while the secretion level of IL-10 and TNF-α increased. The results show that α-helix and β-folding are the main structures of FliCEcN, which can promote the correct folding of its conformation and maintain its three-dimensional structure stability. The FliCEcN protein stimulated Caco-2 cells to secrete IL-6, IL-10, and TNF-α levels is different. [ABSTRACT FROM AUTHOR]

Acetone is a reliable index to evaluate the aging state of oil paper insulation. It is of great significance to study a fast, highly sensitive and accurate method of detecting acetone in oil to ensure the safe and stable operation of oil-immersed transformers. In this paper, a method based on surface enhanced Raman spectroscopy for the detection of acetone in oil is investigated. Based on the mechanism of surface-enhanced Raman spectroscopy (SERS), a simulation model of surface-enhanced substrate was constructed using COMSOL software, and it was determined that the enhancement effect was better when silver nanowires/zinc oxide nanorods (Ag/ZnO) composite structure was selected. Ag/ZnO substrates were prepared by solvothermal method and experimentally tuned and characterized to obtain SERS substrates with high enhancement properties. The substrate coupled partial least square (PLS) model was used to establish a method for the detection of acetone in insulating oils, and its limit of quantification for acetone was 0.003 mg/g, which meets the requirements for engineering testing. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Fuzhou University is the property of Journal of Fuzhou University, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work reports on the development of an analyte sampling strategy on a plasmonic substrate to amplify the detection capability of a dual analytical system, paper spray ionization–mass spectrometry (PSI-MS) and surface-enhanced Raman spectroscopy (SERS). While simply applying only an analyte solution to the plasmonic paper results in a limited degree of SERS enhancement, the introduction of plasmonic gold nanoparticles (AuNPs) greatly improves the SERS signals without sacrificing PSI-MS sensitivity. It is initially revealed that the concentration of AuNPs and the type of analytes highly influence the SERS signals and their variations due to the “coffee ring effect” flow mechanism induced during sampling and the degree of the interfacial interactions (e.g., van der Waals, electrostatic, covalent) between the plasmonic substrate and analyte. Subsequent PSI treatment at high voltage conditions further impacts the overall SERS responses, where the signal sensitivity and homogeneity significantly increase throughout the entire substrate, suggesting the ready migration of adsorbed analytes regardless of their interfacial attractive forces. The PSI-induced notable SERS enhancements are presumably associated with creating unique conditions for local aggregation of the AuNPs to induce effective plasmonic couplings and hot spots (i.e., electromagnetic effect) and for repositioning analytes in close proximity to a plasmonic surface to increase polarizability (i.e., chemical effect). The optimized sampling and PSI conditions are also applicable to multi-analyte analysis by SERS and MS, with greatly enhanced detection capability and signal uniformity.

Perianal fistulising Crohn's disease (PFCD) is different from the characteristics and outcomes of traditional non-inflammatory bowel disease (IBD) anal fistulas. The presence of perianal disease was a poor prognostic indicator for Crohn's disease (CD) patients and PFCD patients were more likely to bear an increased risk of recurrence. However, the effective and accurate diagnosis methods to early distinguish PFCD from simple perianal fistula were still scarce. The purpose of this study is to develop a non-invasive detecting approach to predict CD in patients with perianal fistulas. Data on patients with anal fistulizing disease were collected from July 2020 to September 2020 in two IBD centers. Urine samples from PFCD and simple perianal fistula patients were investigated by surface-enhanced Raman spectroscopy (SERS). Principal component analysis (PCA)-support vector machine (SVM) was utilized to establish classification models to distinguish PFCD from simple perianal fistula. After a case-matched 1:1 selection by age and gender, 110 patients were included in the study. By analyzing the average SERS spectra of PFCD and simple perianal fistula patients, it revealed that there were significant differences in intensities at 11 Raman peaks. The established PCA-SVM model distinguished PFCD from simple perianal fistula with a sensitivity of 71.43%, specificity 80.00% and accuracy 75.71% in the leave-one-patient-out cross-validation. The accuracy of the model in validation cohort was 77.5%. Investigation of urine samples by SERS helps clinicians to predict Crohn's disease from perianal fistulas, which make patients achieve benefit from a more individualized treatment strategy. [Display omitted] [ABSTRACT FROM AUTHOR]

