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Sample records for raman spectroscopy sers

  1. Nanofluidic channel based biosensor using surface enhanced raman spectroscopy (SERS)

    NASA Astrophysics Data System (ADS)

    Chou, I.-Hsien; Beier, Hope T.; Wang, Maio; Jing, Nan; Kameoka, Jun; Coté, Gerard L.

    2007-02-01

    The Raman scattering signature of molecules has been demonstrated to be greatly enhanced, on the order of 10 6-10 12 times, on roughened metal surfaces and clustered structures such as aggregated colloidal gold. Here we describe a method that improves reproducibility and sensitivity of the substrate for surface enhanced Raman spectroscopy (SERS) by using a nanofluidic trapping device. This nanofluidic device has a bottle neck shape composed of a microchannel leading into a nano channel that causes size-dependent trapping of nanoparticles. The analyte and Au nanoparticles, 60 nm in diameter, in aqueous solution was pumped into the channel. The nanoparticles which were larger than the narrow channel are trapped at the edge of the channel to render an enhancement of the Raman signal. We have demonstrated that the Raman scattering signal enhancement on a nanochannel-based colloidal gold cluster is able to detect 10 pM of adenine, the test analyte, without chemical modification. The efficiency and robustness of the device suggests potential for single molecule detection and multicomponent detection for biological applications and/or biotoxins.

  2. Inkjet-fabricated surface enhanced Raman spectroscopy (SERS) sensors on paper for biosensing

    NASA Astrophysics Data System (ADS)

    Restaino, Stephen M.; White, Ian M.

    2015-03-01

    As a bio/chemical sensing technique, surface enhanced Raman spectroscopy (SERS) offers sensitivity comparable to that of fluorescence detection while providing highly specific information about the analyte. Although single molecule identification with SERS was demonstrated nearly 20 years ago, today a need exists to develop practical solutions for point-of-sample and point-of-care SERS systems. Recently, we demonstrated the fabrication of SERS substrates by inkjet printing silver and gold nanostructures onto paper and other microporous membranes. Using these devices, we have been able to achieve detection limits comparable to conventional nanofabricated plasmonic substrates. Furthermore, we leverage the fluidic properties of paper to enhance the performance of the SERS devices while also enabling unprecedented ease of use. Here we report the use of inkjet-fabricated paper SERS substrates as a detection device for biological macromolecules in an easy-to-use format with a low number of steps. The targeted biomarker is specifically detected with SERS through a single step competitive displacement, which dramatically reduces the number of steps as compared to conventional assays. Moreover, we further improve the usability of the assay by incorporating a paper SERS device with a fluidic cartridge format. The wicking nature of the paper sensor eliminates manual sample application steps and is much simpler than the world-to-chip interface of microfluidic devices. The introduction of this paper-based SERS assay is a significant step towards highly sensitive, low-cost, and, importantly, easy to use multiplexed biological assays.

  3. Development of surface enhanced Raman scattering (SERS) spectroscopy monitoring of fuel markers to prevent fraud

    NASA Astrophysics Data System (ADS)

    Wilkinson, Timothy; Clarkson, John; White, Peter C.; Meakin, Nicholas; McDonald, Ken

    2013-05-01

    Governments often tax fuel products to generate revenues to support and stimulate their economies. They also subsidize the cost of essential fuel products. Fuel taxation and subsidization practices are both subject to fraud. Oil marketing companies also suffer from fuel fraud with loss of legitimate sales and additional quality and liability issues. The use of an advanced marking system to identify and control fraud has been shown to be effective in controlling illegal activity. DeCipher has developed surface enhanced Raman scattering (SERS) spectroscopy as its lead technology for measuring markers in fuel to identify and control malpractice. SERS has many advantages that make it highly suitable for this purpose. The SERS instruments are portable and can be used to monitor fuel at any point in the supply chain. SERS shows high specificity for the marker, with no false positives. Multiple markers can also be detected in a single SERS analysis allowing, for example, specific regional monitoring of fuel. The SERS analysis from fuel is also quick, clear and decisive, with a measurement time of less than 5 minutes. We will present results highlighting our development of the use of a highly stable silver colloid as a SERS substrate to measure the markers at ppb levels. Preliminary results from the use of a solid state SERS substrate to measure fuel markers will also be presented.

  4. Raman spectroscopy and SERS analysis of ovarian tumour derived exosomes (TEXs): a preliminary study

    NASA Astrophysics Data System (ADS)

    Kerr, Laura T.; Gubbins, Luke; Weiner Gorzel, Karolina; Sharma, Shiva; Kell, Malcolm; McCann, Amanda; Hennelly, Bryan M.

    2014-05-01

    Here we report a preliminary study based on the application of Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) to investigate the compositional differences between exosomes derived from ovarian carcinoma cells (cell line A2780) grown in normoxia (normal O2 conditions) and hypoxia (1% O2 conditions). Exosomes are integral to cell signalling, and are of interest in the study of how cells communicate within their environment. We are particularly interested in identifying whether hypoxia induced senescent cells can communi- cate via exosomes with neighbouring tumour cells, thereby causing them to become senescent and therefore radio and chemo resistant. With this goal in mind, we performed a preliminary study on the application of Raman spectroscopy and SERS to analyse the biomolecular fingerprint of both groups of exosomes and to investigate whether there exists a different biomolecular composition associated with exosomes derived from hypoxic cells in comparison to those from normoxic cells. We also applied multivariate statistical techniques for the classification of both groups of exosomes.

  5. Rapid detection of acetamiprid in foods using surface-enhanced Raman spectroscopy (SERS).

    PubMed

    Wijaya, Wisiani; Pang, Shintaro; Labuza, Theodore P; He, Lili

    2014-04-01

    Acetamiprid is a neonicotinoid pesticide that is commonly used in modern farming. Acetamiprid residue in food commodities can be a potential harm to human and has been implicated in the honey bee hive die off crisis. In this study, we developed rapid, simple, and sensitive methods to detect acetamiprid in apple juice and on apple surfaces using surface-enhanced Raman spectroscopy (SERS). No pretreatment of apple juice sample was performed. A simple surface swab method was used to recover acetamiprid from the apple surface. Samples were incubated with silver dendrites for several minutes and SERS spectra were taken directly from the silver surface. Detection of a set of 5 apple juice samples can be done within 10 min. The swab-SERS method took 15 min for a set of 5 samples. Resulting spectral data were analyzed using principal component analysis. The highest acetamiprid peak at 634 cm(-1) was used to detect and quantify the amount of acetamiprid spiked in 1:1 water-methanol solvent, apple juice, and on apple surface. The SERS method was able to successfully detect acetamiprid at 0.5 μg/mL (0.5 ppm) in solvent, 3 μg/mL (3 ppm) in apple juice, and 0.125 μg/cm(2) on apple surfaces. The SERS methods provide simple, rapid, and sensitive ways to detect acetamiprid in beverages and on the surfaces of thick skinned fruits and vegetables. PMID:24620941

  6. Detection and quantification of dithiocarbamate pesticides by Surface Enhanced Raman Spectroscopy (SERS)

    NASA Astrophysics Data System (ADS)

    Saute, Benjamin Calvin

    Dithiocarbamates are a subclass of carbamate pesticides that are widely used as insecticidal agents on food crops in the US and abroad. Quantitative determination of trace quantities of dithiocarbamates is necessary in order to mitigate potential human exposure via pesticide residues left on inadequately washed food items as well as groundwater contamination from agricultural runoff. The focus of this research is on the development and optimization of a Surface Enhanced Raman Spectroscopy (SERS) based analytical technique for the quantitative determination of trace amounts of dithiocarbamate pesticides in different matrices. Gold nanoparticles of different shapes and sizes will be investigated to determine the suitability of these materials as SERS active substrates for the trace analysis of dithiocarbamate pesticides. Analytical sensitivity will be evaluated by determining the limits of detection using established statistical methods.

  7. Surface-enhanced Raman spectroscopy (SERS) to detect natural organic coatings on silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Kühn, Melanie; Ivleva, Natalia P.; Klitzke, Sondra; von der Kammer, Frank; Niessner, Reinhard; Baumann, Thomas

    2015-04-01

    Applications for engineered inorganic nanoparticles (EINP) are rising and causing a higher risk for EINP to be released into the environment. Their stability and transport behaviour under environmental conditions is strongly depending on their surface properties which on the other hand depend on the presence or absence of a surface coating. We assume that EINP get coated soon after their release into the environment e.g. by humic substances like humic or fulvic acids and NOM. Often EINP are stabilized by a coating agent like citrate or polyvinylpyrrolidone. Therefore, the replacement of the initial coating material or a multilayer coating has to be considered. Characterization of natural coatings on EINP is crucial to predict their environmental behaviour, but analytical methods to investigate organic coatings are scarce. To investigate humic- and fulvic acid coatings on silver nanoparticles (Ag NP) Raman micro-spectroscopy (RM) was used. RM is limited in its sensitivity, but silver nanoparticles cause an enhancement of the Raman signal of adsorbed substances by a factor of 103-106, so called surface-enhanced Raman spectroscopy (SERS). The Raman spectrum of humic acids is dominated by the carbonaceous parts of the humic acids which are known from carbon analysis and referred to as defect (D) and graphite (G) peak of carbon. Humic acids of different origin (humic acid from a lignite, suwannee river humic acid) showed differences in the D and G ratios indicating a difference in the structure of the contained carbon. With SERS humic and fulvic acid coatings on Ag NP were analysed: 1-100 mg/L humic acid stock solution were mixed with citrate and hydroxylammoniumchloride stabilized Ag NP, centrifuged and resuspended in deionized water (washing) to remove all coating material not associated with Ag NP. This washing step was repeated up to four times. SERS prooved that the coating was still present after the fourth washing step. As SERS is only sensitive for substances in

  8. In situ detection and identification of hair dyes using surface-enhanced Raman spectroscopy (SERS).

    PubMed

    Kurouski, Dmitry; Van Duyne, Richard P

    2015-03-01

    Hair is one of the most common types of physical evidence found at a crime scene. Forensic examination may suggest a connection between a suspect and a crime scene or victim, or it may demonstrate an absence of such associations. Therefore, forensic analysis of hair evidence is invaluable to criminal investigations. Current hair forensic examinations are primarily based on a subjective microscopic comparison of hair found at the crime scene with a sample of suspect's hair. Since this is often inconclusive, the development of alternative and more-accurate hair analysis techniques is critical. In this study, we utilized surface-enhanced Raman spectroscopy (SERS) to demonstrate that artificial dyes can be directly detected on hair. This spectroscopic technique is capable of a confirmatory identification of analytes with single molecule resolution, requires minimal sample, and has the advantage of fluorescence quenching. Our study reveals that SERS can (1) identify whether hair was artificially dyed or not, (2) determine if a permanent or semipermanent colorants were used, and (3) distinguish the commercial brands that are utilized to dye hair. Such analysis is rapid, minimally destructive, and can be performed directly at the crime scene. This study provides a novel perspective of forensic investigations of hair evidence. PMID:25635868

  9. Safranin-O dye in the ground state. A study by density functional theory, Raman, SERS and infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Lofrumento, C.; Arci, F.; Carlesi, S.; Ricci, M.; Castellucci, E.; Becucci, M.

    2015-02-01

    The analysis of ground state structural and vibrational properties of Safranin-O is presented. The experimental results, obtained by FTIR, Raman and SERS spectroscopy, are discussed in comparison to the results of DFT calculations carried out at the B3LYP/6-311 + G(d,p) level of theory. The calculated spectra reproduce quite satisfactorily the experimental data. The calculated Safranin-O equilibrium structure and the assignment of the vibrational spectra are reported as well. From the changes between Raman and SERS spectra a model is presented for the interaction of Safranin-O with silver nanoparticles.

  10. Safranin-O dye in the ground state. A study by density functional theory, Raman, SERS and infrared spectroscopy.

    PubMed

    Lofrumento, C; Arci, F; Carlesi, S; Ricci, M; Castellucci, E; Becucci, M

    2015-02-25

    The analysis of ground state structural and vibrational properties of Safranin-O is presented. The experimental results, obtained by FTIR, Raman and SERS spectroscopy, are discussed in comparison to the results of DFT calculations carried out at the B3LYP/6-311+G(d,p) level of theory. The calculated spectra reproduce quite satisfactorily the experimental data. The calculated Safranin-O equilibrium structure and the assignment of the vibrational spectra are reported as well. From the changes between Raman and SERS spectra a model is presented for the interaction of Safranin-O with silver nanoparticles. PMID:25247839

  11. Using Raman spectroscopy and SERS for in situ studies of rhizosphere bacteria

    NASA Astrophysics Data System (ADS)

    Polisetti, Sneha; Baig, Nameera; Bible, Amber; Morrell-Falvey, Jennifer; Doktycz, Mitchel; Bohn, Paul W.

    2015-08-01

    Bacteria colonize plant roots to form a symbiotic relationship with the plant and can play in important role in promoting plant growth. Raman spectroscopy is a useful technique to study these bacterial systems and the chemical signals they utilize to interact with the plant. We present a Raman study of Pantoea YR343 that was isolated from the rhizosphere of Populus deltoides (Eastern Cottonwood). Pantoea sp. YR343 produce yellowish carotenoid pigment that play a role in protection against UV radiation, in the anti-oxidative pathways and in membrane fluidity. Raman spectroscopy is used to non-invasively characterize the membrane bound carotenoids. The spectra collected from a mutant strain created by knocking out the crtB gene that encodes a phytoene synthase responsible for early stage of carotenoid biosynthesis, lack the carotenoid peaks. Surface Enhanced Raman Spectroscopy is being employed to detect the plant phytoharmone indoleacetic acid that is synthesized by the bacteria. This work describes our recent progress towards utilizing Raman spectroscopy as a label free, non-destructive method of studying plant-bacteria interactions in the rhizosphere.

  12. An operando surface enhanced Raman spectroscopy (SERS) study of carbon deposition on SOFC anodes.

    PubMed

    Li, Xiaxi; Liu, Mingfei; Lee, Jung-pil; Ding, Dong; Bottomley, Lawrence A; Park, Soojin; Liu, Meilin

    2015-09-01

    Thermally robust and chemically inert Ag@SiO2 nanoprobes are employed to provide the surface enhanced Raman scattering (SERS) effect for an in situ/operando study of the early stage of carbon deposition on nickel-based solid oxide fuel cell (SOFC) anodes. The enhanced sensitivity to carbon enables the detection of different stages of coking, offering insights into intrinsic coking tolerance of material surfaces. Application of a thin coating of gadolinium doped ceria (GDC) enhances the resistance to coking of nickel surfaces. The electrochemically active Ni-YSZ interface appears to be more active for hydrocarbon reforming, resulting in the accumulation of different hydrocarbon molecules, which can be readily removed upon the application of an anodic current. Operando SERS is a powerful tool for the mechanistic study of coking in SOFC systems. It is also applicable to the study of other catalytic and electrochemical processes in a wide range of conditions. PMID:25599129

  13. Label-Free Detection of Glycan-Protein Interactions for Array Development by Surface-Enhanced Raman Spectroscopy (SERS).

    PubMed

    Li, Xiuru; Martin, Sharon J H; Chinoy, Zoeisha S; Liu, Lin; Rittgers, Brandon; Dluhy, Richard A; Boons, Geert-Jan

    2016-08-01

    A glyco-array platform has been developed, in which glycans are attached to plasmonic nanoparticles through strain-promoted azide-alkyne cycloaddition. Glycan-protein binding events can then be detected in a label-free manner employing surface-enhanced Raman spectroscopy (SERS). As proof of concept, we have analyzed the binding of Gal1, Gal3, and influenza hemagglutinins (HAs) to various glycans and demonstrated that binding partners can be identified with high confidence. The attraction of SERS for optical sensing is that it can provide unique spectral signatures for glycan-protein complexes, confirm identity through statistical validation, and minimizes false positive results common to indirect methods. Furthermore, SERS is very sensitive and has multiplexing capabilities thereby allowing the simultaneous detection of multiple analytes. PMID:27304194

  14. Nanofluidic Biosensing for β-amyloid Detection Using Surface Enhanced Raman Spectroscopy (SERS)

    PubMed Central

    Chou, I-Hsien; Benford, Melodie; Beier, Hope T.; Coté, Gerard L.; Wang, Miao; Jing, Nan; Kameoka, Jun; Good, Theresa A.

    2008-01-01

    Trace detection of the conformational transition of β-amyloid peptide (Aβ) from a predominantly α-helical structure to β-sheet could have a large impact in understanding and diagnosing Alzheimer’s disease. We demonstrate how a novel nanofluidic biosensor using a controlled, reproducible surface enhanced Raman spectroscopy active site was developed to observe Aβ in different conformational states during the Aβ self-assembly process as well as to distinguish Aβ from confounder proteins commonly found in cerebral spinal fluid. PMID:18489171

  15. Nanowire-based surface-enhanced Raman spectroscopy (SERS) for chemical warfare simulants

    NASA Astrophysics Data System (ADS)

    Hoffmann, J. A.; Miragliotta, J. A.; Wang, J.; Tyagi, P.; Maddanimath, T.; Gracias, D. H.; Papadakis, S. J.

    2012-06-01

    Hand-held instruments capable of spectroscopic identification of chemical warfare agents (CWA) would find extensive use in the field. Because CWA can be toxic at very low concentrations compared to typical background levels of commonly-used compounds (flame retardants, pesticides) that are chemically similar, spectroscopic measurements have the potential to reduce false alarms by distinguishing between dangerous and benign compounds. Unfortunately, most true spectroscopic instruments (infrared spectrometers, mass spectrometers, and gas chromatograph-mass spectrometers) are bench-top instruments. Surface-acoustic wave (SAW) sensors are commercially available in hand-held form, but rely on a handful of functionalized surfaces to achieve specificity. Here, we consider the potential for a hand-held device based on surface enhanced Raman scattering (SERS) using templated nanowires as enhancing substrates. We examine the magnitude of enhancement generated by the nanowires and the specificity achieved in measurements of a range of CWA simulants. We predict the ultimate sensitivity of a device based on a nanowire-based SERS core to be 1-2 orders of magnitude greater than a comparable SAW system, with a detection limit of approximately 0.01 mg m-3.

  16. Highly-Sensitive Surface-Enhanced Raman Spectroscopy (SERS)-based Chemical Sensor using 3D Graphene Foam Decorated with Silver Nanoparticles as SERS substrate

    PubMed Central

    Srichan, Chavis; Ekpanyapong, Mongkol; Horprathum, Mati; Eiamchai, Pitak; Nuntawong, Noppadon; Phokharatkul, Ditsayut; Danvirutai, Pobporn; Bohez, Erik; Wisitsoraat, Anurat; Tuantranont, Adisorn

    2016-01-01

    In this work, a novel platform for surface-enhanced Raman spectroscopy (SERS)-based chemical sensors utilizing three-dimensional microporous graphene foam (GF) decorated with silver nanoparticles (AgNPs) is developed and applied for methylene blue (MB) detection. The results demonstrate that silver nanoparticles significantly enhance cascaded amplification of SERS effect on multilayer graphene foam (GF). The enhancement factor of AgNPs/GF sensor is found to be four orders of magnitude larger than that of AgNPs/Si substrate. In addition, the sensitivity of the sensor could be tuned by controlling the size of silver nanoparticles. The highest SERS enhancement factor of ∼5 × 104 is achieved at the optimal nanoparticle size of 50 nm. Moreover, the sensor is capable of detecting MB over broad concentration ranges from 1 nM to 100 μM. Therefore, AgNPs/GF is a highly promising SERS substrate for detection of chemical substances with ultra-low concentrations. PMID:27020705

  17. Highly-Sensitive Surface-Enhanced Raman Spectroscopy (SERS)-based Chemical Sensor using 3D Graphene Foam Decorated with Silver Nanoparticles as SERS substrate

    NASA Astrophysics Data System (ADS)

    Srichan, Chavis; Ekpanyapong, Mongkol; Horprathum, Mati; Eiamchai, Pitak; Nuntawong, Noppadon; Phokharatkul, Ditsayut; Danvirutai, Pobporn; Bohez, Erik; Wisitsoraat, Anurat; Tuantranont, Adisorn

    2016-03-01

    In this work, a novel platform for surface-enhanced Raman spectroscopy (SERS)-based chemical sensors utilizing three-dimensional microporous graphene foam (GF) decorated with silver nanoparticles (AgNPs) is developed and applied for methylene blue (MB) detection. The results demonstrate that silver nanoparticles significantly enhance cascaded amplification of SERS effect on multilayer graphene foam (GF). The enhancement factor of AgNPs/GF sensor is found to be four orders of magnitude larger than that of AgNPs/Si substrate. In addition, the sensitivity of the sensor could be tuned by controlling the size of silver nanoparticles. The highest SERS enhancement factor of ∼5 × 104 is achieved at the optimal nanoparticle size of 50 nm. Moreover, the sensor is capable of detecting MB over broad concentration ranges from 1 nM to 100 μM. Therefore, AgNPs/GF is a highly promising SERS substrate for detection of chemical substances with ultra-low concentrations.

  18. Raman Spectroscopy.

    ERIC Educational Resources Information Center

    Gerrard, Donald L.

    1984-01-01

    Reviews literature on Raman spectroscopy from late 1981 to late 1983. Topic areas include: instrumentation and sampling; liquids and solutions; gases and matrix isolation; biological molecules; polymers; high-temperature and high-pressure studies; Raman microscopy; thin films and surfaces; resonance-enhanced and surface-enhanced spectroscopy; and…

  19. The implementation of an isotope-edited internal standard for quantification of lowest drug concentrations using surface enhanced Raman spectroscopy (SERS) in a lab on a chip device

    NASA Astrophysics Data System (ADS)

    März, Anne; Rösch, Petra; Henkel, Thomas; Popp, Jürgen

    2009-07-01

    The application of surface enhanced Raman spectroscopy in combination with a microfluidic device and an isotopeedited internal standard seems to be a promising way for a new approach for quantitative SERS measurements. An innovative lab on a chip system offers the possibility for reproducible, quantitative online SERS measurements based on the application of isotope labelled internal standards and liquid/liquid segmented flow based flow-through Raman detection. Errors caused by the used method can be compensated by using an internal standard.

  20. A NEW METHOD FOR IN-SITU CHARACTERIZATION OF IMPORTANT ACTINIDES AND TECHNETIUM COMPOUNDS VIA FIBEROPTIC SURFACE ENHANCED RAMAN SPECTROSCOPY (SERS)

    EPA Science Inventory

    This project serves to fill information gap through the development of a novel surface-enhanced Raman scattering (SERS) spectroscopy to selectively and sensitively monitor and characterize the chemical speciation of radionuclides at trace levels. The SERS technique permits both o...

  1. Development of an electrochemical surface-enhanced Raman spectroscopy (EC-SERS) aptasensor for direct detection of DNA hybridization.

    PubMed

    Karaballi, R A; Nel, A; Krishnan, S; Blackburn, J; Brosseau, C L

    2015-09-01

    Rapid detection of disease biomarkers at the patient point-of-care is essential to timely and effective treatment. The research described herein focuses on the development of an electrochemical surface-enhanced Raman spectroscopy (EC-SERS) DNA aptasensor capable of direct detection of tuberculosis (TB) DNA. Specifically, a plausible DNA biomarker present in TB patient urine was chosen as the model target for detection. Cost-effective screen printed electrodes (SPEs) modified with silver nanoparticles (AgNP) were used as the aptasensor platform, onto which the aptamer specific for the target DNA was immobilized. Direct detection of the target DNA was demonstrated through the appearance of SERS peaks characteristic for adenine, present only in the target strand. Modulation of the applied potential allowed for a sizeable increase in the observed SERS response and the use of thiol back-filling prevented non-specific adsorption of non-target DNA. To our knowledge, this work represents the first EC-SERS study of an aptasensor for the direct, label-free detection of DNA hybridization. Such a technology paves the way for rapid detection of disease biomarkers at the patient point-of-care. PMID:25780805

  2. Multi-bacteria multi-antibiotic testing using surface enhanced Raman spectroscopy (SERS) for urinary tract infection (UTI) diagnosis

    NASA Astrophysics Data System (ADS)

    Hadjigeorgiou, Katerina; Kastanos, Evdokia; Pitris, Costas

    2013-06-01

    The inappropriate use of antibiotics leads to antibiotic resistance, which is a major health care problem. The current method for determination of bacterial susceptibility to antibiotics requires overnight cultures. However most of the infections cannot wait for the results to receive treatment, so physicians administer general spectrum antibiotics. This results in ineffective treatments and aggravates the rising problem of antibiotic resistance. In this work, a rapid method for diagnosis and antibiogram for a bacterial infection was developed using Surface Enhanced Raman Spectroscopy (SERS) with silver nanoparticles. The advantages of this novel method include its rapidness and efficiency which will potentially allow doctors to prescribe the most appropriate antibiotic for an infection. SERS spectra of three species of gram negative bacteria, Escherichia coli, Proteus spp., and Klebsiella spp. were obtained after 0 and 4 hour exposure to the seven different antibiotics. Bacterial strains were diluted in order to reach the concentration of (2x105 cfu/ml), cells/ml which is equivalent to the minimum concentration found in urine samples from UTIs. Even though the concentration of bacteria was low, species classification was achieved with 94% accuracy using spectra obtained at 0 hours. Sensitivity or resistance to antibiotics was predicted with 81%-100% accuracy from spectra obtained after 4 hours of exposure to the different antibiotics. This technique can be applied directly to urine samples, and with the enhancement provided by SERS, this method has the potential to be developed into a rapid method for same day UTI diagnosis and antibiogram.

  3. Electrochemical-surface enhanced Raman spectroscopy (E-SERS) of uric acid: a potential rapid diagnostic method for early preeclampsia detection.

    PubMed

    Goodall, Barbara L; Robinson, Ashley M; Brosseau, Christa L

    2013-02-01

    An increased level of uric acid in urine and plasma is indicative of the development of preeclampsia, a hypertensive disorder that can occur during pregnancy. The preliminary steps towards developing a rapid tool for early diagnosis of preeclampsia using electrochemical SERS (E-SERS) for the detection of uric acid in urine are presented herein. Characterization of the uric acid species was completed using cyclic voltammetry, UV spectroscopy, Raman spectroscopy and electrochemical surface-enhanced Raman spectroscopy (E-SERS). E-SERS was capable of easily detecting uric acid directly at concentrations <1 mM in urine simulant, without the need for costly enzymes and bulky equipment, and thus demonstrates promise as a rapid point-of-care diagnostic tool for detection of early onset preeclampsia in developing nation settings. PMID:23187309

  4. Raman spectroscopy

    SciTech Connect

    Gerrard, D.L.; Bowley, H.J.

    1986-04-01

    The period of this review is from late 1983 to late 1985. During this time over 5000 papers have appeared in the scientific literature dealing with many applications of Raman spectroscopy and extending its use to several new areas of study. As in the previous review in this series most of the applications relevant to solids are covered in one or other of the ten categories, which are the same as those used previously. However, aspects relating to solids which are not covered elsewhere include general reviews and the specific field of semiconductors. This is an area of great current interest in terms of Raman spectroscopy and the characterization of semiconductor materials and surfaces has been reported. Raman scattering also provides a new probe for the elucidation of structural properties of microcrystalline silicon and resonance Raman scattering in silicon at elevated temperatures has been studied. Many studies on carbon have also appeared in the literature including that of the various types of carbon, the use of Raman scattering to investigate disorder and crystallite formation in annealed carbon, in situ studies of intercalation kinetics, structural aspects of cokes and coals, and instrumentation for coal gasification. Raman spectroscopy has been applied to such diverse systems as organic crystals, the determination of modifications in layered crystals, the detection of explosives on silica gel or carbon, diagnostics of heterogeneous chemical processes, and a study of tungsten-halogen bulbs. Laser Raman spectroscopy has also been coupled with liquid chromatography and phase-resolved background suppression has been used to enhance Raman spectra. 397 references.

  5. Complete urinary tract infection (UTI) diagnosis and antibiogram using surface enhanced Raman spectroscopy (SERS)

    NASA Astrophysics Data System (ADS)

    Hadjigeorgiou, Katerina; Kastanos, Evdokia; Kyriakides, Alexandros; Pitris, Costas

    2012-03-01

    There are three stages to a complete UTI diagnosis: (1) identification of a urine sample as positive/negative for an infection, (2) identification of the responsible bacterium, (3) antibiogram to determine the antibiotic to which the bacteria are most sensitive to. Using conventional methods, all three stages require bacterial cultures in order to provide results. This long delay in diagnosis causes a rise in ineffective treatments, chronic infections, health care costs and antibiotic resistance. In this work, SERS is used to identify a sample as positive/negative for a UTI as well as to obtain an antibiogram against different antibiotics. SERS spectra of serial dilutions of E. coli bacteria mixed with silver nanoparticles, showed a linear correlation between spectral intensity and concentration. For antibiotic sensitivity testing, SERS spectra of three species of gram negative bacteria were collected four hours after exposure to the antibiotics ciprofloxacin and amoxicillin. Spectral analysis revealed clear separation between bacterial samples exposed to antibiotics to which they were sensitive and samples exposed to antibiotics to which they were resistant. With the enhancement provided by SERS, the technique can be applied directly to urine samples leading to the development of a new, rapid method for UTI diagnosis and antibiogram.

  6. Material for surface-enhanced Raman spectroscopy, and SER sensors and method for preparing same

    NASA Technical Reports Server (NTRS)

    Farquharson, Stuart (Inventor); Nelson, Chad (Inventor); Lee, Yuan-Hsiang (Inventor)

    2003-01-01

    Metal-doped sol-gel materials, suitable for use as sensors for surface-enhanced Raman spectroscopic analysis for trace chemical detection, are produced by effecting gelation and solvent removal of a doped sol-gel under mild temperature conditions. At least in certain instances reaction and drying will desirably be effected in an oxygen-starved environment. The metal of the sol-gel material functions, when irradiated, to produce a plasmon field for interaction with molecules of an analyte in contact therewith, increasing by orders of magnitude Raman photons that are generate by excitation radiation, and the method allows matching of the metal and metal particle size to a wavelength of light (or incident radiation, e.g., laser radiation) to generate surface plasmons. The porosity of the sol-gel material dramatically increases the surface area, and thereby the amount of metal exposed for analyte interaction. The sensors provided may be in the form of glass vials, fiber optics, multi-well micro-sample plates, etc., having surface coatings of the doped sol-gel material, to provide sampling systems for use in a Raman instrument.

  7. Raman spectroscopy

    SciTech Connect

    Gerrard, D.L.; Bowley, H.J.

    1988-06-15

    The period of this review is from late 1985 to late 1987. During this time over 6000 papers have been published in the scientific literature dealing with many applications of Raman spectroscopy and extending its use to new areas of study. This article covers only those papers that are relevant to the analytical chemist and this necessitates a highly selective approach. There are some areas that have been the subject of many papers with relatively few being of analytical interest. In such cases the reader is referred to appropriate reviews which are detailed in this section.

  8. A New Method for In-situ Characterization of Important Actinides and Technetium Compounds via Fiberoptic Surface Enhanced Raman Spectroscopy (SERS)

    SciTech Connect

    Dai Sheng; Gu, B.

    2005-09-28

    This project serves to fill information gap through the development of a novel surface-enhanced Raman scattering (SERS) spectroscopy to selectively and sensitively monitor and characterize the chemical speciation of radionuclides at trace levels. The SERS technique permits both of these measurements to be made simultaneously, and results in significant improvement over current methods in reducing time of analysis, cost, and sample manipulation. Our overall goal is (a) to develop a scientific basis for this new methodology to detect radionuclides via SERS and (b) to rationally synthesize and evaluate novel sol-gel based SERS substrates tailored to sensitively detect and characterize inorganic radionuclides such as TcO4 -, actinyl ions (e.g. UO2 2+, NpO2 +, and PuO2 2+) and other chemical compounds of interest.

  9. Development of a Loop Mediated Isothermal Amplification (LAMP) - Surface Enhanced Raman spectroscopy (SERS) Assay for the Detection of Salmonella Enterica Serotype Enteritidis

    PubMed Central

    Draz, Mohamed Shehata; Lu, Xiaonan

    2016-01-01

    As a major foodborne pathogen, Salmonella enterica serotype Enteritidis is increasingly rising as a global health concern. Here, we developed an integrated assay that combines loop mediated isothermal amplification (LAMP) and surface enhanced Raman spectroscopy (SERS) for DNA detection of S. Enteritidis using specifically designed Raman active Au-nanoprobes. The target DNA was amplified by LAMP and then labeled with Au-nanoprobes comprised of gold nanoparticle-modified with specific cy5/DNA probes to allow the detection by SERS. The sensitivity of the developed LAMP-SERS detection assay (66 CFU/mL) was ~100-fold higher than the conventional polymerase chain reaction (PCR) method. Significantly, this technique allowed highly specific detection of the target DNA of S. Enteritidis and could differentiate it from the DNA of closely related bacterial species or non-specific contamination, making it more accurate and reliable than the standard LAMP technique. The applicability of detection of S. Enteritidis in milk samples using LAMP-SERS assay was validated as well. In sum, the developed LAMP-SERS assay is highly specific and sensitive, and has the potential to be applied for rapid detection of different foodborne pathogens and other microbial contaminants. PMID:26941845

  10. Development of a Loop Mediated Isothermal Amplification (LAMP) - Surface Enhanced Raman spectroscopy (SERS) Assay for the Detection of Salmonella Enterica Serotype Enteritidis.

