Identification of chemical modification in single human keratinocyte cells exposed to low doses of chlorpyriphos by Raman micro‐spectroscopy

Raman micro‐spectroscopy can be used to investigate biological single cells exposed to different chemicals. Since chronic exposure at low doses of pesticides can promote several diseases, the investigation of cellular changes induced by exposure to non‐cytotoxic doses of pesticides is of increasing interest. The efficiency of Raman micro‐spectroscopy to detect chemical modification in normal human keratinocytes induced by exposure to non‐cytotoxic doses of chlorpyriphos, an organophosphate pesticide present in many plant‐protection products, was investigated. Such modification affects mainly proteineous components (both single amino acids and amide linkages between amino acids) of the nucleus, cellular membranes and cytoplasm as well as the nucleic acid component of the nucleus. Chemical modifications are already detectable after 24 h exposure of keratinocytes at a chlorpyriphos concentration of 10⁻⁶ M , which is three orders of magnitude lower than the cytotoxic concentration (10⁻³ M ). Heavy damage to the lipid component occurs after exposure to the nearly cytotoxic concentration (10⁻⁴ M ). Atomic force microscopy images of keratinocyte cells exposed for 24 h to various chlorpyriphos concentrations show a progressive deterioration of the morphology of cellular membrane as the chlorpyriphos concentration increases. The results of this work may have wide applications in the monitoring of molecular changes in single human cells exposed to toxic agents. Copyright © 2010 John Wiley & Sons, Ltd.     

Analysis of Brain Tissue by FT-IR Microspectroscopy

Biological specimens contain a vast array of cell types, cell layers, extracellular materials, and other components that are structurally and functionally interrelated. Although the histological relationship of each of these constituents has been documented for most mammalian tissues, the chemical relationships between constituents has largely gone unexplored. Fourier transform infrared (FT-IR) spectroscopy can be a powerful tool for analyzing the chemical composition and molecular interactions of biological materials. Analyses of biological materials, however, have been conducted primarily on homogenized and/or purified samples. As a consequence of these limitations, the distribution and concentration of functional groups within different regions of biological tissues have not been appreciated. Several recent technological developments have enabled an FT-IR spectrometer to be combined with microscope optics. This integrated instrument, called an FT-IR microspectrometer, is capable of collecting good quality spectra from small regions of tissues down to a 10 μm × 10 μm square. Spectra collected along a grid pattern can be combined to generate contour or three-dimensional maps that represent the concentration and distribution of functional groups across a tissue. This is important because it permits a correlation of the spatial concentration of chemical functional groups with tissue histology. Analyses can be performed on normal tissue or tissues with unique properties, i.e., developmental or pathological tissues. This review will focus on FT-IR microspectroscopic investigations of normal biological tissue. Particular attention will be given to one example of FT-IR microspectroscopic analysis: white matter of brain tissue. This region was chosen because its infrared profile is very different from other brain regions, and thus it provides a clear illustration of the information that can be obtained by FT-IR microspectroscopy. This review is intended for the spectroscopist who is interested in applying his or her expertise to biological questions as well as to the biologist who is looking for new ways to obtain chemical information about his or her area of study.     

Solid-State 1H-NMR Relaxation Properties of the Fruit of a Wild Relative of Eggplant at Different Proton Larmor Frequencies

¹H longitudinal relaxation time profiles (T1) at different proton Larmor frequencies were registered for a solid-state plant tissue by using fast field cycling (FFC) nuclear magnetic resonance (NMR) spectroscopy. T1 distributions were obtained and the curves deconvoluted in order to differentiate among the different T1 components. Among the components, two were assigned to hydrophobic (e.g., fatty acid) and hydrophilic (e.g., saccharide) molecular systems, whereas the others were attributed to bulk and bound water. This paper shows for the first time solid-state FFC-NMR spectroscopy applied to plant tissue and reveals that relaxometry is a very promising technique for studying plant systems.     