A robust and competitive technology to synthesize arranged high‐density gold nanoparticles on highly uniform Al nanoconcavities substrates is presented. The nanoparticles are formed through sputtering and thermal annealing treatment on Al templates, which are synthesized through particular removal of nanoporous anodic alumina structure with controlled anodization conditions and with phosphoric acid as electrolyte. This scalable fabrication mechanism regulates the particle size, arrangement, shape and interparticle separation across large surface areas, which empowers the optimization of their surface enhanced Raman scattering (SERS) activities. 4‐mercaptopyridine is selected as a probe molecule. Analysis reveals that Au‐decorated Al nanoconcavities substrates are highly competitive for the enhancement of Raman signals and could be employed as self‐sustaining nanosensors. By using these templates, a concentration as low as 10−7 M of 4‐mercaptopyridine is easily detected. Finally, the calculated EF factor of 1.1 × 107 confirms the suitability for effective and sensitive SERS detection of the developed substrates. [ABSTRACT FROM AUTHOR]

The authors propose a way of identifying the composition of paints by means of surface enhanced Raman spectroscopy using signal-amplifying substrates with arrays of vertically standing silver nanowires. A model tempera paint based on egg white with inorganic pigments (red lead, massicot, and emerald green) is used to show that with a reduced concentration of pigment, substrates can greatly improve sensitivity when detecting pigments in lower concentrations up to 0.01 g, compared to signals from the Raman scattering of light on foil. Reinforcing substrates allows the sensitivity of the technique to be improved in order to accurately identify components used individually and in mixtures. [ABSTRACT FROM AUTHOR]

Abstract A robust and competitive technology to synthesize arranged high‐density gold nanoparticles on highly uniform Al nanoconcavities substrates is presented. The nanoparticles are formed through sputtering and thermal annealing treatment on Al templates, which are synthesized through particular removal of nanoporous anodic alumina structure with controlled anodization conditions and with phosphoric acid as electrolyte. This scalable fabrication mechanism regulates the particle size, arrangement, shape and interparticle separation across large surface areas, which empowers the optimization of their surface enhanced Raman scattering (SERS) activities. 4‐mercaptopyridine is selected as a probe molecule. Analysis reveals that Au‐decorated Al nanoconcavities substrates are highly competitive for the enhancement of Raman signals and could be employed as self‐sustaining nanosensors. By using these templates, a concentration as low as 10−7 M of 4‐mercaptopyridine is easily detected. Finally, the calculated EF factor of 1.1 × 107 confirms the suitability for effective and sensitive SERS detection of the developed substrates.

Mycotoxin contamination on food and feed can have deleterious effect on human and animal health. Agricultural crops may contain one or more mycotoxin compounds; therefore, a good multiplex detection method is desirable to ensure food safety. In this study, we developed a rapid method using label-free surface-enhanced Raman spectroscopy (SERS) to simultaneously detect three common types of mycotoxins found on corn, namely aflatoxin B1 (AFB1), zearalenone (ZEN), and ochratoxin A (OTA). The intrinsic chemical fingerprint from each mycotoxin was characterized by their unique Raman spectra, enabling clear discrimination between them. The limit of detection (LOD) of AFB1, ZEN, and OTA on corn were 10 ppb (32 nM), 20 ppb (64 nM), and 100 ppb (248 nM), respectively. Multivariate statistical analysis was used to predict concentrations of AFB1, ZEN, and OTA up to 1.5 ppm (4.8 µM) based on the SERS spectra of known concentrations, resulting in a correlation coefficient of 0.74, 0.89, and 0.72, respectively. The sampling time was less than 30 min per sample. The application of label-free SERS and multivariate analysis is a promising method for rapid and simultaneous detection of mycotoxins in corn and may be extended to other types of mycotoxins and crops. [ABSTRACT FROM AUTHOR]

