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Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for elucidating the molecular makeup of materials. It possesses the unique characteristics of single-molecule sensitivity and extremely high specificity. However, the true potential of SERS, particularly in capturing the biochemical content of particles, remains underexplored. In this study, we harnessed transformer neural networks to interpret SERS spectra, aiming to discern the amino acid profiles within proteins. By training the network on the SERS profiles of 20 amino acids of human proteins, we explore the feasibility of predicting the predominant proteins within the µL-scale detection volume of SERS. Our results highlight a consistent alignment between the models predictions and the proteins known amino acid compositions, deepening our understanding of the inherent information contained within SERS spectra. For instance, the model achieved low root mean square error (RMSE) scores and minimal deviation in the prediction of amino acid compositions for proteins such as Bovine Serum Albumin (BSA), ACE2 protein, and CD63 antigen. This novel methodology offers a robust avenue not only for protein analytics but also sets a precedent for the broader realm of spectral analyses across diverse material categories. It represents a solid step forward to establishing SERS-based proteomics.

DNA walker nanomachines are in fast development for biosensing, medical diagnostics, and food safety monitoring. For practical application, the issues of slow dynamics and low operational efficiency hinder its widespread application. Inspired by the high efficiency of agricultural cooperative machinery, a unique cleaving‐rolling‐assembly integrated nanodevice (CRAIN) is constructed for the high‐performance detection of various biomolecules. In the design, DNA nanotubes are introduced as building loaders to engineer polyoriented walking DNA nanorollers with blocked DNAzyme‐based walking strands and thus to increase the reaction direction and local concentration. Through target‐specific recognition, the activated nanorollers can autonomously and progressively cleave and roll along directional hairpin tracks on a gold substrate, significantly accelerating the reaction rate. Moreover, using nucleic acid‐encoded urchin‐shaped multispike gold‐silver composite nanospheres (nMGSs) as SERS‐enhanced probes, the engineered assembly of nMGSs probes induced by the cleaving‐rolling process promotes the formation of high‐density hotspot domains, further improving the detection sensitivity. With rational design, the CRAIN system can be extended to perform highly sensitive analyses of various analytes, such as microRNA‐21, butyrylcholinesterase activity and organophosphorus pesticides. This integrated assembly strategy can provide new perspectives for clinical diagnosis, biomedical engineering, and environmental science. [ABSTRACT FROM AUTHOR]

Currently, research in the development of high-performance sensing platforms has increased to fulfill the needs of analysis and detection. In this study, we developed a novel type of surface-enhanced Raman scattering (SERS) chip composed of a covalent organic framework (COF)-silver nanoparticles (AgNPs) nanocomposite, and this nanocomposite was fabricated by a one-step method of ultrasonically mixing the obtained COF and AgNPs. The fabricated chip exhibited high sensitivity and repeatable SERS effects. Practical application results showed that the chip was highly sensitive and reliable and capable of detecting DNA bases (adenine) to fit an equation in the range from 0.01 pM to 1 nM, with an R-square of 0.97253 and a detection limit of ~0.026 pM (signal-to-noise ratio (S/N) = 3). Therefore, the proposed SERS system has potential applications in biological assays. Schematic of AgNP@COF as SERS substrates for the detection of DNA bases. [ABSTRACT FROM AUTHOR]

Since its discovery, the phenomenon of Surface Enhanced Raman Scattering (SERS) has gradually become an important tool for analyzing the composition and structure of substances. As a trace technique that can efficiently and nondestructively detect single molecules, the application of SERS has expanded from environmental and materials science to biomedical fields. In the past decade or so, the explosive development of nanotechnology and nanomaterials has further boosted the research of SERS technology, as nanomaterial-based SERS substrates have shown good signal enhancement properties. So far, it is widely recognized that the morphology, size, composition, and stacking mode of nanomaterials have a very great influence on the strength of the substrate SERS effect. Herein, an overview of methods for the preparation of surface-enhanced Raman scattering (SERS) substrates is provided. Specifically, this review describes a variety of common SERS substrate preparation methods and explores the potential and promise of these methods for applications in chemical analysis and biomedical fields. By detailing the influence of different nanomaterials (e.g., metallic nanoparticles, nanowires, and nanostars) and their structural features on the SERS effect, this article aims to provide a comprehensive understanding of SERS substrate preparation techniques. [ABSTRACT FROM AUTHOR]

Over the past three decades, plasmonic nanostructures, particularly spherical ones, have seen remarkable advancements. Recently, attention has shifted toward anisotropic nanoparticles, especially star‐shaped/branched structures such as plasmonic nanostars (PNS), due to their distinct properties. PNS offers superior electromagnetic enhancement effects, larger surface areas, and as well as non‐linear and unusual photothermal properties, setting them apart from spherical counterparts. Despite significant progress in synthetic methods and characterization of the particles, challenges remain in transitioning PNS technology into practical use. In this perspective article, the distinctive attributes of PNS in biosensing applications are discussed, beginning with an exploration of synthesis methodologies. Their optoelectronic properties are examined and discussed how these properties influence their interaction with different molecules from a biosensing perspective. With a focus on PNS, detailed insights are offered into their unique properties, current applications, and future potential. By fostering discussion and understanding of PNS development, this article aims to facilitate the translation of PNS technology into practical applications, encouraging targeted improvements and advancements. [ABSTRACT FROM AUTHOR]

Using strong ligand as morphology directing agent, AuNPs with sheet-like surface sub-structures were successfully synthesized. Arising from the continuous tuning of the strong ligand control, the surface roughness of the AuNPs can be continuously tuned, so thus the LSPR and SERS. [Display omitted] In this work, we reported that by using a strong thiol ligand as the morphology-directing reagent, a series of Au nanoparticles with plate-like surface sub-structures could be successfully obtained via a one-pot seedless synthesis. The size and the density of the plates on the surface of Au can be readily tuned with the amount of the thiol ligand, resembling different roughness of the surface. Arising from the different surface roughness, the localized surface plasmon resonance (LSPR) of these shape and morphological alike Au nanoparticles can be continuously tuned within the visible-NIR region. The broad LSPR absorptions and feasible tunability make the Au nanoparticles suitable candidate for plasmonic-related applications. Interestingly, huge SERS enhancement was simultaneously achieved based on the specific surface roughness. Our results demonstrate the great potentials for tuning the LSPR and SERS of Au nanostructures through the engineering of the surface morphologies, which would assist for the design, synthesis, and applications of Au-based plasmonic nanomaterials in various fields. [ABSTRACT FROM AUTHOR]

AbstractResidues of harmful substances in food can severely damage human health. The content of these substances in food is generally low, making detection difficult. Surface-enhanced Raman scattering (SERS), based on noble metal nanomaterials, mainly gold (Au) and silver (Ag), has exhibited excellent capabilities for trace detection of various substances. Noble metal nanoassemblies, in particular, have extraordinary flexibility and tunable optical properties, which cannot be offered by single nanoparticles (NPs). These nanoassemblies, with their various morphologies synthesized using NPs through artificially induced self-assembly or template-driven preparation, can significantly enhance the local electric field and create “hot spots” due to the gaps between adjacent NPs. Consequently, the SERS properties of NPs become more prominent, leading to improved performance in the trace detection of various substances and detection limits that are considerably lower than the current relevant standards. Noble metal nanoassemblies show promising potential in ensuring food safety. This review discusses the synthesis methods and SERS properties of noble metal nanoassemblies and then concentrates on their application in detecting biotoxins, drug residues, illegal additives, and heavy metals. The study provides valuable references for further research into the application of nanoassemblies in food safety detection. [ABSTRACT FROM AUTHOR]

