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Sample records for raman spectroscopy sers

  1. Normal Raman and SERS spectroscopy of the vitamin E

    NASA Astrophysics Data System (ADS)

    Cai, Tiantian; Gu, Huaimin; Yuan, Xiaojuan; Liu, Fangfang

    2011-01-01

    In this study, surface-enhanced Raman scattering(SERS)spectra of vitamin E were obtained on colloidal silver(Ag). Alpha-(-) tocopherol which is the only form that is recognized to meet human requirements was selected to study. The analytes (±)- -tocopherol were dissolved in chloroform (CHCl3) and the silver colloid was poured into the compound. Silver colloid was reduced by hydroxylamine hydrochloride. The analytes were the supernatant after standing the mixture for the reason that chloroform have no signals in surface-enhanced Raman scattering in the Ag colloid, and it would not affect the determination of the (±)- -tocopherol. The Normal Raman and SERS spectrum of Vitamin E were contrastively studied to realize how the vitamin E stuck to the silver nanoparticles. The results show the fat-soluble substances can be analysed by SERS. The spectra indicate that the molecules are adsorbed on the surface through the COO- groups by the simultaneous involvement of a and -type coordination. These results suggest some important criteria for consideration in SERS measurements and also provide important insights into the problem of predicting SERS activities for different fat-soluble substances.

  2. Determination of resonance Raman cross-sections for use in biological SERS sensing with femtosecond stimulated Raman spectroscopy.

    PubMed

    Silva, W Ruchira; Keller, Emily L; Frontiera, Renee R

    2014-08-05

    Surface-enhanced Raman spectroscopy (SERS) is a promising technique for in vivo bioanalyte detection, but accurate characterization of SERS biosensors can be challenging due to difficulties in differentiating resonance and surface enhancement contributions to the Raman signal. Here, we quantitate the resonance Raman cross-sections for a commonly used near-infrared SERS dye, 3,3'-diethylthiatricarbocyanine (DTTC). It is typically challenging to measure resonance Raman cross-sections for fluorescent dye molecules due to the overwhelming isoenergetic fluorescence signal. To overcome this issue, we used etalon-based femtosecond stimulated Raman spectroscopy, which is intrinsically designed to acquire a stimulated Raman signal without strong fluorescence or interference from signals resulting from other four-wave mixing pathways. Using this technique, we found that the cross-sections for most of the resonantly enhanced modes in DTTC exceed 10(-25) cm(2)/molecule. These cross-sections lead to high signal magnitude SERS signals from even weakly enhancing SERS substrates, as much of what appears to be a SERS signal is actually coming from the intrinsically strong resonance Raman signal. Our work will lead to a more accurate determination of SERS enhancement factors and SERS substrate characterization in the biologically relevant near-infrared region, ultimately leading to a more widespread use of SERS for biosensing and bioimaging applications.

  3. Aromatic amino acids providing characteristic motifs in the Raman and SERS spectroscopy of peptides.

    PubMed

    Wei, Fang; Zhang, Dongmao; Halas, Naomi J; Hartgerink, Jeffrey D

    2008-07-31

    Raman and surface-enhanced Raman spectroscopies (SERS) are potentially important tools in the characterization of biomolecules such as proteins and DNA. In this work, SERS spectra of three cysteine-containing aromatic peptides: tryptophan-cysteine, tyrosine-cysteine, and phenylalanine-cysteine, bound to Au nanoshell substrates, were obtained, and compared to their respective normal Raman spectra. While the linewidths of the SERS peaks are significantly broadened (up to 70%), no significant spectral shifts (<6 cm (-1)) of the major Stokes modes were observed between the two modalities. We show that the Raman and SERS spectra of penetratin, a cell-penetrating peptide oligomer, can be comprised quite reliably from the spectra of its constituent aromatic amino acids except in the backbone regions where the spectral intensities are critically dependent on the length and conformations of the probed molecules. From this study we conclude that, together with protein backbone groups, aromatic amino acid residues provide the overwhelmingly dominant features in the Raman and SERS spectra of peptides and proteins when present. It follows that the Raman modes of these three small constructed peptides may likely apply to the assignment of Raman and SERS features in the spectra of other peptides and proteins.