共振光谱技术在分析空间非均质物质上的应用(英文)

pacc:0765Thispaperdemonstratesthreevibrational spectroscopictechniquesandtheirapplicationsin characterizationofspatiallyheterogamousmateri als,namelystep-scanphasemodulationFTIR photoacousticspectroscopy(S2MPAS),visible(confocal)Ramanmicroscopy(CRM)andF…     

Fluorescence lifetime imaging in biosciences: technologies and applications

The biosciences require the development of methods that allow a non-invasive and rapid investigation of biological systems. In this aspect, high-end imaging techniques allow intravital microscopy in real-time, providing information on a molecular basis. Far-field fluorescence imaging techniques are some of the most adequate methods for such investigations. However, there are great differences between the common fluorescence imaging techniques, i.e., wide-field, confocal one-photon and two-photon microscopy, as far as their applicability in diverse bioscientific research areas is concerned. In the first part of this work, we briefly compare these techniques. Standard methods used in the biosciences, i.e., steady-state techniques based on the analysis of the total fluorescence signal originating from the sample, can successfully be employed in the study of cell, tissue and organ morphology as well as in monitoring the macroscopic tissue function. However, they are mostly inadequate for the quantitative investigation of the cellular function at the molecular level. The intrinsic disadvantages of steady-state techniques are countered by using time-resolved techniques. Among these fluorescence lifetime imaging (FLIM) is currently the most common. Different FLIM principles as well as applications of particular relevance for the biosciences, especially for fast intravital studies are discussed in this work.      

Raman microscopy of prehistoric paintings in French megalithic monuments

Remains of pictorial decorations in a series of six representative megalithic monuments of Brittany (France) and two French stelae have been studied by micro‐Raman spectroscopy for the first time. Fungal colonies on the painted orthostats made it difficult to obtain in situ Raman spectra of the paint components. Nevertheless, paint micro‐specimens studied in the laboratory by micro‐Raman spectroscopy, X‐ray photoelectron spectroscopy and scanning electronic microscopy combined with energy dispersive X‐ray spectroscopy have made possible to characterise the materials present. The minerals α‐quartz, albite, microcline, muscovite, phlogopite, celadonite, beryl and anatase have been identified in the granitic rocks supporting the paintings, while dolomite and calcite are dominant in the calcareous rocky substrata. Haematite is the main component of the red pictographs, whereas amorphous carbon and manganese oxides/oxihydroxides have been used in the black ones. Calcite, gypsum and amorphous carbon have been detected as additional components of the paint in some cases. Contamination with modern tracing materials (polystyrene and ε‐copper‐phthalocyanine blue) has been detected in several cases. The presence of pigments as decorative elements in megalithic monuments of Western France and its possible relation with those of the Iberian Peninsula create interesting expectations for the knowledge of the European megalithic culture. Copyright © 2015 John Wiley & Sons, Ltd.     

Scanning Near-Field Optical Microscopy and Microspectroscopy of Green Fluorescent Protein in Intact Escherichia coli Bacteria

Scanning near-field optical microscopy (SNOM) yields high-resolution topographic and optical information and constitutes an important new technique for visualizing biological systems. By coupling a spectrograph to a near-field microscope, we have been able to perform microspectroscopic measurements with a spatial resolution greatly exceeding that of the conventional optical microscope. Here we present SNOM images of Escherichia coli bacteria expressing a mutant green fluorescent protein (GFP), an important reporter molecule in cell, developmental, and molecular biology. Near-field emission spectra confirm that the fluorescence detected by SNOM arises from bacterially expressed GFP molecules.     

Applications of Raman spectroscopy in dentistry part II: Soft tissue analysis

Raman spectroscopy is rapidly moving from an experimental technique for the analysis of biological molecules to a tool for the real-time clinical diagnosis and in situ evaluation of the oral tissue in medical and dental research. The purpose of this study is to identify various applications of Raman spectroscopy, to evaluate the contemporary status, and to explore future directions in the field of dentistry. Several in-depth applications are presented to illustrate Raman spectroscopy in early diagnosis of soft tissue abnormalities. Raman spectroscopy allows researchers to analyze histological and biochemical composition of biological tissues. The technique not only demonstrates its role in the disclosure of dysplasia and malignancy, but also in performing guided biopsies, diagnosing sialoliths, and assessment of surgical margins. Raman spectroscopy is used to identify the molecular structures and their components to give substantial information about the chemical structure properties of these molecules. In this article, we acquaint the utilization of Raman spectroscopy in analyzing the soft tissues in relation to dentistry.     