ObjectiveTo establish a rapid detection method for enrofloxacin and ciprofloxacin in milk products by surface enhanced Raman spectroscopy.MethodsFive percent acetic acid was used for extraction and dichloromthane was used for liquid-liquid distribution and purification. The parameters including addition amount of colloidal silver， extraction solution and coagulant were determined by single factor experiment.ResultsRaman characteristic shifts of enrofloxacin and ciprofloxacin were （736±5）cm-1， （785±5）cm-1， （1 345±5）cm-1 and （1 395±5）cm-1. According to the position and intensity of probability of detection model， the detection limit of enrofloxacin and ciprofloxacin in milk was 50 μg/kg.ConclusionThe method is simple in pretreatment， the detection is fast and the result is accurate. It only takes 25 min from sample pretreatment to the result issuing. It can be used for the rapid on-site qualitative determination of enrofloxacin and ciprofloxacin in milk.

We present an easy and efficient method for silver particle layer SERS substrate preparation that combines a modified Tollens’ approach with using ultrasound to obtain unique reaction conditions by generating high-energy hot-spots as the arising acoustic cavities implode. The silver layers were deposited on various substrates in a one-step reduction process of silver nitrate. Three different reductants (maltose, glucose, ascorbic acid) were used to obtain silver particle layers with different particle sizes, morphologies, and inter-particle distances. To further optimize the properties of the silver particles for SERS and to provide higher signal enhancement, all the prepared nanoparticle layers were activated in 4 M Cl− solution. The size of silver particles was in most samples under 100 nm and the particles formed clusters, but they were also present on the surface individually. In some of the activated substrates, bigger particles (0.5–1 μm) occur as well. The activated as well as non-activated substrates were tested as SERS substrates using 10−5 M adenine as a model analyte. Laser wavelengths of 455 nm, 532 nm, 633 nm, 780 nm, and 785 nm were used for the SERS measurements. High enhancement factors up to 3.5·105 and 2.8·105 were obtained for SERS measurements using lasers of 532 nm and 780 nm, respectively.

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The SERS intensity of analytes is primarily influenced by the density and distribution of hotspots, which are often difficult to manipulate or regulate. In this study, cucurbit[8]uril (CB[8]), a kind of rigid macrocyclic molecule, was introduced to achieve ~ 1-nm nanogap between gold nanoparticles to increase the density of SERS hotspots. Three kinds of estrogens (estrone (E1), bisphenol A (BPA), and hexestrol (DES)) which are molecules with weak SERS signals were targeted in the hotspots by CB[8] to further improve the sensitivity and selectivity of SERS. It was demonstrated that CB[8] can link gold nanoparticles together through carbonyl groups. In addition, the host–guest interaction of CB[8] and estrogens was proved from the nuclear magnetic resonance hydrogen and infrared spectra. In the presence of CB[8], the SERS intensities of E1, BPA, and DES were increased to 19-fold, 74-fold, and 4-fold, respectively, and the LOD is 3.75 µM, 1.19 µM, and 8.26 µM, respectively. Furthermore, the proposed SERS method was applied to actual milk sample analysis with recoveries of E1 (85.0 ~ 112.8%), BPA (83.0 ~ 103.7%), and DES (62.6 ~ 132.0%). It is expected that the proposed signal enlarging strategy can be applied to other analytes after further development. [ABSTRACT FROM AUTHOR]

Novel hollow Au Ag alloy nano urchins were synthesized via Ag seeds growth method, and self-assembly coated on the wall and end-tip of silica fiber for fiber probe fabrication. The nano urchins homogeneously distributed on fiber surface because of fiber silanization. The sizes and tip sharpness of the nano-urchins could be controlled by Ag seeds. The elements distribution analysis indicated there was high Ag content in tip-top for better surface enhance Raman scattering performance. The detectable concentration could be as low as 10−8 M using crystal violet molecules as analyte. Moreover, the fiber probes were stable in air, due to Au in the alloy. This fiber probe could be used for low content single molecular analysis. [ABSTRACT FROM AUTHOR]