  4. A specially modified surface-enhanced Raman spectroscopy (SERS) substrate for biomedical applications

    NASA Astrophysics Data System (ADS)

    Yuen, Clement; Zheng, Wei; Huang, Zhiwei

    2008-02-01

    Hierarchically-ordered Au film-coated polystyrene beads have been well-known to be employed as surface enhanced Raman spectroscopy (SERS) substrate. In this study, we propose a novel and facile method to modify the performance of this SERS substrate and investigate the chemical components in saliva. Results have demonstrated that there is at least a 4-fold increase in SERS signals using the modified substrates compared to the non-modified substrates. Besides, the SERS performances of substrates modified by different preparation conditions are examined and compared. These findings show that our fabricated substrates are effective in further enhancing SERS signals and have potential for biomedical applications in trace analytes analysis.

  5. Determination of histamine in fish by Surface Enhanced Raman Spectroscopy using silver colloid SERS substrates.

    PubMed

    Janči, Tibor; Valinger, Davor; Gajdoš Kljusurić, Jasenka; Mikac, Lara; Vidaček, Sanja; Ivanda, Mile

    2017-06-01

    This study was focused on development of a rapid and sensitive method for histamine determination in fish based on Surface Enhanced Raman Spectroscopy (SERS) using simple and widely available silver colloid SERS substrate. Extraction of histamine with 0.4M perchloric acid and purification with 1-butanol significantly shortened sample preparation (30min) and provided clear SERS spectra with characteristic Raman bands of histamine. Principal component analysis effectively distinguished SERS spectra of fish samples with different histamine content. Partial least square (PLS) regression models confirmed reliability of detection and spectral analysis of histamine with SERS. In histamine concentration range 0-200mgkg(-1), significant in legislative and fish quality control aspects, PLS regression model based on spectral range 1139.9-1643.7cm(-1) showed linear trend with R(2)pred=0.962, RPD=7.250. Presented protocol for histamine extraction and purification followed by SERS analysis coupled with chemometric approach, enabled development of rapid and inexpensive method for histamine determination in fish.

  6. 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.

  7. 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.

  8. Surface enhanced Raman spectroscopy (SERS) for in vitro diagnostic testing at the point of care

    NASA Astrophysics Data System (ADS)

    Marks, Haley; Schechinger, Monika; Garza, Javier; Locke, Andrea; Coté, Gerard

    2017-06-01

    Point-of-care (POC) device development is a growing field that aims to develop low-cost, rapid, sensitive in-vitro diagnostic testing platforms that are portable, self-contained, and can be used anywhere - from modern clinics to remote and low resource areas. In this review, surface enhanced Raman spectroscopy (SERS) is discussed as a solution to facilitating the translation of bioanalytical sensing to the POC. The potential for SERS to meet the widely accepted "ASSURED" (Affordable, Sensitive, Specific, User-friendly, Rapid, Equipment-free, and Deliverable) criterion provided by the World Health Organization is discussed based on recent advances in SERS in vitro assay development. As SERS provides attractive characteristics for multiplexed sensing at low concentration limits with a high degree of specificity, it holds great promise for enhancing current efforts in rapid diagnostic testing. In outlining the progression of SERS techniques over the past years combined with recent developments in smart nanomaterials, high-throughput microfluidics, and low-cost paper diagnostics, an extensive number of new possibilities show potential for translating SERS biosensors to the POC.

  9. 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. © 2014 Institute of Food Technologists®

  10. Potential of Surface Enhanced Raman Spectroscopy (SERS) in Therapeutic Drug Monitoring (TDM). A Critical Review

    PubMed Central

    Jaworska, Aleksandra; Fornasaro, Stefano; Sergo, Valter; Bonifacio, Alois

    2016-01-01

    Surface-Enhanced Raman Spectroscopy (SERS) is a label-free technique that enables quick monitoring of substances at low concentrations in biological matrices. These advantages make it an attractive tool for the development of point-of-care tests suitable for Therapeutic Drug Monitoring (TDM) of drugs with a narrow therapeutic window, such as chemotherapeutic drugs, immunosuppressants, and various anticonvulsants. In this article, the current applications of SERS in the field of TDM for cancer therapy are discussed in detail and illustrated according to the different strategies and substrates. In particular, future perspectives are provided and special concerns regarding the standardization of self-assembly methods and nanofabrication procedures, quality assurance, and technology readiness are critically evaluated. PMID:27657146

  11. 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.