Conformity and precision of CO2 densimetry in CO2 inclusions: microthermometry versus Raman microspectroscopic densimetry

To assess the ability of densimetry for CO₂ fluid in CO₂ inclusions, we compare two methods, microthermometry and Raman microspectroscopic densimetry for CO₂. The comparative experiment was performed for nine CO₂ inclusions in three mantle xenoliths. The results are as follows: (1) microthermometry precisely determines CO₂ density with the range of 0.65 to 1.18 g/cm³ compared with Raman microspectroscopic densimetry; (2) CO₂ density obtained by Raman microspectroscopic densimetry is fairly consistent with that by microthermometry; (3) it is hard to determine CO₂ density in CO₂ inclusion with diameter of less than around 3 µm using microthermometry; and (4) microthermometry can be applied only to the CO₂ inclusion whose CO₂ density ranges from around 0.65 to 1.18 g/cm³, whereas the Raman microspectroscopic densimetry is applicable to CO₂ density ranging from 0.1 to 1.24 g/cm³. The above features carry the potential for estimation of depth origin of mantle‐derived rocks. The depth where the rocks were trapped by host magma can be estimated using both geothermometric data and CO₂ fluid density in CO₂ inclusions in the rocks. Typical precisions of density of CO₂ in CO₂ inclusions obtained by the Raman microspectroscopic densimetry (~0.01 g/cm³) and by the microthermometry (< 0.001 g/cm³) correspond to uncertainties in the depth origin of 2.4 km and < 1.7 km, respectively, at 1000 ± 50 °C. In case of the mantle under 750–1250 °C and 1 GPa, the CO₂ fluid has a density ranging from 1.06 g/cm³ to 1.21 g/cm³, which are well measured by the Raman microspectroscopic densimetry. Combination of both densimetries for CO₂ in mantle minerals elucidates the deep structure of the Earth. Copyright © 2012 John Wiley & Sons, Ltd.     

Surface-enhanced raman scattering and nonlinear optics applied to electrochemistry

The most recently developed diagnostic technique in metal-electrolyte and metal-gas interfaces adapts spontaneous Raman scattering and nonlinear optical generation, techniques normally applied to bulk media, to surface science investigation. For certain metallic surfaces, an enormous increase exists in the Raman (as much as 10⁶ to 10⁸ times) and nonlinear optical signals resulting from submonolayer coverage of molecular adsorbates at the interface. Spontaneous Raman scattering and nonlinear optical scattering are well developed in both theory and practice for the analysis of molecular structure and concentration in bulk media. Instrumentation to generate and detect these inelastically scattered signals is readily available and is adequate for adaption to surface science. However, the mechanism (or mechanisms) giving rise to such a large enhancement at the interfaces is still being actively researched and remains controversial. Theoretical and experimental investigations related to the underlying physics of this enhancement and the application of such surface enhancement as a vibrational probe for adsorbates on the metal surface have been labeled “surface-enhanced Raman scattering” (SERS) and “surface-enhanced nonlinear optics”. Soon after the recognition that molecules adsorbed onto metal electrodes under certain conditions exhibit an anomalously large Raman scattering efficiency,^1–3 it became evident that such a phenomenon makes possible an in situ diagnostic probe for detailed and unique vibrational signatures of adsorbates in the ambient phase (electrolyte and atmospheric gas surroundings). Optical spectroscopy in the visible range has a much higher energy resolution (e.g., 0. I cm-I) than is presently available in electron energy loss spectroscopy (EELS), as well as the capability to measure much lower frequency modes (e.g., as low as 5 cm^?1) than is possible in infrared spectroscopy. Perhaps the most significant attribute of SERS and surface-enhanced nonlinear optical scattering is that the surrounding media in front of the interface (e.g., several meters of gas and several centimeters of liquid) do not introduce optical loss or overwhelmingly large signals. The recognition that SERS is capable of performing vibrational spectroscopy with this resolution, frequency range, and in such dense surroundings has therefore brought an explosion of activity to the field since 1977.     

Application of monitoring methodology in carbon complex contained solution using surface-enhanced Raman spectroscopy (SERS)

Raman spectroscopy is employed to obtain information that cannot be obtained using other technologies, using inelastic scattering. The development of laser technology enables Raman spectroscopy to overcome its limits and succeed in various fields. For example, compared with other analysis methods that use light, it does not require a sample preparation or long measuring time—thus, it is a great breakthrough for in situ process applications. Also, it is difficult to analyze functional groups that are combined and the influence on the reaction is analyzed during the reaction in chemical solutions. Therefore, Raman spectroscopy provides an analytic method and assists in every step to increase the accuracy of the chemical process. Lately, developed surface-enhanced Raman spectroscopy (SERS) are used in precise analyzing methods. High-resolution SERS needs a specific substrate to satisfy each purpose. Raman spectroscopy is now advanced to be more a powerful analytic tool, combined with surface-enhancing technology, atomic force microscopy (AFM), and other technology.     

