Arsenic-Induced Biochemical Changes in Labeo rohita Kidney: An FTIR Study

ABSTRACT

Arsenic is a toxic heavy metal that occurs naturally in water, soil, and air. It is widespread in the environment as a consequence of both anthropogenic and natural processes. In the current study, an attempt has been made to analyze the arsenic-induced molecular changes in macromolecular components like proteins and lipids in the kidney tissues of edible fish Labeo rohita using Fourier transform infrared (FTIR) spectroscopy. The FTIR spectrum of kidney tissue is quite complex and contains several bands arising from the contribution of different functional groups. The detailed spectral analyses were performed in three distinct wave number regions, namely 3600–3050 cm^?1, 3050–2800 cm^?1, and 1800–800 cm^?1. The current study shows that the kidney tissues are more vulnerable to arsenic intoxication. FTIR spectra reveal significant differences in both absorbance intensities and areas between control and arsenic-intoxicated kidney tissues; this result indicates that arsenic intoxication induces significant alteration on the major biochemical constituents such as lipids and proteins and leads to compositional and structural changes in kidney tissues at the molecular level. The current study confirms that FTIR spectroscopy can be successfully applied to toxicologic and biological studies.     

Application of FTIR Spectroscopy for Identification of Blood and Leukemia Biomarkers: A Review over the Past 15 Years

Abstract

Fourier transform infrared (FTIR) spectroscopy is an effective and nondestructive method for monitoring cellular alterations. Combining the advantages of FTIR spectroscopy with the challenge of cellular characterization, the main objective of this review is to collect information related to the spectroscopic identification of blood cells, focusing on specific biochemical features of leukemia cells detected through FTIR spectral analysis. Some interesting results obtained by different authors regarding human promyelocytic leukemia, white blood cells, chronic lymphocytic leukemia, and human peripheral blood mononuclear cells are presented. In addition, the characterization of two types of cells, namely, leukemia T and a healthy human blood cells, is reported and the identification of biochemical markers provides important information that, associated with clinical examination, can assist in the diagnosis of diseases.     

Spectroscopic analysis of bladder cancer tissues using Fourier transform infrared spectroscopy

Bladder cancer is one of the most common cancers in Africa. It takes several days to reach a diagnosis using histological examinations of specimens obtained by endoscope, which increases the medical expense. Recently, spectroscopic analysis of bladder cancer tissues has received considerable attention as a diagnosis technique due to its sensitivity to biochemical variations in the samples. This study investigated the use of Fourier transform infrared (FTIR) spectroscopy to analyze a number of bladder cancer tissues. Twenty-two samples were collected from 11 patients diagnosed with bladder cancer from different hospitals without any pretreatment. From each patient two samples were collected, one normal and another cancerous. FTIR spectrometer was used to differentiate between normal and cancerous bladder tissues via changes in spectra of these samples. The investigations detected obvious changes in the bands of proteins (1650, 1550 cm^–1), lipids (2925, 2850 cm^–1), and nucleic acid (1080, 1236 cm^–1). The results show that FTIR spectroscopy is promising as a rapid, accurate, nondestructive, and easy to use alternative method for identification and diagnosis of bladder cancer tissues.     

Fourier-transform-infrared-spectroscopy based metabolomic spectral biomarker selection towards optimal diagnostic differentiation of diabetes with and without retinopathy