  12. Potential of Surface Enhanced Raman Spectroscopy (SERS) in Therapeutic Drug Monitoring (TDM). A Critical Review.

    PubMed

    Jaworska, Aleksandra; Fornasaro, Stefano; Sergo, Valter; Bonifacio, Alois

    2016-09-19

    Surface-Enhanced Raman Spectroscopy (SERS) is a label-free technique that enables quick monitoring of substances at low concentrations in biological matrices. These advantages make it an attractive tool for the development of point-of-care tests suitable for Therapeutic Drug Monitoring (TDM) of drugs with a narrow therapeutic window, such as chemotherapeutic drugs, immunosuppressants, and various anticonvulsants. In this article, the current applications of SERS in the field of TDM for cancer therapy are discussed in detail and illustrated according to the different strategies and substrates. In particular, future perspectives are provided and special concerns regarding the standardization of self-assembly methods and nanofabrication procedures, quality assurance, and technology readiness are critically evaluated.

  13. 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

  14. Monitoring cell culture media degradation using surface enhanced Raman scattering (SERS) spectroscopy.

    PubMed

    Calvet, Amandine; Ryder, Alan G

    2014-08-20

    The quality of the cell culture media used in biopharmaceutical manufacturing is a crucial factor affecting bioprocess performance and the quality of the final product. Due to their complex composition these media are inherently unstable, and significant compositional variations can occur particularly when in the prepared liquid state. For example photo-degradation of cell culture media can have adverse effects on cell viability and thus process performance. There is therefore, from quality control, quality assurance and process management view points, an urgent demand for the development of rapid and inexpensive tools for the stability monitoring of these complex mixtures. Spectroscopic methods, based on fluorescence or Raman measurements, have now become viable alternatives to more time-consuming and expensive (on a unit analysis cost) chromatographic and/or mass spectrometry based methods for routine analysis of media. Here we demonstrate the application of surface enhanced Raman scattering (SERS) spectroscopy for the simple, fast, analysis of cell culture media degradation. Once stringent reproducibility controls are implemented, chemometric data analysis methods can then be used to rapidly monitor the compositional changes in chemically defined media. SERS shows clearly that even when media are stored at low temperature (2-8°C) and in the dark, significant chemical changes occur, particularly with regard to cysteine/cystine concentration. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    PubMed

    Kurouski, Dmitry; Van Duyne, Richard P

    2015-03-03

    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.

  16. Surface Enhanced Raman Spectroscopy (SERS) and multivariate analysis as a screening tool for detecting Sudan I dye in culinary spices

    NASA Astrophysics Data System (ADS)

    Di Anibal, Carolina V.; Marsal, Lluís F.; Callao, M. Pilar; Ruisánchez, Itziar

    2012-02-01

    Raman spectroscopy combined with multivariate analysis was evaluated as a tool for detecting Sudan I dye in culinary spices. Three Raman modalities were studied: normal Raman, FT-Raman and SERS. The results show that SERS is the most appropriate modality capable of providing a proper Raman signal when a complex matrix is analyzed. To get rid of the spectral noise and background, Savitzky-Golay smoothing with polynomial baseline correction and wavelet transform were applied. Finally, to check whether unadulterated samples can be differentiated from samples adulterated with Sudan I dye, an exploratory analysis such as principal component analysis (PCA) was applied to raw data and data processed with the two mentioned strategies. The results obtained by PCA show that Raman spectra need to be properly treated if useful information is to be obtained and both spectra treatments are appropriate for processing the Raman signal. The proposed methodology shows that SERS combined with appropriate spectra treatment can be used as a practical screening tool to distinguish samples suspicious to be adulterated with Sudan I dye.