    PubMed

    Draz, Mohamed Shehata; Lu, Xiaonan

    2016-01-01

    As a major foodborne pathogen, Salmonella enterica serotype Enteritidis is increasingly rising as a global health concern. Here, we developed an integrated assay that combines loop mediated isothermal amplification (LAMP) and surface enhanced Raman spectroscopy (SERS) for DNA detection of S. Enteritidis using specifically designed Raman active Au-nanoprobes. The target DNA was amplified by LAMP and then labeled with Au-nanoprobes comprised of gold nanoparticle-modified with specific cy5/DNA probes to allow the detection by SERS. The sensitivity of the developed LAMP-SERS detection assay (66 CFU/mL) was ~100-fold higher than the conventional polymerase chain reaction (PCR) method. Significantly, this technique allowed highly specific detection of the target DNA of S. Enteritidis and could differentiate it from the DNA of closely related bacterial species or non-specific contamination, making it more accurate and reliable than the standard LAMP technique. The applicability of detection of S. Enteritidis in milk samples using LAMP-SERS assay was validated as well. In sum, the developed LAMP-SERS assay is highly specific and sensitive, and has the potential to be applied for rapid detection of different foodborne pathogens and other microbial contaminants. PMID:26941845

  11. Scanning surface-enhanced Raman spectroscopy (SERS) of chemical agent simulants on templated Au-Ag nanowire substrates

    NASA Astrophysics Data System (ADS)

    Hoffmann, J. A.; Miragliotta, J. A.; Wang, J.; Tyagi, P.; Maddanimath, T.; Gracias, D. H.; Papadakis, S. J.

    2009-05-01

    We report the results of scanning micro-Raman spectroscopy obtained on Au-Ag nanowires for a variety of chemical warfare agent simulants. Rough silver segments embedded in gold nanowires showed enhancement of 105 - 107 and allowed unique identification of 3 of 4 chemical agent simulants tested. These results suggest a promising method for detection of compounds significant for security applications, leading to sensors that are compact and selective.

  12. Surface-Enhanced Raman Spectroscopy.

    ERIC Educational Resources Information Center

    Garrell, Robin L.

    1989-01-01

    Reviews the basis for the technique and its experimental requirements. Describes a few examples of the analytical problems to which surface-enhanced Raman spectroscopy (SERS) has been and can be applied. Provides a perspective on the current limitations and frontiers in developing SERS as an analytical technique. (MVL)

  13. The multifunctional application of microfluidic lab-on-a-chip surface enhanced Raman spectroscopy (LOC-SERS) within the field of bioanalytics

    NASA Astrophysics Data System (ADS)

    März, Anne; Mönch, Bettina; Walter, Angela; Bocklitz, Thomas; Schumacher, Wilm; Rösch, Petra; Kiehntopf, Michael; Popp, Jürgen

    2011-07-01

    This contribution will present a variety of applications of lab-on-a-chip surface enhanced Raman spectroscopy in the field of bioanalytic. Beside the quantification and online monitoring of drugs and pharmaceuticals, determination of enzyme activity and discrimination of bacteria are successfully carried out utilizing LOC-SERS. The online-monitoring of drugs using SERS in a microfluidic device is demonstrated for nicotine. The enzyme activity of thiopurine methyltransferase (TPMT) in lysed red blood cells is determined by SERS in a lab-on-a-chip device. To analyse the activity of TPMT the metabolism of 6-mercaptopurine to 6-methylmercaptopurine is investigated. The discrimination of bacteria on strain level is carried out with different E. coli strains. For the investigations, the bacteria are busted by ultra sonic to achieve a high information output. This sample preparation provides the possibility to detect SERS spectra containing information of the bacterial cell walls as well as of the cytoplasm. This contribution demonstrates the great potential of LOC-SERS in the field of bioanalytics.

  14. IR, Raman, SERS and DFT study of amoxicillin

    NASA Astrophysics Data System (ADS)

    Bebu, Andreea; Szabó, László; Leopold, Nicolae; Berindean, Cătălin; David, Leontin

    2011-05-01

    In this work a joint experimental and theoretical study on amoxicillin is reported. The molecular vibrations of amoxicillin were investigated by FTIR, FT-Raman and SERS spectroscopies. In parallel, quantum chemical calculations based on density functional theory (DFT) were used to determine the geometrical, energetic and vibrational characteristics of the molecule with particular emphasis put on the interaction and adsorption geometry of the molecule to the silver colloidal surface. The SERS spectrum of amoxicillin was recorded using a 532 nm laser line and hydroxylamine reduced silver colloid as SERS substrate. FTIR, FT-Raman and SERS spectra of amoxicillin were assigned based on DFT calculations with the hybrid B3LYP exchange-correlation functional, coupled with the standard 6-31G(d) basis set. The calculated molecular electrostatic potential (MEP) was used in conjunction with SERS data to predict the adsorption geometry of the molecule on the silver surface.

  15. Toward food analytics: fast estimation of lycopene and β-carotene content in tomatoes based on surface enhanced Raman spectroscopy (SERS).

    PubMed

    Radu, Andreea Ioana; Ryabchykov, Oleg; Bocklitz, Thomas Wilhelm; Huebner, Uwe; Weber, Karina; Cialla-May, Dana; Popp, Jürgen

    2016-07-21

    Carotenoids are molecules that play important roles in both plant development and in the well-being of mammalian organisms. Therefore, various studies have been performed to characterize carotenoids' properties, distribution in nature and their health benefits upon ingestion. Nevertheless, there is a gap regarding a fast detection of them at the plant phase. Within this contribution we report the results obtained regarding the application of surface enhanced Raman spectroscopy (SERS) toward the differentiation of two carotenoid molecules (namely, lycopene and β-carotene) in tomato samples. To this end, an e-beam lithography (EBL) SERS-active substrate and a 488 nm excitation source were employed, and a relevant simulated matrix was prepared (by mixing the two carotenoids in defined percentages) and measured. Next, carotenoids were extracted from tomato plants and measured as well. Finally, a combination of principal component analysis and partial least squares regression (PCA-PLSR) was applied to process the data, and the obtained results were compared with HPLC measurements of the same extracts. A good agreement was obtained between the HPLC and the SERS results for most of the tomato samples. PMID:27200439

  16. Aqueously Dispersed Silver Nanoparticle-Decorated Boron Nitride Nanosheets for Reusable, Thermal Oxidation-Resistant Surface Enhanced Raman Spectroscopy (SERS) Devices

    NASA Technical Reports Server (NTRS)

    Lin, Yi; Bunker, Christopher E.; Fernandos, K. A. Shiral; Connell, John W.

    2012-01-01

    The impurity-free aqueous dispersions of boron nitride nanosheets (BNNS) allowed the facile preparation of silver (Ag) nanoparticle-decorated BNNS by chemical reduction of an Ag salt with hydrazine in the presence of BNNS. The resultant Ag-BNNS nanohybrids remained dispersed in water, allowing convenient subsequent solution processing. By using substrate transfer techniques, Ag-BNNS nanohybrid thin film coatings on quartz substrates were prepared and evaluated as reusable surface enhanced Raman spectroscopy (SERS) sensors that were robust against repeated solvent washing. In addition, because of the unique thermal oxidation-resistant properties of the BNNS, the sensor devices may be readily recycled by short-duration high temperature air oxidation to remove residual analyte molecules in repeated runs. The limiting factor associated with the thermal oxidation recycling process was the Ostwald ripening effect of Ag nanostructures.

  17. Aqueously dispersed silver nanoparticle-decorated boron nitride nanosheets for reusable, thermal oxidation-resistant surface enhanced Raman spectroscopy (SERS) devices.

    PubMed

    Lin, Yi; Bunker, Christopher E; Fernando, K A Shiral; Connell, John W

    2012-02-01

    The impurity-free aqueous dispersions of boron nitride nanosheets (BNNS) allowed the facile preparation of silver (Ag) nanoparticle-decorated BNNS by chemical reduction of an Ag salt with hydrazine in the presence of BNNS. The resultant Ag-BNNS nanohybrids remained dispersed in water, allowing convenient subsequent solution processing. By using substrate transfer techniques, Ag-BNNS nanohybrid thin film coatings on quartz substrates were prepared and evaluated as reusable surface enhanced Raman spectroscopy (SERS) sensors that were robust against repeated solvent washing. In addition, because ofthe unique thermal oxidation-resistant properties of the BNNS, the sensor devices may be readily recycled by short-duration high temperature air oxidation to remove residual analyte molecules in repeated runs. The limiting factor associated with the thermal oxidation recycling process was the Ostwald ripening effect of Ag nanostructures. PMID:22280102

  18. Design of Raman active nanoparticles for SERS-based detection

    NASA Astrophysics Data System (ADS)

    Garza, Javier T.; Cote, Gerard L.

    2016-03-01

    Timely detection of cardiac biomarkers is needed to diagnose acute myocardial infarction, implement the appropriate early treatment, and significantly reduce the chance of mortality. Ideally, for maximizing patient impact, a point of care device needs to be designed that is fast, sensitive, reliable, and small enough to be used in the ambulance and emergency department. Surface enhanced Raman spectroscopy (SERS) is a sensitive optical technique that can potentially be used to quantify the cardiac biomarkers of interest. In this work, silver nanoparticles were functionalized with a Raman reporter molecule and human cardiac Troponin I (cTnI) as an essential component of binding assays. Aggregated nanoparticles with the Raman reporter molecules were encapsulated in a silica shell to form SERS hotspots. Besides having a specific Raman spectra and binding affinity to cardiac Troponin I antibodies, the nanoparticles were designed to exhibit stability by using silica and polyethylene glycol (PEG) as part of the bioconjugation strategy. The specific narrow peaks from the Raman reporter molecule SERS signal allow for potential multiplexing capabilities as different Raman reporter molecules can be used in functionalized nanoparticles with different cardiac biomarkers. The SERS spectrum of the functionalized nanoparticles was measured to assess its potential to be used in an assay.

  19. Surface-enhanced Raman spectroscopy (SERS) in food analytics: Detection of vitamins B2 and B12 in cereals.

    PubMed

    Radu, Andreea Ioana; Kuellmer, Maria; Giese, Bernd; Huebner, Uwe; Weber, Karina; Cialla-May, Dana; Popp, Jürgen

    2016-11-01

    Food analysis has been gaining interest throughout recent decades for different reasons: the detection of hazardous substances in food and routine investigations of food composition and vitamin/nutrient contents. Regardless of the targeted component, food analysis raises a few challenges regarding the complexity of the matrix and detecting trace amounts of substances. We report herein the results obtained regarding the simultaneous detection of two B vitamins (riboflavin, vitamin B2 and cyanocobalamin, vitamin B12) by means of SERS. SERS provides molecular fingerprint identification and high analytical sensitivity together with a low processing time and cost. All these make SERS a promising tool for the development of food analytical methods. PMID:27591616

  20. Determination of nicotine by surface-enhanced Raman scattering (SERS)

    SciTech Connect

    Barber, T.E.; List, M.S.; Haas, J.W. III; Wachter, E.A. )

    1994-11-01

    The analytical application of surface-enhanced Raman spectroscopy (SERS) to the determination of nicotine is demonstrated. A simple spectroelectrochemical method using a copper or silver electrode as the SERS substrate has been developed, consisting of three steps: polishing a working electrode to a mirror finish; roughening the electrode in an electrolyte solution; and, finally, depositing the nicotine analyte onto the roughened electrode after immersion in a sample solution. During the reduction cycle, a large enhancement in nicotine Raman scattering is observed at the electrode surface. The intensity of the SERS signal on a silver electrode is linear with concentration from 10 to 900 ppb, with an estimated detection limit of 7 ppb. The total analysis time per sample is approximately five minutes. This procedure has been used to analyze the extract from a cigarette side-stream smoke sample (environmental tobacco smoke); the SERS results agree well with those of conventional gas chromatographic analysis.

  1. Detection and identification of Huo-Xue-Hua-Yu decoction (HXHYD) using surface-enhanced Raman scattering (SERS) spectroscopy and multivariate analysis

    NASA Astrophysics Data System (ADS)

    Chen, Weiwei; Lin, Jia; Chen, Rong; Feng, Shangyuan; Yu, Yun; Lin, Duo; Huang, Meizhen; Shi, Hong; Huang, Hao

    2015-04-01

    We have evaluated the capabilities of surface-enhanced Raman scattering (SERS) technology for analyzing two Huo-Xue-Hua-Yu decoctions (HXHYDs) prepared according to different prescriptions. The aim of this study was to evaluate the relevance of SERS technology applied to decoction of traditional Chinese medicines (TCM). HXHYD I was prepared according to the original prescription; the same preparation method was used for the HXHYD II, except for the crudeweight ratio described in the original prescription. There was no Raman signal in conventional Raman spectra of HXHYDs. Silver nanoparticles were directly mixed with HXHYDs to enhance the Raman scattering of biochemical constituents, and high quality SERS spectra were obtained. Significant differences in SERS spectra between HXHYD I and II can be observed, which showed special changes in the percentage of biochemical constituents in different decoctions. Principal components analysis (PCA) combined with linear discriminant analysis (LDA) were employed to generate diagnostic algorithms for classification of SERS spectra of two HXHYDs, and showed that a diagnostic accuracy of 100% can be achieved. This work demonstrated that the SERS technique has potential for spectral characteristic detection for decoction of TCM with high sensitivity, and that this technique, combined with PCA-LDA, can be used for quality control of the extracted decoction of TCM and production management of Chinese herbal preparations.

  2. Detection and quantification of alternative splice sites in Arabidopsis genes AtDCL2 and AtPTB2 with highly sensitive surface enhanced Raman spectroscopy (SERS) and gold nanoprobes.

    PubMed

    Kadam, Ulhas S; Schulz, Burkhard; Irudayaraj, Joseph

    2014-05-01

    Alternative splicing (AS) increases the size of the transcriptome and proteome to enhance the physiological capacity of cells. We demonstrate surface enhanced Raman spectroscopy (SERS) in combination with a DNA hybridization analytical platform to identify and quantify AS genes in plants. AS in AtDCL2 and AtPTB2 were investigated using non-fluorescent Raman probes using a 'sandwich assay'. Utilizing Raman probes conjugated to gold nanoparticles we demonstrate the recognition of RNA sequences specific to AtDCL2 and AtPTB2 splice junction variants with detection sensitivity of up to 0.1 fM. PMID:24631541

  3. On-chip surface-enhanced Raman spectroscopy (SERS)-linked immuno-sensor assay (SLISA) for rapid environmental-surveillance of chemical toxins

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Vinay; Srinivasan, Supriya; McGoron, Anthony J.

    2005-05-01

    The increasing threat of an intentional (attack) or accidental release of toxins, in particular chemical toxins, including chemical warfare agents (CWAs) and toxic industrial chemicals (TICs) has increased public fear. The major problem in such attacks/accidents is to detect toxins present in very low levels. Indeed, several detection techniques are currently being used for the same. However, none of them meet the most critical requirements of a RISE (Rapid, Inexpensive, Simple and Effective) detect-to-protect class of biosensors. To address this critical demand our group has developed a prototype lab-on-a-chip (LOC) using a colloidal silver-based, surface-enhanced Raman spectroscopy (SERS)-linked immuno-sensor assay (SLISA). The LOC-SLISA was tested for the measurement of RAD54, a stress-marker protein expressed by yeast in response to hydrogen peroxide (H2O2), a toxin in the EPA priority list of chemical toxins. We found SLISA has good correlation in accuracy with the traditional ELISA technique and outperforms the latter by being rapid and easy-to-use. SLISA is more sensitive, provides qualitative information on immuno-sensor's chemical characterization and antigen-antibody binding, and allows direct detection with minimal or no chance of uncertainty, which is a stringent limitation of all label-based biosensor technologies including ELISA. For translational significance of our work, we correlated our results to U.S. EPA (environmental protection agency) defined risk exposure guideline levels of H2O2 to validate the commercial potential of our on-chip SLISA. The label-free, cell-based and RISE detection offered by SERS can allow development of biomedical and environmental sensor technology (BEST) needed for direct, rapid and continuous monitoring of human health and environment

  4. A new SERS: scattering enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Bixler, Joel N.; Yakovlev, Vladislav V.

    2014-03-01

    Raman spectroscopy is a powerful technique that can be used to obtain detailed chemical information about a system without the need for chemical markers. It has been widely used for a variety of applications such as cancer diagnosis and material characterization. However, Raman scattering is a highly inefficient process, where only one in 1011 scattered photons carry the needed information. Several methods have been developed to enhance this inherently weak effect, including surface enhanced Raman scattering and coherent anti-Stokes Raman scattering. These techniques suffer from drawbacks limiting their commercial use, such as the need for spatial localization of target molecules to a `hot spot', or the need for complex laser systems. Here, we present a simple instrument to enhance spontaneous Raman scattering using elastic light scattering. Elastic scattering is used to substantially increase the interaction volume. Provided that the scattering medium exhibits very low absorption in the spectral range of interest, a large enhancement factor can be attained in a simple and inexpensive setting. In our experiments, we demonstrate an enhancement of 107 in Raman signal intensity. The proposed novel device is equally applicable for analyzing solids, liquids, and gases.

  5. Auger resonant Raman spectroscopy

    SciTech Connect

    Azuma, Y.; LeBrun, T.; MacDonald, M.; Southworth, S.H.

    1995-08-01

    As noted above, traditional spectroscopy of the electronic structure of the inner shells of atoms, molecules, and solids is limited by the lifetime broadening of the core-excited states. This limitation can also be avoided with the non-radiative analog of X-ray Raman scattering - resonant Auger Raman spectroscopy. We have used this technique to study the K-shell excitation spectrum of argon as the photon energy is continuously scanned across threshold.

  6. Surface-enhanced Raman scattering (SERS) study of anthocyanidins

    NASA Astrophysics Data System (ADS)

    Zaffino, Chiara; Russo, Bianca; Bruni, Silvia

    2015-10-01

    Anthocyanins are an important class of natural compounds responsible for the red, purple and blue colors in a large number of flowers, fruits and cereal grains. They are polyhydroxy- and polymethoxy-derivatives of 2-phenylbenzopyrylium (flavylium) salts, which are present in nature as glycosylated molecules. The aim of the present study is to assess the identification of anthocyanidins, i.e. anthocyanins without the glycosidic moiety, by means of surface-enhanced Raman spectroscopy (SERS), a very chemically-specific technique which is moreover sensitive to subtle changes in molecular structures. These features can lead to elect SERS, among the spectroscopic tools currently at disposal of scientists, as a technique of choice for the identification of anthocyanidins, since: (1) anthocyanidins structurally present the same benzopyrylium moiety and differentiate only for the substitution pattern on their phenyl ring, (2) different species are present in aqueous solution depending on the pH. It will be demonstrated that, while resonance Raman spectra of anthocyanidins are very similar to one another, SER spectra show greater differences, leading to a further step in the identification of such important compounds in diluted solutions by means of vibrational spectroscopy. Moreover, the dependence on the pH of the six most common anthocyanidins, i.e. cyanidin, delphinidin, pelargonidin, peonidin, malvidin and petunidin, is studied. To the best of the authors' knowledge, a complete SERS study of such important molecules is reported in the present work for the first time.

  7. Raman spectroscopy of composites

    SciTech Connect

    Young, R.J.; Andrews, M.C.; Yang, X.; Huang, Y.L.; Gu, X.; Day, R.J.

    1994-12-31

    It is demonstrated that Raman Spectroscopy can be used to follow the micromechanics of the deformation of high-performance fibers within composites. The technique can be applied to a wide range of fiber systems including aramids, carbon and ceramic (using fluorescence spectroscopy) fibers. Well-defined Raman spectra are obtained and the position of the Raman bands shift on the application of stress or strain. It is possible to determine the point-to-point variation of strain along an individual fiber inside a transparent matrix under any general state of stress or strain. Examples are given of the use of the technique to study a variety of phenomena in a wide range of composite systems. The phenomena investigated include thermal stresses, fiber/matrix adhesion, matrix yielding for both fragmentation and pull-out tests. The systems studied include aramid/epoxy, carbon/epoxy and ceramic-fiber/glass composites.

  8. Raman spectroscopy in astrobiology.

    PubMed

    Jorge Villar, Susana E; Edwards, Howell G M

    2006-01-01

    Raman spectroscopy is proposed as a valuable analytical technique for planetary exploration because it is sensitive to organic and inorganic compounds and able to unambiguously identify key spectral markers in a mixture of biological and geological components; furthermore, sample manipulation is not required and any size of sample can be studied without chemical or mechanical pretreatment. NASA and ESA are considering the adoption of miniaturised Raman spectrometers for inclusion in suites of analytical instrumentation to be placed on robotic landers on Mars in the near future to search for extinct or extant life signals. In this paper we review the advantages and limitations of Raman spectroscopy for the analysis of complex specimens with relevance to the detection of bio- and geomarkers in extremophilic organisms which are considered to be terrestrial analogues of possible extraterrestial life that could have developed on planetary surfaces. PMID:16456933

  9. Surface-enhanced Raman scattering (SERS) detection of multiple viral antigens using magnetic capture of SERS-active nanoparticles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A highly sensitive immunoassay based on surface-enhanced Raman scattering (SERS) spectroscopy has been developed for multiplex detection of surface envelope and capsid antigens of the viral zoonotic pathogens West Nile virus (WNV) and Rift Valley fever virus (RVFV). Detection was mediated by antibo...

  10. Detection and differentiation of Salmonella serotypes using Surface Enhanced Raman Scattering (SERS) technique.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface Enhanced Raman Scattering (SERS) can detect pathogens rapidly and accurately. The metal surface for the SERS spectroscopy was a silver nano-particle encapsulated biopolymer polyvinyl alcohol nano-colloid deposited on a stainless steel plate. Salmonella Typhimurium and Salmonella Enteritidis...

  11. Fiber enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Frosch, T.; Yan, D.; Hanf, S.; Popp, J.

    2014-05-01

    Fiber enhanced Raman sensing is presented for versatile and extremely sensitive analysis of pharmaceutical drugs and biogenic gases. Elaborated micro-structured optical fibers guide the light with very low losses within their hollow core and provide at the same time a miniaturized sample container for the analytes. Thus, fiber enhanced Raman spectroscopy (FERS) allows for chemically selective detection of minimal sample amounts with high sensitivity. Two examples are presented in this contribution: (i) the detection of picomolar concentrations of pharmaceutical drugs; and (ii) the analysis of biogenic gases within a complex mixture of gases with analytical sensitivities in the ppm range.

  12. Airborne chemistry coupled to Raman spectroscopy.

    PubMed

    Santesson, Sabina; Johansson, Jonas; Taylor, Lynne S; Levander, Ia; Fox, Shannon; Sepaniak, Michael; Nilsson, Staffan

    2003-05-01

    In this paper, the use of airborne chemistry (acoustically levitated drops) in combination with Raman spectroscopy is explored. We report herein the first Raman studies of crystallization processes in levitated drops and the first demonstration of surface-enhanced Raman scattering (SERS) detection in this medium. Crystallization studies on the model compounds benzamide and indomethacin resulted in the formation of two crystal modifications for each compound, suggesting that this methodology may be useful for investigation of polymorphs. SERS detection resulted in a signal enhancement of 27 000 for benzoic acid and 11 000 for rhodamine 6-G. The preliminary results presented here clearly indicate that several important applications of the combination between Raman spectroscopy and acoustic drop levitation can be expected in the future. PMID:12720359

  13. High fidelity nanohole enhanced Raman spectroscopy.

    SciTech Connect

    Bahns, J. T.; Guo, Q.; Gray, S. K.; Jaeger, H. M.; Chen, L.; Montgomery, J. M.; Univ. of Chicago

    2009-01-01

    Surface enhanced Raman spectroscopy (SERS) is a sensitive technique that can even detect single molecules. However, in many SERS applications, the strongly inhomogeneous distribution of intense local fields makes it very difficult for a quantitive assessment of the fidelity, or reproducibility of the signal, which limits the application of SERS. Herein, we report the development of exceptionally high-fidelity hole-enhanced Raman spectroscopy (HERS) from ordered, 2D hexagonal nanohole arrays. We take the fidelity f to be a measure of the percent deviation of the Raman peaks from measurement to measurement. Overall, area averaged fidelities for 12 gold array samples ranged from f {approx} 2-15% for HERS using aqueous R6G molecules. Furthermore, intensity modulations of the enhanced Raman spectra were measured for the first time as a function of polarization angle. The best of these measurements, which focus on static laser spots on the sample, could be consistent with even higher fidelities than the area-averaged results. Nanohole arrays in silver provided supporting polarization measurements and a more complete enhanced Raman fingerprint for phenylalanine molecules. We also carried out finite-difference time-domain calculations to assist in the interpretation of the experiments, identifying the polarization dependence as possibly arising from hole-hole interactions. Our results represent a step toward making quantitative and reproducible enhanced Raman measurements possible and also open new avenues for a large-scale source of highly uniform hot spots.

  14. Infrared absorption, Raman, and SERS investigations in conjunction with theoretical simulations on a phenothiazine derivative

    NASA Astrophysics Data System (ADS)

    Bolboaca, M.; Iliescu, T.; Kiefer, W.

    2004-03-01

    The vibrational characterization of the most stable conformer of 10-isopentyl-10H-phenothiazine-5,5-dioxide (10-I-10H-P-5,5-D) was performed by means of infrared absorption, Raman and surface-enhanced Raman spectroscopy (SERS). Hartree-Fock and density functional theory calculations were carried out to find the optimised structures and the computed vibrational wavenumbers of the title compound. The comparison of SER spectra obtained only in activated silver colloid with the corresponding Raman spectrum reveals small shifts and changes in the relative intensities proving the partial chemisorption of the molecules on the silver surface. The electromagnetic mechanism represents the main mechanism of the overall SERS enhancement. The changes observed in the SER spectra at different pH values were explained by considering the reorientation of the adsorbed molecule with respect to the metal surface.

  15. Applications of Raman Spectroscopy to Virology and Microbial Analysis

    NASA Astrophysics Data System (ADS)

    Harz, Michaela; Stöckel, Stephan; Ciobotă, Valerian; Cialla, Dana; Rösch, Petra; Popp, Jürgen

    This chapter reports from the utilization of Raman spectroscopic techniques like Raman microscopy, Raman optical activity (ROA), UV-resonance Raman (UVRR)-spectroscopy, surface enhanced Raman spectroscopy (SERS), and tip-enhanced Raman spectroscopy (TERS) for the investigation of viruses and microorganisms, especially bacteria and yeasts for medical and pharmaceutical applications. The application of these Raman techniques allows for the analysis of chemical components of cells and subcellular regions, as well as the monitoring of chemical differences occurring as a result of the growth of microorganisms. In addition, the interaction of microorganisms with active pharmaceutical agents can be investigated. In combination with chemometric methods Raman spectroscopy can also be applied to identify microorganisms both in micro colonies and even on single cells.

  16. Raman Spectroscopy of Cocrystals

    NASA Astrophysics Data System (ADS)

    Rooney, Frank; Reardon, Paul; Ochoa, Romulo; Abourahma, Heba; Marti, Marcus; Dimeo, Rachel

    2010-02-01

    Cocrystals are a class of compounds that consist of two or more molecules that are held together by hydrogen bonding. Pharmaceutical cocrystals are those that contain an active pharmaceutical ingredient (API) as one of the components. Pharmaceutical cocrystals are of particular interest and have gained a lot of attention in recent years because they offer the ability to modify the physical properties of the API, like solubility and bioavailability, without altering the chemical structure of the API. The APIs that we targeted for our studies are theophylline (Tp) and indomethacin (Ind). These compounds have been mixed with complementary coformers (cocrystal former) that include acetamide (AcONH2), melamine (MLM), nicotinic acid (Nic-COOH), 4-cyanopyridine (4-CNPy) and 4-aminopyridine (4-NH2Py). Raman spectroscopy has been used to characterize these cocrystals. Spectra of the cocrystals were compared to those of the coformers to analyze for peak shifts, specifically those corresponding to hydrogen bonding. A 0.5 m CCD Spex spectrometer was used, in a micro-Raman setup, for spectral analysis. An Argon ion Coherent laser at 514.5 nm was used as the excitation source. )

  17. Femtosecond Stimulated Raman Spectroscopy.

    PubMed

    Dietze, Daniel R; Mathies, Richard A

    2016-05-01

    Femtosecond stimulated Raman spectroscopy (FSRS) is an ultrafast nonlinear optical technique that provides vibrational structural information with high temporal (sub-50 fs) precision and high spectral (10 cm(-1) ) resolution. Since the first full demonstration of its capabilities ≈15 years ago, FSRS has evolved into a mature technique, giving deep insights into chemical and biochemical reaction dynamics that would be inaccessible with any other technique. It is now being routinely applied to virtually all possible photochemical reactions and systems spanning from single molecules in solution to thin films, bulk crystals and macromolecular proteins. This review starts with an historic overview and discusses the theoretical and experimental concepts behind this technology. Emphasis is put on the current state-of-the-art experimental realization and several variations of FSRS that have been developed. The unique capabilities of FSRS are illustrated through a comprehensive presentation of experiments to date followed by prospects. PMID:26919612

  18. Detection Of Biochips By Raman And Surface Enhanced Raman Spectroscopies

    NASA Astrophysics Data System (ADS)

    Kantarovich, Keren; Tsarfati, Inbal; Gheber, Levi A.; Haupt, Karsten; Bar, Ilana

    2010-08-01

    Biochips constitute a rapidly increasing research field driven by the versatility of sensing devices and the importance of their applications in the bioanalytical field, drug development, environmental monitoring, food analysis, etc. Common strategies used for creating biochips and for reading them have extensive limitations, motivating development of miniature biochips and label-free formats. To achieve these goals we combined the nano fountain pen method, for printing microscale features with Raman spectroscopy or surface enhanced Raman spectroscopy (SERS) for reading droplets of synthetic receptors. These receptors include molecularly imprinted polymers (MIPs), which are obtained by polymerization of suitable functional and cross-linking monomers around molecular templates. MIPs are characterized by higher physical and chemical stability than biomacromolecules, and therefore are potentially very suitable as recognition elements for biosensors, or biochips. The monitored bands in the Raman and SERS spectra could be related to the taken up compound, allowing direct detection of the template, i.e., the β-blocking drug propranolol in the imprinted droplets, as well as imaging of individual and multiple dots in an array. This study shows that the combination of nanolithography techniques with SERS might open the possibility of miniaturized arrayed MIP sensors with label-free, specific and quantitative detection.

  19. SERS spectroscopy of nanocomposite porous films containing silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Kaganovich, E. B.; Krischenko, I. M.; Kravchenko, S. A.; Manoilov, E. G.; Golichenko, B. O.; Kolomys, A. F.; Strel'chuk, V. V.

    2015-02-01

    It is demonstrated that surface-enhanced Raman scattering spectroscopy allows detecting 10-10 M Rhodamine 6G (Rh 6G) on nanocomposite films containing silver nanoparticles with an amplification factor of 3 × 107. The films used for SERS, which exhibit gradients of thickness and have silver particles and pores of different size, were obtained by pulse laser deposition from the low-energy backward erosion flux. To activate the SERS signal, the films were treated in solutions of metal chlorides and hydrogen chloride to achieve formation of anions of [AgCl2]- complexes. The composition of shells of silver nanoparticles, in particular, replacement of silver compounds preventing Rh 6G adsorption by anions of [AgCl2]- complexes enabling adsorption of Rh 6G cation between them, has been monitored by means of SERS spectroscopy. The obtained SERS spectra of Rh 6G in several locations on the film surface allowed determining the area with an optimal size of silver nanoparticles that gives rise to highest SERS signal intensity. The transmission spectra of the films revealed narrowing of the band corresponding to the local surface plasmon absorption, its shift toward the blue spectral region, and enhancement of plasmon resonance upon introduction of chlorine anion. The changes in absorption spectra of the films correlate with the activation of the Rh 6G SERS spectra.

  20. Adapting and testing a portable Raman spectrometer for SERS analysis of amino acids and small peptides

    NASA Astrophysics Data System (ADS)

    Brambilla, A.; Philippidis, A.; Nevin, A.; Comelli, D.; Valentini, G.; Anglos, D.

    2013-07-01

    Surface-Enhanced Raman Spectroscopy (SERS), a powerful spectrochemical technique enabling highly sensitive analysis of organic and biological materials, is investigated for applications in the analysis of archaeological materials including in situ screening. In this work, a compact mobile Raman spectrometer is employed for acquiring Surface-Enhanced Raman spectra from natural amino acids (L-Arg, L-Phe, L-Met) and a tripeptide (Glutathione), adsorbed on silver colloids. The detection limits of the portable Raman spectrometer, together with an optimization of sample preparation and experimental parameters, are reported. The collection and interpretation of SER spectra of amino acids and peptides is a starting point for the optimization of the instrumentation and its application in the study of more complex biological molecules in the context of detection and analysis of archaeological materials and residues.

  1. IR, Raman, SERS and DFT study of paroxetine

    NASA Astrophysics Data System (ADS)

    Cozar, I. B.; Szabó, L.; Mare, D.; Leopold, N.; David, L.; Chiş, V.