Emerging pollutants, known for their high toxicity, pose significant risks to human health and the environment. However, the identification of these pollutants is difficult and costly due to their low concentration and complex composition. Here, a cost‐effective and scalable identification method is demonstrated to rapidly concentrate and detect emerging pollutants at ultra‐low concentrations. The approach takes advantage of responsive autonomous propulsion R‐Fe3O4@Au@β‐CD‐EG‐PF127 (RAP) nanomotors driven by magnetism, to significantly enhance the efficiency of pollutant adsorption in large‐scale water. Owing to the fast driving capability and multi‐interaction mechanism, nanomotors can effectively capture trace concentrations of emerging pollutants, achieving a capture efficiency of over 90%, while also ensuring that all captured pollutants fall within the enhanced electromagnetic field range of the nanomotors. This leads to highly sensitive surface‐enhanced Raman scattering (SERS) signals with detection limits as low as 10−10 m. Contaminated nanomotors showcase significant self‐cleaning capabilities that can be activated through temperature variations, resulting in a substantial reduction in detection expenses. Even after undergoing cyclic experiments, the nanomotors consistently exhibit remarkable capture efficiency and outstanding SERS sensitivity. This work can provide a scalable and practical technical solution to eliminate and monitor the transport of emerging pollutants in the environment. [ABSTRACT FROM AUTHOR]

Sensing and imaging of biomolecules are crucial to disease diagnosis, prognosis, and therapy where optical techniques have essential utility. Untethered and remotely controlled micro/nanorobots have shown promising sensing and imaging capabilities, especially in complex biological environments. In this review, how micro/nanorobots are used for optical biosensing and imaging while highlighting the significant developments in the field is discussed. Starting is done by exploring colorimetric biosensing methods enabled by micro/nanorobots. Significant advancements in surface‐enhanced Raman spectroscopy‐integrated micro/nanorobots are reviewed. Further, state‐of‐the‐art optical bio‐imaging applications by micro/nanorobots at in vitro intracellular level are highlighted. Novel in vivo bio‐imaging assisted by optical micro/nanorobot sensors is examined. Furthermore, innovations in micro/nanorobots are assessed where motion augmentation is used as a detection mechanism, with applications in point‐of‐care molecular diagnostics. Finally, the challenges associated with micro/nanorobots‐assisted advanced optical biosensing and imaging while discussing insights about potential research directions for this rapidly progressing field are summarized. [ABSTRACT FROM AUTHOR]

Nanoporous gold electrodes are of great interest in electroanalytical chemistry, because of their unusual activity and large surface area. The electrochemical activity can be further improved by coating with molecular catalysts such as the tetraruthenated cobalt‐tetrapyridylporphyrazines investigated in this work. The plasmonic enhancement of the scattered light at the nanoholes and borders modifies the electrode's optical characteristics, improving the transmission through the surface‐enhanced Raman scattering (SERS) effect. When monitored by hyperspectral dark‐field and confocal Raman microscopy, this effect allows probing of the porphyrazine species at the plasmonic nanholes, improving the understanding of the chemically modified gold electrodes. [ABSTRACT FROM AUTHOR]

A miniature multi-channel surface-enhanced Raman scattering (SERS) sensor based on polydimethylsiloxane (PDMS) is constructed to achieve rapid delivery of polluted water and specific identification of multiple components. Hg2+, organic pollutants, and sodium nitrite are successfully identified by the multi-channel SERS sensor using Cy5, cyclodextrin, and urea in the corresponding detection area. This multi-channel sensor exhibits excellent sensitivity and specificity, with detection limits of 3.2 × 10−10 M for Hg2+, 1.0 × 10−8 M for aniline, 6.9 × 10−9 M for diphenylamine, 9.1 × 10−8 M for PCB-77, and 7.5 × 10−9 M for pyrene, and 5.0 × 10−7 M for sodium nitrite. Compared with traditional analysis techniques, this method exhibited excellent recovery for the water pollutants ranging from 82.1 to 115.8%. The PDMS-based microchannel allows for simultaneous and rapid identification of multiple environmental pollutants, offering a portable detection method for emergency testing of environmental pollutants and routine determination of water pollutants. [ABSTRACT FROM AUTHOR]

ABSTRACT Nowadays, surface‐enhanced Raman spectroscopy (SERS) has become a powerful tool for rapidly detecting and analyzing textile cultural relics due to its ability to provide chemical information with single‐molecule sensitivity. However, preserving a high level of detection sensitivity while avoiding sample damage remains a persistent challenge. In this work, we developed a SERS approach with both microextraction and detection functions. The alcohol–water droplet with iodide‐modified Au nanoparticles (AuIMNPs) is directly dropped on the textile, where dyes strongly bound on textiles can be extracted by ethanol (EtOH). As a result, the sample can be well preserved from being damaged. In particular, the volatility of EtOH allows the molecules to be captured in the hot spots through the capillary effect during droplet evaporation, resulting in a dramatic increase in Raman signal intensity. This highly sensitive strategy can be used to measure dyes in plant extracts and mock‐up textiles. Furthermore, the capability of SERS to provide fingerprint information allows us to distinguish different dyes in overdyeing textiles. Eventually, this approach is successfully applied to identify dyes of authentic ancient Chinese textiles. This rapid, universal, and negligibly invasive approach provides a powerful way to study textile cultural relics. [ABSTRACT FROM AUTHOR]

The excessive use of pesticides has detrimental effects on the ecosystem, leading to soil contamination and the spread of pollution beyond the targeted areas. Concerns arise regarding the permissible limits of pesticides, typically around 10−8 mol/L. In this study, we employed surface‐enhanced Raman spectroscopy (SERS), a highly sensitive and selective technique, to investigate the behavior of the pesticide ametrine (AMT) on silver colloids. The Ag nanoparticles (AgNPs) exhibited an average size of (26 ± 2) nm and a zeta potential of (−30 ± 1) mV in the absence of AMT, which decreased to (−24 ± 1) mV in the presence of AMT, resulting in mild AgNPs aggregation, with the average diameter of AgNPs increasing to approximately 300 nm. This aggregation is advantageous, as they provide active sites for pesticide detection. Besides, the purification method employed ensured that AMT remained undegraded, and various conformations of AMT were simulated using Ag clusters to study the SERS effect. Comparison with the experimental spectra indicated that the SERS‐4 conformer closely resembled the experimental spectrum, suggesting simultaneous interaction between the Ag surface and the sulfur (S) and nitrogen (N) atoms of the AMT triazine ring. Notably, changes in the AMT molecule were observed with pH variations: at pH below 5, hydroxylation occurred, resulting in an Ag–Cl stretching at 241 cm−1 in the SERS spectra. Conversely, at pH above 5 (pH 6–13), the presence of bands at 230 and 219 cm−1 in the SERS spectra indicate the formation of Ag–N and Ag–S bonds, respectively, between the AMT and the AgNPs. Furthermore, the study successfully detected AMT at pH 7, establishing a limit of detection (LOD) of 1.36 × 10−8 mol/L (3 ppb) based on the SERS spectra. These findings underscore the applicability of the SERS technique in the sensitive and selective detection of AMT, offering a promising approach for monitoring the presence of this pesticide in environmental samples. [ABSTRACT FROM AUTHOR]