  17. Improving Sensitivity and Reproducibility of SERS Sensing in Microenvironments Using Individual, Optically Trapped Surface-Enhanced Raman Spectroscopy(SERS) Probes.

    PubMed

    Strobbia, Pietro; Mayer, Adam; Cullum, Brian M

    2017-02-01

    Surface-enhanced Raman spectroscopy (SERS) sensors offer many advantages for chemical analyses, including the ability to provide chemical specific information and multiplexed detection capability at specific locations. However, to have operative SERS sensors for probing microenvironments, probes with high signal enhancement and reproducibility are necessary. To this end, dynamic enhancement of SERS (i.e., in-situ amplification of signal-to-noise and signal-to-background ratios) from individual probes has been explored. In this paper, we characterize the use of optical tweezers to amplify SERS signals as well as suppress background signals via trapping of individual SERS active probes. This amplification is achieved through a steady presence of a single "hot" particle in the focus of the excitation laser. In addition to increases in signal and concomitant decreases in non-SERS backgrounds, optical trapping results in an eightfold increase in the stability of the signal as well. This enhancement strategy was demonstrated using both single and multilayered SERS sub-micron probes, producing combined signal enhancements of 24-fold (beyond the native 10(6) SERS enhancement) for a three-layered geometry. The ability to dynamically control the enhancement offers the possibility to develop SERS-based sensors and probes with tailored sensitivities. In addition, since this trapping enhancement can be used to observe individual probes with low laser fluences, it could offer particular interest in probing the composition of microenvironments not amenable to tip-enhanced Raman spectroscopy or other scanning probe methods (e.g., intracellular analyses, etc.).

  18. 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.

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

    SciTech Connect

    Mohseni, Hooman; Agahi, Massoud H.; Razeghi, Manijeh; Polisetti, Sneha; Baig, Nameera; Bible, Amber; Morrell-Falvey, Jennifer; Doktycz, Mitchel; Bohn, Paul W.

    2015-08-21

    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.

  20. Atmospheric oxidation and carbon contamination of silver and its effect on surface-enhanced Raman spectroscopy (SERS)

    PubMed Central

    Matikainen, Antti; Nuutinen, Tarmo; Itkonen, Tommi; Heinilehto, Santtu; Puustinen, Jarkko; Hiltunen, Jussi; Lappalainen, Jyrki; Karioja, Pentti; Vahimaa, Pasi

    2016-01-01

    Surface-enhanced Raman spectroscopy (SERS) is considered a highly promising technology for different analytical purposes. The applications of SERS are still quite limited due its relatively poor quantitative repeatability and the fact that SERS is very sensitive to oxidation, which is a challenge especially with silver based SERS substrates. Here, the link between these phenomena is investigated by exposing silver SERS substrates to ambient laboratory air. We show that SERS intensity decreases exponentially after the exposure, which consequently leads to an increasing standard deviation (σ) in intensity. Within a five-hour measurement window, the SERS intensity already drops by 60%, while σ triples from 7% to 21%. The SERS results are supplemented by elemental analysis, which shows that oxidation and atmospheric carbon contamination coincide with the rapid SERS intensity decrease. The results emphasize how sensitive SERS is towards atmospheric contamination and how it can also reduce the measurement repeatability – even if the substrates are exposed to air just for a very short period of time. PMID:27849010

  1. Atmospheric oxidation and carbon contamination of silver and its effect on surface-enhanced Raman spectroscopy (SERS)

    NASA Astrophysics Data System (ADS)

    Matikainen, Antti; Nuutinen, Tarmo; Itkonen, Tommi; Heinilehto, Santtu; Puustinen, Jarkko; Hiltunen, Jussi; Lappalainen, Jyrki; Karioja, Pentti; Vahimaa, Pasi