    2011-05-01

    Structural investigations by different vibrational spectroscopic methods (FTIR, Raman and SERS), as well as density functional theory (DFT) calculations were performed on paroxetine (IUPAC name: (3S,4R)-3-[(1,3-benzodioxol-5-yloxy)methyl]-4-(4-fluorophenyl)piperidine. After the identification of the lowest energy conformer of the investigated molecule, the FTIR, FT-Raman and SERS spectra were assigned on the basis of DFT calculations at B3LYP/6-31G(d) level of theory. The very good correlation found between experimental and theoretical data is a clear evidence for a reliable assignment of the vibrational bands. The molecular electrostatic potential was calculated and used for the prediction of preferred adsorption sites of the paroxetine molecule on the silver nanoparticles surface. Based on SERS spectra analysis it is shown that the molecule is adsorbed on the silver surface through the benzodioxol ring, in a tilted orientation.

  2. Role of Raman spectroscopy and surface enhanced Raman spectroscopy in colorectal cancer

    PubMed Central

    Jenkins, Cerys A; Lewis, Paul D; Dunstan, Peter R; Harris, Dean A

    2016-01-01

    Colorectal cancer (CRC) is the fourth most common cancer in the United Kingdom and is the second largest cause of cancer related death in the United Kingdom after lung cancer. Currently in the United Kingdom there is not a diagnostic test that has sufficient differentiation between patients with cancer and those without cancer so the current referral system relies on symptomatic presentation in a primary care setting. Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) are forms of vibrational spectroscopy that offer a non-destructive method to gain molecular information about biological samples. The techniques offer a wide range of applications from in vivo or in vitro diagnostics using endoscopic probes, to the use of micro-spectrometers for analysis of biofluids. The techniques have the potential to detect molecular changes prior to any morphological changes occurring in the tissue and therefore could offer many possibilities to aid the detection of CRC. The purpose of this review is to look at the current state of diagnostic technology in the United Kingdom. The development of Raman spectroscopy and SERS in clinical applications relation for CRC will then be discussed. Finally, future areas of research of Raman/SERS as a clinical tool for the diagnosis of CRC are also discussed. PMID:27190582

  3. Ultrafast and nonlinear surface-enhanced Raman spectroscopy.

    PubMed

    Gruenke, Natalie L; Cardinal, M Fernanda; McAnally, Michael O; Frontiera, Renee R; Schatz, George C; Van Duyne, Richard P

    2016-04-21

    Ultrafast surface-enhanced Raman spectroscopy (SERS) has the potential to study molecular dynamics near plasmonic surfaces to better understand plasmon-mediated chemical reactions such as plasmonically-enhanced photocatalytic or photovoltaic processes. This review discusses the combination of ultrafast Raman spectroscopic techniques with plasmonic substrates for high temporal resolution, high sensitivity, and high spatial resolution vibrational spectroscopy. First, we introduce background information relevant to ultrafast SERS: the mechanisms of surface enhancement in Raman scattering, the characterization of plasmonic materials with ultrafast techniques, and early complementary techniques to study molecule-plasmon interactions. We then discuss recent advances in surface-enhanced Raman spectroscopies with ultrafast pulses with a focus on the study of molecule-plasmon coupling and molecular dynamics with high sensitivity. We also highlight the challenges faced by this field by the potential damage caused by concentrated, highly energetic pulsed fields in plasmonic hotspots, and finally the potential for future ultrafast SERS studies. PMID:26848784

  4. Surface-enhanced Raman spectroscopy of pterins

    NASA Astrophysics Data System (ADS)

    Smyth, Ciarán A.; Mirza, Inam; Lunney, James G.; McCabe, Eithne M.

    2012-03-01

    Raman spectroscopy is a useful technique in the identification and characterisation of compounds, but in terms of sensitivity its application is limited. With respect to this the discovery of the surface-enhanced Raman scattering (SERS) phenomenon has proved monumental, and much research has been carried out over the past 30 years developing the technique. Pterins are biological compounds that are found in nature in colour pigmentation and in mammalian metabolic pathways. Moreover, they have been identified in abnormal concentrations in cancer patients, suggesting potential applications in cancer diagnostics. SERS is an ideal technique to identify these compounds, and both nanoparticle suspensions and pulsed laser deposited nanoparticle substrates have been used to examine the spectra of xanthopterin, both in aqueous solution and in different pH environments.

  5. Enhancement of Raman scattering signal of a few molecules using photonic nanojet mediated SERS technique

    NASA Astrophysics Data System (ADS)

    Das, G. M.; Parit, M. K.; Laha, R.; Dantham, V. R.

    2016-05-01

    Now a days, single molecule surface enhanced Raman spectroscopy (SMSERS) has become a fascinating tool for studying the structural properties, static and dynamic events of single molecules (instead of ensemble average), with the help of efficient plasmonic nanostructures. This is extremely useful in the field of proteomics because the structural properties of protein molecules are heterogeneous. Even though, SMSERS provides wealthy information about single molecules, it demands high quality surface enhanced Raman scattering (SERS) substrates. So far, a very few researchers succeeded in demonstrating the single molecule Raman scattering using conventional SERS technique. However, the experimental S/N of the Raman signal has been found to be very poor. Recently, with the help of photonic nanojet of an optical microsphere, we were able to enhance the SERS signal of a few molecules adsorbed on the SERS substrates (gold symmetric and asymmetric nanodimers and trimers dispersed on a glass slide). Herein, we report a few details about photonic nanojet mediated SERS technique, a few experimental results and a detailed theoretical study on symmetric and asymmetric nanosphere dimers to understand the dependence of localised surface plasmon resonance (LSPR) wavelength of a nanodimer on the nanogap size and polarization of the excitation light.

  6. Development of surface-enhanced Raman scattering (SERS) substrates using nanoparticle-based printing inks

    NASA Astrophysics Data System (ADS)

    Figueroa, Manuel A.; Park, Sam; Pourrezaei, Kambiz; Tyagi, Somdev

    2008-02-01

    Raman spectroscopy is now a well-established analytical tool for obtaining rapid and compound specific information for chemical analysis. However, Raman scattering - inelastic scattering of photons - cross sections are typically of the order of 10 -30 cm2 per molecule and thus Raman signals are usually weak. In Surface Enhanced Raman Scattering (SERS) the signals can be greatly amplified by using specially structured metallic (usually Ag, Au, and Cu) substrates. SERS substrates can be fabricated by a variety of methods. Here, we report a method for fabricating SERS substrates from commercially available silver nanoparticle based printing inks. For dilute inks (~ 1-2% Ag by weight) the method involves the airbrushing of inks on heated (~100oC) quartz or polymer substrates followed by heating at 170oC for about 20 minutes. The heating treatment removes the polymer coating used to prevent aggregation of Ag particles in the colloidal suspension and allows partial sintering of particles. More concentrated inks (~ 20 - 30% Ag by weight) can be applied to various substrates at room temperature followed by the thermal treatment. SERS spectra of Rhodamine 6G, and β-carotene molecules are reported. SERS amplification factors of more than 106 can be easily obtained reproducibly.

  7. Towards advanced biological detection using surface enhanced raman scattering (SERS)-based sensors

    NASA Astrophysics Data System (ADS)

    Hankus, Mikella E.; Stratis-Cullum, Dimitra N.; Pellegrino, Paul M.

    2010-08-01

    The Army has a need for an accurate, fast, reliable and robust means to identify and quantify defense related materials. Raman spectroscopy is a form of vibrational spectroscopy that is rapidly becoming a valuable tool for homeland defense applications, as it is well suited for the molecular identification of a variety of compounds, including explosives and chemical and biological hazards. To measure trace levels of these types of materials, surface enhanced Raman scattering (SERS), a specialized form of Raman scattering, can be employed. The SERS enhancements are produced on, or in close proximity to, a nanoscale roughened metal surface and are typically associated with increased local electromagnetic field strengths. However, before application of SERS in the field and in particular to biological and other hazard sensing applications, significant improvements in substrate performance are needed. In this work, we will report the use of several SERS substrate architectures (colloids, film-over-nanospheres (FONs) and commercially available substrates) for detecting and differentiating numerous endospore samples. The variance in spectra as obtained using different sensing architectures will also be discussed. Additionally, the feasibility of using a modified substrate architecture that is tailored with molecular recognition probe system for detecting biological samples will be explored. We will discuss the progress towards an advanced, hybrid molecular recognition with a SERS/Fluorescence nanoprobe system including the optimization, fabrication, and spectroscopic analysis of samples on a commercially available substrate. Additionally, the feasibility of using this single-step switching architecture for hazard material detection will also be explored.

  8. Experimental and density functional theory study of Raman and SERS spectra of 5-amino-2-mercaptobenzimidazole

    NASA Astrophysics Data System (ADS)

    Chen, Yufeng; Yang, Jin; Li, Zonglong; Li, Ran; Ruan, Weidong; Zhuang, Zhiping; Zhao, Bing

    2016-01-01

    Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS) and density functional theory (DFT) simulations were employed to study 5-amino-2-mercaptobenzimidazole (5-A-2MBI) molecules. Ag colloids were used as SERS substrates which were prepared by using hydroxylamine hydrochloride as reducing agent. Raman vibration modes and SERS characteristic peaks of 5-A-2MBI were assigned with the aid of DFT calculations. The molecular electrostatic potential (MEP) of 5-A-2MBI was used to discuss the possible adsorption behavior of 5-A-2MBI on Ag colloids. The spectral analysis showed that 5-A-2MBI molecules were slightly titled via the sulfur atoms adhering to the surfaces of Ag substrates. The obtained SERS spectral intensity decreased when lowering the 5-A-2MBI concentrations. A final detection limit on the concentration of 5 × 10- 7 mol · L- 1 was gained. SERS proved to be a simple, fast and reliable method for the detection and characterization of 5-A-2MBI molecules.

  9. Surface-enhanced Raman scattering (SERS) dosimeter and probe

    DOEpatents

    Vo-Dinh, Tuan

    1995-01-01

    A dosimeter and probe for measuring exposure to chemical and biological compounds is disclosed. The dosimeter or probe includes a collector which may be analyzed by surface-enhanced Raman spectroscopy. The collector comprises a surface-enhanced Raman scattering-active material having a coating applied thereto to improve the adsorption properties of the collector. The collector may also be used in automated sequential devises, in probe array devices.

  10. Surface-enhanced Raman scattering (SERS) dosimeter and probe

    DOEpatents

    Vo-Dinh, T.

    1995-03-21

    A dosimeter and probe for measuring exposure to chemical and biological compounds is disclosed. The dosimeter or probe includes a collector which may be analyzed by surface-enhanced Raman spectroscopy. The collector comprises a surface-enhanced Raman scattering-active material having a coating applied thereto to improve the adsorption properties of the collector. The collector may also be used in automated sequential devices, in probe array devices. 10 figures.

  11. Nanoparticle Based Surface-Enhanced Raman Spectroscopy

    SciTech Connect

    Talley, C E; Huser, T R; Hollars, C W; Jusinski, L; Laurence, T; Lane, S M

    2005-01-03

    Surface-enhanced Raman scattering is a powerful tool for the investigation of biological samples. Following a brief introduction to Raman and surface-enhanced Raman scattering, several examples of biophotonic applications of SERS are discussed. The concept of nanoparticle based sensors using SERS is introduced and the development of these sensors is discussed.

  12. SERS Raman Sensor Based on Diameter-Modulated Sapphire Fiber

    SciTech Connect

    Shimoji, Yutaka

    2010-08-09

    Surface enhanced Raman scattering (SERS) has been observed using a sapphire fiber coated with gold nano-islands for the first time. The effect was found to be much weaker than what was observed with a similar fiber coated with silver nanoparticles. Diameter-modulated sapphire fibers have been successfully fabricated on a laser heated pedestal growth system. Such fibers have been found to give a modest increase in the collection efficiency of induced emission. However, the slow response of the SERS effect makes it unsuitable for process control applications.

  13. Raman spectroscopy in halophile research.

    PubMed

    Jehlička, Jan; Oren, Aharon

    2013-01-01

    Raman spectroscopy plays a major role in robust detection of biomolecules and mineral signatures in halophile research. An overview of Raman spectroscopic investigations in halophile research of the last decade is given here to show advantages of the approach, progress made as well as limits of the technique. Raman spectroscopy is an excellent tool to monitor and identify microbial pigments and other biomolecules in extant and extinct halophile biomass. Studies of bottom gypsum crusts from salterns, native evaporitic sediments, halite inclusions, and endoliths as well as cultures of halophilic microorganisms permitted to understand the content, distribution, and behavior of important molecular species. The first papers describing Raman spectroscopic detection of microbiological and geochemical key markers using portable instruments are highlighted as well. PMID:24339823

  14. Raman spectroscopy in halophile research

    PubMed Central

    Jehlička, Jan; Oren, Aharon

    2013-01-01

    Raman spectroscopy plays a major role in robust detection of biomolecules and mineral signatures in halophile research. An overview of Raman spectroscopic investigations in halophile research of the last decade is given here to show advantages of the approach, progress made as well as limits of the technique. Raman spectroscopy is an excellent tool to monitor and identify microbial pigments and other biomolecules in extant and extinct halophile biomass. Studies of bottom gypsum crusts from salterns, native evaporitic sediments, halite inclusions, and endoliths as well as cultures of halophilic microorganisms permitted to understand the content, distribution, and behavior of important molecular species. The first papers describing Raman spectroscopic detection of microbiological and geochemical key markers using portable instruments are highlighted as well. PMID:24339823

  15. Raman spectroscopy of shocked water

    SciTech Connect

    Holmes, N.C.; Mitchell, A.C.; Nellis, W.J.; Graham, W.B.; Walrafen, G.E.

    1983-07-01

    Raman scattering has been used extensively to study the vibrational and rotational properties of molecules under a variety of conditions. Here, interest is in the behavior of water molecules shocked to high pressures and temperatures. Behind the shock front the water molecules undergo changes in bonding and the molecules may become ionized. Raman spectroscopy can be used to determine the molecular species behind the shock front. In addition, changes in Raman spectra can yield information regarding inter- and intramolecular potentials and the temperature behind the shock front.

  16. Surface-enhanced Raman spectroscopy of creatinine in silver colloid

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Chen, Jiesi; Wu, Yanan; Chen, Yanping; Pan, Jianji; Lei, Jinping; Chen, Yongjian; Sun, Liqing; Feng, Shangyuan; Chen, Rong

    2011-11-01

    Surface enhanced Raman spectroscopy (SERS) technology has already made great progress in bio-molecule detection. It can make the target molecules strongly absorbed onto the surface of metal nanoparticles, and then the Raman signal of its own has been greatly enhanced through physical and chemical enhancement mechanisms. We report the SERS spectra of creatinine in silver colloid, and study the silver colloid enhanced effects on the Raman scattering of creatinine. We can also find that creatinine concentration is linearly related to its SERS peak intensity and the detection limit of creatinine silver sol is found to be 10 mg/dl. In conclusion, we can observe that the silver colloid has very good enhanced effects for the creatinine. The potential applications of SERS in quantitative measurement of the creatinine liquor are demonstrated. The result shows that the SERS approach would provide a unique and fast test method for creatinine detection.

  17. Surface-enhanced Raman spectroscopy of creatinine in silver colloid

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Chen, Jiesi; Wu, Yanan; Chen, Yanping; Pan, Jianji; Lei, Jinping; Chen, Yongjian; Sun, Liqing; Feng, Shangyuan; Chen, Rong

    2012-03-01

    Surface enhanced Raman spectroscopy (SERS) technology has already made great progress in bio-molecule detection. It can make the target molecules strongly absorbed onto the surface of metal nanoparticles, and then the Raman signal of its own has been greatly enhanced through physical and chemical enhancement mechanisms. We report the SERS spectra of creatinine in silver colloid, and study the silver colloid enhanced effects on the Raman scattering of creatinine. We can also find that creatinine concentration is linearly related to its SERS peak intensity and the detection limit of creatinine silver sol is found to be 10 mg/dl. In conclusion, we can observe that the silver colloid has very good enhanced effects for the creatinine. The potential applications of SERS in quantitative measurement of the creatinine liquor are demonstrated. The result shows that the SERS approach would provide a unique and fast test method for creatinine detection.

  18. Raman Spectroscopy of Microbial Pigments

    PubMed Central

    Edwards, Howell G. M.; Oren, Aharon

    2014-01-01

    Raman spectroscopy is a rapid nondestructive technique providing spectroscopic and structural information on both organic and inorganic molecular compounds. Extensive applications for the method in the characterization of pigments have been found. Due to the high sensitivity of Raman spectroscopy for the detection of chlorophylls, carotenoids, scytonemin, and a range of other pigments found in the microbial world, it is an excellent technique to monitor the presence of such pigments, both in pure cultures and in environmental samples. Miniaturized portable handheld instruments are available; these instruments can be used to detect pigments in microbiological samples of different types and origins under field conditions. PMID:24682303

  19. Asphaltene detection using surface enhanced Raman scattering (SERS).

    PubMed

    Alabi, O O; Edilbi, A N F; Brolly, C; Muirhead, D; Parnell, J; Stacey, R; Bowden, S A

    2015-04-28

    Surface enhanced Raman spectroscopy using a gold substrate and excitation at 514 nm can detect sub parts per million quantities of asphaltene and thereby petroleum. This simple format and sensitivity make it transformative for applications including sample triage, flow assurance, environmental protection and analysis of unique one of a kind materials. PMID:25812164

  20. Surface enhanced Raman spectroscopy of neurotransmitters

    NASA Astrophysics Data System (ADS)

    McGlashen, Michael L.; Davis, Kevin L.; Morris, Michael D.

    1989-10-01

    The surface-enhanced Raman spectra (SERS) of neurotransmitters in biological matrices and synthetic solutions are described. The effects of protein adsorption on cathecholamine SERS intensity are discussed. Techniques for obtaining dopamine SERS spectra in cerebrospinal fluid and rat brain dialysate are demonstrated. Preliminary SERS of histamine and tel-methylhistamine are presented.

  1. Surface-enhanced Raman spectroscopy applied to food safety.

    PubMed

    Craig, Ana Paula; Franca, Adriana S; Irudayaraj, Joseph

    2013-01-01

    Surface-enhanced Raman spectroscopy (SERS) is an advanced Raman technique that enhances the vibrational spectrum of molecules adsorbed on or in the vicinity of metal particles and/or surfaces. Because of its readiness, sensitivity, and minimum sample preparation requirements, SERS is being considered as a powerful technique for food inspection. Key aspects of food-safety assurance, spectroscopy methods, and SERS are briefly discussed in an extended introduction of this review. The recent and potential advances in SERS are highlighted in sections that deal with the (a) detection of food-borne pathogenic microorganisms and (b) the detection of food contaminants and adulteration, concentrated specifically on antibiotics, drugs, hormones, melamine, and pesticides. This review provides an outlook of the work done and a perspective on the future directions of SERS as a reliable tool for food-safety assessment. PMID:23297774

  2. Raman Spectroscopy of Amorphous Carbon

    SciTech Connect

    Tallant, D.R.; Friedmann, T.A.; Missert, N.A.; Siegal, M.P.; Sullivan, J.P.

    1998-01-01

    Amorphous carbon is an elemental form of carbon with low hydrogen content, which may be deposited in thin films by the impact of high energy carbon atoms or ions. It is structurally distinct from the more well-known elemental forms of carbon, diamond and graphite. It is distinct in physical and chemical properties from the material known as diamond-like carbon, a form which is also amorphous but which has a higher hydrogen content, typically near 40 atomic percent. Amorphous carbon also has distinctive Raman spectra, whose patterns depend, through resonance enhancement effects, not only on deposition conditions but also on the wavelength selected for Raman excitation. This paper provides an overview of the Raman spectroscopy of amorphous carbon and describes how Raman spectral patterns correlate to film deposition conditions, physical properties and molecular level structure.

  3. Raman gas sensing of modified Ag nanoparticle SERS

    NASA Astrophysics Data System (ADS)

    Myoung, NoSoung; Yoo, Hyung Keun; Hwang, In-Wook

    2014-03-01

    Recent progress in modified Surface Enhanced Raman Scattering (SERS) using Ag nanoparticles makes them promising optical technique for direct gas sensing of interest. However, SERS has been shown to provide sub ppb level detection of the compounds in the vapor phase. The major problem with the sensitivity scaling-up was in the development of fabrication technology for stability and reproducibility of SERS substrates. We report an optimization of 1-propanethiol coated multiple Ag nanoparticle layers on SiO2 substrate as well as new records of real-time, simultaneous vapor phase detection of toluene and 1-2 dichlorobenzene by the radiation of fiber optic coupled 785 nm diode laser and spectrograph. Multiple depositions of Ag NPs were loaded on SiO2 and soaked in 1-propanethiol solution for 24 hours to modify the surface into hydrophobic due to the characteristics of vapor phase of our interests. Raman bands at 1003 cm-1 and 1130 cm-1 for toluene and 12DCB, respectively were compared to 1089 cm-1 and each gas concentration in 1000 mL flask were calculated as a function of each vapor phase ratio. The saturation of toluene and 12DCB were limited only by 800 ppm and the detectable range was 0.6-800 ppm.

  4. Raman spectroscopy of illicit substances

    NASA Astrophysics Data System (ADS)

    Stokes, Robert J.; Faulds, Karen; Smith, W. Ewen

    2007-10-01

    Raman spectroscopy provides a very effective method of identifying an illicit substance in situ without separation or contact other than with a laser beam. The equipment required is steadily improving and is now reliable and simple to operate. Costs are also coming down and hand held portable spectrometers are proving very effective. The main limitations on the use of the technique are that it is insensitive in terms of the number of incident photons converted into Raman scattered photons and fluorescence produced in the sample by the incident radiation interferes. Newer methods, still largely in the development phase, will increase the potential for selected applications. The use of picosecond pulsed lasers can discriminate between fluorescence and Raman scattering and this has been used in the laboratory to examine street samples of illicit drugs. Surface-enhanced Raman scattering, in which the analyte requires to be adsorbed onto a roughened metal surface, creates a sensitivity to compete with fluorescence and quenches fluorescence for molecules on a surface. This provides the ability to detect trace amounts of substances in some cases. The improving optics, detection capability and the reliability of the new methods indicate that the potential for the use of Raman spectroscopy for security purposes will increase with time.

  5. Infrared, Polarized Raman, and SERS Spectra of Borax

    NASA Astrophysics Data System (ADS)

    Devi, S. Arya; Philip, Daizy; Aruldhas, G.

    1994-11-01

    Infrared and polarized Raman spectra of Na2B4O7 · 10H2O are recorded and analyzed. The vibrational assignments are made on the basis of vibrations due to BO4 and BO3 groups, water molecules, and (B)OH bonds. Three types of water molecules exist in the crystal, and the BO4 groups are considerably distorted. Band assignments are confirmed by deuterium substitution. A SERS spectrum recorded in a silver colloid shows three enhanced bands at 800, 480, and 464 cm-1.

  6. Surface enhanced Raman scattering (SERS) of silver ions embedded nanocomposite glass.

    PubMed

    Manikandan, Pitchamuthu; Manikandan, Durgachalam; Manikandan, Elayaperumal; Ferdinand, Arumainathan Christy

    2014-04-24

    Silver nanocomposites (Ag-NCs) glasses are formed by the ion exchange technique of dipping the host matrix in the molten metal salt bath. These ions exchanged glasses are then annealed at different temperatures in air for one hour. They exhibit striking linear and nonlinear optical properties with potential applications in the field of photonics materials. The optical absorption spectra of Ag ion exchanged and annealed glasses confirm the presence of the nano sized metal (Ag) cluster embedded inside the glass matrix. The size and morphology of the embedded silver nanoclusters are studied from their surface plasmon resonance (SPR) and surface enhanced Raman spectroscopy (SERS). Post Ag ion exchange made some structural changes in the soda lime glass which can be observed from Raman spectroscopy. It is observed that diffusion process lead to depolymerization of the glass network as it determined by analyzing the various peaks of SERS spectra. Significant enhancement in the Raman signal by these Ag-NCs, prove them as effective SERS substrates. PMID:24486788

  7. Surface-enhanced Raman spectroscopy of peptides

    NASA Astrophysics Data System (ADS)

    Garrell, Robin L.; Herne, Tonya M.; Ahern, Angela M.; Sullenberger, Eve L.

    1990-07-01

    Surface-enhanced Raman (SER) spectroscopy has been used to probe the adsorption, surface interactions, and orientations of peptides on metal surfaces. Amino acids in homodipeptides give SER spectra with unique features that can be used to characterize the surface interactions of specific functional groups in more complicated peptides. In heterodipeptides, there is a hierarchy of functional group-surface interactions that prescribe their orientation and conformation on metal surfaces. By establishing this hierarchy, it is now possible to predict the interactions that occur between larger peptides and surfaces. Furthermore, the observed trends suggest that it should be possible to control these interactions by varying the solution pH, the charge on the surface, and other parameters of the measurement in order to adsorb species selectively from mixtures of peptides in solution. Potential biomedical applications of this technique will be described.

  8. Application of SERS spectroscopy for detection of trace components in urinary deposits

    NASA Astrophysics Data System (ADS)

    Pucetaite, Milda; Velicka, Martynas; Tamosaityte, Sandra; Sablinskas, Valdas

    2014-03-01

    Surface-enhanced Raman scattering (SERS) spectroscopy can be a useful tool in regard to disease diagnosis and prevention. Advantage of SERS over conventional Raman spectroscopy is its significantly increased signal (up to factor of 106-108) which allows detection of trace amounts of substances in the sample. So far, this technique is successfully used for analysis of food, pieces of art and various biochemical/biomedical samples. In this work, we survey the possibility of applying SERS spectroscopy for detection of trace components in urinary deposits. Early discovery together with the identification of the exact chemical composition of urinary sediments could be crucial for taking appropriate preventive measures that inhibit kidney stone formation or growth processes. In this initial study, SERS spectra (excitation wavelength - 1064 nm) of main components of urinary deposits (calcium oxalate, uric acid, cystine, etc.) were recorded by using silver (Ag) colloid. Spectra of 10-3-10-5 M solutions were obtained. While no/small Raman signal was detected without the Ag colloid, characteristic peaks of the substances could be clearly separated in the SERS spectra. This suggests that even small amounts of the components could be detected and taken into account while determining the type of kidney stone forming in the urinary system. We found for the first time that trace amounts of components constituting urinary deposits could be detected by SERS spectroscopy. In the future study, the analysis of centrifuged urine samples will be carried out.

  9. Raman spectroscopy of bone metastasis

    NASA Astrophysics Data System (ADS)

    Esmonde-White, Karen A.; Sottnik, Joseph; Morris, Michael; Keller, Evan

    2012-02-01

    Raman spectroscopy of bone has been used to characterize chemical changes occurring in diseases such as osteoporosis, osteoarthritis and osteomyelitis. Metastasis of cancer into bone causes changes to bone quality that are similar to those observed in osteoporosis, such as decreased bone strength, but with an accelerated timeframe. In particular, osteolytic (bone degrading) lesions in bone metastasis have a marked effect on patient quality of life because of increased risk of fractures, pain, and hypercalcemia. We use Raman spectroscopy to examine bone from two different mouse models of osteolytic bone metastasis. Raman spectroscopy measures physicochemical information which cannot be obtained through standard biochemical and histological measurements. This study was reviewed and approved by the University of Michigan University Committee on the Care and Use of Animals. Two mouse models of prostate cancer bone metastasis, RM1 (n=3) and PC3-luc (n=4) were examined. Tibiae were injected with RM1 or PC3-luc cancer cells, while the contralateral tibiae received a placebo injection for use as controls. After 2 weeks of incubation, the mice were sacrificed and the tibiae were examined by Raman microspectroscopy (λ=785 nm). Spectroscopic markers corresponding to mineral stoichiometry, bone mineralization, and mineral crystallinity were compared in spectra from the cancerous and control tibiae. X-ray imaging of the tibia confirmed extensive osteolysis in the RM1 mice, with tumor invasion into adjoining soft tissue and moderate osteolysis in the PC3-luc mice. Raman spectroscopic markers indicate that osteolytic lesions are less mineralized than normal bone tissue, with an altered mineral stoichiometry and crystallinity.

  10. The many facets of Raman spectroscopy for biomedical analysis.

    PubMed

    Krafft, Christoph; Popp, Jürgen

    2015-01-01

    A critical review is presented on the use of linear and nonlinear Raman microspectroscopy in biomedical diagnostics of bacteria, cells, and tissues. This contribution is combined with an overview of the achievements of our research group. Linear Raman spectroscopy offers a wealth of chemical and molecular information. Its routine clinical application poses a challenge due to relatively weak signal intensities and confounding overlapping effects. Nonlinear variants of Raman spectroscopy such as coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) have been recognized as tools for rapid image acquisition. Imaging applications benefit from the fact that contrast is based on the chemical composition and molecular structures in a label-free and nondestructive manner. Although not label-free, surface enhanced Raman scattering (SERS) has also been recognized as a complementary biomedical tool to increase sensitivity. The current state of the art is evaluated, illustrative examples are given, future developments are pointed out, and important reviews and references from the current literature are selected. The topics are identification of bacteria and single cells, imaging of single cells, Raman activated cell sorting, diagnosis of tissue sections, fiber optic Raman spectroscopy, and progress in coherent Raman scattering in tissue diagnosis. The roles of networks-such as Raman4clinics and CLIRSPEC on a European level-and early adopters in the translation, dissemination, and validation of new methods are discussed. PMID:25428454

  11. Using Raman Spectroscopy and Surface-Enhanced Raman Scattering to Identify Colorants in Art: An Experiment for an Upper-Division Chemistry Laboratory

    ERIC Educational Resources Information Center

    Mayhew, Hannah E.; Frano, Kristen A.; Svoboda, Shelley A.; Wustholz, Kristin L.

    2015-01-01

    Surface-enhanced Raman scattering (SERS) studies of art represent an attractive way to introduce undergraduate students to concepts in nanoscience, vibrational spectroscopy, and instrumental analysis. Here, we present an undergraduate analytical or physical chemistry laboratory wherein a combination of normal Raman and SERS spectroscopy is used to…

  12. Profiling an electrospray plume using surface-enhanced Raman spectroscopy.

    PubMed

    Davis, Douglas; Portelius, Erik; Zhu, Yu; Feigerle, Charles; Cook, Kelsey D

    2005-12-15

    We report the use of silver nanoparticles to obtain surface-enhanced Raman spectra of Crystal Violet in an electrospray plume. Surface enhancement allowed detection at low concentrations with the high specificity afforded by vibrational spectroscopy. SERS spectra were used to obtain an axial concentration profile closely matching that obtained in previous fluorescence experiments. SERS can provide more analyte structural information than has been obtainable from fluorescence studies of the plume. PMID:16351168

  13. Surface-enhanced Raman spectroscopy of surfactants on silver electrodes

    SciTech Connect

    Sun, Soncheng; Birke, R.L.; Lombardi, J.R. )

    1990-03-08

    Surface-enhanced Raman spectroscopy (SERS) has been used to study different kinds of surfactants (cationic, anionic, and nonionic surfactants) adsorbed on a roughened Ag electrode. Spectral assignments are made for the SERS spectrum of cetylpyridinium chloride (CPC), and it is shown that the molecule is oriented with its pyridinium ring end-on at the electrode surface at potentials positive to the point of zero charge (pzc) on Ag.

  14. FT-Raman Spectroscopy: A Catalyst for the Raman Explosion?

    ERIC Educational Resources Information Center

    Chase, Bruce

    2007-01-01

    The limitations of Fourier transform (FT) Raman spectroscopy, which is used to detect and analyze the scattered radiation, are discussed. FT-Raman has served to revitalize a field that was lagging and the presence of Raman instrumentation as a routine analytical tool is established for the foreseeable future.

  15. Transcutaneous Raman Spectroscopy of Bone

    NASA Astrophysics Data System (ADS)

    Maher, Jason R.

    Clinical diagnoses of bone health and fracture risk typically rely upon measurements of bone density or structure, but the strength of a bone is also dependent upon its chemical composition. One technology that has been used extensively in ex vivo, exposed-bone studies to measure the chemical composition of bone is Raman spectroscopy. This spectroscopic technique provides chemical information about a sample by probing its molecular vibrations. In the case of bone tissue, Raman spectra provide chemical information about both the inorganic mineral and organic matrix components, which each contribute to bone strength. To explore the relationship between bone strength and chemical composition, our laboratory has contributed to ex vivo, exposed-bone animal studies of rheumatoid arthritis, glucocorticoid-induced osteoporosis, and prolonged lead exposure. All of these studies suggest that Raman-based predictions of biomechanical strength may be more accurate than those produced by the clinically-used parameter of bone mineral density. The utility of Raman spectroscopy in ex vivo, exposed-bone studies has inspired attempts to perform bone spectroscopy transcutaneously. Although the results are promising, further advancements are necessary to make non-invasive, in vivo measurements of bone that are of sufficient quality to generate accurate predictions of fracture risk. In order to separate the signals from bone and soft tissue that contribute to a transcutaneous measurement, we developed an overconstrained extraction algorithm that is based upon fitting with spectral libraries derived from separately-acquired measurements of the underlying tissue components. This approach allows for accurate spectral unmixing despite the fact that similar chemical components (e.g., type I collagen) are present in both soft tissue and bone and was applied to experimental data in order to transcutaneously detect, to our knowledge for the first time, age- and disease-related spectral

  16. Raman Spectroscopy of Ocular Tissue

    NASA Astrophysics Data System (ADS)

    Ermakov, Igor V.; Sharifzadeh, Mohsen; Gellermann, Warner

    The optically transparent nature of the human eye has motivated numerous Raman studies aimed at the non-invasive optical probing of ocular tissue components critical to healthy vision. Investigations include the qualitative and quantitative detection of tissue-specific molecular constituents, compositional changes occurring with development of ocular pathology, and the detection and tracking of ocular drugs and nutritional supplements. Motivated by a better understanding of the molecular mechanisms leading to cataract formation in the aging human lens, a great deal of work has centered on the Raman detection of proteins and water content in the lens. Several protein groups and the hydroxyl response are readily detectable. Changes of protein compositions can be studied in excised noncataractous tissue versus aged tissue preparations as well as in tissue samples with artificially induced cataracts. Most of these studies are carried out in vitro using suitable animal models and conventional Raman techniques. Tissue water content plays an important role in optimum light transmission of the outermost transparent ocular structure, the cornea. Using confocal Raman spectroscopy techniques, it has been possible to non-invasively measure the water to protein ratio as a measure of hydration status and to track drug-induced changes of the hydration levels in the rabbit cornea at various depths. The aqueous humor, normally supplying nutrients to cornea and lens, has an advantageous anterior location for Raman studies. Increasing efforts are pursued to non-invasively detect the presence of glucose and therapeutic concentrations of antibiotic drugs in this medium. In retinal tissue, Raman spectroscopy proves to be an important tool for research into the causes of macular degeneration, the leading cause of irreversible vision disorders and blindness in the elderly. It has been possible to detect the spectral features of advanced glycation and advanced lipooxydation end products in

  17. Raman and Photoluminescence Spectroscopy in Mineral Identification

    NASA Astrophysics Data System (ADS)

    Kuehn, J. W.