There has been increasing interest in the use of squaraines with different physicochemical properties. However, their applications in nanoplasmonics are limited. For that, detailed information on the interactions of squaraines with plasmonic nanostructures is required. In this work, we have studied the adsorption of the squaraine cis‐dicyanomethylene squarate (CDSQ) on the surface of Ag nanoparticles (AgNP). We have combined normal Raman, surface‐enhanced Raman scattering (SERS), and DFT calculations to get insights into the configuration of its adsorption. DFT calculations have been carried out using simplified models of different adsorption geometries for comparison with the results of the SERS experiments. A comparison between the relative intensities of the normal Raman and SERS spectra indicates that CDSQ is adsorbed perpendicular to the AgNP surface. The predicted spectra suggest that CDSQ is chemically adsorbed on the silver surface through one of its N atoms. [ABSTRACT FROM AUTHOR]

Pesticide residues seriously impact food safety and environmental protection. Consequently, there is a pressing demand for the development of dependable and efficient methods for pesticide residues detection. In recent years, optical aptamer sensors have emerged as highly sensitive and fast-response sensing platforms for pesticide detection. These developed sensors rely on the selectivity and sensitivity of nucleic acid aptamer to specifically interact with the target pesticide, resulting in an observable signal response. Various optical aptamer sensors such as fluorescence, colorimetry, surface-enhanced Raman scattering (SERS) methods, and chemiluminescence (CL) methods have been effectively employed for accurate and rapid detection of pesticides, encompassing a range of pesticide types including insecticides, fungicides, and herbicides. These sensors offer several advantages including quick response times, high selectivity and sensitivity, user-friendly operation, and enabling real-time monitoring. This paper provides a comprehensive review of recent advancements in the application and development of optical aptamer sensors for pesticide residue assay with the overarching goal of furnishing an invaluable reference point for forthcoming research and advancements in the realm of swift and highly sensitive pesticide residue detection. [ABSTRACT FROM AUTHOR]

Raman spectroscopic data of quenching phases in experiments on the dissolution of Pt in reduced carbonic fluid, containing about 30 mol % of CO, both with and without chlorine at P = 200 MPa and T = 950–1000°C are presented. Water content in the fluid was no more than 4.5 mol %. The only soluble form of Pt determined in the acetone solution of the quenching phases and in the experimental products is platinum carbonyl. Low concentrations of carbonyl (no more than a few ppm) become detectable using Raman spectroscopy due to the SERS effect (Surface-Enhanced Raman Scattering), which is possible in the presence of Pt nanoparticles in the objects under study. Platinum nanoparticles, formed at the decomposition of carbonyls, generates specific photoluminescence (PL) peak approximated by Gaussian with parameters FWHM = 1050–1300 cm–1, kmax = 2050–2100 cm–1 both in acetone solution and experimental samples. The spectra of CO (main band k ≈ 2050 cm–1) adsorbed on Pt nanoparticles supported on glassy carbon, formed during the decomposition of excess CO relative to the CCO buffer, corresponded to nanoparticle sizes of about 2 nm. No convincing evidence of a mixed chloride-carbonyl composition of platinum was found in the spectra, which may reflect the lower thermodynamic stability of these mixed complexes at high P-T parameters. Large concentrations of platinum Pt on carbon (up to 2000–3000 ppm) can be explained by the formation of the Pt-C matrix bond and the weakening of the Pt-CO bond in carbonyls, causing their decomposition. Unusual PL peaks were detected in samples from experiments with chlorine-containing fluids, very reminiscent of the PL background of noble metal nanoparticles and attributed to the effect of carbon nanoparticles. [ABSTRACT FROM AUTHOR]

Furfural is an essential compound that contributes to the distinctive flavor of sauce-flavored Baijiu. However, traditional detection methods are hindered by lengthy and complex sample preparation procedures, as well as the need for expensive equipment. Therefore, there is an urgent need for a new approach that allows rapid detection. In this study, we developed a novel surface-enhanced Raman spectroscopy (SERS) substrate by constructing MXene (Ti3C2TX) @Ag nanoparticles (Ag NPs) through an electrostatic attraction method. The MXene (Ti3C2TX) @Ag NPs were successfully fabricated, with adsorbed NaCl-treated Ag NPs uniformly absorbed on the surface of MXene (Ti3C2TX), creating high-density distributed SERS "hot spots". The prepared substrate demonstrated excellent sensitivity, uniformity, repeatability, and long-term stability, with a low detectable concentration of 10−9 M for R6G (Rhodamine 6G) and an enhancement factor of up to 7.08 × 105. When applied for the in situ SERS detection of furfural in Baijiu, the detection limit was as low as 0.5 mg/L. Overall, the proposed method offers rapid, low-cost, and sensitive quantitative analysis, which is significant not only for detecting furfural in Baijiu but also for identifying hazardous substances and distinguishing between authentic and counterfeit Baijiu products. [ABSTRACT FROM AUTHOR]

Facile, controllable and efficient SERS substrate preparation has always been the focus project in the SERS field, especially the solid-state nanoarray substrate. Herein, a simple and convenient method for preparing a series of homogeneous Ag-stepped nanocone arrays (Ag-SNCAs) using polymer nanocompression printing is presented. By analyzing the 1162cm−1 characteristic peak of crystal violet (CV), the relative standard deviation (RSD) of the Raman intensity was only 4.71%. The detection limit of malachite green (MG) reached 0.001ppm, and it also has good SERS detection results for drug molecules such as melamine, methadone, morphine, methamphetamine and thiabendazole. This work provides a large area uniform and controllable preparation method of sharp cone nanostructure array, which has important application in plasmonic photocatalysis and deep light field regulations. [ABSTRACT FROM AUTHOR]

Artificial compound eye (CE) draws inspiration from nature, offering advanced imaging capabilities and an expansive field of view. In this work, an innovative technique is developed for the creation of CE with tunable dimensions. A solution‐based process is employed that involves in situ polymerization of surface nanodroplets prior to soft lithography to produce CE consisting of millions of ommatidia. The fabricated CE comprised of a densely arranged array of microwells, each with a base radius of 5 µm. Situated on a millimeter‐sized spherical dome, the CE can be tailored to arbitrary dimensions, enhancing its adaptability with a wide angular field of view up to 118°. The CE is used to enhance signal detection in fluorescent compounds, reaching a detection limit of 107 times lower concentration than that without using CEs in bulk solution. The signal enhancement capabilities are further utilized for surface‐enhanced Raman spectroscopy by using a portable handheld device, with an enhancement factor of 2. The fabrication technique underscores the advantages of the approach in simplicity, reproducibility, and efficiency in creating CE. The potential applications of CE may be extended to various domains, such as optical sensing, light‐dependent signal enhancement, motion perception, and medical endoscopy. [ABSTRACT FROM AUTHOR]

Three-dimensional plasma nanostructures with high light–thermal conversion efficiency show the prospect of industrialization in various fields and have become a research hotspot in areas of light–heat utilization, solar energy capture, and so on. In this paper, a simple chemical synthesis method is proposed to prepare gold nanoparticles, and the electrophoretic deposition method is used to assemble large-area three-dimensional gold nanostructures (3D-GNSs). The light–thermal water evaporation monitoring and surface-enhanced Raman scattering (SERS) measurements of 3D-GNSs were performed via theoretical simulation and experiments. We reveal the physical processes of local electric field optical enhancement and the light–thermal conversion of 3D-GNSs. The results show that with the help of the efficient optical trapping and super-hydrophilic surface properties of 3D-GNSs, they have a significant effect in accelerating water evaporation, which was increased by nearly eight times. At the same time, the three-dimensional SERS substrates based on gold nanosphere particles (GNSPs) and gold nanostar particles (GNSTs) had limited sensitivities of 10−10 M and 10−12 M to R6G molecules, respectively. Therefore, 3D-GNSs show strong competitiveness in the fields of solar-energy-induced water purification and the Raman trace detection of organic molecules. [ABSTRACT FROM AUTHOR]