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Fenton technology is one of advanced oxidation process (AOP) methods to treat wastewater through chemical oxidation. Due to the limitations of classical iron-based catalysts, it is still challenging to find suitable catalysts for Fenton-like reactions. Here, MoS2/Au heterojunctions were successfully synthesized by reduction of chloroauric acid in the solution of layered MoS2 prepared by hydrothermal method. As a model molecule, methylene blue (MB) was used as the species to be degraded to evaluate the performance of the catalyst. It was determined by UV–visible spectra that the optimal catalyst can be obtained when MoS2 (mg): HAuCl4 (wt. % mL) is 2:2. The Fenton-like reaction process was monitored by introducing highly sensitive surface enhanced Raman spectroscopy (SERS). The results show that MB can be degraded by 83% in the first 10 min of the reaction, indicating that MoS2/Au has good catalytic performance. In addition, as a fingerprint spectrum, SERS was used to preliminarily analyze the molecular structure changes during the degradation process. The result showed that C-N-C bond was easier to break than the C-S-C bond. NH2 group and the fused ring were destroyed at the comparable speed at the first 30 min. In terms of application applicability, it was showed that MB degradation had exceeded 95% at all the three pH values of 1.4, 5.0, and 11.1 after the reaction was carried out for 20 min. The test and analysis of the light environment showed that the catalytic efficiency was significantly improved in the natural light of the laboratory compared to dark conditions. The possible mechanism based on ·OH and ·O2− from ESR data was proposed. In addition, it was demonstrated to be a first-order reaction from the perspective of kinetics. This study made a positive contribution to broaden of the applicable conditions and scope of Fenton-like reaction catalysts. It is expected to be used as a non-iron catalyst in practical industrial applications. From the perspective of detection method, we expect to develop SERS as a powerful tool for the in situ monitoring of Fenton-like reactions, and to further deepen our understanding of the mechanism. [ABSTRACT FROM AUTHOR]

Polyelectrolytes (PEs) serve as the critical medium for electrochemical reactions in membrane-based electrochemical devices, such as fuel cells and membrane electrolyzers. To optimize membrane-based electrochemical device performance and elucidate reaction mechanisms, there is a pressing need for detailed microscopic molecular information at gas diffusion electrode/PE interfaces. In this work, we designed a novel membrane-based-electrochemical-device-like gas diffusion electrode/polyelectrolyte electrochemical in-situ Raman cell. The cell's configuration and gas transfer characteristics closely mimic those of membrane-based electrochemical devices under working conditions. We created a Pt/Nafion(s) interface by hot-pressing satellite Au@SiO 2 -Pt loaded carbon cloth with a Nafion membrane, and used this interface for electrochemical in-situ surface enhanced Raman spectroscopy (SERS) observation, including oxygen adsorption/desorption processes, structure of interfacial water and functional groups of Nafion under Ar. The cell enables negatively polarize the potential down to -1.6 V vs. RHE without stripping of the solid/solid interface, despite vigorous H 2 generation. The stability of the interface under extreme conditions demonstrates rapid gas transfer at the interface. This observation underscores the potential of our in-situ Raman cell for studying various gas-involved reactions under conditions that closely resemble those in operational membrane-based electrochemical devices. [ABSTRACT FROM AUTHOR]

