- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Sensitive and Reproducible Gold SERS Sensor Based on Interference Lithography and Electrophoretic Deposition
摘要： Surface-enhanced Raman spectroscopy (SERS) is a promising analytical tool due to its label-free detection ability and superior sensitivity, which enable the detection of single molecules. Since its sensitivity is highly dependent on localized surface plasmon resonance, various methods have been applied for electric ?eld-enhanced metal nanostructures. Despite the intensive research on practical applications of SERS, fabricating a sensitive and reproducible SERS sensor using a simple and low-cost process remains a challenge. Here, we report a simple strategy to produce a large-scale gold nanoparticle array based on laser interference lithography and the electrophoretic deposition of gold nanoparticles, generated through a pulsed laser ablation in liquid process. The fabricated gold nanoparticle array produced a sensitive, reproducible SERS signal, which allowed Rhodamine 6G to be detected at a concentration as low as 10?8 M, with an enhancement factor of 1.25 × 105. This advantageous fabrication strategy is expected to enable practical SERS applications.
关键词： laser interference lithography,electrophoretic deposition,gold nanoparticle array,surface enhanced Raman spectroscopy,pulsed laser ablation in liquid
更新于2025-09-10 09:29:36
-
Surface-enhanced Raman spectroscopy (SERS) in cotton fabrics analysis
摘要： This article presents some aspects of application the dispersive Micro-Raman Spectroscopy in textile fibers analysis. Research were dedicated to the methodology of surface enhancement Raman spectroscopy (SERS) studies on cotton fabric and possibility of its application in fibers characterization. Studies were carried out on dyed cotton fabrics modified by silver nanowires (AgNWs). Three reactive dyes (blue, yellow, red) and four color intensities (0.5%, 1%, 2% and 5%) were used. AgNWs colloid was deposited on undyed and dyed cotton fabrics by dipping and drying method. Dyed fabrics were examined by spectroscopic methods: FTIR ATR, Raman, UV-Vis Diffuse Reflectance Spectroscopy, Fluorescence Spectroscopy. Raman signal enhancement phenomena occurring on the silver nanoparticles increases the possibility of fiber and dye identification especially in the case of dyes used in cotton dyeing reveals fluorescence.
关键词： UV-Vis Diffuse Reflectance Spectroscopy,SERS,Fluorescence Spectroscopy,reactive dyes,FTIR ATR,Micro-Raman spectroscopy,Cotton fibers
更新于2025-09-09 09:28:46
-
EXPRESS: Bulk Protein and Oil Prediction in Soybean Using Transmission Raman Spectroscopy: A Comparison of Approaches to Optimize Accuracy
摘要： Rapid measurements of protein and oil content are important for a variety of uses, from sorting of soybeans at the point of harvest to feedback during soybean meal production. In this study, our goal is to develop a simple protocol to permit rapid and robust quantitative prediction of soybean constituents using transmission Raman spectroscopy (TRS). To develop this approach, we systematically varied the various elements of the measurement process to provide a diverse test bed. First, we utilized an in-house-built benchtop TRS instrument such that suitable optical configurations could be rapidly deployed and analyzed for experimental data collection for individual soybean grains. Second, we also utilized three different soybean varieties with relatively low (33.97%), medium (36.98%), and high protein (41.23%) contents to test the development process. Third, samples from each variety were prepared using whole bean and three different sample treatments (i.e., ground bean, whole meal, and ground meal). In each case, we modeled the data obtained using partial least squares (PLS) regression and assessed spectral metric-based multiple linear regression (metric-MLR) approaches to build robust prediction models. The metric-MLR models showed lower root mean square errors (RMSEPs), and hence better prediction, compared to corresponding classical PLS regression models for both bulk protein and oil for all treatment types. Comparing different sample preparation approaches, a lower RMSEPs was observed for whole meal treatment and thus the metric-MLR modeling with ground meal treatment was considered to be optimal protocol for bulk protein and oil prediction in soybean, with RMSEP values of 1.15±0.04 (R2= 0.87) and 0.80±0.02 (R2= 0.87) for bulk protein and oil, respectively. These predictions were nearly two- to three-fold better (i.e., lower RMSEPs) than the corresponding NIR spectroscopy measurements (i.e., secondary gold standards in grain industry). For content prediction in whole soybean, incorporating physical attributes of individual grains in metric-MLR approach show up to 22% improvement in bulk protein and a relatively mild (up to ~ 5%) improvement in bulk oil prediction. The unique combination of metric-MLR modeling approach (which is rare in the field of grain analysis) and sample treatments resulted in improved prediction models, and using the physical attributes of individual grains is suggested as a novel measure for improving accuracy in prediction.