    2016-11-01

    Surface-enhanced Raman spectroscopy (SERS) is considered a highly promising technology for different analytical purposes. The applications of SERS are still quite limited due its relatively poor quantitative repeatability and the fact that SERS is very sensitive to oxidation, which is a challenge especially with silver based SERS substrates. Here, the link between these phenomena is investigated by exposing silver SERS substrates to ambient laboratory air. We show that SERS intensity decreases exponentially after the exposure, which consequently leads to an increasing standard deviation (σ) in intensity. Within a five-hour measurement window, the SERS intensity already drops by 60%, while σ triples from 7% to 21%. The SERS results are supplemented by elemental analysis, which shows that oxidation and atmospheric carbon contamination coincide with the rapid SERS intensity decrease. The results emphasize how sensitive SERS is towards atmospheric contamination and how it can also reduce the measurement repeatability - even if the substrates are exposed to air just for a very short period of time.

  2. Atmospheric oxidation and carbon contamination of silver and its effect on surface-enhanced Raman spectroscopy (SERS).

    PubMed

    Matikainen, Antti; Nuutinen, Tarmo; Itkonen, Tommi; Heinilehto, Santtu; Puustinen, Jarkko; Hiltunen, Jussi; Lappalainen, Jyrki; Karioja, Pentti; Vahimaa, Pasi

    2016-11-16

    Surface-enhanced Raman spectroscopy (SERS) is considered a highly promising technology for different analytical purposes. The applications of SERS are still quite limited due its relatively poor quantitative repeatability and the fact that SERS is very sensitive to oxidation, which is a challenge especially with silver based SERS substrates. Here, the link between these phenomena is investigated by exposing silver SERS substrates to ambient laboratory air. We show that SERS intensity decreases exponentially after the exposure, which consequently leads to an increasing standard deviation (σ) in intensity. Within a five-hour measurement window, the SERS intensity already drops by 60%, while σ triples from 7% to 21%. The SERS results are supplemented by elemental analysis, which shows that oxidation and atmospheric carbon contamination coincide with the rapid SERS intensity decrease. The results emphasize how sensitive SERS is towards atmospheric contamination and how it can also reduce the measurement repeatability - even if the substrates are exposed to air just for a very short period of time.

  3. Surface-enhanced Raman spectroscopy (SERS) for sub-micromolar detection of DNA/RNA mononucleotides.

    PubMed

    Bell, Steven E J; Sirimuthu, Narayana M S

    2006-12-13

    Surface-enhanced Raman (SER) spectra of all the DNA/RNA mononucleotides have been obtained with high sensitivity using citrate-reduced silver colloids aggregated with MgSO4, rather than the more usual halide ions, which were found to prevent enhancement of these compounds. The SERS spectra of adenine, guanine, thymine, cytosine, and uracil were recorded along with their corresponding nucleosides and 5'-deoxynucleotides. For the cytosine series, all three spectra had similar relative band intensities but the spectra of adenine were different from those of adenosine and dAMP, probably due to differences in orientation on the surface. No enhanced bands from the phosphate or sugar groups were observed. There were general similarities between the SERS spectra of the purine mononucleotides and the pyrimidine mononucleotides, but the spectra were sufficiently different to allow each of them to be distinguished. This method can therefore be used for high sensitivity, label-free identification of mononucleotides.

  4. Discrimination of gastric cancer from normal by serum RNA based on surface-enhanced Raman spectroscopy (SERS) and multivariate analysis

    PubMed Central

    Chen, Yanping; Chen, Gang; Zheng, Xiongwei; He, Cheng; Feng, Shangyuan; Chen, Yan; Lin, Xiaoqian; Chen, Rong; Zeng, Haisan

    2012-01-01

    Purpose: Here, the authors explore the feasibility of discriminating cancer patients from healthy controls by serum RNA detection based on surface-enhanced Raman spectroscopy (SERS) and multivariate analysis. Methods: MgSO4-aggregated silver nanoparticles (Ag NP) as the SERS-active substrate presented strong SERS signals to RNA. SERS measurements were performed on two groups of serum RNA samples: one group from patients (n = 31) with gastric cancer and the other group from healthy volunteers (n = 34). Results: Tentative assignments of the Raman bands in the normalized SERS spectra demonstrated that there are differential expressions of circulating RNA between the gastric cancer group and the control group. Principal component analysis (PCA) combined with linear discriminate analysis (LDA) was introduced to differentiate gastric cancer from normal and achieved sensitivity of 100% and specificity of 94.1%. Conclusions: This exploratory study demonstrated potential for developing serum RNA SERS analysis into a useful clinical tool for noninvasive screening and detection of cancer. PMID:22957632