Abstract

The purpose of this study is to identify Fourier transform infrared (FTIR) spectroscopy-based serum metabolomic spectral biomarkers using chemometrics for the diagnosis of Diabetic Retinopathy. FTIR spectroscopy was performed on 85 human serum samples [30 type 2 diabetes patients each without retinopathy and with retinopathy along with 25 normal healthy individuals as control]. Difference between mean spectra (DBMS), forward feature selection (FFS), and Mann–Whitney’s U tests were applied for spectral biomarker selection. Classification of disease conditions was achieved using analysis of different combinations of spectral features with linear, quadratic, and cubic Support Vector Machine at 10-fold cross validation. Twelve spectral signatures extracted by FFS could differentiate diabetes and diabetic retinopathy with 90% sensitivity, 92.7% specificity, and 90.5% overall accuracy. Two peaks (1042, 1114.18?cm^?1) were associated with carbohydrate and polysaccharide content and five peaks (1114.18, 1165, 1211.18, 1402.70, 1451.14, 1657?cm^?1) represented aberrations in total lipid content. Four peaks (1114.18, 1117, 1147, 1165?cm^?1) were associated with protein phosphorylation and three peaks (1527, 1544.71, 1591.10?cm^?1) with Amide II group. Again, lipidic signatures were strongly corroborated with glycosylated hemoglobin levels in diabetic retinopathy and diabetic subjects. Spectral signatures also revealed an elevated level of β-sheet containing proteins in serum in diabetic retinopathy condition. The method was validated through spectral biomarker selection by the DBMS technique. Thus, this method has the capability of diagnostic cost minimization for detection of diabetic retinopathy by label-free spectral biomarker identification.     

Offline Monitoring of Hydroxyethyl Methacrylate and 3-Dimethylaminopropyl Methacrylamide Copolymerization: Correlation Between FTIR and GC Quantifications

Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy is classically used to monitor homopolymerizations. In this article, this analytical technique was extended to monitor the synthesis of VIVIPRINT 300, which is a copolymer of 2-hydroxyethyl methacrylate (HEMA) and N-[3-dimethylaminopropyl]methacrylamide (DMAPMA). The calibration curves devised for this study were based on the two homopolymers P(HEMA) and P(DMAPMA). A good correlation was realized between the FTIR absorbance intensities observed respectively at 1300 cm^?1 (polymerized C-O ester bond) and 1230 cm^?1 (polymerized C-N amide bond) and the level of residual HEMA and DMAPMA monomers determined by GC. Application of these calibration curves to the copolymerization also exhibited a good correlation of data relating to residual monomer determination by FTIR and GC, validating the success of this spectroscopic in situ technique.     

Preparation and properties of sulfonated polybenzimidazole-polyimide block copolymers as electrolyte membranes

Sulfonated polybenzimidazole-polyimide block copolymers are synthesized through condensation polymerization at high temperature. The length of the polyimide chain is varied to give a series of block copolymers with various block lengths. The as-synthesized block polymers are used to prepare the corresponding membranes through the solvent evaporation method. The structure of the block copolymers is characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). Their mechanical strength, thermal behavior, water uptake, swelling ratio, and proton conductivity, as well as oxidative stability are also investigated. All the block copolymers exhibit good thermal stability, dimensional stability, mechanical strength, and proton conductivity. Compared to the random sulfonated polyimide-containing benzimidazole membranes with the same degree of sulfonation, the membranes prepared from the block copolymers show higher proton conductivities. The proton conductivities of the block copolymer membranes range from 6.2?×?10^?4 to 1.1?×?10^?2?S cm^?1 at 105 °C. The block copolymer membrane doped with phosphoric acid exhibits proton conductivity higher than 0.2 S cm^?1 at 160 °C, indicating its potential applications in proton exchange membrane fuel cells operated under high temperature and low humidity conditions.     

Depth‐resolved in vivo micro‐Raman spectroscopy of a murine skin tumor model reveals cancer‐specific spectral biomarkers

We have developed a micro‐Raman spectrometer system for use to differentiate tumor lesions from normal skin using an in vivo animal model. A study of 494 Raman spectra from 24 mice revealed different spectral patterns at different depths and between normal and tumor‐bearing skin sites. A peak at 899 cm⁻¹ (possibly from proline or fatty acids) and one with higher intensity in the 1325–1330 cm⁻¹ range (assigned to nucleic acids) were correlated with the presence of tumors, which can potentially be used as biomarkers for skin cancer detection. Spectral diagnosis performed on the murine tumor model achieved a diagnostic sensitivity of 95.8% and specificity of 93.8%. These results encourage us to develop further the use of confocal Raman spectroscopy as a clinical tool for noninvasive human skin biochemical analysis, particularly in relation to skin cancer. Copyright © 2010 John Wiley & Sons, Ltd.     