关键词： near-infrared spectroscopy,Soybean,NIR spectroscopy,MLR,transmission Raman spectroscopy,multiple liner regression,PLS regression
更新于2025-09-09 09:28:46
-
Excitation-Tunable Tip-Enhanced Raman Spectroscopy
摘要： Tip-enhanced Raman spectroscopy is a powerful tool to investigate chemical composition, for obtaining molecular information, and for recording images with a spatial resolution on the nanometer scale. However, it typically has been limited to a fixed excitation wavelength. We demonstrate excitation-dependent hyperspectral imaging by implementing a wavelength tunable laser to our TERS setup. Varying the excitation wavelength during TERS experiments is a key to perform spatially resolved resonant Raman scattering (RRS) with nanometer resolution, which enables mapping of transition centers and to study for example the quantum properties of electrons and phonons. To present the application potential and to verify the setup, we recorded excitation-dependent hyperspectral nanoimages of a densely packed film of carbon nanotubes (CNTs) on an Au surface and use the spectral position and intensity of the radial breathing modes for a unique assignment of the CNTs. We succeeded in identifying and imaging at least nine different tube species. The nanoimages revealed the exact position and the distribution of certain CNTs inside the film. e-TERS will have manifold application in nanoimaging, for chemical analysis and electronic studies on the nanometer scale, making it highly interesting in fields ranging from biomedicine and chemistry to material science.
关键词： nanoimaging,Tip-enhanced Raman spectroscopy,resonant Raman scattering,carbon nanotubes,hyperspectral imaging
更新于2025-09-09 09:28:46
-
Visualization of Primary Particles in a Tablet Based on Raman Crystal Orientation Mapping
摘要： Objective: The morphology of the primary particles in the active pharmaceutical ingredient (API) is one of the most important determinants for formulation function. However, it has not been possible to visualize primary particles in a tablet using various imaging methods, including spectroscopic mappings, because these particles usually exist as aggregated clusters in tablets. We revealed that the Raman spectrum of crystalline particles is determined depending upon the angle between the crystallographic axis and the polarization direction of the excitation laser. In this paper, we report a method to visualize primary particles within the aggregated cluster based on the Raman spectral change on the boundary of primary particles. Method: Metformin hydrochloride was chosen as a model API for this study. The crystal structure of metformin hydrochloride was solved using X-ray crystal structure analysis. The Raman spectra of metformin hydrochloride crystal along the xyz axes were recorded and resolved into components along the abc axes. Using the abc components, Raman mapping of metformin hydrochloride in tablets was performed to visualize the crystal orientation at each data point. Results: Metformin hydrochloride crystals recrystallized from water/ethanol formed a primitive monoclinic cell. Datasets of five distinct peak areas from the metformin hydrochloride Raman spectrum were used for analyses. Raman crystal orientation mapping (RCOM) from the tablet cross-section provided an image of primary particles within the aggregation cluster of metformin hydrochloride in the tablet. Conclusion: Based on the RCOM, we developed a visualization method for primary API particles in tablets. Because the morphology of primary particles is the key factor of formulation function, this method would contribute to better formulation development and quality control.