Gold nanostructures (AuNSs) were used to fabricate surface-enhanced Raman spectroscopy (SERS) substrates. These AuNSs were produced using the solid-state dewetting method from thin films. The fragmentation process was studied at 300 °C, with durations of thermal treatment of 1, 3, 6, and 12 h. These SERS substrates were then employed to detect Rhodamine B (RhB) as the model analyte, simulating a contaminant in the water at a concentration of 5 ppm. The morphology of the AuNSs was examined using SEM, which revealed a spheroidal shape that began to coalesce at 12 h. The size of the AuNSs was estimated to range from 22 ± 7 to 24 ± 6 nm, depending on the annealing time. The localized surface plasmon resonance of the AuNSs was determined using absorption spectroscopy, showing a shift as the annealing time increased. The SERS signals of RhB adsorbed on the AuNS substrates were validated by performing a 10 × 10 point map scan over each sample surface (1, 3, 6, and 12 h), and a comparative analysis showed no significant differences in the positions of the bands; however, variations in intensity enhancement ranged from 5 to 123 times at 6 and 1 h, respectively. [ABSTRACT FROM AUTHOR]

Cyclodextrins (CDs) are macrocycles that are well suited for forming inclusion complexes for surface-enhanced Raman scattering (SERS) detection of analytes due to their low Raman activity, which minimizes background SERS signals and enhances the detection of target molecules without interference. In this paper, we systematically investigated the synthesis of both silver (Ag) and gold (Au) nanoparticles (NPs) using CDs as reducing and capping agents in a basic environment using microwave (MW), ultrasound (US), and room temperature (RT) synthesis. We found that replacing NaOH with K2CO3 as an alkaline environment almost doubles the size (from <10 nm to around 20 nm) of AgNPs in the MW-assisted synthesis. Synthesis using the US produces less stable particles due to the sample evolution after US irradiation. Ag (20 nm) and Au (11 nm) were successfully obtained at room temperature in the presence of CDs and K2CO3. All synthesized particles present SERS activity. CD capping allowed us to detect hydrophobic molecules like naphthalene and melamine. In the case of methylene blue, the CD capping prevents the changes induced in the SERS by a basic pH. We also demonstrate that the newly synthesized NPs can discriminate by SERS the propranolol enantiomers. Moreover, propranolol inclusion in CDs leads to a dramatic change in its SERS spectrum. [ABSTRACT FROM AUTHOR]

Nanocellulose has become an attractive biodegradable material for surface-enhanced Raman scattering (SERS) sensors. However, the development of nanofibrillar cellulose-based SERS substrates that are simultaneously flexible, highly sensitive, uniform, and stable remains a great challenge. Herein, a highly sensitive, reliable, and flexible gold nanoparticle-decorated bacterial nanocellulose (AuNPs@BNC) SERS substrate with three-dimensional (3D) high-density hot spots was constructed by the combination of in situ chemical reduction and vacuum filtration. The homogeneous AuNPs were grown in situ on the surface of networked bacterial cellulose nanofibers to form 3D high-density SERS hotspots. In addition, the hydrophilic BNC with good adsorption and permeability properties could capture target molecules in the high-density hotspot region to further enhance the SERS performance. As a result, the 3D AuNPs@BNC SERS substrate not only demonstrates a high detection sensitivity of up to 1.0 × 10–10 M and an enhancement factor of 1.8 × 107 for methylene blue molecules but also shows excellent signal reproducibility (relative standard deviation (RSD) = 8.3%) and long-term storage stability (over two months). Furthermore, the flexible 3D AuNPs@BNC SERS substrate is also able to detect trace malachite green (MG) with a low detection limit of 1.0 × 10–11 M and prominent signal homogeneity of RSD = 7.8%. Besides, hazardous MG residues on the surface of shrimp could be directly identified by using flexible AuNPs@BNC SERS substrates through a feasible wipe-and-peel method. The flexible, reliable, and stable AuNPs@BNC substrate is promising for direct, sensitive, and rapid on-site detection of toxic molecules on seafood. [ABSTRACT FROM AUTHOR]

Traumatic brain injury (TBI), serving as a global health problem, is the primary cause of death and disability. However, the lack of a simple, accurate, and rapid method to diagnose and distinguish the injury severity of TBI in the acute phase and further improve the prognosis has been plaguing clinicians. To solve this problem, a highly sensitive surface-enhanced Raman spectroscopy (SERS) sensor, which was based on gold nanorod (AuNR) arrays, has been designed for the quantitative determination of TBI biomarkers. To create this effective SERS sensor, the AuNRs were fabricated via optimizing the particle morphology and, by evaporative self-assembly, optimizing AuNRs were assembled on microsilicon wafers to form AuNR array platforms with an enhancement factor of 1.24 × 106 and a limit of detection reaching 10–2 fg·mL–1. The ideal SERS sensors were further proven to have excellent sensitivity and reliability after being employed to analyze the various levels of S100β and IL-10 both in animal model blood samples and human blood samples. All results revealed that our biosensors can be a promising strategy for point-of-care clinical diagnosis and TBI severity distinction. [ABSTRACT FROM AUTHOR]

3D surface‐enhanced Raman scattering (SERS) platforms with multi‐dimensional hotspots and better tolerance to laser misfocus show great potential for the rapid detection of trace fentanyl. However, the complex fabrication process of 3D fine structures limits the wide‐ranging application of the SERS technique. Herein, a 3D SERS‐active platform is fabricated utilizing a scalable and cost‐effective strategy that involves the electroless deposition of dense Au nanoparticles on natural butterfly wing scales (b‐wings@Au). The resultant b‐wings@Au proves to be sensitive and reliable, with a lower limit of detection of 4× 10−12 m and an enhancement factor (EFexp) of 1.74 × 108 for fentanyl. Furthermore, it exhibits excellent reproducibility, as evidenced by a relative standard deviation of less than 5%, and also demonstrates outstanding stability. The obtained high EFexp is due to the combined effects of the electromagnetic mechanism, involving the enhanced electromagnetic field generated by 3D periodic hotspots, and the chemical mechanism, involving the charge transfer from fentanyl to Au surface. Additionally, the as‐prepared 3D substrate realizes the trace detection of nine fentanyl analogs. This study provides new ideas for the controllable construction of sensitive SERS platforms for drug detection, ultimately advancing the fields of 3D substrates in booming SERS‐based technologies. [ABSTRACT FROM AUTHOR]

Echinococcosis chiefly includes cystic and alveolar echinococcosis, which is a parasitic disease. It is very important to find a quick and non‐staining method to determine whether a tissue sample has echinococcosis lesions; it is not only conducive to the diagnosis of echinococcosis but also conducive to the judgment after surgery. In the study, tissue surface‐enhanced Raman spectroscopy (SERS) in combination with deep learning was used to classify cystic and alveolar echinococcosis and healthy controls. Silver nanoparticles served as SERS‐enhanced substrates, and a large amount of tissue SERS spectra was collected. There were 24 cases of cystic echinococcosis tissue, 14 cases of alveolar echinococcosis tissue, and 21 cases of healthy control tissues, and the numbers of SERS spectra collected were 594, 410, and 990, respectively, for a total of 1994 spectra. The convolutional neural network (CNN) was used to categorize SERS spectra into three types. Four other common machine learning classification algorithms were compared with the CNN model to highlight the classification effect of the CNN model. The results show that the model with the best effect is the CNN model, whose accuracy reaches 95%. Therefore, SERS combined with the CNN model has great potential for distinguishing the tissues of cystic and alveolar echinococcosis. [ABSTRACT FROM AUTHOR]