Micro Raman spectroscopy for monitoring alterations between human skin keratinocytes HaCaT and their tumorigenic derivatives A5RT3—toward a Raman characterization of a skin carcinoma model

Raman scattering provides molecular information about biochemical differences between healthy and cancerous cells in a non‐invasive and non‐destructive fashion. We have monitored such changes for the human skin keratinocyte cell line HaCaT and its cancerogenic counterpart A5RT3 at 514.5 and 647 nm excitations, with either fixed‐cell droplets or adherent fixed and living cells for repeated preparations over time in order to discriminate intrinsic characteristic changes. Cell droplets yielded average but rather reproducible information and helped to rapidly determine such changes. The Raman spectra show differences in the relative intensity ratios of the protein amide I band at 1656 cm⁻¹ and amide III bands around 1250 cm⁻¹ and of the phenylalanine ring mode at 1003.6 cm⁻¹ to the CH₂ deformation band at 1448 cm⁻¹, which are considerably greater for HaCaT cells than A5RT3 cells. Interestingly, these observations were accompanied by severe and consistent changes in the amide III region and in the collagen marker region around 936 cm⁻¹, therefore providing an unambiguous evidence of protein degradation and changes in the essential amino acid phenylalanine and in the lipid components in tumorigenic A5RT3 cells. Ultimately, in light of these intrinsic changes, the present findings are consistent with the passage number of the non‐tumorigenic HaCaT cells, because low pass HaCaT showed less pronounced alterations than high pass HaCaT, suggesting a correlation of tumorigenic transformation with primarily genetic instabilities in HaCaT cells. This work represents the first Raman spectroscopy discrimination of the skin carcinoma model cell lines, the non‐tumorigenic HaCaT and the cancerous A5RT3 cells, addressing the importance of delineating nonspecific variations from intrinsic characteristic changes and giving a spectroscopic indication for the influence of the passage number of HaCaT cells on the tumorigenic development. Copyright © 2009 John Wiley & Sons, Ltd.     

FTIR spectroscopic studies of the matrix photoionization and photolysis products of methylene halides

Matrix photoionization of methylene bromide produced absorptions at 1019, 897, and 788 cm^?1 identified previously as CBr₂⁺, CHBr₂⁺, and CHBr₂. High-resolution FTIR spectra revealed overlapping 1/2/1 triplets for natural bromine isotopes with individual linewidths near 0.2 cm^?1. New absorptions at 3121, 2897, and 1345 cm^?1 are assigned to the (CH₂Br⁺)Br cation complex which yields CHBr₂⁺ on photolysis. A substantially increased yield of the CHCl₂⁺ species made possible observation of the CH stretching mode at 3033 cm^?1 and the symmetric CCl₂ stretching mode at 845 cm^?1 along with the previously observed stronger 1291- and 1044-cm^?1 fundamentals. The high resolution and enhanced signal-to-noise capability of the FTIR are clearly demonstrated in this investigation.     

An Infrared Method,with Reduced Solvent Consumption,for the Determination of Chlorsulfuron in Pesticide Formulations

A simple method has been developed for the determination of Chlorsulfuron in pesticide formulations by Fourier Transform Infrared (FTIR). Samples were diluted with CHCl_3^? , and the FTIR spectra of the samples and standards were obtained at a nominal resolution of 4 cm^? 1 from 4000 to 900 cm^? 1 with the accumulation of 25 scans. Chlorsulfuron determination was based on the measurement of peak area values from 1373 to 1363 cm^? 1 which were corrected by use of a two points baseline defined from 1401 to 1302 cm^? 1. The limit of detection achieved, which was of the order of 6 µg g^? 1, was appropriate for the determination of Chlorsulfuron in commercially available formulations. FTIR results were statistically comparable with those found by High Performance Liquid Chromatography (HPLC). The procedure reduces organic solvent consumption per sample to less than 3 ml CHCl₃, reduces waste generation and increases the sample measurement frequency up to 60 h^? 1.     