关键词： Raman mapping,Metformin,Formulation,Primary particle,Raman spectroscopy
更新于2025-09-09 09:28:46
-
Paper-based Versatile SERS Chip with Smartphone-based Raman Analyzer for Point of Care Application
摘要： With the advanced development of the miniaturized Raman spectroscopy, surface enhanced Raman spectroscopy (SERS) has extended its applications into the field of Point of Care Testing (POCT) and demonstrated its great significance in virtue non-invasive property and capability of fingerprint identification. In the SERS-based analysis and/or sensing system, the preparation of low cost, high-performance SERS substrate is critically important. In this manuscript, vacuum filtration is utilized to fabricate the silver nanoparticles (AgNPs) embedded nylon filter membrane (ANFM) as flexible paper-based SERS chips. By characterizing the typical analytes with the miniaturized smartphone-based Raman analyzer, the proposed SERS chips have successfully demonstrated good sensitivity, repeatability and stability. The lowest concentration as detected can approach 1 pmol for Rhodamine 6G (RH6G) and 10 pmol for both crystal violet (CV) and malachite green (MG), respectively. With the help of microporous structure of the membrane, the ANFM based SERS chips can implement the separation of small molecules from complex mixture and can achieve “purified” SERS signals of targeted molecules. Besides, with the function of anti-friction resistance and flexibility, the ANFM can serve as SERS papers to pre-concentrate the contaminates by multiple swapping and further enhance the SERS signals for point of care analysis. Therefore, we demonstrate multi-functions of the flexible ANFM based SERS chips, which provides a promising solution for the POCT analysis with SERS technique on account of its flexibility and low fabrication cost.
关键词： silver nanoparticles,SERS chips,nylon filter membrane,Point of Care Testing,smartphone-based Raman analyzer,Surface-enhanced Raman spectroscopy
更新于2025-09-09 09:28:46
-
Preparation of TiO <sub/>2</sub> nanoparticles by hydrolysis of TiCl <sub/>4</sub> using water and glycerol solvent system
摘要： The anatase phase TiO2 nanoparticles (NPs) were synthesized by precipitation method using TCl4 as a precursor in a new reaction medium containing water and glycerol. The as-synthesized photocatalysts were characterized by Raman spectroscopy, Fourier Transform Infra-red Spectroscopy (FT-IR), UV-Visible spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). The Raman spectra indicate the formation of crystalline anatase phase TiO2 NPs after calcination at 300 and 4000C. TiO2 NPs formation was confirmed by observing the major characteristic, FT-IR vibration bands of Ti-O network. The band gap calculated from UV-Vis DRS spectra ranged from 3.02-3.28 eV. FESEM images exhibit spherical shape TiO2 NPs in the form of nano-clusters with crystallite sizes ranged from 9.50-26.14 nm. FESEM images show that as the calcination temperature increases, the sizes of the TiO2 NPs also increase. The inclusion of glycerol promotes the formation of smaller particles and lowers the band gap of TiO2 NPs.
关键词： precipitation method,TiO2 nanoparticles,hydrolysis,anatase phase,Raman spectroscopy,FESEM,UV-Visible spectroscopy,water and glycerol solvent system,FT-IR,TiCl4
更新于2025-09-09 09:28:46
-
Encyclopedia of Spectroscopy and Spectrometry || Spatially Offset Raman Spectroscopy
摘要： Spatially offset Raman spectroscopy (SORS) is a type of vibrational spectroscopy that provides a means to obtain chemically specific information from below the surfaces beneath materials, up to several millimeters have been demonstrated. The chemical identification of materials represents a fundamental analytical requirement that spans the physical, biological, and medical sciences. In manufacturing, it is utilized in methods to ensure product quality (including purity), usually under governmental legislation, and in healthcare to differentiate between a healthy and diseased state. For many applications there may be a strict protocol to ensure that the sample suffers no damage and this limits the type of analysis that can be performed. Generally most spectroscopic methods fit the non-destructive criteria but all-too-often to perform an analysis there is a need to perform some preliminary sample preparation and recovery wet chemistry and this may not be advisable, particularly when the environment the sample is in is difficult to get at and/or, as for example in medical applications performing a biopsy may lead to unwanted complications and stress to patients. Raman spectroscopy provides a unique capability in terms of every chemical’s spectral signature is a unique fingerprint that can allow its identification. However, there are certain limitations to Raman spectroscopy. For example, Raman scattering cross sections are very small, typically 10 orders of magnitude weaker than typical organic molecules UV–Visible absorption cross section. The advent of lasers coupled with the development of excellent transmission optics and modern CCD cameras has revolutionized Raman spectroscopy in the last 20 years, to the point that samples can be examined be-they gas, liquid or solid, animal, vegetable, or mineral. However, for solid systems standard Raman methods are confined to characterization of the surface. This includes confocal Raman microscopy regularly used to study solids that is restricted to depths of the order of 100 mm below material surface. However, this limitation has recently been overcome using SORS and this new technology is being applied to a range of systems to characterize subsurface diffusely scattering materials, including tissue.