The quality of food is one of the emergent points worldwide. Many microorganisms produce toxins that are harmful for human and animal health. In particular, mycotoxins from Fusarium fungi are strictly controlled in cereals. Simple and robust biosensors are necessary for 'in field' control of the crops and processed products. Nucleic acid-based sensors (aptasensors) offer a new era of point-of-care devices with excellent stability and limits of detection for a variety of analytes. Here we report the development of a surface-enhanced Raman spectroscopy (SERS)-based aptasensor for the detection of T-2 and deoxynivalenol in wheat grains. The aptasensor was able to detect as low as 0.17% of pathogen fungi in the wheat grains. The portable devices, inexpensive SERS substrate, and short analysis time encourage further implementation of the aptasensors outside of highly equipped laboratories. [ABSTRACT FROM AUTHOR]

In this paper, a three-layer structure of silver particle (AgNP)-dielectric-metal is proposed and constructed based on the characteristics of AgNPs that can excite LSPR (Localized Surface Plasmon Resonance) in free space. In order to overcome the problem of AgNPs easily oxidizing in the air, this paper synthesizes AgNPs using the improved Tollens method and effectively suppresses the coffee-ring effect by changing the solution evaporation conditions, so that the distribution of AgNPs in the deposition area is relatively uniform. The structure proposed in this paper takes advantage of the flexibility of nanoparticle application. The AgNPs deposited on the dielectric layer can effectively localize energy and regulate the LSPR of the device well. The structure can not only achieve precise regulation of the LSPR resonance peak of AgNPs but also can be used as a SERS substrate. [ABSTRACT FROM AUTHOR]

Surface-Enhanced Raman Spectroscopy (SERS) is a powerful, non-destructive technique for enhancing molecular spectra, first discovered in 1974. This study investigates the enhancement of Raman signals from single- and few-layer molybdenum disulfide (MoS2) when interacting with silver nanoparticles. We synthesized a MoS2 membrane primarily consisting of monolayers and bilayers through a wet chemical vapor deposition method using metal salts. The silver nanoparticles were either directly grown on the MoS2 membrane or placed beneath it. Raman measurements revealed a significant increase in signal intensity from the MoS2 membrane on the silver nanoparticles, attributed to localized surface plasmon resonances that facilitate SERS. Our results indicate that dichalcogenide/plasmonic systems have promising applications in the semiconductor industry. [ABSTRACT FROM AUTHOR]

Since the discovery of the phenomenon of surface-enhanced Raman scattering (SERS), it has gradually become an important tool for the analysis of material compositions and structures. The applications of SERS have been expanded from the fields of environmental and materials science to biomedicine due to the extremely high sensitivity and non-destructiveness of SERS-based analytical technology that even allows single-molecule detection. This article provides a comprehensive overview of the surface-enhanced Raman scattering (SERS) phenomenon. The content is divided into several main sections: basic principles and the significance of Raman spectroscopy; historical advancements and technological progress in SERS; and various practical applications across different fields. We also discuss how electromagnetic fields contribute to the SERS effect, the role of chemical interactions in enhancing Raman signals, a modeling and computational approaches to understand and predict SERS effects. [ABSTRACT FROM AUTHOR]

Since the colorimetric method has the characteristics of being simple and low cost, the fluorescence spectrum has the characteristics of a strong signal, and Surface-enhanced Raman scattering (SERS) detection has the characteristics of high sensitivity and strong specificity, people usually use these three methods for detection, but the detection of a single sample takes more time. If multiple samples can be tested at the same time, the detection efficiency and sensitivity can be improved, and the selectivity and reliability will be greatly improved. Multiplex sensing also provides a new direction for researchers. To fully understand the research of multiplex sensing based on the plasmonic optics of noble metal nanostructures, this review summarizes all the results previously reported in this field. It also discusses the principles of various detection methods and the biochemical application of multiple detections and finally summarizes the challenges and prospects. [ABSTRACT FROM AUTHOR]

Surface enhanced Raman spectroscopy (SERS) by using gold nanoparticles (AuNPs) has gained relevance for the identification of biomolecules and some cancer cells. Searching for greener NPs synthesis alternatives, we evaluated the SERS properties of AuNPs produced by using different filamentous fungi. The AuNPs were synthesized utilizing the supernatant of Botrytis cinerea, Trichoderma atroviride, Trichoderma asperellum, Alternaria sp. and Ganoderma sessile. The AuNPs were characterized by ultraviolet–visible spectroscopy (UV–Vis) to identify its characteristic surface plasmon resonance, which was located at 545 nm (B. cinerea), 550 nm (T. atroviride), 540 nm (T. asperellum), 530 nm (Alternaria sp.), and 525 nm (G. sessile). Morphology, size and crystal structure were characterized through transmission electron microscopy (TEM); colloidal stability was assessed by Z-potential measurements. We found that, under specific incubation conditions, it was possible to obtain AuNPs with spherical and quasi-spherical shapes, which mean size range depends on the fungal species supernatant with 92.9 nm (B. cinerea), 24.7 nm (T. atroviride), 16.4 nm (T. asperellum), 9.5 nm (Alternaria sp.), and 13.6 nm (G. sessile). This, as it can be expected, has an effect on Raman amplification. A micro-Raman spectroscopy system operated at a wavelength of 532 nm was used for the evaluation of the SERS features of the AuNPs. We chose methylene blue as our target molecule since it has been widely used for such a purpose in the literature. Our results show that AuNPs synthesized with the supernatant of T. atroviride, T. asperellum and Alternaria sp. produce the stronger SERS effect, with enhancement factor (EF) of 20.9, 28.8 and 35.46, respectively. These results are promising and could serve as the base line for the development of biosensors through a facile, simple, and low-cost green alternative. [ABSTRACT FROM AUTHOR]

In this work, Surface-Enhanced Raman Spectroscopy (SERS) was employed as an effective detection technique for folpet, characterized by its notable specificity and sensitivity. The investigation involved the use of UV–Vis, Raman, and SERS spectroscopy of folpet at different concentrations for a comprehensive study of plasmon-driven effects such as plasmon resonance, plasmon hybridization, and electric field enhancement resulting in the SERS' intensification. Specifically, SERS detection of folpet solutions at concentrations below 100 µM is presented in detail by using Ag nanoparticles prepared with hydroxylamine reduction. The experimentation encompassed diverse conditions to optimize the detection process, with Raman spectra acquired for both folpet powder and aqueous solution of folpet at the natural pH. SERS analyses were conducted across a concentration range of 9.5 × 10−8 to 1.61 × 10−4 M, employing 532 nm excitation. The differences in the spectral profiles observed for folpet Raman powder and SERS are ascribed to N–S cleavage; these changes are attributed to plasmon catalysis induced by the used Ag nanoparticles. Transmission electron microscopy (TEM) was also important in the present analysis to better understand which mechanism of nanoparticles aggregation is more favorable for the SERS detection regarding the formation of hot spots in the suspension. Complementing the experimental data, the molecular structure and theoretical Raman spectra of the folpet molecule were calculated through density functional theory (DFT) methods. The outcomes of these calculations were crucial in the elucidation of folpet's vibrational modes. The culmination of this research resulted in the successful detection of folpet, achieving a notable limit of detection at 4.78 × 10−8 M. This comprehensive approach amalgamates experimental and theoretical methodologies, offering significant insights into the detection capabilities and molecular characteristics of folpet via SERS analysis. [ABSTRACT FROM AUTHOR]