17β-E 2 is used in animal growth regulation and agricultural fertilizer, and even ng L−1 mass concentration levels can show biological effects. In this work, Ag NPs was used as surface-enhanced Raman spectroscopy (SERS) source and WS 2 was synthesized by a simple method to provide a uniform distribution platform for Ag NPs. The MIP was the shell, which can selectively enrich the target molecule, pull the distance between the target molecule and SERS source, and protect Ag NPs. A cyclable SERS substrate with high sensitivity for detecting 17β-E 2 in food was constructed. The optimized WS 2 /Ag@MIP as SERS substrate has the advantages of high Enhanced Factor (EF = 2.78 × 109), low detection limit (LOD = 0. 0958 pM), strong anti-interference ability, and good recycling performance. Moreover, the detection of 17β-E 2 in real samples still has good accuracy. This work provides a new possibility for the trace detection of 17β-E 2 in food. • Sandwich WS 2 /Ag@MIP composite material was prepared for the first time and used as SERS base to achieve sensitive detection of 17β-E 2. • Ag NPs was used as SERS source and WS 2 provided a platform for uniform distribution of Ag NPs. The outermost layer was coated with MIP layer, which realized selective adsorption of 17β-E 2 , shortened the distance between 17β-E 2 and Ag NPs and protected the deterioration of Ag NPs. • WS 2 /Ag@MIP as SERS substrate realized sensitivity detect of 17β-E 2 , EF value was 2.78 × 109, the LOD value was 9.58 × 10−13 M. By elution of target molecules in MIP, the SERS substrate can be recycled. • WS 2 /Ag@MIP as SERS substrate realized the detection of 17β-E 2 in real samples. In the actual spiked sample detection, the recovery of 17β-E 2 in milk samples were 97.38% - 105.46%, and RSDs were 3.96% - 5.04%. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel aptamer-based SERS sandwich method for detecting E. coli was developed. • The fabrication of SH-apt@Au-Ag@Si TP was simple and rapid, which needed 20.5 h. • The detection process of E. coli took approximate 3 h by using SH-apt@Au-Ag@Si TP. • The SERS sandwich method could detect E. coli with the LOD of 2.8 CFU/mL. • The method was successfully used to detect E. coli in spiked Xinhuang tablet sample. Escherichia coli contamination in food and pharmaceutical preparations needs to be strictly controlled according to the regulations in many countries. However, rapid and sensitive E. coli detection is still a challenge. In this study, an aptamer-based surface-enhanced Raman spectroscopy (SERS) sandwich method was developed for the rapid and sensitive detection of E. coli using an aptamer-functionalized Au-Ag@Si triangular pyramid (TP) substrate. The Au-Ag@Si TP substrate was functionalized with E. coli aptamer to work as both the capture probe and SERS tag by integrating with Raman reporter (6-carboxy-X-rhodamine). The fabrication of the capture probe, SH-apt@Au-Ag@Si TP, was simple and rapid (20.5 h). This method could selectively and rapidly detect E. coli with a limit of detection of 2.8 CFU/mL within approximately 3 h. It was successfully applied to a traditional Chinese medicine preparation, Xinhuang tablets, with recoveries ranging from 90.19 % to 104.17 %. The results indicated that the developed method was simple and rapid, and it could be a promising alternative for the on-site detection of E. coli in pharmaceutical and food samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • CPS is insufficient to classify cancer patients' responsiveness to immunotherapy. • Au-shelled/Ag-core/Si nanocone arrays enhance SERS sensitivity and reliability. • SERS accurately evaluates the sensitivity of HNSCC patients to NAIT via serum. • SERS can monitor NAIT's efficacy faster and more conveniently than imaging. Head and neck squamous cell carcinoma poses a formidable treatment challenge owing to its complex anatomy and essential functions of the organs involved. Neoadjuvant immunotherapies, particularly PD-1 inhibitors, have shown promise in improving patient outcomes. Nevertheless, the ability to accurately predict which patients will benefit from neoadjuvant immunotherapy continues to be a significant hurdle. We investigated 46 patients diagnosed with head and neck squamous cell carcinoma. Combined positive score was assessed before treatment. Serum samples were collected both before and after neoadjuvant immunotherapy, and subsequently analyzed utilizing surface-enhanced Raman spectroscopy. Significant differences in Raman spectral peaks were observed between the partial response and stable disease groups before treatment, particularly in the regions of 516–525 cm−1, 1240–1400 cm−1, 1600–1636 cm−1, and 1647–1680 cm−1. These peaks represent different cancer-related biochemical components, including protein and nucleic acid vibrations, disulfide bonds, amide III bands, CH2/CH3 deformations, and amide I bands. Principal Component Analysis-Linear Discriminant Analysis and Receiver Operating Characteristic analysis demonstrated that surface-enhanced Raman spectroscopy exhibited remarkable sensitivity and specificity, surpassing the combined positive score in assessing patient responses to neoadjuvant immunotherapy. Surface-enhanced Raman spectroscopy offers significant potential to surpass the conventional combined positive score in predicting responses to neoadjuvant immunotherapy. [ABSTRACT FROM AUTHOR]