关键词： chemical identification,subsurface analysis,Spatially offset Raman spectroscopy,SORS,vibrational spectroscopy
更新于2025-09-09 09:28:46
-
Chemical analysis of in vivo–irradiated dentine of head and neck cancer patients by ATR-FTIR and Raman spectroscopy
摘要： Objectives To evaluate the effect of in vivo radiotherapy on the chemical properties of human dentine by Fourier-transform infrared spectroscopy (FTIR) and Raman analysis. Materials and methods Chemical composition was evaluated comparing control and irradiated group (n = 8). Irradiated teeth were obtained from radiotherapy patients subjected to fractionated X-ray radiation of 1.8 Gy daily totaling 72 Gy. The teeth were sectioned according to the type of dentine (crown or root dentine), obtaining 3-mm dentine cervical slices. The analyzed parameters by FTIR and Raman spectroscopies were mineral/matrix ratio (M:M), carbonate/mineral ratio (C:M), amide I/amide III ratio, and amide I/CH2 ratio. Raman also calculated the phosphate and carbonate crystallinity. Results FTIR revealed that M:M had a decrease in both factors (p = 0.008; p = 0.043, respectively) and root dentine showed a lower C:M in the irradiated group (p = 0.003). Raman revealed a higher phosphate crystallinity and a lower carbonate crystallinity in crown dentine of irradiated group (p = 0.021; p = 0.039). For amide I/amide III, the irradiated showed a lower ratio when compared to the control group (FTIR p = 0.002; Raman p = 0.017). For amide I/CH2, the root dentine showed a higher ratio than the crown dentine in both methods (p < 0.001). Conclusions Radiotherapy altered the chemical composition of human dentine. The exchange of phosphate-carbonate ions in the hydroxyapatite and higher concentration of organic components was found after radiotherapy. Clinical relevance The increased risk of radiation-related caries in patients undergoing head and neck radiotherapy is due not only to salivary, dietary, and microbiological changes but also to changes in tooth chemical composition.
关键词： Radiotherapy,Raman spectroscopy,Head and neck cancer,Fourier-transform infrared spectroscopy,Dentine
更新于2025-09-09 09:28:46
-
Raman and infrared spectroscopy reveal that proliferating and quiescent human fibroblast cells age by biochemically similar but not identical processes
摘要： Dermal fibroblast cells can adopt different cell states such as proliferation, quiescence, apoptosis or senescence, in order to ensure tissue homeostasis. Proliferating (dividing) cells pass through the phases of the cell cycle, while quiescent and senescent cells exist in a non-proliferating cell cycle-arrested state. However, the reversible quiescence state is in contrast to the irreversible senescence state. Long-term quiescent cells transit into senescence indicating that cells age also when not passing through the cell cycle. Here, by label-free in vitro vibrational spectroscopy, we studied the biomolecular composition of quiescent dermal fibroblast cells and compared them with those of proliferating and senescent cells. Spectra were examined by multivariate statistical analysis using a PLS-LDA classification model, revealing differences in the biomolecular composition between the cell states mainly associated with protein alterations (variations in the side chain residues of amino acids and protein secondary structure), but also within nucleic acids and lipids. We observed spectral changes in quiescent compared to proliferating cells, which increased with quiescence cultivation time. Raman and infrared spectroscopy, which yield complementary biochemical information, clearly distinguished contact-inhibited from serum-starved quiescent cells. Furthermore, the spectra displayed spectral differences between quiescent cells and proliferating cells, which had recovered from quiescence. This became more distinct with increasing quiescence cultivation time. When comparing proliferating, (in particular long-term) quiescent and senescent cells, we found that Raman as well as infrared spectroscopy can separate these three cellular states from each other due to differences in their biomolecular composition. Our spectroscopic analysis shows that proliferating and quiescent fibroblast cells age by similar but biochemically not identical processes. Despite their aging induced changes, over long time periods quiescent cells can return into the cell cycle. Finally however, the cell cycle arrest becomes irreversible indicating senescence.
关键词： PLS-LDA classification model,Raman spectroscopy,infrared spectroscopy,quiescence,senescence,proliferation,fibroblast cells,biomolecular composition
更新于2025-09-09 09:28:46