Metal aerogels (MAs) are emerging all‐nanometal‐structured self‐standing porous materials featuring exceptional performances in diverse fields. They have recently been adopted as 3D surface‐enhanced Raman scattering (SERS) substrates, while the less utilization of the unique porous structure leads to limited performance. Here, a fascinating compression‐mediated regulation strategy is presented to largely boost the SERS performance of Au–Ag aerogels. By gently pressing, both the density of hot spots and the inter‐ligament distance can be efficiently modulated, thus enabling to flexibly manipulate the SERS properties of MAs. On this basis, a record‐high misfocus tolerance (∼8.8 mm), low detection limit (down to 0.1 nM), high stability (>1 month), reusability, and multiplex detection ability are concurrently realized. This study may point out a new direction for engineering 3D SERS substrates with tunable and exceptional performance. [ABSTRACT FROM AUTHOR]

Rapid, in situ, and real‐time molecule mapping on rough surfaces with high accuracy has long been one of the paramount challenges in many fields. Here, an effortless Ag NPs doped glycerol liquid film SERS substrate (g‐LFS) is developed to investigate the distribution of contaminants on different types of rough surfaces. After substrate optimization, the g‐LFS is characterized in terms of uniformity, reproducibility, and stability with time. The substrate showed an excellent signal stability, even after 96.5 h of usage or 19 days of storage, together with great uniformity (7.4% RSD) and reproducibility (7.1% RSD). As a proof of concept, the distribution of Rhodamine 6G(R6G) dye on rough fabric and the R6G migration in different plant types and tissues have been explored. The g‐LFS substrate demonstrated great accuracy, detecting R6G even in deep fabric grooves, recovering 82.4% of the initial concentration. Moreover, the g‐LFS SERS substrate detected significantly different concentrations in root, stem and leave tissues of bean sprouts, as well as between xylem and phloem in vascular plant branches. Overall, the g‐LFS substrate is proven to be well‐suited for in situ detection on rough surfaces with great versatility and robustness, aggregating new opportunities for contaminant investigation on food and plants using SERS. [ABSTRACT FROM AUTHOR]

Gold nanostars have shown enormous potential as the main enablers of advanced applications ranging from biomedicine to sensing or catalysis. Their unique anisotropic structure featuring sharp spikes that grow from a central core offers enhanced optical capabilities and spectral tunability. Although several synthesis methods yield NSs of different morphologies and sizes up to several hundred nanometers, obtaining small NSs, while maintaining their plasmonic properties in the near-infrared, has proven challenging and elusive. Here, we show that Cu2+ addition during NS synthesis in polyvinylpyrrolidone/dimethylformamide generates more crystallographic defects and promotes the directional growth, giving rise to NSs with a larger number of much sharper spikes. They are also formed at smaller volumes, enabling the generation of ultrasmall nanostars, with a volume as small as 421 nm3 (i.e., 9.2 nm of volume-equivalent diameter), while maintaining a plasmon resonance in the near-infrared. To this end, we systematically evaluate the influence of synthesis parameters on the nanostar size and optical characteristics and demonstrate their properties for applications in catalysis, surface-enhanced Raman spectroscopy sensing, and hyperthermia. The ultrasmall nanostars show excellent attributes in all of them, leveraging their small size to enhance properties related to a higher surface-to-volume ratio or colloidal diffusivity. [ABSTRACT FROM AUTHOR]

Zirconium nitride (ZrN) nanoparticles (NPs) can offer appealing plasmonic properties for biomedical applications, but the synthesis of nontoxic, water-dispersible nanoformulations exhibiting plasmonic features in the biotransparency window presents a great challenge. Here, we report the synthesis, by methods of laser ablation, of small ZrN-based NPs, which are unique in combining photothermal heating and near-field enhancement in the transparency window. Depending on the synthesis environment, the formed ZrN-based NPs exhibit plasmonic absorption bands with maxima around 660–670 and 610–630 nm, which are largely red-shifted compared to what is expected from pure ZrN NPs. The observed shift is explained by the inclusion of zirconium oxide ZrOx (1 < x < 2) into NP composition and NP coating by naturally formed ZrOx. We then explored biophotonic applications of ZrN NPs. While pure NPs demonstrate their nontoxicity in vitro, their conjugation with anti-HER1 affibody ZHER1:1907 and subsequent photothermal heating with NIR-I laser cause 100% cancer cell death. In addition, profiting from the field enhancement, we demonstrate bioimaging functionality using a designed surface-enhanced Raman scattering probe based on an NP-conjugated azobenzene-CN-OH molecule as a Raman reporter. Combining a strong photothermal effect and the imaging option, laser-synthesized ZrN/ZrOx NPs promise a major advancement of theranostic modalities based on plasmonic nanomaterials. [ABSTRACT FROM AUTHOR]

Recent advancements in medical science have ushered in the era of "Personalized Medicine," which tailors treatments to individual genetics, lifestyle, and environmental factors. A cornerstone of this approach is continuous monitoring and adjustment of treatment regimens to optimize effectiveness while minimizing side effects. In therapeutic drug monitoring (TDM), crucial for drugs like doxorubicin (DOX) with severe side effects, traditional methods such as spectrofluorimetry and chromatography are utilized, but they suffer from cost and complexity issues. Biosensors, especially those leveraging Localized Surface Plasmon Resonance (LSPR) and surface-enhanced Raman spectroscopy (SERS), offer a promising alternative. This study focuses on developing a cost-effective plasmonic biosensor using gold nanoislands semiembedded in a glass substrate. The LSPR platform, based on gold nanoislands (Au NIs) with an average diameter of 23 nm, offers a rapid method for ultrasensitive, label-free detection of DOX in biological fluids up to the nanomolar range, even in diluted (1:10) and undiluted blood serum samples from cancer patients receiving the drug. The method capitalizes on the extraordinary adhesion between the nanoislands and the glass matrix, preserving plasmon integrity while enhancing the electric field surrounding the nanoislands for improved sensitivity. Moreover, by exploiting nanoislands with Au/Al2O3 core/shell structures with an average diameter and gap of about 70 and 7 nm, respectively, highly efficient SERS-active platforms are created, enabling the detection of ultralow DOX concentrations down to picomolar range, where the LSPR system is insensitive. The combined use of both systems enables the detection of DOX across a broad range, from low to high nanomolar concentrations, in biological fluids. This integration of semiembedded nanoislands presents a scalable and multifunctional approach suitable for point-of-care diagnostics, offering reproducible and stable characteristics over time. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) remains a significant area of research since it's discovery 50 years ago. The surface-based technique has been used in a wide variety of fields, most prominently in chemical detection, cellular imaging and medical diagnostics, offering high sensitivity and specificity when probing and quantifying a chosen analyte or monitoring nanoparticle uptake and accumulation. However, despite its promise, SERS is mostly confined to academic laboratories and is not recognised as a gold standard analytical technique. This is due to the variations that are observed in SERS measurements, mainly caused by poorly characterised SERS substrates, lack of universal calibration methods and uncorrelated results. To convince the wider scientific community that SERS should be a routinely used analytical technique, the field is now focusing on methods that will increase the reproducibility of the SERS signals and how to validate the results with more well-established techniques. This review explores the difficulties experienced by SERS users, the methods adopted to reduce variation and suggestions of best practices and strategies that should be adopted if one is to achieve absolute quantification. [ABSTRACT FROM AUTHOR]