Recent advances in linear and nonlinear Raman spectroscopy. Part VII

The aim of this paper is to provide an overview of advances in the field of Raman spectroscopy as reflected in articles published each year in the Journal of Raman Spectroscopy as well as in trends across related journals publishing in this research area. The context for this review is derived from statistical data on article counts obtained from Thomson Reuters ISI Web of Knowledge by year and by subfield of Raman spectroscopy. Additional information is gleaned from presentations featuring Raman spectroscopy presented at the International Conference on Advanced Vibrational Spectroscopy in Kobe Japan in August 2013 and at SCIX 2013 sponsored by the Federation of Analytical Chemistry and Spectroscopy Societies in Milwaukee, Wisconsin, USA, October 2013. Papers published in the Journal of Raman Spectroscopy in 2012 are highlighted in this review and reflect topics and advances at the frontier of Raman spectroscopy, a field that is expanding rapidly as a sensitive photonic probe of matter at the molecular level in an ever widening sphere of novel applications. Copyright © 2013 John Wiley & Sons, Ltd.     

Quantitative analysis of ethanol–methanol–water ternary solutions using Raman spectroscopy

Raman spectroscopy was used for rapid in-situ measurement of alcohols in ethanol-methanol-water ternary systems. Mass fractions of the individual components were determined using calibration curves for binary systems of ethanol-water, methanol-water, and ethanol-methanol. Calibration curves were constructed by calculating the ratio of the Raman peak intensity of a component and that of an external standard (acetonitrile). Assuming additivity of the spectra, simultaneous equations were written, and mass fractions of ethanol, methanol, and water in the ternary solutions were determined by solving the system of equations through calculating an inverse matrix. The relative errors between the mass fractions obtained from the Raman spectra and those obtained from mass measurements were <0.6%.     

Recent advances in linear and non‐linear Raman spectroscopy. Part IX

This annual review is published to provide an overview of advances in the field of Raman spectroscopy as reflected in papers published each year in the Journal of Raman Spectroscopy (JRS) as well as in trends across related journals that have published papers in the broad field of Raman spectroscopy. The content is obtained from statistical data on article counts obtained from Thomson Reuters ISI Web of Science Core Collection by year and by subfield of Raman spectroscopy. Additional information is gleaned from presentations at the VIII International Conference on Advanced Vibrational Spectroscopy (ICAVS‐8) in Vienna, Austria in July 2015 and those featuring Raman scattering at SCIX 2015 organized by the Federation of Analytical Chemistry and Spectroscopy Societies (FACSS) in Providence, Rhode Island, USA, in September/October 2015. Coverage is also provided for topics from the conference ECONOS 2015 held in April in Leuven, Belgium. Finally, papers published in JRS in 2014 are highlighted and arranged by topics at the frontier of Raman spectroscopy. Taken from these various viewpoints, it is clear that Raman spectroscopy continues to be a rapidly expanding field that provides sensitive photonic information of matter at the molecular level in an ever‐widening arena of novel applications. Copyright © 2015 John Wiley & Sons, Ltd.     

Molecular orientation analysis of organic thin films by z‐polarization Raman microscope

Polarization‐dependent Raman microscopy is a powerful technique to perform both structural and chemical analyses with submicron spatial resolution. In conventional Raman microscopy, the polarization measurements are limited only in the direction parallel to the sample plane. In this work, we overcome the limit of conventional measurements by controlling the incident polarization by a spatially modulated waveplate. In this method, the polarization perpendicular to the sample surface (z‐polarization) can be detected together with the parallel polarization (xy‐polarization). Because of this unique polarization control, our Raman microscope has the ability to image the molecular orientation, together with the molecular analysis. Here, we have investigated thin films of pentacene molecules that are widely studied as an organic semiconductor material. The orientations of pentacene molecules are imaged with a spatial resolution of 300 nm. Our results clearly indicate that the lamellar grains show the lower tilt angles compared to the neighboring islands, which has not been proved in conventional methods. The substrate effects and the thickness dependence of the film are also studied. These results provide knowledge about the relationship between the devise performance and the film structures, which is indispensable for future device exploitations. Copyright © 2012 John Wiley & Sons, Ltd.     