    2014-06-01

    Raman spectroscopy is particularly useful for rapid identification of minerals and gemstones. Raman spectrometers also allow PL studies for authentication of samples and geological provenance, diamond type screening and detection of HPHT treatments.

  18. SERS detection of indirect viral DNA capture using colloidal gold and methylene blue as a Raman label

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An indirect capture model assay using colloidal Au nanoparticles is demonstrated for surface enhanced Raman scattering (SERS) spectroscopy detection of DNA. The sequence targeted for capture is derived from the West Nile Virus (WNV) RNA genome and was selected on the basis of exhibiting minimal seco...

  19. Distinguishing Cancerous Liver Cells Using Surface-Enhanced Raman Spectroscopy.

    PubMed

    Huang, Jing; Liu, Shupeng; Chen, Zhenyi; Chen, Na; Pang, Fufei; Wang, Tingyun

    2016-02-01

    Raman spectroscopy has been widely used in biomedical research and clinical diagnostics. It possesses great potential for the analysis of biochemical processes in cell studies. In this article, the surface-enhanced Raman spectroscopy (SERS) of normal and cancerous liver cells incubated with SERS active substrates (gold nanoparticle) was measured using confocal Raman microspectroscopy technology. The chemical components of the cells were analyzed through statistical methods for the SERS spectrum. Both the relative intensity ratio and principal component analysis (PCA) were used for distinguishing the normal liver cells (QSG-7701) from the hepatoma cells (SMMC-7721). The relative intensity ratio of the Raman spectra peaks such as I937/I1209, I1276/I1308, I1342/I1375, and I1402/I1435 was set as the judge boundary, and the sensitivity and the specificity using PCA method were calculated. The results indicated that the surface-enhanced Raman spectrum could provide the chemical information for distinguishing the normal cells from the cancerous liver cells and demonstrated that SERS technology possessed the possible applied potential for the diagnosis of liver cancer. PMID:25432931

  20. Raman spectroscopies in shock-compressed materials

    SciTech Connect

    Schmidt, S.C.; Moore, D.S.; Shaner, J.W.

    1983-01-01

    Spontaneous Raman spectroscopy, stimulated Raman scattering and coherent anti-Stokes Raman scattering have been used to measure temperatures and changes in molecular vibrational frequencies for detonating and shocked materials. Inverse Raman and Raman induced Kerr effect spectroscopies have been suggested as diagnostic probes for determining and phenomenology of shock-induced chemical reactions. The practicality, advantages, and disadvantages of using Raman scattering techniques as diagnostic probes of microscopic phenomenology through and immediately behind the shock front of shock-compressed molecular systems are discussed.

  1. Imaging EGFR distribution using surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lucas, L.; Chen, X. K.; Smith, A.; Korbelik, M.; Zeng, H.; Lee, P. W. K.; Hewitt, K. C.

    2009-02-01

    The purpose of this study is to explore the feasibility of using Surface Enhanced Raman Spectroscopy (SERS) to image the distribution of Epidermal Growth Factor Receptor (EGFR) in cells. To accomplish this task, 30 nm gold nanoparticles (AuNPs) tagged with antibodies to EGFR (1012 per ml) are incubated with cells (106 per ml) of the A431 human epidermoid carcinoma cell line and normal human bronchial epithelial (NHBE) cells. Using the 632.8 nm excitation line of a He-Ne laser, Raman spectroscopy measurements are performed using a point mapping scheme. SERS signals are observed with an overall enhancement of 4-7 orders of magnitude. Raman intensity maps of the 1480 and 1583 cm-1 peaks correlate well with the expected distribution of AuNPs and EGFR. Normal cells show little to no enhancement. The results therefore present a simple yet effective means to image EGFR over-expression.

  2. Tailored micro-extraction method for Raman/SERS detection of indigoids in ancient textiles.

    PubMed

    Platania, Elena; Lofrumento, Cristiana; Lottini, Elisabetta; Azzaro, Elena; Ricci, Marilena; Becucci, Maurizio

    2015-08-01

    Indigoid dyes are well known as vat dyes. In their oxidized dichetonic form they are stable and insoluble in water, whereas in their reduced form, commonly known as leuco, they are soluble in water and able to be attached to fabric for dyeing purposes. These blue dyes are usually easily detectable in art objects by means of Raman spectroscopy by adopting for analyses a laser line at a high wavelength, such as a 785 nm diode laser. Unfortunately, in ancient artworks, that are often highly degraded, it is not always possible to collect high quality Raman spectra, which makes the analysis and identification of these compounds particularly challenging. In this work, we present a tailor-made methodology for the extraction and the recognition of indigoid dyes in works of art, which exploits the solubility of these compounds in their reduced form. Excellent Raman and surface enhanced Raman spectroscopy (SERS) spectra of indigo were acquired after micro-extraction on ancient and reference textiles, confirming the reliability of the presented procedure. Moreover, the methodology has been applied also for the extraction of the indigoid dye Tyrian purple on a reference textile, showing excellent results. This analytical method has been found to be extremely safe both for the reference textiles and the investigated ancient textiles, thus being a promising procedure for the selective analysis and detection of indigoid compounds in objects of artistic relevance. PMID:26082395

  3. Towards field malaria diagnosis using surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Keren; Xiong, Aoli; Yuen, Clement; Preiser, Peter; Liu, Quan

    2016-04-01

    We report three strategies of surface enhanced Raman spectroscopy (SERS) for β-hematin and hemozoin detection in malaria infected human blood, which can be potentially developed for field malaria diagnosis. In the first strategy, we used silver coated magnetic nanoparticles (Fe3O4@Ag) in combination with an external magnetic field to enhance the Raman signal of β-hematin. Then we developed two SERS methods without the requirement of magnetic field for malaria infection diagnosis. In Method 1, silver nanoparticles were synthesized separately and then mixed with lysed blood just like in traditional SERS measurements; while in Method 2, we developed an ultrasensitive SERS method by synthesizing silver nanoparticles directly inside the parasites of Plasmodium falciparum. Method 2 can be also used to detect single parasites in the ring stage.

  4. Nanotextured surfaces for surface enhanced Raman spectroscopy and sensors

    NASA Astrophysics Data System (ADS)

    Balčytis, Armandas; JuodkazytÄ--, Jurga; Seniutinas, Gediminas; Li, Xijun; Niaura, Gediminas; Juodkazis, Saulius

    2016-03-01

    Nanotextured surfaces which have surface features spanning 10-100 nm in length and height scales are among the most promising for surface enhanced Raman scattering/spectroscopy (SERS). Randomness of the feature sizes and surface morphology of such sensors brings an added benefit of spectrally broadband action and, consequently, augmented SERS intensity. Surfaces which are most promising for high sensitivity yet cost efficient for large scale production are overviewed with black CuO, which is made by chemical oxidation of Cu foil, as a representative example. Application potential and challenges to establishing quantitative SERS measurements are outlined.

  5. Polymer-coated surface enhanced Raman scattering (SERS) gold nanoparticles for multiplexed labeling of chronic lymphocytic leukemia cells

    NASA Astrophysics Data System (ADS)

    MacLaughlin, Christina M.; Parker, Edward P. K.; Walker, Gilbert C.; Wang, Chen

    2012-01-01

    The ease and flexibility of functionalization and inherent light scattering properties of plasmonic nanoparticles make them suitable contrast agents for measurement of cell surface markers. Immunophenotyping of lymphoproliferative disorders is traditionally undertaken using fluorescence detection methods which have a number of limitations. Herein, surface-enhanced Raman scattering (SERS) gold nanoparticles conjugated to monoclonal antibodies are used for the selective targeting of CD molecules on the surface of chronic lymphocytic leukemia (CLL) cells. Raman-active reporters were physisorbed on to the surface of 60 nm spherical Au nanoparticles, the particles were coated with 5kDa polyethylene glycol (PEG) including functionalities for conjugation to monoclonal IgG1 antibodies. A novel method for quantifying the number of antibodies bound to SERS probes on an individual basis as opposed to obtaining averages from solution was demonstrated using metal dots in transmission electron microscopy (TEM). The specificity of the interaction between SERS probes and surface CD molecules of CLL cells was assessed using Raman spectroscopy and dark field microscopy. An in-depth study of SERS probe targeting to B lymphocyte marker CD20 was undertaken, and proof-of-concept targeting using different SERS nanoparticle dyes specific for cell surface CD19, CD45 and CD5 demonstrated using SERS spectroscopy.

  6. SERS spectroscopy and multivariate analysis of globulin in human blood

    NASA Astrophysics Data System (ADS)

    Wang, J.; Zeng, Y. Y.; Lin, J. Q.; Lin, L.; Wang, X. C.; Chen, G. N.; Huang, Z. F.; Li, B. H.; Zeng, H. S.; Chen, R.

    2014-06-01

    Globulin plays a significant role in body processes, acts as an important marker for disease diagnosis and determines blood type. Moreover, recent reports about the strong association between cancer risk and blood type imply that further studying these relationships may yield new findings on the biological mechanisms of tumorigenesis. In this paper, we propose and evaluate the efficacy of surface-enhanced Raman scattering (SERS) for the determination of this important globulin derived from human blood. Comparing globulins from different blood types by utilizing SERS spectroscopy and multivariate analysis, we show that primary structures of globulins from different blood types are similar to each other, but subtle differences in structures which may be vital for determining blood type are still observed. The abilities of globulins from different blood types to approach silver surfaces seem to differ, which also indicates that there are structural differences in blood type related globulins. Furthermore, this method differentiates blood type A from type B, type A from type O, type B from type O, type AB from type A, type AB from type B, and type AB from type O with sensitivities and specificities as follows: (90.0%, 95.0%), (80.0%, 83.9%), (95.0%, 90.3%), (97.3%, 96.7%), (94.6%, 95.5%), (100%, 100%), suggesting a potential feasibility for use in blood type identification. Our method sheds new light on blood type analysis, paves the way for the study of relationships between cancer risk and blood types, and expands the flexibility of SERS for useful applications in the life sciences.

  7. Surface enhanced Raman spectroscopy on a flat graphene surface

    PubMed Central

    Xu, Weigao; Ling, Xi; Xiao, Jiaqi; Dresselhaus, Mildred S.; Kong, Jing; Xu, Hongxing; Liu, Zhongfan; Zhang, Jin

    2012-01-01

    Surface enhanced Raman spectroscopy (SERS) is an attractive analytical technique, which enables single-molecule sensitive detection and provides its special chemical fingerprints. During the past decades, researchers have made great efforts towards an ideal SERS substrate, mainly including pioneering works on the preparation of uniform metal nanostructure arrays by various nanoassembly and nanotailoring methods, which give better uniformity and reproducibility. Recently, nanoparticles coated with an inert shell were used to make the enhanced Raman signals cleaner. By depositing SERS-active metal nanoislands on an atomically flat graphene layer, here we designed a new kind of SERS substrate referred to as a graphene-mediated SERS (G-SERS) substrate. In the graphene/metal combined structure, the electromagnetic “hot” spots (which is the origin of a huge SERS enhancement) created by the gapped metal nanoislands through the localized surface plasmon resonance effect are supposed to pass through the monolayer graphene, resulting in an atomically flat hot surface for Raman enhancement. Signals from a G-SERS substrate were also demonstrated to have interesting advantages over normal SERS, in terms of cleaner vibrational information free from various metal-molecule interactions and being more stable against photo-induced damage, but with a comparable enhancement factor. Furthermore, we demonstrate the use of a freestanding, transparent and flexible “G-SERS tape” (consisting of a polymer-layer-supported monolayer graphene with sandwiched metal nanoislands) to enable direct, real time and reliable detection of trace amounts of analytes in various systems, which imparts high efficiency and universality of analyses with G-SERS substrates. PMID:22623525

  8. Surface-Enhanced Raman Spectroscopy for the Analysis of Works of Art: Milestones Reached and New Horizons

    NASA Astrophysics Data System (ADS)

    Casadio, F.; Pozzi, F.; Chang, L.; Kurouski, D.; Zaleski, S.; Van Duyne, R. P.; Shah, N. C.

    2014-06-01

    This work presents recent case studies drawn from the authors’ work in the area of Surface-Enhanced Raman Spectroscopy SERS for the identification of colorants in art including new developments in separation/SERS and Tip-Enhanced Raman spectroscopy (TERS).

  9. Vibrational fingerprinting of bacterial pathogens by surface enhanced Raman scattering (SERS)

    NASA Astrophysics Data System (ADS)

    Premasiri, W. Ranjith; Moir, D. T.; Ziegler, Lawrence D.

    2005-05-01

    The surface enhanced Raman scattering (SERS) spectra of vegetative whole-cell bacteria were obtained using in-situ grown gold nanoparticle cluster-covered silicon dioxide substrates excited at 785 nm. SERS spectra of Gram-negative bacteria; E. coli and S. typhimurium, and Gram-positive bacteria; B. subtilis, B. cereus, B. thuringeinsis and B. anthracis Sterne, have been observed. Raman enhancement factors of ~104-105 per cell are found for both Gram positive and Gram negative bacteria on this novel SERS substrate. The bacterial SERS spectra are species specific and exhibit greater species differentiation and reduced spectral congestion than their corresponding non-SERS (bulk) Raman spectra. Fluorescence observed in the 785 nm excited bulk Raman emission of Bacillus species is not apparent in the corresponding SERS spectra. The surface enhancement effect allows the observation of Raman spectra at the single cell level excited by low incident laser powers (< 3 mW) and short data acquisition times (~20 sec.). Comparison with previous SERS studies suggests that these SERS vibrational signatures are sensitively dependent on the specific morphology and nature of the SERS active substrate. Exposure to biological environments, such as human blood serum, has an observable effect on the bacterial SERS spectra. However, reproducible, species specific SERS vibrational fingerprints are still obtained. The potential of SERS for detection and identification of bacteria with species specificity on these gold nanoparticle coated substrates is demonstrated by these results.

  10. Raman spectroscopy of Bacillus thuringiensis physiology and inactivation

    NASA Astrophysics Data System (ADS)

    Morrow, J. B.; Almeida, J.; Cole, K. D.; Reipa, V.

    2012-12-01

    The ability to detect spore contamination and inactivation is relevant to developing and determining decontamination strategy success for food and water safety. This study was conducted to develop a systematic comparison of nondestructive vibrational spectroscopy techniques (Surface-Enhanced Raman Spectroscopy, SERS, and normal Raman) to determine indicators of Bacillus thuringiensis physiology (spore, vegetative, outgrown, germinated and inactivated spore forms). SERS was found to provide better resolution of commonly utilized signatures of spore physiology (dipicolinic acid at 1006 cm-1 and 1387 cm-1) compared to normal Raman and native fluorescence indigenous to vegetative and outgrown cell samples was quenched in SERS experiment. New features including carotenoid pigments (Raman features at 1142 cm-1, 1512 cm-1) were identified for spore cell forms. Pronounced changes in the low frequency region (300 cm-1 to 500 cm-1) in spore spectra occurred upon germination and inactivation (with both free chlorine and by autoclaving) which is relevant to guiding decontamination and detection strategies using Raman techniques.

  11. Multifunctional porous silicon nanopillar arrays: antireflection, superhydrophobicity, photoluminescence, and surface-enhanced Raman scattering (SERS)

    PubMed Central

    Kiraly, Brian; Yang, Shikuan

    2014-01-01

    We have fabricated porous silicon nanopillar arrays over large areas with a rapid, simple, and low-cost technique. The porous silicon nanopillars show unique longitudinal features along their entire length and have porosity with dimensions on the single-nanometer scale. Both Raman spectroscopy and photoluminescence data were used to determine the nanocrystallite size to be < 3 nm. The porous silicon nanopillar arrays also maintained excellent ensemble properties, reducing reflection nearly fivefold from planar silicon in the visible range without any optimization and approaching superhydrophobic behavior with increasing aspect ratio, demonstrating contact angles up to 138°. Finally, the porous silicon nanopillar arrays were made into sensitive surface enhanced Raman scattering (SERS) substrates by depositing metal onto the pillars. The SERS performance of the substrates was demonstrated using a chemical dye Rhodamine 6G. With their multitude of properties (i.e., antireflection, superhydrophobicity, photoluminescence, and sensitive SERS), the porous silicon nanopillar arrays described here can be valuable in applications such as solar harvesting, electrochemical cells, self-cleaning devices, and dynamic biological monitoring. PMID:23703091

  12. Raman Spectroscopy and Related Techniques in Biomedicine

    PubMed Central

    Downes, Andrew; Elfick, Alistair

    2010-01-01

    In this review we describe label-free optical spectroscopy techniques which are able to non-invasively measure the (bio)chemistry in biological systems. Raman spectroscopy uses visible or near-infrared light to measure a spectrum of vibrational bonds in seconds. Coherent anti-Stokes Raman (CARS) microscopy and stimulated Raman loss (SRL) microscopy are orders of magnitude more efficient than Raman spectroscopy, and are able to acquire high quality chemically-specific images in seconds. We discuss the benefits and limitations of all techniques, with particular emphasis on applications in biomedicine—both in vivo (using fiber endoscopes) and in vitro (in optical microscopes). PMID:21151763

  13. SERS, FT-Raman and FT-IR studies of dithiocarbamates

    NASA Astrophysics Data System (ADS)

    Mylrajan, M.

    1995-03-01

    Surface-enhanced Raman scattering (SERS) spectra of dimethyl and diehtyldithiocarbamate (DMDTC and DEDTC) ions were obtained with different wavelength excitations in citrate reduced silver sol and compared with FT-Raman and FT-IR spectra. The red wavelength excitation shows large enhancement compared to green excitation. SERS spectra were compared with normal Raman spectra in both solid and solution form and assignments were made.

  14. Surface enhanced Raman spectroscopy of L-alanyl-L-tryptophan dipeptide adsorbed on Si substrate decorated with triangular silver nanoplates

    NASA Astrophysics Data System (ADS)

    Ramanauskaite, Lina; Snitka, Valentinas

    2015-03-01

    Raman and surface enhanced Raman spectroscopies have been used to investigate interaction of L-alanyl-L-tryptophan (Ala-Trp) dipeptide with nanostructured silver surface. A highly sensitive surface enhanced Raman scattering (SERS)-based biosensor has been employed for label-free dipeptide detection and its orientation on the nanostructured surface. The synthesis of SERS substrate was based on direct silver ions reduction on hydrofluoric acid etched silicon wafer. Raman and SERS spectra of Ala-Trp were recorded in liquid to keep native environment for dipeptide. To the best of our knowledge, this work is a first attempt to analyze the structure of Ala-Trp dipeptide by Raman spectroscopy.

  15. Raman spectroscopy of transition metal dichalcogenides

    NASA Astrophysics Data System (ADS)

    Saito, R.; Tatsumi, Y.; Huang, S.; Ling, X.; Dresselhaus, M. S.

    2016-09-01

    Raman spectroscopy of transition metal dichalcogenides (TMDs) is reviewed based on our recent theoretical and experimental works. First, we discuss the semi-classical and quantum mechanical description for the polarization dependence of Raman spectra of TMDs in which the optical dipole transition matrix elements as a function of laser excitation energy are important for understanding the polarization dependence of the Raman intensity and Raman tensor. Overviewing the symmetry of TMDs, we discuss the dependence of the Raman spectra of TMDs on layer thickness, polarization, laser energy and the structural phase. Furthermore, we discuss the Raman spectra of twisted bilayer and heterostructures of TMDs. Finally, we give our perspectives on the Raman spectroscopy of TMDs.

  16. Raman spectroscopy of transition metal dichalcogenides.

    PubMed

    Saito, R; Tatsumi, Y; Huang, S; Ling, X; Dresselhaus, M S

    2016-09-01

    Raman spectroscopy of transition metal dichalcogenides (TMDs) is reviewed based on our recent theoretical and experimental works. First, we discuss the semi-classical and quantum mechanical description for the polarization dependence of Raman spectra of TMDs in which the optical dipole transition matrix elements as a function of laser excitation energy are important for understanding the polarization dependence of the Raman intensity and Raman tensor. Overviewing the symmetry of TMDs, we discuss the dependence of the Raman spectra of TMDs on layer thickness, polarization, laser energy and the structural phase. Furthermore, we discuss the Raman spectra of twisted bilayer and heterostructures of TMDs. Finally, we give our perspectives on the Raman spectroscopy of TMDs. PMID:27388703

  17. Electrochemical Tip-Enhanced Raman Spectroscopy.

    PubMed

    Zeng, Zhi-Cong; Huang, Sheng-Chao; Wu, De-Yin; Meng, Ling-Yan; Li, Mao-Hua; Huang, Teng-Xiang; Zhong, Jin-Hui; Wang, Xiang; Yang, Zhi-Lin; Ren, Bin

    2015-09-23

    Interfacial properties are highly important to the performance of some energy-related systems. The in-depth understanding of the interface requires highly sensitive in situ techniques that can provide fingerprint molecular information at nanometer resolution. We developed an electrochemical tip-enhanced Raman spectroscopy (EC-TERS) by introduction of the light horizontally to the EC-STM cell to minimize the optical distortion and to keep the TERS measurement under a well-controlled condition. We obtained potential-dependent EC-TERS from the adsorbed aromatic molecule on a Au(111) surface and observed a substantial change in the molecule configuration with potential as a result of the protonation and deprotonation of the molecule. Such a change was not observable in EC-SERS (surface-enhanced), indicating EC-TERS can more faithfully reflect the fine interfacial structure than EC-SERS. This work will open a new era for using EC-TERS as an important nanospectroscopy tool for the molecular level and nanoscale analysis of some important electrochemical systems including solar cells, lithium ion batteries, fuel cells, and corrosion. PMID:26351986

  18. Applications of Raman spectroscopy in life science

    NASA Astrophysics Data System (ADS)

    Martin, Airton A.; T. Soto, Cláudio A.; Ali, Syed M.; Neto, Lázaro P. M.; Canevari, Renata A.; Pereira, Liliane; Fávero, Priscila P.

    2015-06-01

    Raman spectroscopy has been applied to the analysis of biological samples for the last 12 years providing detection of changes occurring at the molecular level during the pathological transformation of the tissue. The potential use of this technology in cancer diagnosis has shown encouraging results for the in vivo, real-time and minimally invasive diagnosis. Confocal Raman technics has also been successfully applied in the analysis of skin aging process providing new insights in this field. In this paper it is presented the latest biomedical applications of Raman spectroscopy in our laboratory. It is shown that Raman spectroscopy (RS) has been used for biochemical and molecular characterization of thyroid tissue by micro-Raman spectroscopy and gene expression analysis. This study aimed to improve the discrimination between different thyroid pathologies by Raman analysis. A total of 35 thyroid tissues samples including normal tissue (n=10), goiter (n=10), papillary (n=10) and follicular carcinomas (n=5) were analyzed. The confocal Raman spectroscopy allowed a maximum discrimination of 91.1% between normal and tumor tissues, 84.8% between benign and malignant pathologies and 84.6% among carcinomas analyzed. It will be also report the application of in vivo confocal Raman spectroscopy as an important sensor for detecting advanced glycation products (AGEs) on human skin.

  19. FT-Raman, surface-enhanced Raman spectroscopy and theoretical investigations of diclofenac sodium

    NASA Astrophysics Data System (ADS)

    Iliescu, T.; Baia, M.; Kiefer, W.

    2004-03-01

    Raman and surface-enhanced Raman (SER) spectroscopies have been applied to the vibrational characterization of diclofenac sodium (DCF-Na). Theoretical calculations (DFT and ab initio) of two DCF-Na conformers have been performed to find the optimized structure and computed vibrational wavenumbers of the most stable one. SER spectra in silver colloid at different pH values have been also recorded and analyzed. Good SER spectra have been obtained in acidic and neutral environments, proving the chemisorption of the DCF-Na molecule on the silver surface. In the investigated pH range the carboxylate anion has been bonded to the silver surface through the lone pair oxygen electrons. The phenyl rings' orientation with respect to the silver surface changed on passing from acidic to neutral pH from a tilted close to flat to a more perpendicular one.

  20. Surface- and Tip-Enhanced Raman Spectroscopy in Catalysis.

    PubMed

    Hartman, Thomas; Wondergem, Caterina S; Kumar, Naresh; van den Berg, Albert; Weckhuysen, Bert M

    2016-04-21

    Surface- and tip-enhanced Raman spectroscopy (SERS and TERS) techniques exhibit highly localized chemical sensitivity, making them ideal for studying chemical reactions, including processes at catalytic surfaces. Catalyst structures, adsorbates, and reaction intermediates can be observed in low quantities at hot spots where electromagnetic fields are the strongest, providing ample opportunities to elucidate reaction mechanisms. Moreover, under ideal measurement conditions, it can even be used to trigger chemical reactions. However, factors such as substrate instability and insufficient signal enhancement still limit the applicability of SERS and TERS in the field of catalysis. By the use of sophisticated colloidal synthesis methods and advanced techniques, such as shell-isolated nanoparticle-enhanced Raman spectroscopy, these challenges could be overcome. PMID:27075515

  1. Surface- and Tip-Enhanced Raman Spectroscopy in Catalysis

    PubMed Central

    2016-01-01

    Surface- and tip-enhanced Raman spectroscopy (SERS and TERS) techniques exhibit highly localized chemical sensitivity, making them ideal for studying chemical reactions, including processes at catalytic surfaces. Catalyst structures, adsorbates, and reaction intermediates can be observed in low quantities at hot spots where electromagnetic fields are the strongest, providing ample opportunities to elucidate reaction mechanisms. Moreover, under ideal measurement conditions, it can even be used to trigger chemical reactions. However, factors such as substrate instability and insufficient signal enhancement still limit the applicability of SERS and TERS in the field of catalysis. By the use of sophisticated colloidal synthesis methods and advanced techniques, such as shell-isolated nanoparticle-enhanced Raman spectroscopy, these challenges could be overcome. PMID:27075515

  2. Raman and surface-enhanced Raman spectroscopy of amino acids and nucleotide bases for target bacterial vibrational mode identification

    NASA Astrophysics Data System (ADS)

    Guicheteau, Jason; Argue, Leanne; Hyre, Aaron; Jacobson, Michele; Christesen, Steven D.

    2006-05-01

    Raman and surface-enhanced Raman spectroscopy (SERS) studies of bacteria have reported a wide range of vibrational mode assignments associated with biological material. We present Raman and SER spectra of the amino acids phenylalanine, tyrosine, tryptophan, glutamine, cysteine, alanine, proline, methionine, asparagine, threonine, valine, glycine, serine, leucine, isoleucine, aspartic acid and glutamic acid and the nucleic acid bases adenosine, guanosine, thymidine, and uridine to better characterize biological vibrational mode assignments for bacterial target identification. We also report spectra of the bacteria Bacillus globigii, Pantoea agglomerans, and Yersinia rhodei along with band assignments determined from the reference spectra obtained.

  3. Raman Spectroscopy and instrumentation for monitoring soil carbon systems.

    SciTech Connect

    Stokes, D.L.

    2003-12-08

    This work describes developments in the application of Raman scattering and surface-enhanced Raman scattering (SERS) towards the assessment/characterization of carbon in soil. In the past, the nonspecific total carbon mass content of soil samples has generally been determined through mass loss techniques and elemental analysis. However, because of the concern over CO{sub 2} buildup in the atmosphere and its possible role in the ''Greenhouse Effect,'' there is a need for better-defined models of global cycling of carbon. As a means towards this end, there is a need to know more about the structure and functionality of organic materials in soil. Raman spectroscopy may therefore prove to be an exceptional tool in soil carbon analysis. Based on vibrational transitions of irradiated molecules, it provides structural information that is often suitable for sample identification. Furthermore, Raman scattering yields very fine spectral features which offer the potential for multicomponent sample analysis with minimal or no sample pretreatment. Although the intensity of Raman scattering is generally extremely low, the surface-enhanced Raman scattering (SERS) effect can greatly enhance Raman signals (10{sup 6}-10{sup 8} range) through the adsorption of compounds on specially roughened metal surfaces. In our laboratory, we have investigated copper, gold and silver as possible substrate metals in the fabrication of SERS substrates. These substrates have included metal-coated microparticles, metal island films, and redox-roughened metal foils. We have evaluated several laser excitation sources spanning the 515-785 nm range for both Raman and SERS analysis. For this particular study, we have selected fulvic and humic acids as models for establishing the feasibility of using Raman and SERS in soil carbon analysis. Our studies thus far have demonstrated that copper substrates perform best in the SERS detection of humic and fulvic acids, particularly when coupled to electrochemical

  4. Raman spectroscopy: the gateway into tomorrow's virology.

    PubMed

    Lambert, Phelps J; Whitman, Audy G; Dyson, Ossie F; Akula, Shaw M

    2006-01-01

    In the molecular world, researchers act as detectives working hard to unravel the mysteries surrounding cells. One of the researchers' greatest tools in this endeavor has been Raman spectroscopy. Raman spectroscopy is a spectroscopic technique that measures the unique Raman spectra for every type of biological molecule. As such, Raman spectroscopy has the potential to provide scientists with a library of spectra that can be used to unravel the makeup of an unknown molecule. However, this technique is limited in that it is not able to manipulate particular structures without disturbing their unique environment. Recently, a novel technology that combines Raman spectroscopy with optical tweezers, termed Raman tweezers, evades this problem due to its ability to manipulate a sample without physical contact. As such, Raman tweezers has the potential to become an incredibly effective diagnostic tool for differentially distinguishing tissue, and therefore holds great promise in the field of virology for distinguishing between various virally infected cells. This review provides an introduction for a virologist into the world of spectroscopy and explores many of the potential applications of Raman tweezers in virology. PMID:16805914

  5. Raman spectroscopy: the gateway into tomorrow's virology

    PubMed Central

    Lambert, Phelps J; Whitman, Audy G; Dyson, Ossie F; Akula, Shaw M

    2006-01-01

    In the molecular world, researchers act as detectives working hard to unravel the mysteries surrounding cells. One of the researchers' greatest tools in this endeavor has been Raman spectroscopy. Raman spectroscopy is a spectroscopic technique that measures the unique Raman spectra for every type of biological molecule. As such, Raman spectroscopy has the potential to provide scientists with a library of spectra that can be used to unravel the makeup of an unknown molecule. However, this technique is limited in that it is not able to manipulate particular structures without disturbing their unique environment. Recently, a novel technology that combines Raman spectroscopy with optical tweezers, termed Raman tweezers, evades this problem due to its ability to manipulate a sample without physical contact. As such, Raman tweezers has the potential to become an incredibly effective diagnostic tool for differentially distinguishing tissue, and therefore holds great promise in the field of virology for distinguishing between various virally infected cells. This review provides an introduction for a virologist into the world of spectroscopy and explores many of the potential applications of Raman tweezers in virology. PMID:16805914

  6. Study of virus by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Moor, K.; Kitamura, H.; Hashimoto, K.; Sawa, M.; Andriana, B. B.; Ohtani, K.; Yagura, T.; Sato, H.

    2013-02-01

    Problem of viruses is very actual for nowadays. Some viruses, which are responsible for human of all tumors, are about 15 %. Main purposes this study, early detection virus in live cell without labeling and in the real time by Raman spectroscopy. Micro Raman spectroscopy (mRs) is a technique that uses a Raman spectrometer to measure the spectra of microscopic samples. According to the Raman spectroscopy, it becomes possible to study the metabolites of a live cultured cell without labeling. We used mRs to detect the virus via HEK 293 cell line-infected adenovirus. We obtained raman specters of lives cells with viruses in 24 hours and 7 days after the infection. As the result, there is some biochemical changing after the treatment of cell with virus. One of biochemical alteration is at 1081 cm-1. For the clarification result, we use confocal fluorescent microscopy and transmission electron microscopy (TEM).

  7. From near-infrared and Raman to surface-enhanced Raman spectroscopy: progress, limitations and perspectives in bioanalysis.