Volatile Organic Compounds (VOC) are a major class of environmental pollutants hazardous to human health, but also highly relevant in other fields including early disease diagnostics and organoleptic perception of aliments. Therefore, accurate analysis of VOC is essential, and a need for new analytical methods is witnessed for rapid on‐site detection without complex sample preparation. Surface‐Enhanced Raman Spectroscopy (SERS) offers a rapidly developing versatile analytical platform for the portable detection of chemical species. Nonetheless, the need for efficient docking of target analytes at the metallic surface significantly narrows the applicability of SERS. This limitation can be circumvented by interfacing the sensor surface with Metal–Organic Frameworks (MOF). These materials featuring chemical and structural versatility can efficiently pre‐concentrate low molecular weight species such as VOC through their ordered porous structure. This review presents recent trends in the development of MOF‐based SERS substrates with a focus on elucidating respective design rules for maximizing analytical performance. An overview of the status of the detection of harmful VOC is discussed in the context of industrial and environmental monitoring. In addition, a survey of the analysis of VOC biomarkers for medical diagnosis and emerging applications in aroma and flavor profiling is included. [ABSTRACT FROM AUTHOR]

This work describes our recent PCB-based plasmonic nanostructured platform patent (US 11,828,747B2) for the detection of biomarkers in breast cancer serum (BCS). A 50 nm thin gold film (TGF) was immersion-coated on PCB (i.e., PCB-TGF) and immobilized covalently with gold nanourchin (GNU) via a 1,6-Hexanedithiol (HDT) linkage to produce a plasmonic activated nanostructured thin film (PANTF) platform. A label-free SERS immunosensor was fabricated by conjugating the platform with monoclonal HER-II antibodies (mAb) in a directional orientation via adipic acid dihydrazide (ADH) to provide higher accessibility to overexpressed HER-II biomarkers (i.e., 2+ (early), 3+ (locally advanced), and positive (meta) in BCS. An enhancement factor (EF) of 0.3 × 105 was achieved for PANTF using Rhodamine (R6G), and the morphology was studied by scanning electron microscopy (SEM) and atomic force microscope (AFM). UV-vis spectroscopy showed the peaks at 222, 231, and 213 nm corresponding to ADH, mAb, and HER-II biomarkers, respectively. The functionalization and conjugation were investigated by Fourier Transform Near Infrared (FT-NIR) where the most dominant overlapped spectra of 2+, 3+, and Pos correspond to OH-combination of carbohydrate, RNH2 1st overtone, and aromatic CH 1st overtone of mAb, respectively. SERS data were filtered using the filtfilt filter from scipy.signals, baseline corrected using the Improved Asymmetric Least Squares (isals) function from the pybaselines.Whittaker library. The results showed the common peaks at 867, 1312, 2894, 3026, and 3258 cm−1 corresponding to glycine, alanine ν (C-N-C) assigned to the symmetric C-N-C stretch mode; tryptophan and α helix; C-H antisymmetric and symmetric stretching; NH3+ in amino acids; and N-H stretch primary amide, respectively, with the intensity of Pos > 3+ > 2+. This trend is justifiable considering the stage of each sample. Principal Component Analysis (PCA) and Linear Discrimination Analysis (LDA) were employed for the statistical analysis of data. [ABSTRACT FROM AUTHOR]

Colorectal cancer remains a major global health concern. Colonoscopy, the gold-standard colorectal cancer diagnostic, relies on the visual detection of lesions and necessitates invasive biopsies for confirmation. Alternative diagnostic methods, based on nanomedicine, can facilitate early detection of malignancies. Here, we examine the uptake of surface-enhanced Raman scattering nanoparticles (SERS NPs) as a marker for intestinal tumor detection and imaging using an established Drosophila melanogaster model for gut disease. Young and old Oregon-R and w1118 flies were orally administered SERS NPs and scanned without and upon gut lumen clearance to assess nanoparticle retention as a function of aging. Neither young nor old flies showed significant NP retention in their body after gut lumen clearance. Moreover, tumorigenic flies of the esg-Gal4/UAS-RasV12 genotype were tested for SERS NP retention 2, 4 and 6 days after RasV12 oncogene induction in their midgut progenitor cells. Tumorigenic flies showed a statistically significant NP retention signal at 2 days, well before midgut epithelium impairment. The signal was then visualized in scans of dissected guts revealing areas of NP uptake in the posterior midgut region of high stem cell activity. [ABSTRACT FROM AUTHOR]

Aromatic amines are important commercial chemicals, but their carcinogenicity poses a threat to humans and other organisms, making their rapid quantitative detection increasingly urgent. Here, amorphous MoO3 (a‐MoO3) monolayers with localized surface plasmon resonance (LSPR) effect in the visible region are designed for the trace detection of carcinogenic aromatic amine molecules. The hot‐electron fast decay component of a‐MoO3 decreases from 301 fs to 150 fs after absorption with methyl orange (MO) molecules, indicating the plasmon‐induced hot‐electron transfer (PIHET) process from a‐MoO3 to MO. Therefore, a‐MoO3 monolayers present high SERS performance due to the synergistic effect of electromagnetic enhancement (EM) and PIHET, proposing the EM‐PIHET synergistic mechanism in a‐MoO3. In addition, a‐MoO3 possesses higher electron delocalization and electronic state density than crystal MoO3 (c‐MoO3), which is conducive to the PIHET. The limit of detection (LOD) for o‐aminoazotoluene (o‐AAT) is 10−9 M with good uniformity, acid resistance, and thermal stability. In this work, trace detection and identification of various carcinogenic aromatic amines based on a‐MoO3 monolayers is realized, which is of great significance for reducing cancer infection rates. [ABSTRACT FROM AUTHOR]

A series of non‐spherical metallic Au and bimetallic core@shell AuAg nanoparticles (NPs) have been synthesized for SERS improvements. The bimetallic core@shell AuAg NPs were obtained through a controlled overgrowth of an Ag shell onto the surface of two types of non‐spherical Au NPs, used as seeds, Au nanooctaheda (Au NOc) and Au nanotriangles (Au NTs). This Ag overgrowth was able to produce bimetallic core@shell structures such as nanocubes and nanopyramids, respectively. Transmission electron microscopy (TEM) was used to determine the particle size and particle morphology for metallic and bimetallic NPs, and energy‐dispersive X‐ray (EDX) elemental mapping analysis confirmed the core@shell structure of the bimetallic NPs. The plasmonic absorption bands exhibited for each nanosystem were observed by UV–vis spectroscopy. The concentration of Au and Ag in the bimetallic systems was determined by inductively coupled plasma mass spectrometry (ICP‐MS). After synthesis and characterization, p‐aminothiophenol (PATP) was used as a model analyte to investigate the surface‐enhanced Raman spectroscopy (SERS) capabilities of the synthesized metallic and bimetallic nanosystems. In PATP, a dimerization reaction to 4,4′‐dimercaptoazobenzene (DMAB) is produced when it is adsorbed onto the surface of certain noble metals. This SERS analysis was performed at 10−4 M of PATP and by using two different laser wavelengths (532 and 785 nm) in all cases. In this context, we were able to detect the dimerization reaction of PATP to DMAB only for the bimetallic structures and under the 532 nm laser line. Moreover, we have found that the dimerization capacity also depends on the nanoparticle morphology. [ABSTRACT FROM AUTHOR]