Low beam current density Auger spectroscopy and surface analysis

Auger and secondary electron spectroscopy become a more and more routine technique in surface characterization. Even with primary electron beam current density as low as 10^?2 or 10^?3 A cm^?2 beam damage were reported in both Auger and LEED experiments. So we developed and compared counting method, brightness modulation and Harris' modulation techniques in terms of signal to noise ratio. The two first methods offer the advantage of a primary beam current density decreasing about 10⁴ times. So various mechanisms of beam damage were identified as thermal, chemical and electrical. The advantage of the method is shown with hydrocarbons adsorption layer; the beam cracking of the organic chain produces a chemical shift of the C_KLL maximum Auger line about 5 eV. This progressive shift is observed with current densities of 10^?5 A cm^?2 order of magnitude. The reproducibility of this low current density Auger spectroscopy allowed the study of the background and the true secondary electron yield modifications when adsorbed layers are built up.     

Laser-Raman spectroscopy of living cells

Investigations into the laser—Raman shift spectra of bacterial and mammalian cells have revealed that many Raman lines observed at 4–6 K, do not appear in the spectra of cells held at 300 K. At 300 K, Raman activity, at set frequencies, is observed only when the cells are metabolically active; however, the actual live cell spectrum, between 0 and 3400 cm^?1, has been found to alter in a specific way with time as the cells' progress through their life cycles. Lines above 300 cm^?1, from in vivo Raman active states, appear to shift to higher wave numbers whereas those below 300 cm^?1 seem to shift to lower ones. The transient nature of many shift lines observed and the intensity of them when present in the spectrum indicates that, in vivo, a metabolically induced condensation of closely related states occurs at a set time in the life of a living cell. In addition, the calculated ratio between the intensities of Stokes and anti-Stokes lines observed suggests that the metabolically induced “collective” Raman active states are produced, in vivo, by non thermal means. It appears, therefore, that the energetics of the well established cell “time clock” may be studied by laser—Raman spectroscopy; moreover, Raman spectroscopy may yield a new type of information regarding the physics of such biological phenomena as nutrition, virus infection and oncogenesis.     

Study on the effect of PEG in ionic transport for CMC-NH<Subscript>4</Subscript>Br-based solid polymer electrolyte

The present study investigates the ion transport properties and structural analysis of plasticized solid polymer electrolytes (SPEs) based on carboxymethyl cellulose (CMC)-NH₄Br-PEG. The SPE system was successfully prepared via solution casting and has been characterized by using electrical impedance spectroscopy (EIS), Fourier transform infrared (FTIR) spectroscopy, and x-ray diffraction (XRD) technique. The highest conductivity of the SPE system at ambient temperature (303 K) was found to be 1.12?×?10^?4 S/cm for un-plasticized sample and 2.48?×?10^?3 S cm^?1 when the sample is plasticized with 8 wt% PEG. Based on FTIR analysis, it shows that interaction had occurred at O–H, C=O, and C–O moiety from CMC when PEG content was added. The ionic conductivity tabulation of SPE system was found to be influenced by transport properties and amorphous characteristics as revealed by IR deconvolution method and XRD analysis.     