    PubMed

    Dumont, Elodie; De Bleye, Charlotte; Sacré, Pierre-Yves; Netchacovitch, Lauranne; Hubert, Philippe; Ziemons, Eric

    2016-05-01

    Over recent decades, spreading environmental concern entailed the expansion of green chemistry analytical tools. Vibrational spectroscopy, belonging to this class of analytical tool, is particularly interesting taking into account its numerous advantages such as fast data acquisition and no sample preparation. In this context, near-infrared, Raman and mainly surface-enhanced Raman spectroscopy (SERS) have thus gained interest in many fields including bioanalysis. The two former techniques only ensure the analysis of concentrated compounds in simple matrices, whereas the emergence of SERS improved the performances of vibrational spectroscopy to very sensitive and selective analyses. Complex SERS substrates were also developed enabling biomarker measurements, paving the way for SERS immunoassays. Therefore, in this paper, the strengths and weaknesses of these techniques will be highlighted with a focus on recent progress. PMID:27079546

  8. Rapid chemical agent identification by surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lee, Yuan-Hsiang; Farquharson, Stuart

    2001-08-01

    Although the Chemical Weapons Convention prohibits the development, production, stockpiling, and use of chemical warfare agents (CWAs), the use of these agents persists due to their low cost, simplicity in manufacturing and ease of deployment. These attributes make these weapons especially attractive to low technology countries and terrorists. The military and the public at large require portable, fast, sensitive, and accurate analyzers to provide early warning of the use of chemical weapons. Traditional laboratory analyzers such as the combination of gas chromatography and mass spectroscopy, although sensitive and accurate, are large and require up to an hour per analysis. New, chemical specific analyzers, such as immunoassays and molecular recognition sensors, are portable, fast, and sensitive, but are plagued by false-positives (response to interferents). To overcome these limitations, we have been investigating the potential of surface-enhanced Raman spectroscopy (SERS) to identify and quantify chemical warfare agents in either the gas or liquid phase. The approach is based on the extreme sensitivity of SERS demonstrated by single molecule detection, a new SERS material that we have developed to allow reproducible and reversible measurements, and the molecular specific information provided by Raman spectroscopy. Here we present SER spectra of chemical agent simulants in both the liquid and gas phase, as well as CWA hydrolysis phase.

  9. Inverse Raman bands in ultrafast Raman loss spectroscopy

    NASA Astrophysics Data System (ADS)

    Qiu, Xueqiong; Li, Xiuting; Niu, Kai; Lee, Soo-Y.

    2011-10-01

    Ultrafast Raman loss spectroscopy (URLS) is equivalent to anti-Stokes femtosecond stimulated Raman spectroscopy (FSRS), using a broadband probe pulse that extends to the blue of the narrow bandwidth Raman pump, and can be described as inverse Raman scattering (IRS). Using the Feynman dual time-line diagram, the third-order polarization for IRS with finite pulses can be written down in terms of a four-time correlation function. An analytic expression is obtained for the latter in the harmonic approximation which facilitates computation. We simulated the URLS of crystal violet (CV) for various resonance Raman pump excitation wavelengths using the IRS polarization expression with finite pulses. The calculated results agreed well with the experimental results of S. Umapathy et al., J. Chem. Phys. 133, 024505 (2010). In the limit of monochromatic Raman pump and probe pulses, we obtain the third-order susceptibility for multi-modes, and for a single mode we recover the well-known expression for the third-order susceptibility, χ _{IRS}^{(3)}, for IRS. The latter is used to understand the mode dependent phase changes as a function of Raman pump excitation in the URLS of CV.

  10. Emerging Dental Applications of Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Choo-Smith, Lin-P'ing; Hewko, Mark; Sowa, Michael G.

    Until recently, the application of Raman spectroscopy to investigate dental tissues has primarily focused on using microspectroscopy to characterize dentin and enamel structures as well as to understand the adhesive interface of various resin and bonding agents used in restorative procedures. With the advent of improved laser, imaging/mapping and fibre optic technologies, the applications have expanded to investigate various biomedical problems ranging from oral cancer, bacterial identification and early dental caries detection. The overall aim of these applications is to develop Raman spectroscopy into a tool for use in the dental clinic. This chapter presents the recent dental applications of Raman spectroscopy as well as discusses the potential, strengths and limitations of the technology in comparison with alternative techniques. In addition, a discussion and rationale about combining Raman spectroscopy with other optical techniques will be included.

  11. Label-free direct surface-enhanced Raman scattering (SERS) of nucleic acids (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Guerrini, Luca; Morla-Folch, Judit; Gisbert-Quilis, Patricia; Xie, Hainan; Alvarez-Puebla, Ramon

    2016-03-01

    Recently, plasmonic-based biosensing has experienced an unprecedented level of attention, with a particular focus on the nucleic acid detection, offering efficient solutions to engineer simple, fast, highly sensitive sensing platforms while overcoming important limitations of PCR and microarray techniques. In the broad field of plasmonics, surface-enhanced Raman scattering (SERS) spectroscopy has arisen as a powerful analytical tool for detection and structural characterization of biomolecules. Today applications of SERS to nucleic acid analysis largely rely on indirect strategies, which have been demonstrated very effective for pure sensing purposes but completely dismiss the exquisite structural information provided by the direct acquisition of the biomolecular vibrational fingerprint. Contrarily, direct label-free SERS of nucleic acid shows an outstanding potential in terms of chemical-specific information which, however, remained largely unexpressed mainly because of the inherent poor spectral reproducibility and/or limited sensitivity. To address these limitations, we developed a fast and affordable high-throughput screening direct SERS method for gaining detailed genomic information on nucleic acids (DNA and RNA) and for the characterization and quantitative recognition of DNA interactions with exogenous agents. The simple strategy relies on the electrostatic adhesion of DNA/RNA onto positively-charged silver colloids that promotes the nanoparticle aggregation into stable clusters yielding intense and reproducible SERS spectra at picogram level (i.e. the analysis can be performed without the necessity of amplification steps thus providing realistic direct information of the nucleic acid in its native state). We anticipate this method to gain a vast impact and set of applications in different fields, including medical diagnostics, genomic screening, drug discovery, forensic science and even molecular electronics.

  12. FT-Raman and SERS spectra of rivanol in silver sol.

    PubMed

    Iliescu, T; Cinta, S; Kiefer, W

    2000-10-01

    FT-Raman of solid rivanol (2-ethoxy-6,9-diaminoacridinium lactate C(15)H(16)N(3)O-C(3)H(5)O(3) . H(2)O) and surface-enhanced Raman scattering (SERS) on silver surface of rivanol solution at pH 5.5 have been obtained and compared. The assignment of vibrational modes has been made for the monocation specie of rivanol. SERS spectrum shows a physisorption of rivanol on the silver surface. PMID:18968095

  13. Micro-mirror arrays for Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Duncan, W. M.

    2015-03-01

    In this research we study Raman and fluorescence spectroscopies as non-destructive and noninvasive methods for probing biological material and "living systems." Particularly for a living material any probe need be non-destructive and non-invasive, as well as provide real time measurement information and be cost effective to be generally useful. Over the past few years the components needed to measure weak and complex processes such as Raman scattering have evolved substantially with the ready availability of lasers, dichroic filters, low noise and sensitive detectors, digitizers and signal processors. A Raman spectrum consists of a wavelength or frequency spectrum that corresponds to the inelastic (Raman) photon signal that results from irradiating a "Raman active" material. Raman irradiation of a material usually and generally uses a single frequency laser. The Raman fingerprint spectrum that results from a Raman interaction can be determined from the frequencies scattered and received by an appropriate detector. Spectra are usually "digitized" and numerically matched to a reference sample or reference material spectra in performing an analysis. Fortunately today with the many "commercial off-the-shelf" components that are available, weak intensity effects such as Raman and fluorescence spectroscopy can be used for a number of analysis applications. One of the experimental limitations in Raman measurement is the spectrometer itself. The spectrometer is the section of the system that either by interference plus detection or by dispersion plus detection that "signal" amplitude versus energy/frequency signals are measured. Particularly in Raman spectroscopy, optical signals carrying desired "information" about the analyte are extraordinarily weak and require special considerations when measuring. We will discuss here the use of compact spectrometers and a micro-mirror array system (used is the digital micro-mirror device (DMD) supplied by the DLP® Products group of

  14. Nanogap structures: combining enhanced Raman spectroscopy and electronic transport.

    PubMed

    Natelson, Douglas; Li, Yajing; Herzog, Joseph B

    2013-04-21

    Surface-enhanced Raman spectroscopy (SERS) is an experimental tool for accessing vibrational and chemical information, down to the single molecule level. SERS typically relies on plasmon excitations in metal nanostructures to concentrate the incident radiation and to provide an enhanced photon density of states to couple emitted radiation to the far field. Many common SERS platforms involve metal nanoparticles to generate the required electromagnetic enhancements. Here we concentrate on an alternative approach, in which the relevant plasmon excitations are supported at a truly nanoscale gap between extended electrodes, rather than discrete subwavelength nanoparticles. The ability to fabricate precise gaps on demand, and in some cases to tune the gap size in situ, combined with the additional capability of simultaneous electronic transport measurements of the nanogap, provides access to information not previously available in standard SERS. We summarize the rich plasmonic physics at work in these extended systems and highlight the recent state of the art including tip-enhanced Raman spectroscopy (TERS) and the application of mechanical break junctions and electromigrated junctions. We describe in detail how we have performed in situ gap-enhanced Raman measurements of molecular-scale junctions while simultaneously subjecting these structures to electronic transport. These extended electrode structures allow us to study the pumping of vibrational modes by the flow of tunneling electrons, as well as the shifting of vibrational energies due to the applied bias. These experiments extend SERS into a tool for examining fundamental processes of dissipation, and provide insight into the mechanisms behind SERS spectral diffusion. We conclude with a brief discussion of future directions. PMID:23385304

  15. Occlusal caries detection using polarized Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Ionita, I.; Bulou, A.

    2008-02-01

    The tooth enamel, because of its hydroxyapatite composition, must present a Raman spectrum with strong polarization anisotropy. Carious lesions of the enamel will produce an alteration of local symmetry and will increase much more scattering of light. This will reduce the anisotropy of the Raman spectra. Because of the difference between high sensitivity to polarization of the 959 cm -1 Raman peak in sound enamel and low sensitivity in carried enamel, Raman polarized spectroscopy could be a useful method to early detect teeth caries.

  16. Practical substrate and apparatus for static and continuous monitoring by surface-enhanced raman spectroscopy

    DOEpatents

    Vo-Dinh, Tuan

    1987-01-01

    A substrate for use in surface-enhanced Raman spectroscopy (SERS) is disclosed, comprising a support, preferably flexible, coated with roughness-imparting microbodies and a metallized overcoating. Also disclosed is apparatus for using the aforesaid substrate in continuous and static SERS trace analyses, especially of organic compounds.

  17. Raman spectroscopy and polarization: Selected case studies

    NASA Astrophysics Data System (ADS)

    Ossikovski, Razvigor; Picardi, Gennaro; Ndong, Gérald; Chaigneau, Marc

    2012-10-01

    We show, through several selected case studies, the potential benefits that can be obtained by controlling the polarization states of the exciting and scattered radiations in a Raman scattering experiment. When coupled with polarization control, Raman spectroscopy is thus capable of providing extra information on the structural properties of the materials under investigation. The experimental examples presented in this work are taken from the area of both conventional, i.e., far-field, as well as from near-field Raman spectroscopy. They cover topics such as the stress tensor measurement in strained semiconductor structures, the vibration mode assignment in pentacene thin films and the Raman scattering tensor determination from near-field measurements on azobenzene monolayers. The basic theory necessary for modelling the far- and near-field polarized Raman responses is also given and the model efficiency is illustrated on the experimental data.

  18. Applications of Raman spectroscopy to gemology.

    PubMed

    Bersani, Danilo; Lottici, Pier Paolo

    2010-08-01

    Being nondestructive and requiring short measurement times, a low amount of material, and no sample preparation, Raman spectroscopy is used for routine investigation in the study of gemstone inclusions and treatments and for the characterization of mounted gems. In this work, a review of the use of laboratory Raman and micro-Raman spectrometers and of portable Raman systems in the gemology field is given, focusing on gem identification and on the evaluation of the composition, provenance, and genesis of gems. Many examples are shown of the use of Raman spectroscopy as a tool for the identification of imitations, synthetic gems, and enhancement treatments in natural gemstones. Some recent developments are described, with particular attention being given to the semiprecious stone jade and to two important organic materials used in jewelry, i.e., pearls and corals. PMID:20419294

  19. Transcutaneous Glucose Sensing by Surface-Enhanced Spatially Offset Raman Spectroscopy in a Rat Model

    PubMed Central

    Yuen, Jonathan M.; Shah, Nilam C.; Walsh, Joseph T.; Glucksberg, Matthew R.; Van Duyne, Richard P.

    2010-01-01

    This letter presents the first quantitative, in vivo, transcutaneous glucose measurements using surface enhanced Raman spectroscopy (SERS). Silver film over nanosphere (AgFON) surfaces were functionalized with a mixed self-assembled monolayer (SAM) and implanted subcutaneously in a Sprague-Dawley rat. The glucose concentration was monitored in the interstitial fluid. SER spectra were collected from the sensor chip through the skin using spatially offset Raman spectroscopy (SORS). The combination of SERS and SORS is a powerful new approach to the challenging problem of in vivo metabolite and drug sensing. PMID:20845919

  20. Flexible and Transparent Surface-Enhanced Raman Scattering (SERS)-Active Metafilm for Visualizing Trace Molecules via Raman Spectral Mapping.

    PubMed

    Liu, Xiangjiang; Wang, Jingjing; Wang, Jiajun; Tang, Longhua; Ying, Yibin

    2016-06-21

    Raman spectral mapping is a powerful tool for directly visualizing the composition, structure, and distribution of molecules on any surface of interest. However, one major limitation of Raman mapping is its overlong imaging time caused by the intrinsic weak Raman signal. Here, we developed a fast Raman imaging approach based on a flexible and transparent surface-enhanced Raman scattering (SERS)-active metafilm. This particular SERS substrate can be conformably attached to a sample surface to enhance the Raman signal of analytes and the good optical transparency allow excitation and collection of signal from the backside of the substrate. Therefore, by simply attaching it to the surface of interest, a fast Raman imaging can be realized. We noticed that the imaging speed can be increased by several orders of magnitude, compared to a conventional Raman mapping approach. Importantly, the proposed approach required little or no sample preparation and exhibited good generalizability that can be performed perfectly on different surfaces. It is believed that the proposed methodology will provide new trends for chemical imaging using Raman microscopy. PMID:27219332

  1. Stamping surface-enhanced Raman spectroscopy for label-free, multiplexed, molecular sensing and imaging

    NASA Astrophysics Data System (ADS)

    Li, Ming; Lu, Jing; Qi, Ji; Zhao, Fusheng; Zeng, Jianbo; Yu, Jorn Chi-Chung; Shih, Wei-Chuan

    2014-05-01

    We report stamping surface-enhanced Raman spectroscopy (S-SERS) for label-free, multiplexed, molecular sensing and large-area, high-resolution molecular imaging on a flexible, nonplasmonic surface without solution-phase molecule transfer. In this technique, a polydimethylsiloxane (PDMS) thin film and nanoporous gold disk SERS substrate play the roles as molecule carrier and Raman signal enhancer, respectively. After stamping the SERS substrate onto the PDMS film, SERS measurements can be directly taken from the "sandwiched" target molecules. The performance of S-SERS is evaluated by the detection of Rhodamine 6G, urea, and its mixture with acetaminophen, in a physiologically relevant concentration range, along with the corresponding SERS spectroscopic maps. S-SERS features simple sample preparation, low cost, and high reproducibility, which could lead to SERS-based sensing and imaging for point-of-care and forensics applications.

  2. Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

    SciTech Connect

    Meyer, Matthew W.

    2013-01-01

    This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include the inherently weak Raman cross section and susceptibility to fluorescence interference.

  3. Online fluorescence suppression in modulated Raman spectroscopy.

    PubMed

    De Luca, Anna Chiara; Mazilu, Michael; Riches, Andrew; Herrington, C Simon; Dholakia, Kishan

    2010-01-15

    Label-free chemical characterization of single cells is an important aim for biomedical research. Standard Raman spectroscopy provides intrinsic biochemical markers for noninvasive analysis of biological samples but is often hindered by the presence of fluorescence background. In this paper, we present an innovative modulated Raman spectroscopy technique to filter out the Raman spectra from the fluorescence background. The method is based on the principle that the fluorescence background does not change whereas the Raman scattering is shifted by the periodical modulation of the laser wavelength. Exploiting this physical property and importantly the multichannel lock-in detection of the Raman signal, the modulation technique fulfills the requirements of an effective fluorescence subtraction method. Indeed, once the synchronization and calibration procedure is performed, minimal user intervention is required, making the method online and less time-consuming than the other fluorescent suppression methods. We analyze the modulated Raman signal and shifted excitation Raman difference spectroscopy (SERDS) signal of 2 mum-sized polystyrene beads suspended in a solution of fluorescent dye as a function of modulation rate. We show that the signal-to-noise ratio of the modulated Raman spectra at the highest modulation rate is 3 times higher than the SERDS one. To finally evaluate the real benefits of the modulated Raman spectroscopy, we apply our technique to Chinese hamster ovary cells (CHO). Specifically, by analyzing separate spectra from the membrane, cytoplasm, and nucleus of CHO cells, we demonstrate the ability of this method to obtain localized sensitive chemical information from cells, away from the interfering fluorescence background. In particular, statistical analysis of the Raman data and classification using PCA (principal component analysis) indicate that our method allows us to distinguish between different cell locations with higher sensitivity and

  4. Difference Raman spectroscopy of DNA molecules

    NASA Astrophysics Data System (ADS)

    Anokhin, Andrey S.; Gorelik, Vladimir S.; Dovbeshko, Galina I.; Pyatyshev, Alexander Yu; Yuzyuk, Yury I.

    2015-01-01

    In this paper the micro-Raman spectra of calf DNA for different points of DNA sample have been recorded. The Raman spectra were made with help of difference Raman spectroscopy technique. Raman spectra were recorded with high spatial resolution from different points of the wet and dry samples in different spectral range (100÷4000cm-1) using two lasers: argon (514.5 nm) and helium -neon (632.8 nm). The significant differences in the Raman spectra for dry and wet DNA and for different points of DNA molecules were observed. The obtained data on difference Raman scattering spectra of DNA molecules may be used for identification of DNA types and for analysis of genetic information associated with the molecular structure of this molecule.

  5. Raman spectroscopy at the tritium laboratory Karlsruhe

    SciTech Connect

    Schloesser, M.; Bornschein, B.; Fischer, S.; Kassel, F.; Rupp, S.; Sturm, M.; James, T.M.; Telle, H.H.

    2015-03-15

    Raman spectroscopy is employed successfully for analysis of hydrogen isotopologues at the Tritium Laboratory Karlsruhe (TLK). Raman spectroscopy is based on the inelastic scattering of photons off molecules. Energy is transferred to the molecules as rotational/vibrational excitation being characteristic for each type of molecule. Thus, qualitative analysis is possible from the Raman shifted light, while quantitative information can be obtained from the signal intensities. After years of research and development, the technique is now well-advanced providing fast (< 10 s), precise (< 0.1%) and true (< 3%) compositional analysis of gas mixtures of hydrogen isotopologues. In this paper, we summarize the recent achievements in the further development on this technique, and the various applications for which it is used at TLK. Raman spectroscopy has evolved as a versatile, highly accurate key method for quantitative analysis complementing the port-folio of analytic techniques at the TLK.

  6. Mobile Raman spectroscopy in astrobiology research.

    PubMed

    Vandenabeele, Peter; Jehlička, Jan

    2014-12-13

    Raman spectroscopy has proved to be a very useful technique in astrobiology research. Especially, working with mobile instrumentation during fieldwork can provide useful experiences in this field. In this work, we provide an overview of some important aspects of this research and, apart from defining different types of mobile Raman spectrometers, we highlight different reasons for this research. These include gathering experience and testing of mobile instruments, the selection of target molecules and to develop optimal data processing techniques for the identification of the spectra. We also identify the analytical techniques that it would be most appropriate to combine with Raman spectroscopy to maximize the obtained information and the synergy that exists with Raman spectroscopy research in other research areas, such as archaeometry and forensics. PMID:25368355

  7. The biochemical origins of the surface-enhanced Raman spectra of bacteria: a metabolomics profiling by SERS.

    PubMed

    Premasiri, W Ranjith; Lee, Jean C; Sauer-Budge, Alexis; Théberge, Roger; Costello, Catherine E; Ziegler, Lawrence D

    2016-07-01

    The dominant molecular species contributing to the surface-enhanced Raman spectroscopy (SERS) spectra of bacteria excited at 785 nm are the metabolites of purine degradation: adenine, hypoxanthine, xanthine, guanine, uric acid, and adenosine monophosphate. These molecules result from the starvation response of the bacterial cells in pure water washes following enrichment from nutrient-rich environments. Vibrational shifts due to isotopic labeling, bacterial SERS spectral fitting, SERS and mass spectrometry analysis of bacterial supernatant, SERS spectra of defined bacterial mutants, and the enzymatic substrate dependence of SERS spectra are used to identify these molecular components. The absence or presence of different degradation/salvage enzymes in the known purine metabolism pathways of these organisms plays a central role in determining the bacterial specificity of these purine-base SERS signatures. These results provide the biochemical basis for the development of SERS as a rapid bacterial diagnostic and illustrate how SERS can be applied more generally for metabolic profiling as a probe of cellular activity. Graphical Abstract Bacterial typing by metabolites released under stress. PMID:27100230

  8. Using Raman spectroscopy to characterize biological materials.

    PubMed

    Butler, Holly J; Ashton, Lorna; Bird, Benjamin; Cinque, Gianfelice; Curtis, Kelly; Dorney, Jennifer; Esmonde-White, Karen; Fullwood, Nigel J; Gardner, Benjamin; Martin-Hirsch, Pierre L; Walsh, Michael J; McAinsh, Martin R; Stone, Nicholas; Martin, Francis L

    2016-04-01

    Raman spectroscopy can be used to measure the chemical composition of a sample, which can in turn be used to extract biological information. Many materials have characteristic Raman spectra, which means that Raman spectroscopy has proven to be an effective analytical approach in geology, semiconductor, materials and polymer science fields. The application of Raman spectroscopy and microscopy within biology is rapidly increasing because it can provide chemical and compositional information, but it does not typically suffer from interference from water molecules. Analysis does not conventionally require extensive sample preparation; biochemical and structural information can usually be obtained without labeling. In this protocol, we aim to standardize and bring together multiple experimental approaches from key leaders in the field for obtaining Raman spectra using a microspectrometer. As examples of the range of biological samples that can be analyzed, we provide instructions for acquiring Raman spectra, maps and images for fresh plant tissue, formalin-fixed and fresh frozen mammalian tissue, fixed cells and biofluids. We explore a robust approach for sample preparation, instrumentation, acquisition parameters and data processing. By using this approach, we expect that a typical Raman experiment can be performed by a nonspecialist user to generate high-quality data for biological materials analysis. PMID:26963630

  9. Raman spectroscopy of white wines.

    PubMed

    Martin, Coralie; Bruneel, Jean-Luc; Guyon, François; Médina, Bernard; Jourdes, Michael; Teissedre, Pierre-Louis; Guillaume, François

    2015-08-15

    The feasibility of exploiting Raman scattering to analyze white wines has been investigated using 3 different wavelengths of the incoming laser radiation in the near-UV (325 nm), visible (532 nm) and near infrared (785 nm). To help in the interpretation of the Raman spectra, the absorption properties in the UV-visible range of two wine samples as well as their laser induced fluorescence have also been investigated. Thanks to the strong intensity enhancement of the Raman scattered light due to electronic resonance with 325 nm laser excitation, hydroxycinnamic acids may be detected and analyzed selectively. Fructose and glucose may also be easily detected below ca. 1000 cm(-1). This feasibility study demonstrates the potential of the Raman spectroscopic technique for the analysis of white wines. PMID:25794745

  10. Emerging technology: applications of Raman spectroscopy for prostate cancer.

    PubMed

    Kast, Rachel E; Tucker, Stephanie C; Killian, Kevin; Trexler, Micaela; Honn, Kenneth V; Auner, Gregory W

    2014-09-01

    There is a need in prostate cancer diagnostics and research for a label-free imaging methodology that is nondestructive, rapid, objective, and uninfluenced by water. Raman spectroscopy provides a molecular signature, which can be scaled from micron-level regions of interest in cells to macroscopic areas of tissue. It can be used for applications ranging from in vivo or in vitro diagnostics to basic science laboratory testing. This work describes the fundamentals of Raman spectroscopy and complementary techniques including surface enhanced Raman scattering, resonance Raman spectroscopy, coherent anti-Stokes Raman spectroscopy, confocal Raman spectroscopy, stimulated Raman scattering, and spatially offset Raman spectroscopy. Clinical applications of Raman spectroscopy to prostate cancer will be discussed, including screening, biopsy, margin assessment, and monitoring of treatment efficacy. Laboratory applications including cell identification, culture monitoring, therapeutics development, and live imaging of cellular processes are discussed. Potential future avenues of research are described, with emphasis on multiplexing Raman spectroscopy with other modalities. PMID:24510129

  11. [Research Progress of Raman Spectroscopy on Dyestuff Identification of Ancient Relics and Artifacts].

    PubMed

    He, Qiu-ju; Wang, Li-qin

    2016-02-01

    As the birthplace of Silk Road, China has a long dyeing history. The valuable information about the production time, the source of dyeing material, dyeing process and preservation status were existed in organic dyestuff deriving from cultural relics and artifacts. However, because of the low contents, complex compositions and easily degraded of dyestuff, it is always a challenging task to identify the dyestuff in relics analyzing field. As a finger-print spectrum, Raman spectroscopy owns unique superiorities in dyestuff identification. Thus, the principle, characteristic, limitation, progress and development direction of micro-Raman spectroscopy (MRS/µ-Raman), near infrared reflection and Fourier transform Raman spectroscopy (NIR-FT-Raman), surface-enhanced Raman spectroscopy (SERS) and resonance raman spectroscopy (RRS) have been introduced in this paper. Furthermore, the features of Raman spectra of gardenia, curcumin and other natural dyestuffs were classified by MRS technology, and then the fluorescence phenomena of purpurin excitated with different wavelength laser was compared and analyzed. At last, gray green silver colloidal particles were made as the base, then the colorant of madder was identified combining with thin layer chromatography (TLC) separation technology and SERS, the result showed that the surface enhancement effect of silver colloidal particles could significantly reduce fluorescence background of the Raman spectra. It is pointed out that Raman spectroscopy is a rapid and convenient molecular structure qualitative methodology, which has broad application prospect in dyestuff analysis of cultural relics and artifacts. We propose that the combination of multi-Raman spectroscopy, separation technology and long distance transmission technology are the development trends of Raman spectroscopy. PMID:27209739

  12. DNA-based Nanoconstructs for the Detection of Ions and Biomolecules with Related Raman/SERS Signature Studies

    NASA Astrophysics Data System (ADS)

    Brenneman, Kimber L.

    The utilization of DNA aptamers and semiconductor quantum dots (QDs) for the detection of ions and biomolecules was investigated. In recent years, there have been many studies based on the use of DNA and RNA aptamers, which are single stranded oligonucleotides capable of binding to biomolecules, other molecules, and ions. In many of these cases, the conformational changes of these DNA and RNA aptamers are suitable to use fluorescence resonant energy transfer (FRET) or nanometal surface energy transfer (NSET) techniques to detect such analytes. Coupled with this growth in such uses of aptamers, there has been an expanded use of semiconductor quantum dots as brighter, longer-lasting alternatives to fluorescent dyes in labeling and detection techniques of interest in biomedicine and environmental monitoring. Thrombin binding aptamer (TBA) and a zinc aptamer were used to detect mercury, lead, zinc, and cadmium. These probes were tested in a liquid assay as well as on a filter paper coupon. Biomolecules were also studied and detected using surface-enhanced Raman spectroscopy (SERS), including DNA aptamers and C-reactive protein (CRP). Raman spectroscopy is a useful tool for sensor development, label-free detection, and has the potential for remote sensing. Raman spectra provide information on the vibrational modes or phonons, between and within molecules. Therefore, unique spectral fingerprints for single molecules can be obtained. SERS is accomplished through the use of substrates with nanometer scale geometries made of metals with many free electrons, such as silver, gold, or copper. In this research silver SERS substrates were used to study the SERS signature of biomolecules that typically produce very weak Raman signals.

  13. Raman and SERS microspectroscopy on living cells: a promising tool toward cellular drug response and medical diagnosis

    NASA Astrophysics Data System (ADS)

    Beljebbar, Abdelilah; Sockalingum, Ganesh D.; Morjani, Hamid; Manfait, Michel

    1999-04-01

    Raman spectroscopy has been sued to differentiate between sensitive and MDR-resistant cells using Raman spectral imaging with a 632.8 nm excitation wavelength. The comparison between two spectral images allowed to quantify the differences between sensitive and resistant cell lines in term of proteins, lipids when MDR phenotype is expressed. SER spectroscopy has become a powerful and non-invasive probe for investigating the molecular and cellular interaction of drugs with their targets. The comparison between these models allow to elucidate the biological effect of the drugs. The development of new types of SERS- active substrates has extended the applicability of this technique to medical diagnosis. Two kinds of SERS active substrates, characterized as 'bio-compatible' systems, can be used for investigation on single living cells: colloid suspensions and microelectrodes and island films. This methodology is used for the study of cell membrane components in interaction with the SERS substrates with the aim to understand the resistance mechanism. The constitution of a data bank will allow the follow-up of cancer and future monitoring of therapeutic intervention.

  14. Lipid-encapsulation of surface enhanced Raman scattering (SERS) nanoparticles and targeting to chronic lymphocytic leukemia (CLL) cells

    NASA Astrophysics Data System (ADS)

    Ip, Shell Y.; MacLaughlin, Christina M.; Mullaithilaga, Nisa; Joseph, Michelle; Wala, Samantha; Wang, Chen; Walker, Gilbert C.

    2012-01-01

    60 nm diameter gold nanoparticles (AuNP) were coated with a ternary mixture of lipids and targeted to human lymphocytes. Previously, the versatility, stability and ease of application of the lipid coating was demonstrated by the incorporation of three classes of Raman-active species. In the present study, lipid encapsulated AuNPs were conjugated to two targeting species, namely whole antibodies and antibody fragments (Fab), by two methods. Furthermore, in vitro targeting of lipid-encapsulated Au nanoparticles to patient-derived chronic lymphocytic leukemia (CLL) cells was demonstrated by Raman spectroscopy, Raman mapping, and darkfield microscopy. These results further demonstrate the versatility of the lipid layer for imparting stability, SERS activity, and targeting capability, which make these particles promising candidates for biodiagnostics.

  15. Multiplex coherent raman spectroscopy detector and method

    NASA Technical Reports Server (NTRS)

    Chen, Peter (Inventor); Joyner, Candace C. (Inventor); Patrick, Sheena T. (Inventor); Guyer, Dean R. (Inventor)

    2004-01-01

    A multiplex coherent Raman spectrometer (10) and spectroscopy method rapidly detects and identifies individual components of a chemical mixture separated by a separation technique, such as gas chromatography. The spectrometer (10) and method accurately identify a variety of compounds because they produce the entire gas phase vibrational Raman spectrum of the unknown gas. This is accomplished by tilting a Raman cell (20) to produce a high-intensity, backward-stimulated, coherent Raman beam of 683 nm, which drives a degenerate optical parametric oscillator (28) to produce a broadband beam of 1100-1700 nm covering a range of more than 3000 wavenumber. This broadband beam is combined with a narrowband beam of 532 nm having a bandwidth of 0.003 wavenumbers and focused into a heated windowless cell (38) that receives gases separated by a gas chromatograph (40). The Raman radiation scattered from these gases is filtered and sent to a monochromator (50) with multichannel detection.

  16. Multiplex coherent raman spectroscopy detector and method

    DOEpatents

    Chen, Peter; Joyner, Candace C.; Patrick, Sheena T.; Guyer, Dean R.

    2004-06-08

    A multiplex coherent Raman spectrometer (10) and spectroscopy method rapidly detects and identifies individual components of a chemical mixture separated by a separation technique, such as gas chromatography. The spectrometer (10) and method accurately identify a variety of compounds because they produce the entire gas phase vibrational Raman spectrum of the unknown gas. This is accomplished by tilting a Raman cell (20) to produce a high-intensity, backward-stimulated, coherent Raman beam of 683 nm, which drives a degenerate optical parametric oscillator (28) to produce a broadband beam of 1100-1700 nm covering a range of more than 3000 wavenumber. This broadband beam is combined with a narrowband beam of 532 nm having a bandwidth of 0.003 wavenumbers and focused into a heated windowless cell (38) that receives gases separated by a gas chromatograph (40). The Raman radiation scattered from these gases is filtered and sent to a monochromator (50) with multichannel detection.

  17. Identification of gemstone treatments with Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Kiefert, Lore; Haenni, Henry A.; Chalain, Jean-Pierre

    2000-09-01

    The newest gemstone treatment concerns brownish diamonds of type IIa. These can be improved to near colorless by an enhancement process developed by General Electric, USA, using high temperature and pressure. A comparison of Raman spectroscopic features in the visible area (luminescence bands) of both treated and untreated colorless diamonds is given. Finally, examples of artificially colored peals and corals and their detection with Raman spectroscopy are shown.