In order to investigate the adsorption process of malachite green (MG) on gold nanoparticles, a simple gold nanoparticles‐assembled film was prepared as a substrate of surface‐enhanced Raman spectroscopy (SERS), and it was soaked in MG solutions of different concentrations. The kinetic adsorption process was investigated by SERS method and density functional theoretical calculations. When saturated adsorption was achieved, the relationship between the characteristic SERS band signal intensity and the logarithm of solution concentration of MG was consistent with Temkin adsorption isotherm model, where the R2 value was greater than 0.995, and the linear range was 1 × 10−3–1 × 10−7 M. Finally, a SERS quantitative analysis model of the relationship between the adsorption properties of surface species and the bulk concentration was established. According to the electrostatic interaction and co‐adsorption, we proposed the surface adsorption configurations and adsorption process of MG on the nanostructured gold films. [ABSTRACT FROM AUTHOR]

The early monitoring and inactivation of bacteria are of crucial importance in preventing the further spread of foodborne pathogens. Staphylococcus aureus (S. aureus), a prototypical foodborne pathogen, is widely present in the natural environment and has the capability to trigger a range of diseases at low concentrations. In this work, we designed Fe3O4@SiO2-Au core–shell–satellite nanocomposites (NCs) modified with aptamer for efficient capture, high-sensitivity surface-enhanced Raman scattering (SERS) detection, and photothermal therapy (PTT) against S. aureus. Fe3O4@SiO2-Au NCs with tunable Au nanocrystal nanogaps were prepared. By combining the finite-difference time-domain (FDTD) method and experimental results, we studied the electric field distribution of Fe3O4@SiO2-Au under different Au nanogaps and ultimately obtained the optimal SERS substrate FSA-60. The modification of aptamer on the surfaces of FSA-60 could be used for the specific capture and selective detection of S. aureus, achieving a detection limit of as low as 50 cfu/mL. Furthermore, Apt-FSA-60 possessed excellent photothermal properties, demonstrating the strong photothermal killing ability against S. aureus. Therefore, Apt-FSA-60 is a promising high-sensitivity SERS substrate and efficient photothermal agent and is expected to be widely applied and promoted in future disease prevention and treatment. [ABSTRACT FROM AUTHOR]

Bacteriophages are emerging as a promising alternative in combating antibiotic-resistant bacteria amidst the escalating global antimicrobial resistance crisis. Recently, there has been a notable resurgence of interest in phages, prompting extensive research into their therapeutic potential. Beyond conventional microbiology and virology techniques, such as genomics and proteomics, novel phenotypic and chemical characterization methods are being explored. Among these, there is a growing interest in vibrational spectroscopy, especially in advanced modalities such as surface-enhanced Raman spectroscopy (SERS), tip-enhanced Raman spectroscopy (TERS), and atomic force microscopy-infrared spectroscopy (AFM-IR), which offer improved sensitivity and spatial resolution. This review explores the spectrum of uses of vibrational spectroscopy for bacteriophages, including its role in diagnostics, biosensing, phage detection, assistance in phage-based therapy, and advancing basic research. [ABSTRACT FROM AUTHOR]

The presence of copper ions (Cu2+) in excessive amounts can pose significant health risks. Therefore, the development of a rapid and highly sensitive technique for detecting even trace quantities of Cu2+ is of paramount importance. The proposed detection approach leverages the core-shell design of Au@Ag NPs functioning as the sensing substrate. The substrates were coupled with Raman probe molecules, namely, 4-mercaptobenzoic acid (4-MBA) and iodine ions (I−), resulting in the formation of the Au@Ag NPs-4-MBA-I− detection system. In this system, interactions between Cu2+ and I− took place, leading to the generation of I2, which in turn initiated the etching process of the Ag shell layer. Consequently, the thickness of the Ag shell decreased gradually. This reduction in the shell layer impaired the surface-enhanced Raman scattering (SERS) enhancement effect, causing a gradual decrease in the Raman signal intensity at 1586 cm−1 which was attributed to the characteristic peak of 4-MBA. Notably, a linear correlation existed between the thickness of the Ag shell and the intensity of the Raman signal. The proposed method for Cu2+ detection exhibits robust resistance to interference and high reproducibility under optimal SERS testing conditions. It boasted a wide linear detection range from 10−9 to 10−4 M and achieves a low detection limit (LOD) of 1.108 10−9 M. Moreover, this sensor was environmentally friendly, offered rapid recognition capabilities, and incurred minimal detection costs. Its versatility extended to diverse water systems, making it suitable for detecting Cu2+ not only in tap water but also in various other water sources. [ABSTRACT FROM AUTHOR]

Phthalate plasticizers (PAEs) illegally used in food pose a great threat to human health. A new and efficient sensing platform for the sensitive detection of the PAE residues in biological fluids needs to be designed and developed. Here, we report a simple and reliable surface-enhanced Raman spectroscopy (SERS) active platform with extralong hot spots of Au nanobipyramids@Ag nanorods (Au NBPs@Ag NRs) for the rapid and sensitive detection of PAEs in biological fluids. To achieve high activity, Au NBPs@Ag NRs with different shell lengths were fabricated by controlling the synthesis conditions, and the corresponding SERS properties were investigated by using crystal violet (CryV) and butyl benzyl phthalate (BBP). The experimental results showed that a longer shell length correlated to greater Raman activity, which was confirmed by finite-difference time-domain (FDTD) electromagnetic simulation. More importantly, the extralong hot spots of the Au NBPs@Ag NR SERS-active substrate showed excellent homogeneity and reproducibility for the CryV probe molecules (6.21%), and the detection limit was 10−9 M for both BBP and diethylhexyl phthalate (DEHP). Furthermore, through the standard addition method, an extralong hot spots SERS substrate could achieve highly sensitive detection of BBP and DEHP in serum and tears fluids, and the detection limit was as low as 3.52 × 10−8 M and 2.82 × 10−8 M. Therefore, the Au NBPs@Ag NR substrate with an extraordinarily long surface is efficient and versatile, and can potentially be used for high-efficiency sensing analysis in complex biological fluids. [ABSTRACT FROM AUTHOR]

Current label-free surface-enhanced Raman spectroscopy (SERS) assay for the detection and analysis of organophosphorus pesticides has achieved initial success, but the application still faces constraints of substrate portability and specificity. To this end, this paper demonstrates a method for portable, rapid, and specific detection of low concentrations of fenthion pesticides based on a solid substrate of gold nanoparticle monolayers combined with molecularly imprinted polymers (MIPs). The nano-monolayers were transferred to the surface of mercapto-silicon wafers by interfacial self-assembly technique to form a stable connection with S–Au bonds and, at the same time, prevent nanoparticles from dropping off during the surfactant removal process. Then, the fenthion MIPs were directly generated on the surface of the monolayer film by spin-coating with a pre-polymerization solution and ultraviolet-induced polymerization. Tests showed that the molecular imprint was able to accurately bind to fenthion, but not other molecules, in a mixture of structural analogs, achieving a low concentration detection of 10–8 mol/L. The composite substrate maintained a signal uniformity of a relative standard deviation (RSD) = 7.05% and a batch-to-batch reproducibility of RSD = 10.40%, making it a potential pathway for the extended application of SERS technology. [ABSTRACT FROM AUTHOR]