Estimation of carbonate concentration and characterization of marine sediments by Fourier Transform Infrared Spectroscopy

Fourier Transform Infrared Spectroscopy (FTIR) is a well established method for the characterization of mineralogical and geochemical properties of marine sediments. Understanding the biogeochemical changes in marine ecosystems is challenging task since it requires adequate analytical techniques and efforts. Biogeochemical characteristics of twenty one marine sediment samples collected off Chennai coast, Bay of Bengal, India were analyzed using FTIR spectroscopy. The FTIR peaks at 1460 cm⁻¹ (stretching vibration) and 880 cm⁻¹ (bending vibration) were used for carbonate determination. To verify the FTIR results, the obtained carbonate data were compared with carbonate values obtained by chemical analyses. The ranges of carbonate in sediments using FTIR and chemical analyses were 4.5–9.6% and 4.8–10%, respectively. The significant positive relationship was obtained between the carbonate results of FTIR and chemical analyses. This study demonstrates that instead of expensive and time consuming chemical methods, FTIR spectroscopic technique is found as a suitable, rapid and effective method for the quantification of carbonate in marine sediments.     

Comparison of molecular images as defined by Raman spectra between normal mucosa and squamous cell carcinoma in the oral cavity

Raman spectroscopy has been effectively applied to clinically differentiate normal and cancerous mucosal tissues. Micro‐Raman spectroscopy provides a tool to better understand the molecular basis for the Raman clinical signal. The objective of the current study was to utilize micro‐Raman spectroscopy to define the molecular/spectral differences between normal and abnormal squamous cell carcinoma (SCC) in oral mucosa (in vitro). Understanding this may help in identifying unique spectra or may be useful for in vivo application of this technology. Micro‐Raman (confocal) spectroscopy was used to obtain molecular images of normal and SCC cells of human oral mucosa. Four fresh flashed‐frozen tumor and four matched normal tongue specimens were studied. The spectra covered a wavenumber range from 300 to 4000 cm⁻¹ with a spectral resolution of 8 cm⁻¹ and a spatial resolution of 1.0 µm. The cells were located within thin sections of tongue mucosa biopsies. The excitation wavelength of 515 nm was used. We were able to obtain Raman images with rich information about the spectroscopic and structural features within the cytoplasm, cell membrane, and cell nuclei. Significant spectral differences were observed between the Raman images of normal and malignant squamous cells. The heterogeneity of tumor cells within the abnormal tissue was also demonstrated. Spectral differences demonstrated between both tissue types have provided important information regarding the origins of specific signals within the cells of each tissue type. In our search for specific spectral biomarkers, we believe that a cell surface protein, greatly upregulated in SCC cells, was discovered at 1583 cm⁻¹. Copyright © 2010 John Wiley & Sons, Ltd.     

Diagnostics of skin pathologies based on spectral analysis of backward and raman scattering

A mathematical model of the interaction of optical radiation with skin tissues is developed taking into account stimulated Raman scattering. Numerical experiments show that the backscattering spectra possess specific features typical of skin pathologies. It is shown that the pathology type can be determined from an analysis of the differential ratios of the Raman scattering intensities at 1271 and 1663 cm^?1 to the intensity in the region of 1454 cm^?1. It is found that the difference in the differential ratios of the Raman scattering intensities for pathologically changed and normal layers may exceed 40%.     

Spin-coating deposition of PbS and CdS thin films for solar cell application

In this work, we describe a simple spin-coating deposition technique for lead sulphide (PbS) and cadmium sulphide (CdS) films from a methanolic metal–thiourea complex. The characterization of the films by X-ray diffraction and X-ray photoelectron spectroscopy techniques revealed that pure cubic phase PbS and CdS layers were formed via this method. As shown by atomic force microscopy and scanning electron microscopy results, both films were homogeneous and presented a smooth surface. Optical properties showed that the energy band gap of PbS and CdS films were around 1.65 and 2.5 eV, respectively. The PbS film is p-type in nature with an electrical conductivity of around 0.8 S/cm. The hole concentration and mobility were 2.35 × 10¹⁸ cm^?3 and 2.16 × 10^?3 cm²/V/s, respectively, as determined from Hall measurement. Both films were used to develop a thin film solar cell device of graphite/PbS/CdS/ITO/glass. Device characterization showed the power conversion efficiency of around 0.24 %. The corresponding open circuit voltage, short circuit current and fill factor were 0.570 V, 1.32 mA/cm² and 0.32, respectively.     