  18. Raman spectroscopy under extreme conditions

    SciTech Connect

    Goncharov, A F; Crowhurst, J C

    2004-11-05

    We report the results of Raman measurements of various materials under simultaneous conditions of high temperature and high pressure in the diamond anvil cell (DAC). High temperatures are generated by laser heating or internal resistive (ohmic) heating or a combination of both. We present Raman spectra of cubic boron nitride (cBN) to 40 GPa and up to 2300 K that show a continuous pressure and temperature shift of the frequency of the transverse optical mode. We have also obtained high-pressure Raman spectra from a new noble metal nitride, which we synthesized at approximately 50 GPa and 2000 K. We have obtained high-temperature spectra from pure nitrogen to 39 GPa and up to 2000 K, which show the presence of a hot band that has previously been observed in CARS measurements. These measurements have also allowed us to constrain the melting curve and to examine changes in the intramolecular potential with pressure.

  19. Analysis of lipsticks using Raman spectroscopy.

    PubMed

    Gardner, P; Bertino, M F; Weimer, R; Hazelrigg, E

    2013-10-10

    In this study, 80 lipsticks were obtained and evaluated using Raman spectroscopy at excitation wavelengths of 532 and 780 nm. Fluorescence severely limited analysis with the 532 nm line while the 780 nm line proved useful for all samples analyzed. It was possible to differentiate 95% of the lipsticks evaluated based on one or more Raman peaks. However, there were no peak trends observed that could be used to identify a manufacturer or categorize a sample. In situ analysis of lipstick smears was found to be possible even from several Raman active substrates, but was occasionally limited by background fluorescence and in extreme cases, photodegradation. PMID:24053867

  20. Genomic DNA characterization of pork spleen by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Guzmán-Embús, D. A.; Orrego Cardozo, M.; Vargas-Hernández, C.

    2013-11-01

    In this paper, the study of Raman signal enhancement due to interaction between ZnO rods and pork spleen DNA is reported. ZnO microstructures were synthesized by the Sol-Gel method and afterward combined with porcine spleen DNA extracted in the previous stages, following standardized cell lysis, deproteinization, and precipitation processes. Raman spectroscopy was used for the characterization of structures of ZnO and ZnO-DNA complex, and the results show the respective bands of ZnO wurtzite hexagonal phase for modes E2 (M), A1(TO), E2(High), E1(LO), and 2LO. Due to the SERS effect in the spectral range from 200 to 1800 cm,-1 Raman bands caused by vibrations of the deoxyribose C-O-C binding were also observed, producing deformation of the ring as shown in the 559 cm-1 peak. The broad band at 782 cm-1, together with the complex vibration of the string 5'-COPO-C3', is over a wide band of thymine (790 cm-1) or cytosine (780 cm-1). A prominent band near 1098 cm-1 assigned to symmetric stretching vibration phosphodioxy group (PO2-) DNA backbone is most favoured in intensity by the addition of ZnO particles originated by the SERS effect. This effect suggests a possible mechanism for enhancing the Raman signal due to the electromagnetic interaction between a DNA molecule and the flat surface of the ZnO rod.

  1. Raman and multichannel Raman spectroscopy of biological systems

    NASA Astrophysics Data System (ADS)

    Bertoluzza, Alessandro; Caramazza, R.; Fagnano, C.

    1991-05-01

    Raman and multichannel Raman spectroscopy are molecular techniques able to monitor the bulk and surface structure of a biomaterial, in a non destructive and non invasive way, giving therefore useful information on physical and chemical aspects of biocompatibility. The same techniques can also be adequately used for the characterization of the biomaterial-host tissue interface, hence providing structural information on the biochemical aspect of biocompatibility. Moreover, multichannel Raman spectroscopy can also determine "in vivo" and "in situ" the bulk and surface structure of a biomaterial and the molecular interactions between biomaterials and tissues. Useful information at a molecular level on the biomaterial-tissue system can so be deduced. In particular, the application of traditional Paman spectroscopy to bioactive glasses (glasses derived from Hench's bioglass and meta and oligophosphates of calcium by themselves and with the addition of sodium and aluminium) useful in orthopedics and the application to hydrophobic (PMMA) and hydrophilic (PHEMA and PVP) organic polymers useful in ophthalmology are shown. Instead the applications of multichannel Paman spectroscopy are elucidated in the case of intraocular lenses (lOLs) based on PMMA and contact lenses (CLs) based on hydrophi I ic polymers.

  2. Coherent Raman spectroscopy for supersonic flow measurments

    NASA Technical Reports Server (NTRS)

    She, C. Y.

    1986-01-01

    In collaboration with NASA/Langley Research Center, a truly nonintrusive and nonseeding method for measuring supersonic molecular flow parameters was proposed and developed at Colorado State University. The feasibility of this Raman Doppler Velocimetry (RDV), currently operated in a scanning mode, was demonstrated not only in a laboratory environment at Colorado State University, but also in a major wind tunnel at NASA/Langley Research Center. The research progress of the RDV development is summarized. In addition, methods of coherent Rayleigh-Brillouin spectroscopy and single-pulse coherent Raman spectroscopy are investigated, respectively, for measurements of high-pressure and turbulent flows.

  3. Au-coated ZnO nanostructures for surface enhanced Raman spectroscopy applications

    SciTech Connect

    Dikovska, A O; Nedyalkov, N N; Imamova, S E; Atanasova, G B; Atanasov, P A

    2012-03-31

    Thin ZnO nanostructured films were produced by pulsed laser deposition (PLD) for surface enhanced Raman spectroscopy (SERS) studies. The experimental conditions used for preparation of the samples were chosen to obtain different types of ZnO nanostructures. The Raman spectra of rhodamine 6G (R6G) were measured at an excitation wavelength of 785 nm after coating the ZnO nanostructures with a thin Au layer. The influence of the surface morphology on the Raman signal obtained from the samples was investigated. High SERS signal enhancement was observed from all Au-coated ZnO nanostructures.

  4. Spectroscopic characterization of biological agents using FTIR, normal Raman and surface-enhanced Raman spectroscopies

    NASA Astrophysics Data System (ADS)

    Luna-Pineda, Tatiana; Soto-Feliciano, Kristina; De La Cruz-Montoya, Edwin; Pacheco Londoño, Leonardo C.; Ríos-Velázquez, Carlos; Hernández-Rivera, Samuel P.

    2007-04-01

    FTIR, Raman spectroscopy and Surface Enhanced Raman Scattering (SERS) requires a minimum of sample allows fast identification of microorganisms. The use of this technique for characterizing the spectroscopic signatures of these agents and their stimulants has recently gained considerable attention due to the fact that these techniques can be easily adapted for standoff detection from considerable distances. The techniques also show high sensitivity and selectivity and offer near real time detection duty cycles. This research focuses in laying the grounds for the spectroscopic differentiation of Staphylococcus spp., Pseudomonas spp., Bacillus spp., Salmonella spp., Enterobacter aerogenes, Proteus mirabilis, Klebsiella pneumoniae, and E. coli, together with identification of their subspecies. In order to achieve the proponed objective, protocols to handle, cultivate and analyze the strains have been developed. Spectroscopic similarities and marked differences have been found for Spontaneous or Normal Raman spectra and for SERS using silver nanoparticles have been found. The use of principal component analysis (PCA), discriminate factor analysis (DFA) and a cluster analysis were used to evaluate the efficacy of identifying potential threat bacterial from their spectra collected on single bacteria. The DFA from the bacteria Raman spectra show a little discrimination between the diverse bacterial species however the results obtained from the SERS demonstrate to be high discrimination technique. The spectroscopic study will be extended to examine the spores produced by selected strains since these are more prone to be used as Biological Warfare Agents due to their increased mobility and possibility of airborne transport. Micro infrared spectroscopy as well as fiber coupled FTIR will also be used as possible sensors of target compounds.

  5. Theory of femtosecond stimulated Raman spectroscopy.

    PubMed

    Lee, Soo-Y; Zhang, Donghui; McCamant, David W; Kukura, Philipp; Mathies, Richard A

    2004-08-22

    Femtosecond broadband stimulated Raman spectroscopy (FSRS) is a new technique that produces high-resolution (time-resolved) vibrational spectra from either the ground or excited electronic states of molecules, free from background fluorescence. FSRS uses simultaneously a narrow bandwidth approximately 1-3 ps Raman pump pulse with a continuum approximately 30-50 fs Stokes probe pulse to produce sharp Raman gains, at positions corresponding to vibrational transitions in the sample, riding on top of the continuum Stokes probe spectrum. When FSRS is preceded by a femtosecond actinic pump pulse that initiates the photochemistry of interest, time-resolved Raman spectroscopy can be carried out. We present two theoretical approaches to FSRS: one is based on a coupling of Raman pump and probe light waves with the vibrations in the medium, and another is a quantum-mechanical description. The latter approach is used to discuss the conditions of applicability and limitations of the coupled-wave description. Extension of the quantum-mechanical description to the case where the Raman pump beam is on resonance with an excited electronic state, as well as when FSRS is used to probe a nonstationary vibrational wave packet prepared by an actinic pump pulse, is also discussed. PMID:15303930

  6. Surface-Enhanced Raman Spectroscopy Sensors From Nanobiosilica With Self-Assembled Plasmonic Nanoparticles

    PubMed Central

    Ren, Fanghui; Campbell, Jeremy; Rorrer, Gregory L.; Wang, Alan X.

    2014-01-01

    We present an innovative surface-enhanced Raman spectroscopy (SERS) sensor based on a biological-plasmonic hybrid nanostructure by self-assembling silver (Ag) nanoparticles into diatom frustules. The photonic-crystal-like diatom frustules provide a spatially confined electric field with enhanced intensity that can form hybrid photonic-plasmonic modes through the optical coupling with Ag nanoparticles. The experimental results demonstrate 4–6× and 9–12× improvement of sensitivities to detect the Raman dye for resonance and nonresonance SERS sensing, respectively. Such low-cost and high-sensitivity SERS sensors have significant potentials for label-free biosensing. PMID:25309113

  7. Temporal drift in Raman signal intensity during SERS measurements performed on analytes in liquid solutions.

    PubMed

    Setti, G O; Joanni, E; Poppi, R J; Dos Santos, D P; Jesus, D P de

    2016-08-15

    In this communication, we report one factor that could limit the quantitative analysis by SERS, which has not yet been discussed in the literature. Our results show that SERS experiments performed with the substrate immersed in liquid solutions are subjected to a temporal drift in the Raman signal intensity. Measurements were performed using gold nanoparticle suspensions and gold-covered nanostructured ITO surfaces as SERS substrates, immersed in analyte solutions of crystal violet and 4-mercaptobenzoic acid. Depending on the substrate and the conditions used for measurements, the Raman signal can take between 30 min and several hours to stabilize. This effect, if not taken into account, could have a negative impact on the results of the quantitative chemical analysis by SERS performed in situ in liquid solutions. PMID:27471752

  8. Porous Silicon Covered with Silver Nanoparticles as Surface-Enhanced Raman Scattering (SERS) Substrate for Ultra-Low Concentration Detection.

    PubMed

    Kosović, Marin; Balarin, Maja; Ivanda, Mile; Đerek, Vedran; Marciuš, Marijan; Ristić, Mira; Gamulin, Ozren

    2015-12-01

    Microporous and macro-mesoporous silicon templates for surface-enhanced Raman scattering (SERS) substrates were produced by anodization of low doped p-type silicon wafers. By immersion plating in AgNO3, the templates were covered with silver metallic film consisting of different silver nanostructures. Scanning electron microscopy (SEM) micrographs of these SERS substrates showed diverse morphology with significant difference in an average size and size distribution of silver nanoparticles. Ultraviolet-visible-near-infrared (UV-Vis-NIR) reflection spectroscopy showed plasmonic absorption at 398 and 469 nm, which is in accordance with the SEM findings. The activity of the SERS substrates was tested using rhodamine 6G (R6G) dye molecules and 514.5 nm laser excitation. Contrary to the microporous silicon template, the SERS substrate prepared from macro-mesoporous silicon template showed significantly broader size distribution of irregular silver nanoparticles as well as localized surface plasmon resonance closer to excitation laser wavelength. Such silver morphology has high SERS sensitivity that enables ultralow concentration detection of R6G dye molecules up to 10(-15) M. To our knowledge, this is the lowest concentration detected of R6G dye molecules on porous silicon-based SERS substrates, which might even indicate possible single molecule detection. PMID:26556231

  9. Disposable sheath that facilitates endoscopic Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, Wenbo; Short, Michael; Tai, Isabella T.; Zeng, Haishan

    2016-02-01

    In vivo endoscopic Raman spectroscopy of human tissue using a fiber optic probe has been previously demonstrated. However, there remain several technical challenges, such as a robust control over the laser radiation dose and measurement repeatability during endoscopy. A decrease in the signal to noise was also observed due to aging of Raman probe after repeated cycles of harsh reprocessing procedures. To address these issues, we designed and tested a disposable, biocompatible, and sterile sheath for use with a fiber optic endoscopic Raman probe. The sheath effectively controls contamination of Raman probes between procedures, greatly reduces turnaround time, and slows down the aging of the Raman probes. A small optical window fitted at the sheath cap maintained the measurement distance between Raman probe end and tissue surface. To ensure that the sheath caused a minimal amount of fluorescence and Raman interference, the optical properties of materials for the sheath, optical window, and bonding agent were studied. The easy-to-use sheath can be manufactured at a moderate cost. The sheath strictly enforced a maximum permissible exposure standard of the tissue by the laser and reduced the spectral variability by 1.5 to 8.5 times within the spectral measurement range.

  10. Applications of high resolution inverse Raman spectroscopy

    SciTech Connect

    Owyoung, A.; Esherick, P.

    1980-01-01

    The use of high-power, narrow-band lasers has significantly improved the resolving power and sensitivity of inverse Raman spectroscopy of gases. In this paper we shall describe this technique, illustrate its capabilities by showing some Q-branch spectra of heavy spherical tops, and survey some possible future applications.

  11. Raman Spectroscopy Cell-based Biosensors

    PubMed Central

    Notingher, Ioan

    2007-01-01

    One of the main challenges faced by biodetection systems is the ability to detect and identify a large range of toxins at low concentrations and in short times. Cell-based biosensors rely on detecting changes in cell behaviour, metabolism, or induction of cell death following exposure of live cells to toxic agents. Raman spectroscopy is a powerful technique for studying cellular biochemistry. Different toxic chemicals have different effects on living cells and induce different time-dependent biochemical changes related to cell death mechanisms. Cellular changes start with membrane receptor signalling leading to cytoplasmic shrinkage and nuclear fragmentation. The potential advantage of Raman spectroscopy cell-based systems is that they are not engineered to respond specifically to a single toxic agent but are free to react to many biologically active compounds. Raman spectroscopy biosensors can also provide additional information from the time-dependent changes of cellular biochemistry. Since no cell labelling or staining is required, the specific time dependent biochemical changes in the living cells can be used for the identification and quantification of the toxic agents. Thus, detection of biochemical changes of cells by Raman spectroscopy could overcome the limitations of other biosensor techniques, with respect to detection and discrimination of a large range of toxic agents. Further developments of this technique may also include integration of cellular microarrays for high throughput in vitro toxicological testing of pharmaceuticals and in situ monitoring of the growth of engineered tissues.

  12. Raman Spectroscopy of Bone and Cartilage

    NASA Astrophysics Data System (ADS)

    Morris, Michael

    This chapter will reviews the Raman spectroscopy of the subject tissues. After a brief introduction to the structure, biology, and function of these tissues, we will describe the spectra and band assignments of the tissues and then summarize applications to studies of tissue development, mechanical function and competence, and pathology. Both metabolic diseases and genetic disorders will be covered.

  13. Raman spectroscopy of shocked water

    SciTech Connect

    Holmes, N.C.; Nellis, W.J.; Graham, W.B.; Walrafen, G.E.

    1985-08-01

    We describe a new technique for recording spontaneous Raman spectra from molecules during the passage of strong shock waves. We have used this technique to study the OH-stretch band of liquid H/sub 2/O shocked to pressure up to 26 GPa and 1700 K. The shape of the band changes over the range 7.5-26 GPa, and is described well by a two-component mixture model, implying changes in the intermolecular coupling of shock compressed water molecules. We discuss the implications of the spectra on the mechanism responsible for the electrical conductivity of shocked H/sub 2/O. 22 refs., 7 figs., 2 tabs.

  14. Raman spectroscopy of saliva as a perspective method for periodontitis diagnostics Raman spectroscopy of saliva

    NASA Astrophysics Data System (ADS)

    Gonchukov, S.; Sukhinina, A.; Bakhmutov, D.; Minaeva, S.

    2012-01-01

    In view of its potential for biological tissues analyses at a molecular level, Raman spectroscopy in optical range has been the object of biomedical research for the last years. The main aim of this work is the development of Raman spectroscopy for organic content identifying and determination of biomarkers of saliva at a molecular level for periodontitis diagnostics. Four spectral regions were determined: 1155 and 1525 cm-1, 1033 and 1611 cm-1, which can be used as biomarkers of this widespread disease.

  15. Raman spectroscopy of Alzheimer's diseased tissue

    NASA Astrophysics Data System (ADS)

    Sudworth, Caroline D.; Krasner, Neville

    2004-07-01

    Alzheimer's disease is one of the most common forms of dementia, and causes steady memory loss and mental regression. It is also accompanied by severe atrophy of the brain. However, the pathological biomarkers of the disease can only be confirmed and examined upon the death of the patient. A commercial (Renishaw PLC, UK) Raman system with an 830 nm NIR diode laser was used to analyse brain samples, which were flash frozen at post-mortem. Ethical approval was sought for these samples. The Alzheimer's diseased samples contained a number of biomarkers, including neuritic plaques and tangles. The Raman spectra were examined by order to differentiate between normal and Alzheimer's diseased brain tissues. Preliminary results indicate that Alzheimer's diseased tissues can be differentiated from control tissues using Raman spectroscopy. The Raman spectra differ in terms of peak intensity, and the presence of a stronger amide I band in the 1667 cm-1 region which occurs more prominently in the Alzheimer's diseased tissue. These preliminary results indicate that the beta-amyloid protein originating from neuritic plaques can be identified with Raman spectroscopy.

  16. Autoenhanced Raman Spectroscopy via Plasmonic Trapping for Molecular Sensing.

    PubMed

    Hong, Soonwoo; Shim, On; Kwon, Hyosung; Choi, Yeonho

    2016-08-01

    As a label-free and sensitive biosensor, surface-enhanced Raman spectroscopy (SERS) is a rapidly emerging technique. However, because SERS spectra are obtained in the area of light excitation and the enhancement effect can be varied depending on the position of a substrate, it is important to match the enhanced area with an illuminated spot. Here, in order to overcome such difficulty, we demonstrated a new technique combining SERS with plasmonic trapping. By plasmonic trapping, we can collect gold nanoparticles (GNPs) in the middle of initially fabricated nanobowtie structures where a laser is excited. As a result of trapping GNPs, hot-spots are formed at that area. Because SERS is measured in the area irradiated by a laser, hot-spot can be simultaneously coincided with a detection site for SERS. By using this, we detected Rhodamine 6G to 100 pM. To further verify and improve the reproducibility of our technique, we also calculated the electric field distribution, trapping force and trapping potential. PMID:27396542

  17. Raman spectroscopy of 'Bisphenol A'

    NASA Astrophysics Data System (ADS)

    Ullah, Ramzan; Zheng, Yuxiang

    2016-03-01

    Raman spectra (95 - 3000 cm-1) of 'Bisphenol A' are presented. Absorption peaks have been assigned by Density Functional Theory (DFT) with B3LYP 6 - 311 ++ G (3df, 3pd) and wB97XD 6 - 311 ++ G (3df, 3pd). B3LYP 6 - 311 ++ G (3df, 3pd) gives frequencies which are nearer to experimental frequencies than wB97XD 6 - 311 ++ G (3df, 3pd) which involves empirical dispersion. Scale factor for wB97XD 6 - 311 ++ G (3df, 3pd) is found out to be 0.95008 by least squares fit.

  18. Raman spectroscopy in head and neck cancer

    PubMed Central

    2010-01-01

    In recent years there has been much interest in the use of optical diagnostics in cancer detection. Early diagnosis of cancer affords early intervention and greatest chance of cure. Raman spectroscopy is based on the interaction of photons with the target material producing a highly detailed biochemical 'fingerprint' of the sample. It can be appreciated that such a sensitive biochemical detection system could confer diagnostic benefit in a clinical setting. Raman has been used successfully in key health areas such as cardiovascular diseases, and dental care but there is a paucity of literature on Raman spectroscopy in Head and Neck cancer. Following the introduction of health care targets for cancer, and with an ever-aging population the need for rapid cancer detection has never been greater. Raman spectroscopy could confer great patient benefit with early, rapid and accurate diagnosis. This technique is almost labour free without the need for sample preparation. It could reduce the need for whole pathological specimen examination, in theatre it could help to determine margin status, and finally peripheral blood diagnosis may be an achievable target. PMID:20923567

  19. Stable silver/biopolymer hybrid plasmonic nanostructures for high performance surface enhanced raman scattering (SERS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Silver/biopolymer nanoparticles were prepared by adding 100 mg silver nitrate to 2% polyvinyl alcohol solution and reduced the silver nitrate into silver ion using 2 % trisodium citrate for high performance Surface Enhanced Raman Scattering (SERS) substrates. Optical properties of nanoparticle were ...

  20. Towards ultrasensitive malaria diagnosis using surface enhanced Raman spectroscopy

    PubMed Central

    Chen, Keren; Yuen, Clement; Aniweh, Yaw; Preiser, Peter; Liu, Quan

    2016-01-01

    We report two methods of surface enhanced Raman spectroscopy (SERS) for hemozoin detection in malaria infected human blood. In the first method, silver nanoparticles were synthesized separately and then mixed with lysed blood; while in the second method, silver nanoparticles were synthesized directly inside the parasites of Plasmodium falciparum. It was observed that the first method yields a smaller variation in SERS measurements and stronger correlation between the estimated contribution of hemozoin and the parasitemia level, which is preferred for the quantification of the parasitemia level. In contrast, the second method yields a higher sensitivity to a low parasitemia level thus could be more effective in the early malaria diagnosis to determine whether a given blood sample is positive. PMID:26858127

  1. Towards ultrasensitive malaria diagnosis using surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Keren; Yuen, Clement; Aniweh, Yaw; Preiser, Peter; Liu, Quan

    2016-02-01

    We report two methods of surface enhanced Raman spectroscopy (SERS) for hemozoin detection in malaria infected human blood. In the first method, silver nanoparticles were synthesized separately and then mixed with lysed blood; while in the second method, silver nanoparticles were synthesized directly inside the parasites of Plasmodium falciparum. It was observed that the first method yields a smaller variation in SERS measurements and stronger correlation between the estimated contribution of hemozoin and the parasitemia level, which is preferred for the quantification of the parasitemia level. In contrast, the second method yields a higher sensitivity to a low parasitemia level thus could be more effective in the early malaria diagnosis to determine whether a given blood sample is positive.

  2. Raman Spectroscopy of Soft Musculoskeletal Tissues

    PubMed Central

    Esmonde-White, Karen

    2015-01-01

    Tendon, ligament, and joint tissues are important in maintaining daily function. They can be affected by disease, age, and injury. Slow tissue turnover, hierarchical structure and function, and nonlinear mechanical properties present challenges to diagnosing and treating soft musculoskeletal tissues. Understanding these tissues in health, disease, and injury is important to improving pharmacologic and surgical repair outcomes. Raman spectroscopy is an important tool in the examination of soft musculoskeletal tissues. This article highlights exciting basic science and clinical/translational Raman studies of cartilage, tendon, and ligament. PMID:25286106

  3. Candida parapsilosis Biofilm Identification by Raman Spectroscopy

    PubMed Central

    Samek, Ota; Mlynariková, Katarina; Bernatová, Silvie; Ježek, Jan; Krzyžánek, Vladislav; Šiler, Martin; Zemánek, Pavel; Růžička, Filip; Holá, Veronika; Mahelová, Martina

    2014-01-01

    Colonies of Candida parapsilosis on culture plates were probed directly in situ using Raman spectroscopy for rapid identification of specific strains separated by a given time intervals (up to months apart). To classify the Raman spectra, data analysis was performed using the approach of principal component analysis (PCA). The analysis of the data sets generated during the scans of individual colonies reveals that despite the inhomogeneity of the biological samples unambiguous associations to individual strains (two biofilm-positive and two biofilm-negative) could be made. PMID:25535081

  4. Candida parapsilosis biofilm identification by Raman spectroscopy.

    PubMed

    Samek, Ota; Mlynariková, Katarina; Bernatová, Silvie; Ježek, Jan; Krzyžánek, Vladislav; Šiler, Martin; Zemánek, Pavel; Růžička, Filip; Holá, Veronika; Mahelová, Martina

    2014-01-01

    Colonies of Candida parapsilosis on culture plates were probed directly in situ using Raman spectroscopy for rapid identification of specific strains separated by a given time intervals (up to months apart). To classify the Raman spectra, data analysis was performed using the approach of principal component analysis (PCA). The analysis of the data sets generated during the scans of individual colonies reveals that despite the inhomogeneity of the biological samples unambiguous associations to individual strains (two biofilm-positive and two biofilm-negative) could be made. PMID:25535081

  5. Raman spectroscopy of triolein under high pressures

    NASA Astrophysics Data System (ADS)

    Tefelski, D. B.; Jastrzębski, C.; Wierzbicki, M.; Siegoczyński, R. M.; Rostocki, A. J.; Wieja, K.; Kościesza, R.

    2010-03-01

    This article presents results of the high pressure Raman spectroscopy of triolein. Triolein, a triacylglyceride (TAG) of oleic acid, is an unsaturated fat, present in natural oils such as olive oil. As a basic food component and an energy storage molecule, it has considerable importance for food and fuel industries. To generate pressure in the experiment, we used a high-pressure cylindrical chamber with sapphire windows, presented in (R.M. Siegoczyński, R. Kościesza, D.B. Tefelski, and A. Kos, Molecular collapse - modification of the liquid structure induced by pressure in oleic acid, High Press. Res. 29 (2009), pp. 61-66). Pressure up to 750 MPa was applied. A Raman spectrometer in "macro"-configuration was employed. Raman spectroscopy provides information on changes of vibrational modes related to structural changes of triolein under pressure. Interesting changes in the triglyceride C‒H stretching region at 2650-3100 cm-1 were observed under high-pressures. Changes were also observed in the ester carbonyl (C˭ O) stretching region 1700-1780 cm-1 and the C‒C stretching region at 1050-1150 cm-1. The overall luminescence of the sample decreased under pressure, making it possible to set longer spectrum acquisition time and obtain more details of the spectrum. The registered changes suggest that the high-pressure solid phase of triolein is organized as β-polymorphic, as was reported in (C. Akita, T. Kawaguchi, and F. Kaneko, Structural study on polymorphism of cis-unsaturated triacylglycerol: Triolein, J. Phys. Chem. B 110 (2006), pp. 4346-4353; E. Da Silva and D. Rousseau, Molecular order and thermodynamics of the solid-liquid transition in triglycerides via Raman spectroscopy, Phys. Chem. Chem. Phys. 10 (2008), pp. 4606-4613) (with temperature-induced phase transitions). The research has shown that Raman spectroscopy in TAGs under pressure reveals useful information about its structural changes.

  6. Electronic Resonance Enhancement in Raman and CARS Spectroscopy: Surface Enhanced Scattering of Highly Fluorescent Molecules

    NASA Astrophysics Data System (ADS)

    Lawhead, Carlos; Ujj, Laszlo

    2015-03-01

    Surface enhanced Raman spectroscopy (SERS) is an extremely useful tool in increasing sensitivity of Raman spectroscopy; this technique significantly increases the signal from vibrational resonances which can overcome background fluoresces. Silver nanoparticles coated substrates and the silver nanoparticles in solution were used on a variety of fluorescent molecules in order to overcome sample complexities and measure the vibrational spectra. The possible enhancement of SERS using a coherent Raman (CARS) method was investigated, but enhancement factors due to Surface Enhanced CARS have yet to be verified. The instrument used was developed in the University of West Florida Physics Department utilized the second harmonic of a Nd:YAG laser to provide the excitation wavelength at 532 nm and is capable of both transmission and reflection Raman measurements. Special thanks to the UWF Office of Undergraduate Research.

  7. Femtosecond laser induced nanostructuring for surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Messaoudi, H.; Das, S. K.; Lange, J.; Heinrich, F.; Schrader, S.; Frohme, M.; Grunwald, R.

    2014-03-01

    The formation of periodical nanostructures with femtosecond laser pulses was used to create highly efficient substrates for surface-enhanced Raman spectroscopy (SERS). We report about the structuring of silver and copper substrates and their application to the SERS of DNA (herring sperm) and protein molecules (egg albumen). The maximum enhancement factors were found on Ag substrates processed with the second harmonic generation (SHG) of a 1-kHz Ti:sapphire laser and structure periods near the SHG wavelength. In the case of copper, however, the highest enhancement was obtained with long-period ripples induced with at fundamental wavelength. This is explained by an additional significant influence of nanoparticles on the surface. Nanostructured areas in the range of 1.25 mm2 were obtained in 10 s. The surfaces were characterized by scanning electron microscopy, Fast Fourier Transform and Raman spectroscopy. Moreover, the role of the chemical modification of the metal structures is addressed. Thin oxide layers resulting from working in atmosphere which improve the biocompatibility were indicated by vibration spectra. It is expected that the detailed study of the mechanisms of laser-induced nanostructure formation will stimulate further applications of functionalized surfaces like photocatalysis, selective chemistry and nano-biology.

  8. Calculating average surface enhancement factors of randomly nanostructured electrodes by a combination of SERS and impedance spectroscopy.

    PubMed

    Kozuch, J; Petrusch, N; Gkogkou, D; Gernert, U; Weidinger, I M

    2015-09-01

    Polyhedron Ag nanostructures were created on top of a polished Au electrode via step-wise electrodeposition and tested as substrates for SERS spectroscopy. Average Raman enhancement factors were derived by combining SERS measurements with electrochemical impedance spectroscopy (EIS), which is able to determine the electroactive surface area of a randomly nanostructured surface. Depending on the deposition step an alternating increase and decrease of surface area was observed while the SERS intensity showed a clear maximum for the first deposition cycle. SEM pictures reveal the formation of Ag polyhedrons that are randomly dispersed on the Au surface. Furthermore the presence of a sub nanostructure on top of the polyhedron after the first deposition cycle is observed which becomes smoother after subsequent deposition cycles. Correlating the SEM pictures with SERS and EIS measurements it is concluded that the coral-like sub nanostructure is dominating the enhancement factor while the polyhedron structure itself only plays a minor role for electromagnetic field enhancement. PMID:25599525

  9. Characterization of Kevlar Using Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Washer, Glenn; Brooks, Thomas; Saulsberry, Regor

    2007-01-01

    This paper explores the characterization of Kevlar composite materials using Raman spectroscopy. The goal of the research is to develop and understand the Raman spectrum of Kevlar materials to provide a foundation for the development of nondestructive evaluation (NDE) technologies based on the interaction of laser light with the polymer Kevlar. The paper discusses the fundamental aspects of experimental characterization of the spectrum of Kevlar, including the effects of incident wavelength, polarization and laser power. The effects of environmental exposure of Kevlar materials on certain characteristics of its Raman spectrum are explored, as well as the effects of applied stress. This data may provide a foundation for the development of NDE technologies intended to detect the in-situ deterioration of Kevlar materials used for engineering applications that can later be extended to other materials such as carbon fiber composites.

  10. Remote adjustable focus Raman spectroscopy probe

    DOEpatents

    Schmucker, John E.; Blasi, Raymond J.; Archer, William B.

    1999-01-01

    A remote adjustable focus Raman spectroscopy probe allows for analyzing Raman scattered light from a point of interest external probe. An environmental barrier including at least one window separates the probe from the point of interest. An optical tube is disposed adjacent to the environmental barrier and includes a long working length compound lens objective next to the window. A beam splitter and a mirror are at the other end. A mechanical means is used to translated the prove body in the X, Y, and Z directions resulting in a variable focus optical apparatus. Laser light is reflected by the beam splitter and directed toward the compound lens objective, then through the window and focused on the point of interest. Raman scattered light is then collected by the compound lens objective and directed through the beam splitter to a mirror. A device for analyzing the light, such as a monochrometer, is coupled to the mirror.