Recent advances in linear and nonlinear Raman spectroscopy. Part IV

The purpose of the review is to provide a concise overview of recent advances in the broadly defined field of Raman spectroscopy as reflected in part by the many articles published each year in the Journal of Raman Spectroscopy (JRS) as well as in trends across all related journals publishing in this research area. Context for the review is provided by considering statistical data on citations for the Thompson Reuters ISI Web of Science by year and by subfield of Raman spectroscopy. Additional statistics of number of papers and posters presented by category at the XXII International Conference on Raman Spectroscopy (ICORS 2010) is also provided. Papers published in JRS in 2009, as reviewed here, reflect trends at the cutting edge of Raman spectroscopy which is expanding rapidly as a sensitive photonic probe of matter at the molecular level with an ever widening sphere of novel applications. Copyright © 2010 John Wiley & Sons, Ltd.     

Towards a rational drug design: Raman micro‐spectroscopy analysis of prostate cancer cells treated with an aqueous extract of Nerium Oleander

Raman spectroscopy is an efficient optical technique used to identify and grade cancer on the basis of the molecular composition of the cell. In this work Raman spectroscopy is used to study the chemical alteration occurring inside a prostate cancer cell as a result of a treatment with a low‐concentration aqueous extract of Nerium Oleander. The results show that Nerium Oleander affects the protein and lipid concentration of cancer cells. Copyright © 2009 John Wiley & Sons, Ltd.     

Spectroscopic Trends for the Determination of Illicit Drugs in Oral Fluid

Abstract

The present work aims to review all of the articles published so far, focused on the determination of drugs of abuse in oral fluid. This fluid provides a simpler, faster, and more controllable sampling in comparison with the other biological fluids, such as blood or urine. Actually, the main goal of the researchers is to lower the limit of detection (LOD) to detect quantities of drugs smaller than the cut-off limits established by law for drug controls. Advances in Raman, infrared (IR), and nuclear magnetic resonance (NMR) spectroscopy applications are discussed. Surface-enhanced Raman spectroscopy (SERS) has been shown as the most sensitive technique for the detection of illicit drugs in oral fluid. The use of IR spectroscopy for determining drugs of abuse in oral fluid is growing, although the LODs obtained until now do not yet satisfy the necessities in the forensic field. Finally, NMR spectroscopy has seldom been used to determine drugs in oral fluid. Another future trend seems to be related with the use of portable instrumentation, which would allow us to perform in-situ analysis. This last application seems to be particularly promising to perform roadside drug tests and to identify overdose drugs in patients in emergency conditions.     

Electrochemical tip-enhanced Raman Spectroscopy for microscopic studies of electrochemical interfaces

The review describes electrochemical applications of tip-enhanced Raman spectroscopy (TERS). These applications combine the merits of both scanning probe microscopy (SPM) and Raman spectroscopy, which enables us to simultaneously obtain high-resolution images of surface morphology and chemical information under the electrochemical environment. This review, first summarizes the pioneering work done on the TERS systems that operate in liquid and electrochemical environments, and then gives an overview of the typical instrumentation of electrochemical TERS (EC-TERS) based on electrochemical scanning tunneling microscopy (EC-STM). Furthermore, this review summarizes the advancements in EC-TERS studies of events that occur at the interfaces. These include potential dependent structural changes and electrochemical reactions. Finally, we discuss the current issues and future prospects of EC-TERS for microscopic studies of electrochemical interfaces.     

Analysis of self‐repair mechanisms of Phaseolus vulgaris var. saxa using near‐infrared surface‐enhanced Raman spectroscopy

We used surface‐enhanced Raman spectroscopy (SERS) to investigate ultrastructural changes in cell‐wall composition during the self‐repair of lacerated hypocotyls of Phaseolus vulgaris var. saxa. A detailed study of self‐repair mechanisms requires localized information about cell‐wall structure and morphology in addition to the chemical cell‐wall composition. Characteristic Raman and SER spectra yielded two‐dimensional maps of cross sections of P. vulgaris var. saxa visualizing chemical compositions in the walls of different cell types and during various repair phases. SERS substrate particles were produced by the reduction of gold chloride on the plant tissue surface and characterized with absorption spectroscopy, scanning electron microscopy and energy‐dispersive X‐ray spectroscopy. The SERS results were compared with stained cross sections of the same plant using dark‐field microscopy with focus on lignin and suberin contents in repairing cells. In addition, SERS measurements revealed Au cyanide compounds on the cell surface, indicating the formation of hydrogen cyanide during the self‐repair phase. Copyright © 2009 John Wiley & Sons, Ltd.