Vibrational Spectroscopy of the Borate Mineral Priceite—Implications for the Molecular Structure

ABSTRACT

Priceite is a calcium borate mineral and occurs as white crystals in the monoclinic pyramidal crystal system. We have used a combination of Raman spectroscopy with complimentary infrared spectroscopy and scanning electron microscopy with Energy-dispersive X-ray Spectroscopy (EDS) to study the mineral priceite. Chemical analysis shows a pure phase consisting of B and Ca only. Raman bands at 956, 974, 991, and 1019 cm^?1 are assigned to the BO stretching vibration of the B₁₀O₁₉ units. Raman bands at 1071, 1100, 1127, 1169, and 1211 cm^?1 are attributed to the BOH in-plane bending modes. The intense infrared band at 805 cm^?1 is assigned to the trigonal borate stretching modes. The Raman band at 674 cm^?1 together with bands at 689, 697, 736, and 602 cm^?1 are assigned to the trigonal and tetrahedral borate bending modes. Raman spectroscopy in the hydroxyl stretching region shows a series of bands with intense Raman band at 3555 cm^?1 with a distinct shoulder at 3568 cm^?1. Other bands in this spectral region are found at 3221, 3385, 3404, 3496, and 3510 cm^?1. All of these bands are assigned to water stretching vibrations. The observation of multiple bands supports the concept of water being in different molecular environments in the structure of priceite. The molecular structure of a natural priceite has been assessed using vibrational spectroscopy.     

RF-sputtered LiCoO2 thick films: microstructure and electrochemical performance as cathodes in aqueous and nonaqueous microbatteries

Films of LiCoO₂ are prepared on metallized silicon substrates using RF-magnetron sputtering technique. The microstructural properties of the films are investigated by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. The films deposited at a substrate temperature of 250 °C with subsequent annealing at 650 °C exhibited hexagonal layered structure with R $ \overline 3 $ m symmetry. The kinetics of lithium ions in LiCoO₂ film cathode host matrix and its cycleability are studied in aqueous Pt//LiCoO₂ and nonaqueous Li//LiCoO₂ cell. Both the electrochemical cells at same current density of 50 μA cm^?2 delivered the same initial discharge capacity of about 60 μA h?cm^?2 μm^?1 with a chemical diffusion coefficient of ca. 10^?11 cm² s^?1 for Li⁺ ions. The capacity fade rates for the Pt//LiCoO₂ and Li//LiCoO₂ cells, in average are 3.0 and 0.15 % per cycle, respectively, for the first 20 cycles. The Pt//LiCoO₂ cell is found to be advantageous for small number of cycles and is cost effective than the Li//LiCoO₂ cell.     

Broadly tunable quantum cascade laser in cantilever-enhanced photoacoustic infrared spectroscopy of solids

An external cavity quantum cascade laser (EC-QCL) is applied in the photoacoustic detection of solid samples. The EC-QCL used has a broad tuning range of 676 cm^?1 (970–1,646 cm^?1) in the mid-infrared region, which enables accurate broadband spectroscopy of large molecules. The high spectral power density of the EC-QCL is combined with an extremely sensitive optical cantilever microphone of the photoacoustic detector to achieve an ultimate sensitivity. The carbon black, polyethylene, and hair fiber samples were measured with the EC-QCL photoacoustic detection using electrical amplitude modulation to demonstrate the possibilities of the setup. The same measurements were repeated with a Fourier transform infrared (FTIR) spectrometer combined with a photoacoustic detector for a comparison. The EC-QCL photoacoustic setup yielded roughly a decade better signal-to-noise ratios than the FTIR setup with the same measurement time.