  11. Drug Stability Analysis by Raman Spectroscopy

    PubMed Central

    Shende, Chetan; Smith, Wayne; Brouillette, Carl; Farquharson, Stuart

    2014-01-01

    Pharmaceutical drugs are available to astronauts to help them overcome the deleterious effects of weightlessness, sickness and injuries. Unfortunately, recent studies have shown that some of the drugs currently used may degrade more rapidly in space, losing their potency before their expiration dates. To complicate matters, the degradation products of some drugs can be toxic. Here, we present a preliminary investigation of the ability of Raman spectroscopy to quantify mixtures of four drugs; acetaminophen, azithromycin, epinephrine, and lidocaine, with their primary degradation products. The Raman spectra for the mixtures were replicated by adding the pure spectra of the drug and its degradant to determine the relative percent contributions using classical least squares. This multivariate approach allowed determining concentrations in ~10 min with a limit of detection of ~4% of the degradant. These results suggest that a Raman analyzer could be used to assess drug potency, nondestructively, at the time of use to ensure crewmember safety. PMID:25533308

  12. Characterization of diatomaceous silica by Raman spectroscopy.

    PubMed

    Yuan, P; He, H P; Wu, D Q; Wang, D Q; Chen, L J

    2004-10-01

    The network characteristic of a selection of diatomaceous silica derived from China has been investigated using Raman spectroscopy. Before any thermal treatment of the sample, two prominent bands of 607 and circa 493 cm(-1) are resolved in the Raman spectra of diatomaceous silica, corresponding to the (SiO)3-ring breathing mode of D2-line and the O3SiOH tetrahedral vibration mode of D1-line, respectively. This is more similar to the pyrogenic silica rather than the silica gel. For the latter, to obtain a (SiO)3-ring, the sample must be heated between 250 and 450 degrees C. Significant difference is also found between the diatomaceous silica and other natural silicas, e.g. in the Raman spectra of sedimentary and volcanic opals, neither D1 nor D2 band is detected in previous reports. PMID:15350933

  13. Characterization of diatomaceous silica by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Yuan, P.; He, H. P.; Wu, D. Q.; Wang, D. Q.; Chen, L. J.

    2004-10-01

    The network characteristic of a selection of diatomaceous silica derived from China has been investigated using Raman spectroscopy. Before any thermal treatment of the sample, two prominent bands of 607 and circa 493 cm -1 are resolved in the Raman spectra of diatomaceous silica, corresponding to the (SiO) 3-ring breathing mode of D 2-line and the O 3SiOH tetrahedral vibration mode of D 1-line, respectively. This is more similar to the pyrogenic silica rather than the silica gel. For the latter, to obtain a (SiO) 3-ring, the sample must be heated between 250 and 450 °C. Significant difference is also found between the diatomaceous silica and other natural silicas, e.g. in the Raman spectra of sedimentary and volcanic opals, neither D 1 nor D 2 band is detected in previous reports.

  14. Drug stability analysis by Raman spectroscopy.

    PubMed

    Shende, Chetan; Smith, Wayne; Brouillette, Carl; Farquharson, Stuart

    2014-01-01

    Pharmaceutical drugs are available to astronauts to help them overcome the deleterious effects of weightlessness, sickness and injuries. Unfortunately, recent studies have shown that some of the drugs currently used may degrade more rapidly in space, losing their potency before their expiration dates. To complicate matters, the degradation products of some drugs can be toxic. Here, we present a preliminary investigation of the ability of Raman spectroscopy to quantify mixtures of four drugs; acetaminophen, azithromycin, epinephrine, and lidocaine, with their primary degradation products. The Raman spectra for the mixtures were replicated by adding the pure spectra of the drug and its degradant to determine the relative percent contributions using classical least squares. This multivariate approach allowed determining concentrations in ~10 min with a limit of detection of ~4% of the degradant. These results suggest that a Raman analyzer could be used to assess drug potency, nondestructively, at the time of use to ensure crewmember safety. PMID:25533308

  15. Adsorption of vapreotide on gold colloids studied by surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Gómez, J. A.; Cabanzo, R.; Mejia Ospino, E.

    2016-02-01

    Surface Enhanced Raman Spectroscopy (SERS) has been used to investigate the somatostatin (SST) analogue Vapreotide (VAP) in gold colloids. The optimum conditions to detect SERS signals of VAP have been studied. The observed SERS bands correspond to different vibrational modes of the peptide; being the most dominant SERS signals the ones derived from the aromatic amino acids Tryptophan (Trp), Phenylalanine (Phe) and Tyrosine (Tyr). Changes in enhancement and wavenumber of the proper bands upon adsorption on gold colloid are consistent with VAP adsorption, primarily through Tryptophan residues.

  16. Hierarchical porous plasmonic metamaterials for reproducible ultrasensitive surface-enhanced Raman spectroscopy.

    PubMed

    Zhang, Xinyi; Zheng, Yuanhui; Liu, Xin; Lu, Wei; Dai, Jiyan; Lei, Dang Yuan; MacFarlane, Douglas R

    2015-02-11

    Hierarchical porous plasmonic metamaterials consisting of periodic nanoholes with tunable diameter and uniformly distributed mesopores over the bulk are developed as a new class of 3D surface-enhanced Raman spectroscopy (SERS) substrates. This multiscale architecture not only facilitates efficient cascaded electromagnetic enhancement but also provides an enormous number of Raman-active binding sites, exhibiting excellent reproducibility and ultrasensitive detection of aromatic molecules down to 10(-13) M. PMID:25534763

  17. Examination of pterins using surface-enhanced Raman spectroscopy using low-volume samples

    NASA Astrophysics Data System (ADS)

    Mehigan, Sam; Smyth, Ciarán.; McCabe, Eithne M.

    2013-02-01

    Raman spectroscopy is a very useful tool for analysing compounds, however its ability to detect low concentrations of a substance are very limited. Surface Enhanced Raman Spectroscopy (SERS) overcomes that issue and is reported to have achieved single molecule detection. Its main shortcoming is the reproducibility of SERS spectra. The variation in signal strength prevents SERS from being usable as a quantitative analytical technique. This variability have been investigated in this work and key factors in improving reproducibility have been considered. Pterins, such as xanthopterin are studied in this paper. Pterins are a group of biological compounds that are found in nature in colour pigmentation and in mammal's metabolic pathways. Moreover, they have been identified in abnormal concentrations in the urine of people suffering from certain kinds of cancer. The potential for pterin's use as a cancer diagnostic points to the importance of SERS detection for pterins.

  18. Detecting changes during pregnancy with Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Vargis, Elizabeth; Robertson, Kesha; Al-Hendy, Ayman; Reese, Jeff; Mahadevan-Jansen, Anita

    2010-02-01

    Preterm labor is the second leading cause of neonatal mortality and leads to a myriad of complications like delayed development and cerebral palsy. Currently, there is no way to accurately predict preterm labor, making its prevention and treatment virtually impossible. While there are some at-risk patients, over half of all preterm births do not fall into any high-risk category. This study seeks to predict and prevent preterm labor by using Raman spectroscopy to detect changes in the cervix during pregnancy. Since Raman spectroscopy has been used to detect cancers in vivo in organs like the cervix and skin, it follows that spectra will change over the course of pregnancy. Previous studies have shown that fluorescence decreased during pregnancy and increased during post-partum exams to pre-pregnancy levels. We believe significant changes will occur in the Raman spectra obtained during the course of pregnancy. In this study, Raman spectra from the cervix of pregnant mice and women will be acquired. Specific changes that occur due to cervical softening or changes in hormonal levels will be observed to understand the likelihood that a female mouse or a woman will enter labor.

  19. Raman spectroscopy for analysis of thorium compounds

    NASA Astrophysics Data System (ADS)

    Su, Yin-Fong; Johnson, Timothy J.; Olsen, Khris B.

    2016-05-01

    The thorium fuel cycle is an alternative to the uranium fuel cycle in that when 232Th is irradiated with neutrons it is converted to 233U, another fissile isotope. There are several chemical forms of thorium which are used in the Th fuel cycle. Recently, Raman spectroscopy has become a very portable and facile analytical technique useful for many applications, including e.g. determining the chemical composition of different materials such as for thorium compounds. The technique continues to improve with the development of ever-more sensitive instrumentation and better software. Using a laboratory Fourier-transform (FT)-Raman spectrometer with a 785 nm wavelength laser, we were able to obtain Raman spectra from a series of thorium-bearing compounds of unknown origin. These spectra were compared to the spectra of in-stock-laboratory thorium compounds including e.g. ThO2, ThF4, Th(CO3)2 and Th(C2O4)2. The unknown spectra showed very good agreement to the known standards, demonstrating the applicability of Raman spectroscopy for detection and identification of these nuclear materials.

  20. Raman spectroscopy of ion-implanted silicon

    SciTech Connect

    Tuschel, D.D.; Lavine, J.P.

    1997-11-01

    Raman spectroscopy is used to characterize silicon implanted with boron at a dose of 10{sup 14}/cm{sup 2} or less and thermally annealed. The Raman scattering strengths and band shapes of the first-order optical mode at 520 cm{sup {minus}1} and of the second-order phonon modes are investigated to determine which modes are sensitive to the boron implant. The as-implanted samples show diminishing Raman scattering strength as the boron dose increases when the incident laser beam is 60{degree} with respect to the sample normal. Thermal annealing restores some of the Raman scattering strength. Three excitation wavelengths are used and the shortest, 457.9 nm, yields the greatest spectral differences from unimplanted silicon. The backscattering geometry shows a variety of changes in the Raman spectrum upon boron implantation. These involve band shifts of the first-order optical mode, bandwidth variations of the first-order optical mode, and the intensity of the second-order mode at 620 cm{sup {minus}1}.

  1. Urine surface-enhanced Raman spectroscopy for non-invasive diabetic detection based on a portable Raman spectrometer

    NASA Astrophysics Data System (ADS)

    Zou, Ye; Huang, Meizhen; Wang, Kehui; Song, Biao; Wang, Yang; Chen, Jie; Liu, Xi; Li, Xia; Lin, Lulu; Huang, Gaozhong

    2016-06-01

    A feasibility study for non-invasive diabetic detection based on a low cost portable Raman spectrometer and urine surface-enhanced Raman spectroscopy (SERS) is presented. SERS of 41 urine samples (20 diabetic patients and 21 healthy volunteers) mixed with silver nanoparticles are measured by a self-developed portable Raman spectrometer (Hx-Spec) which is excited by a 785 nm diode laser and the spectrum range is 200–2700 cm‑1 with a resolution (FWHM) of 6 cm‑1. By methods of principal components analysis and linear discriminant analysis, a diagnostic sensitivity of 85% and a specificity of 90.5% are achieved in separating diabetic samples from normal urine specimens. The corresponding receiver operating characteristic is 0.836, indicting the accuracy of the predictive model.

  2. Surface Enhanced Raman Spectroscopy of Organic Molecules on Magnetite (Fe3O4) Nanoparticles.

    PubMed

    Lee, Namhey; Schuck, P James; Nico, Peter S; Gilbert, Benjamin

    2015-03-19

    Surface-enhanced Raman spectroscopy (SERS) of species bound to environmentally relevant oxide nanoparticles is largely limited to organic molecules structurally related to catechol that facilitate a chemical enhancement of the Raman signal. Here, we report that magnetite (Fe3O4) nanoparticles provide a SERS signal from oxalic acid and cysteine via an electric field enhancement. Magnetite thus likely provides an oxide substrate for SERS study of any adsorbed organic molecule. This substrate combines benefits from both metal-based and chemical SERS by providing an oxide surface for studies of environmentally and catalytically relevant detailed chemical bonding information with fewer restrictions of molecular structure or binding mechanisms. Therefore, the magnetite-based SERS demonstrated here provides a new approach to establishing the surface interactions of environmentally relevant organic ligands and mineral surfaces. PMID:26262854

  3. Identification and analysis of Triphenyltin chloride with surface enhanced Raman scattering spectroscopy.

    PubMed

    Jiang, Juan; Gao, Jun-Min; Guo, Jin-Song; Zhou, Qiu-Hong; Liu, Xiao-Hong; Ouyang, Wen-Juan; Zhang, Peng; Fu, Wei-Ling; Zhang, Wei; He, Shi-Xuan

    2016-10-01

    Triphenyltin (TPhT) is a kind of organotin compounds which have been used ubiquitously as herbicide, pesticide, and fungicide in agriculture. The present study provides the possibility to detect and monitor TPhT with normal Raman spectroscopy and surface enhanced Raman scattering (SERS) spectroscopy. Firstly, the complete vibrational Raman spectra characterization of TPhT along with the IR spectroscopy were reported for the first time. Then a wide range of pH values were carried out to choose the optimal pH value in TPhT detection by using Raman spectroscopy. Afterwards, Raman spectra of various TPhT solutions were collected and analyzed. The results indicate that the optimal pH value for TPhT detection by Raman spectroscopy is 5.5, and with silver nanoparticles (Ag NPs) as SERS substrate is an effective technique for trace TPhT detection with an enhancement by 5 orders of magnitude and the detection limit can be as low as 0.6 ng/L within less than 30 s. Finally, in this study, the residual of TPhT on apple peel was investigated by casting different concentrations of TPhT on apple peel under the current optimized condition. The result demonstrates that TPhT could be detected based on its SESR spectra at 6.25 ng/cm(2) in standard solutions. PMID:27423126

  4. Raman Spectroscopy of Irradiated Tissue Samples

    NASA Astrophysics Data System (ADS)

    Alexa, P.; Synytsya, A.; Volka, K.; de Boer, J.; Besserer, J.; Froschauer, S.; Loewe, M.; Moosburger, M.; Würkner, M.

    2003-06-01

    Tissue samples (skin of mice, normal and tumor, skin of a woman, normal and tumor) were irradiated by protons from the Munich tandem accelerator. The samples were analysed using Raman spectroscopy at the Institute of Chemical Technology in Prague by measuring the intensity of signals sensitive to radiation damage. Effects depending on the delivered dose were found. Proton-irradiation effects are then compared to those of gamma-irradiation.

  5. A simple preparation of Ag@graphene nanocomposites for surface-enhanced Raman spectroscopy of fluorescent anticancer drug

    NASA Astrophysics Data System (ADS)

    Meng, Ying; Yan, Xueying; Wang, Yi

    2016-05-01

    A simple method was developed to synthesize Ag@graphene nanocomposites with rough Ag nanoparticles (AgNPs) conjugated with graphene nanosheets, and the nanocomposites could be used as substrates for effective surface-enhanced Raman spectroscopy (SERS) of fluorescent anticancer drug (Dox) since they could not only enhance the Raman signals but also suppress the fluorescent signals.

  6. New Material for Surface-Enhanced Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Farquharson, Stuart; Nelson, Chad; Lee, Yuan

    2004-01-01

    A chemical method of synthesis and application of coating materials that are especially suitable for surface-enhanced Raman spectroscopy (SERS) has been developed. The purpose of this development is to facilitate the utilization of the inherently high sensitivity of SERS to detect chemicals of interest (analytes) in trace amounts, without need for lengthy sample preparation. Up to now, the use of SERS has not become routine because the methods available have not been able to reproduce sampling conditions and provide quantitative measurements. In contrast, the coating materials of the present method enable analysis with minimum preparation of samples, and SERS measurements made using these materials are reproducible and reversible. Moreover, unlike in methods investigated in prior efforts to implement SERS, sampling is not restricted to such specific environments as electrolytes or specific solvents. The coating materials of this method are porous glasses, formed in sol-gel processes, that contain small particles of gold or silver metal. Materials of this type can be applied to the sample-contact surfaces of a variety of sampling and sensing devices, including glass slides, glass vials, fiber-optic probes, and glass tubes. Glass vials with their insides coated according to this method are particularly convenient for SERS to detect trace chemicals in solutions: One simply puts a sample solution containing the analyte(s) into a vial, then puts the vial into a Raman spectrometer for analysis. The chemical ingredients and the physical conditions of the sol-gel process have been selected so that the porous glass formed incorporates particles of the desired metal with size(s) to match the wavelength(s) of the SERS excitation laser in order to optimize the generation of surface plasmons. The ingredients and processing conditions have further been chosen to tailor the porosity and polarity of the glass to optimize the sample flow and the interaction between the analyte

  7. Surface enhanced Raman spectroscopy for microfluidic pillar arrayed separation chips

    SciTech Connect

    Taylor, Lisa; Kirchner, Teresa B; Lavrik, Nickolay V; Sepaniak, Michael

    2012-01-01

    Numerous studies have addressed the challenges of implementing miniaturized microfluidic platforms for chemical and biological separation applications. However, the integration of real time detection schemes capable of providing valuable sample information under continuous, ultra low volume flow regimes has not fully been addressed. In this report we present a chip based chromatography system comprising of a pillar array separation column followed by a reagent channel for passive mixing of a silver colloidal solution into the eluent stream to enable surface enhanced Raman spectroscopy (SERS) detection. Our design is the first integrated chip based microfluidic device to combine pressure driven separation capability with real time SERS detection. With this approach we demonstrate the ability to collect distinctive SERS spectra with or without complete resolution of chromatographic bands. Computational fluidic dynamic (CFD) simulations are used to model the diffusive mixing behavior and velocity profiles of the two confluent streams in the microfluidic channels. We evaluate the SERS spectral band intensity and chromatographic efficiency of model analytes with respect to kinetic factors as well as signal acquisition rates. Additionally, we discuss the use of a pluronic modified silver colloidal solution as a means of eliminating contamination generally caused by nanoparticle adhesion to channel surfaces.

  8. Spectroscopic fingerprint of tea varieties by surface enhanced Raman spectroscopy.

    PubMed

    Buyukgoz, Guluzar Gorkem; Soforoglu, Mehmet; Basaran Akgul, Nese; Boyaci, Ismail Hakki

    2016-03-01

    The fingerprinting method is generally performed to determine specific molecules or the behavior of specific molecular bonds in the desired sample content. A novel, robust and simple method based on surface enhanced Raman spectroscopy (SERS) was developed to obtain the full spectrum of tea varieties for detection of the purity of the samples based on the type of processing and cultivation. For this purpose, the fingerprint of seven different varieties of tea samples (herbal tea (rose hip, chamomile, linden, green and sage tea), black tea and earl grey tea) combined with silver colloids was obtained by SERS in the range of 200-2000 cm(-1) with an analysis time of 20 s. Each of the thirty-nine tea samples tested showed its own specific SERS spectra. Principal Component Analysis (PCA) was also applied to separate of each tea variety and different models developed for tea samples including three different models for the herbal teas and two different models for black and earl grey tea samples. Herbal tea samples were separated using mean centering, smoothing and median centering pre-processing steps while baselining and derivatisation pre-processing steps were applied to SERS data of black and earl grey tea. The novel spectroscopic fingerprinting technique combined with PCA is an accurate, rapid and simple methodology for the assessment of tea types based on the type of processing and cultivation differences. This method is proposed as an alternative tool in order to determine the characteristics of tea varieties. PMID:27570296

  9. Raman and photothermal spectroscopies for explosive detection

    NASA Astrophysics Data System (ADS)

    Finot, Eric; Brulé, Thibault; Rai, Padmnabh; Griffart, Aurélien; Bouhélier, Alexandre; Thundat, Thomas

    2013-06-01

    Detection of explosive residues using portable devices for locating landmine and terrorist weapons must sat- isfy the application criteria of high reproducibility, specificity, sensitivity and fast response time. Vibrational spectroscopies such as Raman and infrared spectroscopies have demonstrated their potential to distinguish the members of the chemical family of more than 30 explosive materials. The characteristic chemical fingerprints in the spectra of these explosives stem from the unique bond structure of each compound. However, these spectroscopies, developed in the early sixties, suffer from a poor sensitivity. On the contrary, MEMS-based chemical sensors have shown to have very high sensitivity lowering the detection limit down to less than 1 picogram, (namely 10 part per trillion) using sensor platforms based on microcantilevers, plasmonics, or surface acoustic waves. The minimum amount of molecules that can be detected depends actually on the transducer size. The selectivity in MEMS sensors is usually realized using chemical modification of the active surface. However, the lack of sufficiently selective receptors that can be immobilized on MEMS sensors remains one of the most critical issues. Microcantilever based sensors offer an excellent opportunity to combine both the infrared photothermal spectroscopy in their static mode and the unique mass sensitivity in their dynamic mode. Optical sensors based on localized plasmon resonance can also take up the challenge of addressing the selectivity by monitoring the Surface Enhanced Raman spectrum down to few molecules. The operating conditions of these promising localized spectroscopies will be discussed in terms of reliability, compactness, data analysis and potential for mass deployment.

  10. The Impact of Array Detectors on Raman Spectroscopy

    ERIC Educational Resources Information Center

    Denson, Stephen C.; Pommier, Carolyn J. S.; Denton, M. Bonner

    2007-01-01

    The impact of array detectors in the field of Raman spectroscopy and all low-light-level spectroscopic techniques is examined. The high sensitivity of array detectors has allowed Raman spectroscopy to be used to detect compounds at part per million concentrations and to perform Raman analyses at advantageous wavelengths.

  11. Raman Spectroscopy: Incorporating the Chemical Dimension into Dermatological Diagnosis

    PubMed Central

    Sharma, Amit; Sharma, Shruti; Zarrow, Anna; Schwartz, Robert A; Lambert, W Clark

    2016-01-01

    Raman spectroscopy provides chemical analysis of tissue in vivo. By measuring the inelastic interactions of light with matter, Raman spectroscopy can determine the chemical composition of a sample. Diseases that are visually difficult to visually distinguish can be delineated based on differences in chemical composition of the affected tissue. Raman spectroscopy has successfully found spectroscopic signatures for skin cancers and differentiated those of benign skin growths. With current and on-going advances in optics and computing, inexpensive and effective Raman systems may soon be available for clinical use. Raman spectroscopy provides direct analyses of skin lesions, thereby improving both disease diagnosis and management. PMID:26955087

  12. Surface enhanced Raman spectroscopy of individual rhodamine 6G molecules on large Ag nanocrystals

    SciTech Connect

    Michaels, A.M.; Nirmal, M.; Brus, L.E.

    1999-11-03

    To explore the relationship between local electromagnetic field enhancement and the large SERS (surface enhanced Raman scattering) enhancement that enables the observation of single molecule Raman spectra, they measure both resonant Rayleigh scattering spectra and rhodamine 6G Raman spectra from single Ag particles. The apparatus combines the techniques of dark-field optical microscopy for resonant Rayleigh measurements, and grazing incidence Raman spectroscopy. The Rayleigh spectra show that the citrate-reduced Ag colloid is extremely heterogeneous. Only the larger particles, in part created by salt induced aggregation, show a large SERS effect. In agreement with the work of Nie and Emory, a few nanocrystals show huge single molecule R6G SERS intensities. While all SERS active particles have some resonant Rayleigh scattering at the 514.5 nm laser wavelength, there is no correlation between the resonant Rayleigh spectra and the SERS intensity. A model is discussed in which huge SERS intensities result from single chemisorbed molecules interacting with ballistic electrons in optically excited large Ag particles. This model is a natural consequence of the standard local electromagnetic field model for SERS and the high surface sensitivity of plasmon dephasing in the noble metals.

  13. Surface enhanced raman spectroscopy technique in rapid detection of live and dead salmonella cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many research proved that Surface Enhanced Raman Spectroscopy (SERS) can detect pathogens rapidly and accurately. In this study, a silver metal substrate was used for the selected common food pathogen Salmonella typhimurium bacteria. Nano silver rods were deposited on a thin titanium coating over t...

  14. Detection of viruses: atomic force microscopy and surface enhanced raman spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper demonstrated the capability of atomic force microscopy (AFM) and surface enhanced Raman spectroscopy (SERS) to function effectively as ultra-sensitive readout tools for chip-scale platforms designed for pathogen detection in complex biological media. AFM allows direct (i.e. label-free) vi...

  15. Investigation of surface enhanced Raman spectroscopy for hemozoin detection in malaria diagnosis

    NASA Astrophysics Data System (ADS)

    Chen, Keren; Xiong, Aoli; Yuen, Clement; Preiser, Peter; Liu, Quan

    2016-03-01

    We report two methods of surface enhanced Raman spectroscopy (SERS) for hemozoin detection in malaria infected human blood. In the first method, silver nanoparticles were synthesized separately and then mixed with lysed blood; while in the second method, silver nanoparticles were synthesized directly inside the parasites of Plasmodium falciparum.

  16. Nanostructure-based plasmon-enhanced Raman spectroscopy for surface analysis of materials

    NASA Astrophysics Data System (ADS)

    Ding, Song-Yuan; Yi, Jun; Li, Jian-Feng; Ren, Bin; Wu, De-Yin; Panneerselvam, Rajapandiyan; Tian, Zhong-Qun

    2016-06-01

    Since 2000, there has been an explosion of activity in the field of plasmon-enhanced Raman spectroscopy (PERS), including surface-enhanced Raman spectroscopy (SERS), tip-enhanced Raman spectroscopy (TERS) and shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). In this Review, we explore the mechanism of PERS and discuss PERS hotspots — nanoscale regions with a strongly enhanced local electromagnetic field — that allow trace-molecule detection, biomolecule analysis and surface characterization of various materials. In particular, we discuss a new generation of hotspots that are generated from hybrid structures combining PERS-active nanostructures and probe materials, which feature a strong local electromagnetic field on the surface of the probe material. Enhancement of surface Raman signals up to five orders of magnitude can be obtained from materials that are weakly SERS active or SERS inactive. We provide a detailed overview of future research directions in the field of PERS, focusing on new PERS-active nanomaterials and nanostructures and the broad application prospect for materials science and technology.

  17. Raman spectroscopy of C-irradiated graphite

    SciTech Connect

    Hembree, D.M. Jr.; Pedraza, D.F.; Romanoski, G.R.; Withrow, S.P.; Annis, B.K.

    1994-09-01

    Highly oriented pyrolytic graphite samples were irradiated with C{sup +} ions at 35 keV in a direction normal to the basal plane and subsequently annealed up to 1373 K. Substantial surface topography changes were observed at fluences of 5 {times} 10{sup 18} ions/m{sup 2} and higher using scanning electron and atomic force microscopies. Intricate networks of surface cracks and ridges developed after high dose implantation. A systematic study of the irradiation effects was conducted using Raman spectroscopy. Microstructural changes in irradiated regions were first detected at a dose of 1 {times} 10{sup 17} ions/m{sup 2} through the appearance of the Raman D-line at {approx}1360 cm{sup {minus}1}. The intensity of this line increases while that of the Raman G-line at 1580 cm{sup {minus}1} decreases as the irradiation dose is increased or the irradiation temperature is decreased. After irradiation at 280K to a fluence of 5 {times} 10{sup 19} ions/m{sup 2} or higher the first order spectrum exhibits one single line at a wavelength intermediate between the D- and G-lines. Damage recovery upon thermal annealing depends not only on the initial damage state but also on the annealing temperature sequence. Samples irradiated to a damage level where two distinct Raman peaks are no longer resolvable exhibited upon direct annealing at a high temperature two distinct Raman lines. By contrast, pre-annealing these highly irradiated specimens at lower temperatures produced less pronounced changes in the Raman spectra. Pre-annealing appears to stabilize damage structures that are more resistant to high-temperature annealing than those induced by irradiation.

  18. Molecular fiber sensor probes based on surface enhanced Raman scattering (SERS)

    NASA Astrophysics Data System (ADS)

    Shi, Chao

    Molecular sensors based on surface enhanced Raman scattering (SERS) and optical fibers have been widely used in biological, environmental and chemical detection procedures due to their unique advantages, such as molecular specificity, high sensitivity and flexibility. In this thesis, I review the development and highlight some of the important milestones of SERS fiber sensor development with emphasis on recent work to improve the sensitivity of the fiber sensors. In particular in the area to increase the sensitivity, we've developed various methods of sample preparation as well as different fiber SERS sensors. One way is to strengthen the field enhancement around the surface of the probe tip and the other is to increase the number of the interacting particles during the SERS process. These techniques are known as the double substrate "sandwich" structure (DSSS) and the liquid core photonic crystal fiber (LCPCF) respectively, and in both cases the sensitivities are significantly improved. The combination of these two mechanisms is also proposed as inner wall coated hollow core waveguide (IWCHCW). As the portable Raman spectrometer is developed and commercially available, a portable fiber SERS sensor system is demonstrated as well in order to make it practical in out of laboratory applications. These fiber sensors were tested with Rhodamine 6G, human insulin, tryptophan, prostate specific antigen, and alpha-synuclein and showed excellent performance.

  19. Principal component analysis of bacteria using surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Guicheteau, Jason; Christesen, Steven D.

    2006-05-01

    Surface-enhanced Raman scattering (SERS) provides rapid fingerprinting of biomaterial in a non-destructive manner. The problem of tissue fluorescence, which can overwhelm a normal Raman signal from biological samples, is largely overcome by treatment of biomaterials with colloidal silver. This work presents a study into the applicability of qualitative SER spectroscopy with principal component analysis (PCA) for the discrimination of four biological threat simulants; Bacillus globigii, Pantoea agglomerans, Brucella noetomae, and Yersinia rohdei. We also demonstrate differentiation of gram-negative and gram-positive species and as well as spores and vegetative cells of Bacillus globigii.

  20. Raman spectroscopy for diagnosis of glioblastoma multiforme

    NASA Astrophysics Data System (ADS)

    Clary, Candace Elise

    Glioblastoma multiforme (GBM), the most common and most fatal malignant brain tumor, is highly infiltrative and incurable. Although improved prognosis has been demonstrated by surgically resecting the bulk tumor, a lack of clear borders at the tumor margins complicates the selection decision during surgery. This dissertation investigates the potential of Raman spectroscopy for distinguishing between normal and malignant brain tissue and sets the groundwork for a surgical diagnostic guide for resection of gross malignant gliomas. These studies revealed that Raman spectroscopy was capable of discriminating between normal scid mouse brain tissue and human xenograft tumors induced in those mice. The spectra of normal and malignant tissue were normalized by dividing by the respective magnitudes of the peaks near 1440 cm -1. Spectral differences include the shape of the broad peaks near 1440 cm-1 and 1660 cm-1 and the relative magnitudes of the peaks at 1264 cm-1, 1287 cm-1, 1297 cm-1, 1556 cm -1, 1586 cm-1, 1614 cm-1, and 1683 cm-1. From these studies emerged questions regarding how to objectively normalize and compare spectra for future automation. Some differences in the Raman spectra were shown to be inherent in the disease states of the cells themselves via differences in the Raman spectra of normal human astrocytes in culture and cultured cells derived from GBM tumors. The spectra of astrocytes and glioma cells were normalized by dividing by the respective magnitudes of the peaks near 1450 cm-1. The differences between the Raman spectra of normal and transformed cells include the ratio of the 1450 cm-1/1650 cm-1 peaks and the relative magnitudes of the peaks at 1181 cm-1, 1191 cm-1, 1225 cm-1, 1263 cm -1, 1300 cm-1, 1336 cm-1, 1477 cm-1, 1494 cm-1, and 1695 cm -1. Previous Raman spectroscopic studies of biological cells have shown that the magnitude of the Raman signal decreases over time, indicating sample damage. Cells exposed to laser excitation at similar power

  1. Electronic resonances in broadband stimulated Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Batignani, G.; Pontecorvo, E.; Giovannetti, G.; Ferrante, C.; Fumero, G.; Scopigno, T.

    2016-01-01

    Spontaneous Raman spectroscopy is a formidable tool to probe molecular vibrations. Under electronic resonance conditions, the cross section can be selectively enhanced enabling structural sensitivity to specific chromophores and reaction centers. The addition of an ultrashort, broadband femtosecond pulse to the excitation field allows for coherent stimulation of diverse molecular vibrations. Within such a scheme, vibrational spectra are engraved onto a highly directional field, and can be heterodyne detected overwhelming fluorescence and other incoherent signals. At variance with spontaneous resonance Raman, however, interpreting the spectral information is not straightforward, due to the manifold of field interactions concurring to the third order nonlinear response. Taking as an example vibrational spectra of heme proteins excited in the Soret band, we introduce a general approach to extract the stimulated Raman excitation profiles from complex spectral lineshapes. Specifically, by a quantum treatment of the matter through density matrix description of the third order nonlinear polarization, we identify the contributions which generate the Raman bands, by taking into account for the cross section of each process.

  2. Electronic resonances in broadband stimulated Raman spectroscopy

    PubMed Central

    Batignani, G.; Pontecorvo, E.; Giovannetti, G.; Ferrante, C.; Fumero, G.; Scopigno, T.

    2016-01-01

    Spontaneous Raman spectroscopy is a formidable tool to probe molecular vibrations. Under electronic resonance conditions, the cross section can be selectively enhanced enabling structural sensitivity to specific chromophores and reaction centers. The addition of an ultrashort, broadband femtosecond pulse to the excitation field allows for coherent stimulation of diverse molecular vibrations. Within such a scheme, vibrational spectra are engraved onto a highly directional field, and can be heterodyne detected overwhelming fluorescence and other incoherent signals. At variance with spontaneous resonance Raman, however, interpreting the spectral information is not straightforward, due to the manifold of field interactions concurring to the third order nonlinear response. Taking as an example vibrational spectra of heme proteins excited in the Soret band, we introduce a general approach to extract the stimulated Raman excitation profiles from complex spectral lineshapes. Specifically, by a quantum treatment of the matter through density matrix description of the third order nonlinear polarization, we identify the contributions which generate the Raman bands, by taking into account for the cross section of each process. PMID:26728791

  3. Noninvasive glucose sensing by transcutaneous Raman spectroscopy

    PubMed Central

    Shih, Wei-Chuan; Bechtel, Kate L.; Rebec, Mihailo V.

    2015-01-01

    Abstract. We present the development of a transcutaneous Raman spectroscopy system and analysis algorithm for noninvasive glucose sensing. The instrument and algorithm were tested in a preclinical study in which a dog model was used. To achieve a robust glucose test system, the blood levels were clamped for periods of up to 45 min. Glucose clamping and rise/fall patterns have been achieved by injecting glucose and insulin into the ear veins of the dog. Venous blood samples were drawn every 5 min and a plasma glucose concentration was obtained and used to maintain the clamps, to build the calibration model, and to evaluate the performance of the system. We evaluated the utility of the simultaneously acquired Raman spectra to be used to determine the plasma glucose values during the 8-h experiment. We obtained prediction errors in the range of ∼1.5−2  mM. These were in-line with a best-case theoretical estimate considering the limitations of the signal-to-noise ratio estimates. As expected, the transition regions of the clamp study produced larger predictive errors than the stable regions. This is related to the divergence of the interstitial fluid (ISF) and plasma glucose values during those periods. Two key contributors to error beside the ISF/plasma difference were photobleaching and detector drift. The study demonstrated the potential of Raman spectroscopy in noninvasive applications and provides areas where the technology can be improved in future studies. PMID:25688542

  4. Noninvasive glucose sensing by transcutaneous Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Shih, Wei-Chuan; Bechtel, Kate L.; Rebec, Mihailo V.

    2015-05-01

    We present the development of a transcutaneous Raman spectroscopy system and analysis algorithm for noninvasive glucose sensing. The instrument and algorithm were tested in a preclinical study in which a dog model was used. To achieve a robust glucose test system, the blood levels were clamped for periods of up to 45 min. Glucose clamping and rise/fall patterns have been achieved by injecting glucose and insulin into the ear veins of the dog. Venous blood samples were drawn every 5 min and a plasma glucose concentration was obtained and used to maintain the clamps, to build the calibration model, and to evaluate the performance of the system. We evaluated the utility of the simultaneously acquired Raman spectra to be used to determine the plasma glucose values during the 8-h experiment. We obtained prediction errors in the range of ˜1.5-2 mM. These were in-line with a best-case theoretical estimate considering the limitations of the signal-to-noise ratio estimates. As expected, the transition regions of the clamp study produced larger predictive errors than the stable regions. This is related to the divergence of the interstitial fluid (ISF) and plasma glucose values during those periods. Two key contributors to error beside the ISF/plasma difference were photobleaching and detector drift. The study demonstrated the potential of Raman spectroscopy in noninvasive applications and provides areas where the technology can be improved in future studies.

  5. Diagnosing breast cancer by using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Haka, Abigail S.; Shafer-Peltier, Karen E.; Fitzmaurice, Maryann; Crowe, Joseph; Dasari, Ramachandra R.; Feld, Michael S.

    2005-08-01

    We employ Raman spectroscopy to diagnose benign and malignant lesions in human breast tissue based on chemical composition. In this study, 130 Raman spectra are acquired from ex vivo samples of human breast tissue (normal, fibrocystic change, fibroadenoma, and infiltrating carcinoma) from 58 patients. Data are fit by using a linear combination model in which nine basis spectra represent the morphologic and chemical features of breast tissue. The resulting fit coefficients provide insight into the chemical/morphological makeup of the tissue and are used to develop diagnostic algorithms. The fit coefficients for fat and collagen are the key parameters in the resulting diagnostic algorithm, which classifies samples according to their specific pathological diagnoses, attaining 94% sensitivity and 96% specificity for distinguishing cancerous tissues from normal and benign tissues. The excellent results demonstrate that Raman spectroscopy has the potential to be applied in vivo to accurately classify breast lesions, thereby reducing the number of excisional breast biopsies that are performed. Author contributions: M.F., J.C., R.R.D., and M.S.F. designed research; A.S.H. and K.E.S.-P. performed research; A.S.H. and M.F. analyzed data; and A.S.H. wrote the paper.This paper was submitted directly (Track II) to the PNAS office.Abbreviations: DEH, ductal epithelial hyperplasia; ROC, receiver operating characteristic; N/C, nuclear-to-cytoplasm.

  6. Probing of different conformations of piperazine using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    SenGupta, Sumana; Maiti, Nandita; Chadha, Ridhima; Kapoor, Sudhir

    2014-06-01

    Piperazine exists in a number of energetically close structural conformations, and here, we investigated the dependence of their relative abundance on the surrounding conditions by using Raman and SERS spectroscopy in pure solid, aqueous solution and Ag hydrosol. The experimental results were interpreted by DFT calculations using B3LYP functional with aug-cc-pvdz/LANL2DZ basis sets. In the chair form of piperazine, which is more stable than the skewed boat by ∼8 kcal mol-1, the two N-H bonds can remain equatorial or axial, leading to three different conformations, eq-eq, eq-ax and ax-ax. The calculated Raman spectrum of the lowest energy eq-eq conformation corresponds well with the experimental spectrum in pure solid, indicating eq-eq to be predominant. But, the contribution of the eq-ax conformation was found to be maximum in aqueous solution. The SERS spectrum revealed that eq-ax conformation was preferably adopted as piperazine was adsorbed vertically through its axial N-atom over silver nanoparticle surface.

  7. Single-particle Raman measurements of gold nanoparticles used in surface-enhanced Raman scattering (SERS)-based sandwich immunoassays

    NASA Astrophysics Data System (ADS)

    Park, Hye-Young; Lipert, Robert J.; Porter, Marc D.

    2004-12-01

    The effect of particle size on the intensity of surface-enhanced Raman scattering (SERS) using labeled gold nanoparticles has been investigated. Two sets of experiments were preformed, both of which employed 632.8-nm laser excitation. The first entailed a sandwich immunoassay in which an antibody coupled to a smooth gold substrate selectively captured free-prostate specific antigen (f-PSA) from buffered aqueous solutions. The presence of captured f-PSA was then detected by the response of Raman-labeled immunogold nanoparticles with nominal diameters of 30, 40, 50, 60, or 80 nm. The resulting SERS responses were correlated to particle densities, which were determined by atomic force microscopy, by calculating the average response per particle after accounting for differences in particle surface area. This analysis showed that the magnitude of the SERS response increased with increasing particle size. The second set of experiments examined the response of individual nanoparticles. These experiments differed in that the labeled nanoparticles were coupled to the smooth gold substrate by an amine-terminated thiolate, yielding a much smaller average separation between the particles and substrate. The results revealed that particles with a diameter of ~70 nm exhibited the largest enhancement. The origin of the difference in the two sets of findings, which is attributed to the distance dependence of the plasmon coupling between the nanoparticles and underlying substrate, is briefly discussed.

  8. Surface-Enhanced Raman Spectroscopy of Polyelectrolyte-Wrapped Gold Nanoparticles in Colloidal Suspension

    PubMed Central

    Sivapalan, Sean T.; DeVetter, Brent M.; Yang, Timothy K.; Schulmerich, Matthew V.; Bhargava, Rohit; Murphy, Catherine J.

    2013-01-01

    The rapidly expanding field of surface-enhanced Raman spectroscopy (SERS) has helped fuel an intense interest in noble metal nanoparticle synthesis. An in-suspension approach for quantifying SERS enhancement and relating that enhancement to a spontaneous Raman equivalent signal is described. Gold nanoparticles of various shapes were wrapped with polyelectrolyte multilayers that trapped Raman reporter molecules at defined distances from the metal core. Electrospray ionization liquid chromatography mass spectrometry (ESI-LC-MS) on digested samples was employed to measure the average number of bound Raman reporter molecules per gold nanoparticle, and inductively coupled plasma mass spectrometry (ICP-MS) was used to measure the average number of gold atoms per nanoparticle. Using these data, SERS signal intensity was compared to a spontaneous Raman calibration curve to compute a spontaneous Raman equivalent factor. Three different geometries of gold nanoparticles (cubes, spheres, and trisoctahedra) were synthesized to investigate edge and corner effects using these quantitative techniques. Finite element method (FEM) electromagnetic simulations examined the relationship between the different geometries and the observed SERS signal intensities. The experimental observations and theoretical results indicate that cubic gold nanoparticles have the highest effective signal. PMID:24224064

  9. Laser tweezers Raman spectroscopy of single cells

    NASA Astrophysics Data System (ADS)

    Chen, De

    Raman scattering is an inelastic collision between the vibrating molecules inside the sample and the incident photons. During this process, energy exchange takes place between the photon and the scattering molecule. By measuring the energy change of the photon, the molecular vibration mode can be probed. The vibrational spectrum contains valuable information about the disposition of atomic nuclei and chemical bonds within a molecule, the chemical compositions and the interactions between the molecule and its surroundings. In this dissertation, laser tweezers Raman spectroscopy (LTRS) technique is applied for the analysis of biological cells and human cells at single cell level. In LTRS, an individual cell is trapped in aqueous medium with laser tweezers, and Raman scattering spectra from the trapped cell are recorded in real-time. The Raman spectra of these cells can be used to reveal the dynamical processes of cell growth, cell response to environment changes, and can be used as the finger print for the identification of a bacterial cell species. Several biophysical experiments were carried out using LTRS: (1) the dynamic germination process of individual spores of Bacillus thuringiensis was detected via Ca-DPA, a spore-specific biomarker molecule; (2) inactivation and killing of Bacillus subtilis spores by microwave irradiation and wet heat were studied at single cell level; (3) the heat shock activation process of single B. subtilis spores were analyzed, in which the reversible transition from glass-like state at low temperature to liquid-like state at high temperature in spore was revealed at the molecular level; (4) the kinetic processes of bacterial cell lysis of E. coli by lysozyme and by temperature induction of lambda phage were detected real-time; (5) the fixation and rehydration of human platelets were quantitatively evaluated and characterized with Raman spectroscopy method, which provided a rapid way to quantify the quality of freeze-dried therapeutic

  10. Lignin analysis by FT-Raman spectroscopy

    SciTech Connect

    Agarwal, U.P.; Obst, J.R.; Cannon, A.B.

    1996-10-01

    Traditional methods of lignin analysis, such as Klason (acid insoluble) lignin determinations, give satisfactory results, are widely accepted, and often are considered as standard analyses. However, the Klason lignin method is laborious and time consuming; it also requires a fairly large-amount of isolated analyte. FT-Raman spectroscopy offers an opportunity to simplify and speed up lignin analyses. FT-Raman data for a number of hardwoods (angiosperms) and softwoods (gymnosperms) are compared with data obtained using other analytical methods, including Klason lignin (with corrections for acid soluble lignin), acetyl bromide, and FT-IR determinations. In addition, 10 different specimens of Nothofagus dombeyii (chosen because of the widely varying syringyl:guaiacyl monomer compositions of their lignins) were also analyzed. Lignin monomer compositions were determined by thioacidolysis of by nitrobenzene oxidation.

  11. Experimental correlation of electric fields and Raman signals in SERS and TERS

    NASA Astrophysics Data System (ADS)

    Schultz, Zachary D.; Wang, Hao; Kwasnieski, Daniel T.; Marr, James M.

    2015-08-01

    Enhanced Raman scattering from plasmonic nanostructures associated with surface enhanced (SERS) and tip enhanced (TERS) is seeing a dramatic increase in applications from bioimaging to chemical catalysis. The importance of gapmodes for high sensitivity indicates plasmon coupling between nanostructures plays an important role. However, the observed Raman scattering can change with different geometric arrangements of nanoparticles, excitation wavelengths, and chemical environments; suggesting differences in the local electric field. Our results indicate that molecules adsorbed to the nanostructures are selectively enhanced in the presence of competing molecules. This selective enhancement arises from controlled interactions between nanostructures, such as an isolated nanoparticle and a TERS tip. Complementary experiments suggest that shifts in the vibrational frequency of reporter molecules can be correlated to the electric field. Here we present a strategy that utilizes the controlled formation of coupled plasmonic structures to experimentally measure both the magnitude of the electric fields and the observed Raman scattering.

  12. Experimental correlation of electric fields and Raman signals in SERS and TERS

    PubMed Central

    Schultz, Zachary D.; Wang, Hao; Kwasnieski, Daniel T.; Marr, James M.

    2015-01-01

    Enhanced Raman scattering from plasmonic nanostructures associated with surface enhanced (SERS) and tip enhanced (TERS) is seeing a dramatic increase in applications from bioimaging to chemical catalysis. The importance of gap-modes for high sensitivity indicates plasmon coupling between nanostructures plays an important role. However, the observed Raman scattering can change with different geometric arrangements of nanoparticles, excitation wavelengths, and chemical environments; suggesting differences in the local electric field. Our results indicate that molecules adsorbed to the nanostructures are selectively enhanced in the presence of competing molecules. This selective enhancement arises from controlled interactions between nanostructures, such as an isolated nanoparticle and a TERS tip. Complementary experiments suggest that shifts in the vibrational frequency of reporter molecules can be correlated to the electric field. Here we present a strategy that utilizes the controlled formation of coupled plasmonic structures to experimentally measure both the magnitude of the electric fields and the observed Raman scattering. PMID:26412927

  13. Simultaneous Conoscopic Holography and Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Schramm, Harry F.; Kaiser, Bruce

    2005-01-01

    A new instrument was developed for chemical characterization of surfaces that combines the analytical power of Raman spectroscopy with the three-dimensional topographic information provided by conoscopic holography. The figure schematically depicts the proposed hybrid instrument. The output of the conoscopic holographic portion of the instrument is a topographical map of the surface; the output of the Raman portion of the instrument is hyperspectral Raman data, from which the chemical and/or biological composition of the surface would be deduced. By virtue of the basic principles of design and operation of the instrument, the hyperspectral image data would be inherently spatially registered with the topographical data. In conoscopic holography, the object and reference beams of classical holography are replaced by the ordinary and extraordinary components generated by a single beam traveling through a birefringent, uniaxial crystal. In the basic conoscopic configuration, a laser light is projected onto a specimen and the resulting illuminated spot becomes a point source of diffuse light that propagates in every direction. The laser beam is rasterscanned in two dimensions (x and y) perpendicular to the beam axis (z), and at each x,y location, the pattern of interference between the ordinary and extraordinary rays is recorded. The recorded interferogram constitutes the conoscopic hologram. Of particular significance for the proposed instrument is that the conoscopic hologram contains information on the z coordinate (height) of the illuminated surface spot. Hence, a topographical map of the specimen is constructed point-by-point by rastering the laser beam in the x and y directions and correlating the x and y coordinates with the z information obtained from the interferograms. Conoscopic imaging is an established method, and conoscopic laboratory instruments for surface metrology are commercially available. In Raman spectroscopy of a surface, one measures the spectrum

  14. Monosodium glutamate in its anhydrous and monohydrate form: Differentiation by Raman spectroscopies and density functional calculations

    NASA Astrophysics Data System (ADS)

    Peica, N.; Lehene, C.; Leopold, N.; Schlücker, S.; Kiefer, W.

    2007-03-01

    Monosodium glutamate (MSG), a common flavor enhancer, is detected in aqueous solutions by Raman and surface-enhanced Raman (SERS) spectroscopies at the micromolar level. The presence of different species, such as protonated and unprotonated MSG, is demonstrated by concentration and pH dependent Raman and SERS experiments. In particular, the symmetric bending modes of the amino group and the stretching modes of the carboxy moiety are employed as marker bands. The protonation of the NH 2 group at acidic pH values, for example, is detected in the Raman spectra. From the measured SERS spectra, a strong chemical interaction of MSG with the colloidal particles is deduced and a geometry of MSG adsorbed on the silver surface is proposed. In order to assign the observed Raman bands, calculations employing density functional theory (DFT) were performed. The calculated geometries, harmonic vibrational wavenumbers and Raman scattering activities for both MSG forms are in good agreement with experimental data. The set of theoretical data enables a complete vibrational assignment of the experimentally detected Raman spectra and the differentiation between the anhydrous and monohydrate forms of MSG.

  15. Derivatization reaction-based surface-enhanced Raman scattering (SERS) for detection of trace acetone.

    PubMed

    Zheng, Ying; Chen, Zhuo; Zheng, Chengbin; Lee, Yong-Ill; Hou, Xiandeng; Wu, Li; Tian, Yunfei

    2016-08-01

    A facile method was developed for determination of trace volatile acetone by coupling a derivatization reaction to surface-enhanced Raman scattering (SERS). With iodide modified Ag nanoparticles (Ag IMNPs) as the SERS substrate, acetone without obvious Raman signal could be converted to SERS-sensitive species via a chemical derivatization reaction with 2,4-dinitrophenylhydrazine (2,4-DNPH). In addition, acetone can be effectively separated from liquid phase with a purge-sampling device and then any serious interference from sample matrices can be significantly reduced. The optimal conditions for the derivatization reaction and the SERS analysis were investigated in detail, and the selectivity and reproducibility of this method were also evaluated. Under the optimal conditions, the limit of detection (LOD) for acetone was 5mgL(-1) or 0.09mM (3σ). The relative standard deviation (RSD) for 80mgL(-1) acetone (n=9) was 1.7%. This method was successfully used for the determination of acetone in artificial urine and human urine samples with spiked recoveries ranging from 92% to 110%. The present method is convenient, sensitive, selective, reliable and suitable for analysis of trace acetone, and it could have a promising clinical application in early diabetes diagnosis. PMID:27216660

  16. Surface-enhanced Raman scattering (SERS) evaluation protocol for nanometallic surfaces.

    PubMed

    Guicheteau, Jason A; Farrell, Mikella E; Christesen, Steven D; Fountain, Augustus W; Pellegrino, Paul M; Emmons, Erik D; Tripathi, Ashish; Wilcox, Phillip; Emge, Darren

    2013-04-01

    We present the results of a three-year collaboration between the U.S. Army Edgewood Chemical Biological Center and the U.S. Army Research Laboratory-Aldelphi Laboratory Center on the evaluation of selected nanometallic surfaces developed for the Defense Advanced Research Projects Agency Surface-Enhanced Raman Scattering (SERS) Science and Technology Fundamentals program. The primary role of the two Army labs was to develop the analytical and spectroscopic figures of merit to unambiguously compare the sensitivity and reproducibility of various SERS substrates submitted by the program participants. We present the design and implementation of an evaluation protocol for SERS active surfaces enabling an enhancement value calculation from which different substrates can be directly compared. This method was established to: (1) collect physical and spectral characterization data from the small number of substrates (performer supplied) typically encountered, and (2) account for the complex fabrication technique and varying nature of the substrate platforms encountered within this program. PMID:23601539

  17. Prospects for point-of-care pathogen diagnostics using surface-enhanced Raman scattering (SERS).

    PubMed

    Granger, Jennifer H; Schlotter, Nicholas E; Crawford, Alexis C; Porter, Marc D

    2016-07-11

    Surface-enhanced Raman scattering (SERS) has enabled the detection of pathogens and disease markers at extremely low levels. This review examines the potential impact of SERS in addressing unmet needs in pathogen diagnostics both in a traditional clinical setting and in the point of care (POC) arena. It begins by describing the strengths and weaknesses of today's diagnostics technologies in order to set a contextual stage for an overview which highlights a few of the many recent developments using SERS in biodefense, human and animal health, and monitoring food and water safety. These sections are followed by discussions of the challenges for the translation of these developments to POC settings, including the performance attributes and metrics for quantification of analytical and clinical figures of merit (e.g., limit of detection and clinical accuracy), and the pathways for large-scale test validation and the build-out of instrumentation and tests kits for POC deployment. PMID:27048939

  18. Surface-enhanced Raman spectroscopy at single-molecule scale and its implications in biology.

    PubMed

    Wang, Yuling; Irudayaraj, Joseph

    2013-02-01

    Single-molecule (SM) spectroscopy has been an exciting area of research offering significant promise and hope in the field of sensor development to detect targets at ultra-low levels down to SM resolution. To the experts and developers in the field of surface-enhanced Raman spectroscopy (SERS), this has often been a challenge and a significant opportunity for exploration. Needless to say, the opportunities and excitement of this multidisciplinary area impacts span the fields of physics, chemistry and engineering, along with a significant thrust in applications constituting areas in medicine, biology, environment and agriculture among others. In this review, we will attempt to provide a quick snapshot of the basics of SM-SERS, nanostructures and devices that can enable SM Raman measurement. We will conclude with a discussion on SERS implications in biomedical sciences. PMID:23267180

  19. Surface-enhanced Raman spectroscopy at single-molecule scale and its implications in biology

    PubMed Central

    Wang, Yuling; Irudayaraj, Joseph

    2013-01-01

    Single-molecule (SM) spectroscopy has been an exciting area of research offering significant promise and hope in the field of sensor development to detect targets at ultra-low levels down to SM resolution. To the experts and developers in the field of surface-enhanced Raman spectroscopy (SERS), this has often been a challenge and a significant opportunity for exploration. Needless to say, the opportunities and excitement of this multidisciplinary area impacts span the fields of physics, chemistry and engineering, along with a significant thrust in applications constituting areas in medicine, biology, environment and agriculture among others. In this review, we will attempt to provide a quick snapshot of the basics of SM-SERS, nanostructures and devices that can enable SM Raman measurement. We will conclude with a discussion on SERS implications in biomedical sciences. PMID:23267180

  20. Serum albumin analysis for type II diabetes detection using surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lin, Jinyong; Cao, Gang; Lin, Juqiang; Liu, Nenrong; Liao, Fadian; Ruan, Qiuyong; Wu, Shanshan; Huang, Zufang; Li, Ling; Chen, Rong

    2014-09-01

    Surface-enhanced Raman scattering (SERS) spectroscopy combined with membrane electrophoresis (ME) was firstly employed to detect albumin variation in type II diabetic development. Albumin was first purified from human serum by ME and then mixed with silver nanoparticles to perform SERS spectral analysis. SERS spectra were obtained from blood albumin samples of 20 diabetic patients and 19 healthy volunteers. Subtle but discernible changes in the acquired mean spectra of the two groups were observed. Tentative assignment of albumin SERS bands indicated specific structural changes of albumin molecule with diabetic development. Meanwhile, PCA-LDA diagnostic algorithms were employed to classify the two kinds of albumin SERS spectra, yielding the diagnostic sensitivity of 90% and specificity of 94.7%. The results from this exploratory study demonstrated that the EM-SERS method in combination with multivariate statistical analysis has great potential for the label-free detection of albumin variation for improving type II diabetes screening.

  1. Characterization of Thalidomide using Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Cipriani, Penelope; Smith, Candace Y.

    2008-02-01

    Thalidomide is a potent anticancer therapeutic drug whose mechanism of action has not yet been elucidated. In this report, experimental Raman spectroscopy is used to determine and characterize the vibrational frequencies of the drug. These normal modes are then compared to their quantum mechanical counterparts, which have been computed using density functional theory. Upon analysis of the spectra, we found that there was a high level of agreement between the wavenumbers. As such, this spectroscopic technique may be a viable tool for examining the way in which this drug interacts with its target molecules.

  2. Rich variety of substrates for surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Nguyen, Bich Ha; Hieu Nguyen, Van; Nhung Tran, Hong

    2016-09-01

    The efficiency of the application of surface enhanced Raman spectroscopy (SERS) technique to each specified purpose significantly depends on the choice of the SERS substrate with an appropriate structure as well as on its performance. Until the present time a rich variety of SERS substrates was fabricated. They can be classified according to their structures. The present work is a review of main types of SERS substrates for using in the trace analysis application. They can be classified into 4 groups: (1) Substrates using gold nanoparticles (AuNPs) with spherical shape such as colloidal AuNPs, AuNPs fabricated by pulsed laser deposition, by sputtering or by capillary force assembly (CFA), substrates fabricated by electrospinning technique, substrates using metallic nanoparticle arrays fabricated by electron beam lithography combined with CFA method, substrates using silver nanoparticle (AgNP) arrays grain by chemical seeded method, substrates with tunable surface plasmon resonance, substrates based on precies subnanometer plasmonic junctions within AuNP assemblies, substrates fabricated by simultaneously immobilizing both AuNPs and AgNPs on the same glass sides etc. (2) Substrates using nanostructures with non-spherical shapes such as gold nanowire (NW), or highly anisotropic nickel NW together with large area, free-standing carpets, substrates with obviously angular, quasi-vertically aligned cuboid-shaped TiO2 NW arrays decorated with AgNPs, substrates using gold nanoprism monolayer films, substrates using silver nanocube dimmers or monodisperse close-packed gold nanotriangle monolayers. (3) Substrates using multiparticle complex nanostructure such as nanoparticle cluster arrays, gold nanoflowers and nanodendrites. (4) Flexible substrate such as paper-based swab with gold nanorods, adhesive polymer tapes fabricated by inkjet printing method and flexible and adhesive SERS tapes fabricated by decorating AuNPs via the conventional drop-dry method.

  3. Quantum Chemical Study of Raman Spectroscopy of Substituted Benzene Derivatives Adsorbed on Metal Surfaces

    NASA Astrophysics Data System (ADS)

    Wu, De-Yin; Tian, Zhong-Qun

    2011-06-01

    Surface-enhanced Raman spectroscopy (SERS) can be applied to obtain the information of molecules at the noble metal surfaces. But there are a number of difficulties to clearly correlate Raman spectra with microscopic molecular structures on metal surfaces. The main reason is that it is difficult to characterize unambiguously the metal surface structures and the influence of the binding interaction on SERS signals of the probe molecules. According to the surface selection rule of SERS, the electromagnetic enhancement will not change relative Raman intensities of vibrational modes with the same irreducible representation. Therefore, the change of the relative Raman intensities of the total symmetric modes may only originate from the chemical enhancement. In order to understand how the chemical interaction modulates the Raman intensity of individual modes, it is necessary to systematically investigate the Raman spectra of probe molecules themselves and the dependence of SERS signals on the binding interaction, adsorption sites, excitation wavelengths and metal property. Some probe molecules, including aniline, 1,4-benzenediamine, p-aminothiophenol, benzyl chlorine, and 4,4^'-bipyridine are investigated based on quantum chemical calculations. Raman spectra of these molecules and their adsorbed species were predicted and compared with experimentally measured spectra. The metal surfaces were mimicked using the metallic cluster model, where the silver or gold surfaces were replaced by silver or gold clusters, respectively. The density functional theory approach was employed to obtain the optimized structures and vibrational spectra by combining all-electron basis sets of 6-311+G** for atoms in the molecules and the poseudopotential basis set of LANL2DZ for metal atoms. The vibrational frequency shift and the relative Raman intensity are related to the adsorption configuration of the probe molecules. For all these molecules, the ring breathing mode and the C-C stretching

  4. Chemical analysis of acoustically levitated drops by Raman spectroscopy.

    PubMed

    Tuckermann, Rudolf; Puskar, Ljiljana; Zavabeti, Mahta; Sekine, Ryo; McNaughton, Don

    2009-07-01

    An experimental apparatus combining Raman spectroscopy with acoustic levitation, Raman acoustic levitation spectroscopy (RALS), is investigated in the field of physical and chemical analytics. Whereas acoustic levitation enables the contactless handling of microsized samples, Raman spectroscopy offers the advantage of a noninvasive method without complex sample preparation. After carrying out some systematic tests to probe the sensitivity of the technique to drop size, shape, and position, RALS has been successfully applied in monitoring sample dilution and preconcentration, evaporation, crystallization, an acid-base reaction, and analytes in a surface-enhanced Raman spectroscopy colloidal suspension. PMID:19418043

  5. Chemical agent detection by surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Farquharson, Stuart; Gift, Alan; Maksymiuk, Paul; Inscore, Frank E.; Smith, Wayne W.; Morrisey, Kevin; Christesen, Steven D.

    2004-03-01

    In the past decade, the Unites States and its allies have been challenged by a different kind of warfare, exemplified by the terrorist attacks of September 11, 2001. Although suicide bombings are the most often used form of terror, military personnel must consider a wide range of attack scenarios. Among these is the intentional poisoning of water supplies to obstruct military operations in Afghanistan and Iraq. To counter such attacks, the military is developing portable analyzers that can identify and quantify potential chemical agents in water supplies at microgram per liter concentrations within 10 minutes. To aid this effort we have been investigating the value of a surface-enhanced Raman spectroscopy based portable analyzer. In particular we have been developing silver-doped sol-gels to generate SER spectra of chemical agents and their hydrolysis products. Here we present SER spectra of several chemical agents measured in a generic tap water. Repeat measurements were performed to establish statistical error associated with SERS obtained using the sol-gel coated vials.

  6. Surface-enhanced raman spectroscopy substrate for arsenic sensing in groundwater

    DOEpatents

    Yang, Peidong; Mulvihill, Martin; Tao, Andrea R.; Sinsermsuksakul, Prasert; Arnold, John

    2015-06-16

    A surface-enhanced Raman spectroscopy (SERS) substrate formed from a plurality of monolayers of polyhedral silver nanocrystals, wherein at least one of the monolayers has polyvinypyrrolidone (PVP) on its surface, and thereby configured for sensing arsenic is described. Highly active SERS substrates are formed by assembling high density monolayers of differently shaped silver nanocrystals onto a solid support. SERS detection is performed directly on this substrate by placing a droplet of the analyte solution onto the nanocrystal monolayer. Adsorbed polymer, polyvinypyrrolidone (PVP), on the surface of the nanoparticles facilitates the binding of both arsenate and arsenite near the silver surface, allowing for highly accurate and sensitive detection capabilities.

  7. Surface-Enhanced Raman Spectroscopy Biosensing: In Vivo Diagnostics and Multimodal Imaging.

    PubMed

    Henry, Anne-Isabelle; Sharma, Bhavya; Cardinal, M Fernanda; Kurouski, Dmitry; Van Duyne, Richard P

    2016-07-01

    This perspective presents recent developments in the application of surface-enhanced Raman spectroscopy (SERS) to biosensing, with a focus on in vivo diagnostics. We describe the concepts and methodologies developed to date and the target analytes that can be detected. We also discuss how SERS has evolved from a "point-and-shoot" stand-alone technique in an analytical chemistry laboratory to an integrated quantitative analytical tool for multimodal imaging diagnostics. Finally, we offer a guide to the future of SERS in the context of clinical diagnostics. PMID:27268724

  8. UTI diagnosis and antibiogram using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Kastanos, Evdokia; Kyriakides, Alexandros; Hadjigeorgiou, Katerina; Pitris, Constantinos

    2009-07-01

    Urinary tract infection diagnosis and antibiogram require a 48 hour waiting period using conventional methods. This results in ineffective treatments, increased costs and most importantly in increased resistance to antibiotics. In this work, a novel method for classifying bacteria and determining their sensitivity to an antibiotic using Raman spectroscopy is described. Raman spectra of three species of gram negative Enterobacteria, most commonly responsible for urinary tract infections, were collected. The study included 25 samples each of E.coli, Klebsiella p. and Proteus spp. A novel algorithm based on spectral ratios followed by discriminant analysis resulted in classification with over 94% accuracy. Sensitivity and specificity for the three types of bacteria ranged from 88-100%. For the development of an antibiogram, bacterial samples were treated with the antibiotic ciprofloxacin to which they were all sensitive. Sensitivity to the antibiotic was evident after analysis of the Raman signatures of bacteria treated or not treated with this antibiotic as early as two hours after exposure. This technique can lead to the development of new technology for urinary tract infection diagnosis and antibiogram with same day results, bypassing urine cultures and avoiding all undesirable consequences of current practice.

  9. Disease recognition by infrared and Raman spectroscopy.

    PubMed

    Krafft, Christoph; Steiner, Gerald; Beleites, Claudia; Salzer, Reiner

    2009-02-01

    Infrared (IR) and Raman spectroscopy are emerging biophotonic tools to recognize various diseases. The current review gives an overview of the experimental techniques, data-classification algorithms and applications to assess soft tissues, hard tissues and body fluids. The methodology section presents the principles to combine vibrational spectroscopy with microscopy, lateral information and fiber-optic probes. A crucial step is the classification of spectral data by a variety of algorithms. We discuss unsupervised algorithms such as cluster analysis or principal component analysis and supervised algorithms such as linear discriminant analysis, soft independent modeling of class analogies, artificial neural networks support vector machines, Bayesian classification, partial least-squares regression and ensemble methods. The selected topics include tumors of epithelial tissue, brain tumors, prion diseases, bone diseases, atherosclerosis, kidney stones and gallstones, skin tumors, diabetes and osteoarthritis. PMID:19343682

  10. Coronagraphic Notch Filter for Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Cohen, David; Stirbl, Robert

    2004-01-01

    A modified coronagraph has been proposed as a prototype of improved notch filters in Raman spectrometers. Coronagraphic notch filters could offer alternatives to both (1) the large and expensive double or triple monochromators in older Raman spectrometers and (2) holographic notch filters, which are less expensive but are subject to environmental degradation as well as to limitations of geometry and spectral range. Measurement of a Raman spectrum is an exercise in measuring and resolving faint spectral lines close to a bright peak: In Raman spectroscopy, a monochromatic beam of light (the pump beam) excites a sample of material that one seeks to analyze. The pump beam generates a small flux of scattered light at wavelengths slightly greater than that of the pump beam. The shift in wavelength of the scattered light from the pump wavelength is known in the art as the Stokes shift. Typically, the flux of scattered light is of the order of 10 7 that of the pump beam and the Stokes shift lies in the wave-number range of 100 to 3,000 cm 1. A notch filter can be used to suppress the pump-beam spectral peak while passing the nearby faint Raman spectral lines. The basic principles of design and operation of a coronagraph offer an opportunity for engineering the spectral transmittance of the optics in a Raman spectrometer. A classical coronagraph may be understood as two imaging systems placed end to end, such that the first system forms an intermediate real image of a nominally infinitely distant object and the second system forms a final real image of the intermediate real image. If the light incident on the first telescope is collimated, then the intermediate image is a point-spread function (PSF). If an appropriately tailored occulting spot (e.g., a Gaussian-apodized spot with maximum absorption on axis) is placed on the intermediate image plane, then the instrument inhibits transmission of light from an on-axis source. However, the PSFs of off-axis light sources are