  5. Surface Enhanced Raman Spectroscopy (SERS) methods for endpoint and real-time quantification of miRNA assays

    NASA Astrophysics Data System (ADS)

    Restaino, Stephen M.; White, Ian M.

    2017-03-01

    Surface Enhanced Raman spectroscopy (SERS) provides significant improvements over conventional methods for single and multianalyte quantification. Specifically, the spectroscopic fingerprint provided by Raman scattering allows for a direct multiplexing potential far beyond that of fluorescence and colorimetry. Additionally, SERS generates a comparatively low financial and spatial footprint compared with common fluorescence based systems. Despite the advantages of SERS, it has remained largely an academic pursuit. In the field of biosensing, techniques to apply SERS to molecular diagnostics are constantly under development but, most often, assay protocols are redesigned around the use of SERS as a quantification method and ultimately complicate existing protocols. Our group has sought to rethink common SERS methodologies in order to produce translational technologies capable of allowing SERS to compete in the evolving, yet often inflexible biosensing field. This work will discuss the development of two techniques for quantification of microRNA, a promising biomarker for homeostatic and disease conditions ranging from cancer to HIV. First, an inkjet-printed paper SERS sensor has been developed to allow on-demand production of a customizable and multiplexable single-step lateral flow assay for miRNA quantification. Second, as miRNA concentrations commonly exist in relatively low concentrations, amplification methods (e.g. PCR) are therefore required to facilitate quantification. This work presents a novel miRNA assay alongside a novel technique for quantification of nuclease driven nucleic acid amplification strategies that will allow SERS to be used directly with common amplification strategies for quantification of miRNA and other nucleic acid biomarkers.

  6. 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

    2015-09-07

    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.

  7. Raman spectroscopy

    USDA-ARS?s Scientific Manuscript database

    Raman spectroscopy has gained increased use and importance in recent years for accurate and precise detection of physical and chemical properties of food materials, due to the greater specificity and sensitivity of Raman techniques over other analytical techniques. This book chapter presents Raman s...

  8. 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…

  9. 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…

  10. Detection of deoxyribonucleic acid (DNA) targets using polymerase chain reaction (PCR) and paper surface-enhanced Raman spectroscopy (SERS) chromatography.

    PubMed

    Hoppmann, Eric P; Yu, Wei W; White, Ian M

    2014-01-01

    Surface-enhanced Raman spectroscopy (SERS) enables multiplex detection of analytes using simple, portable equipment consisting of a single excitation source and detector. Thus, in theory, SERS is ideally suited to replace fluorescence in assays that screen for numerous deoxyribonucleic acid (DNA) targets, but in practice, SERS-based assays have suffered from complexity and elaborate processing steps. Here, we report an assay in which a simple inkjet-fabricated plasmonic paper device enables SERS-based detection of multiple DNA targets within a single polymerase chain reaction (PCR). In prior work, we demonstrated the principles of chromatographic separation and SERS-based detection on inkjet-fabricated plasmonic paper. The present work extends that capability for post-PCR gene sequence detection. In this design, hydrolysis DNA probes with 5' Raman labels are utilized; if the target is present, the probe is hydrolyzed during PCR, freeing the reporter. After applying the PCR sample to a paper SERS device, an on-device chromatographic separation and concentration is conducted to discriminate between hydrolyzed and intact probes. SERS is then used to detect the reporter released by the hydrolyzed probes. This simple separation and detection on paper eliminates the need for complex sample processing steps. In this work, we simultaneously detect the methicillin-resistant Staphylococcus aureus genes mecA and femB to illustrate the concept. We envision that this approach could contribute to the development of multiplex DNA diagnostic tests enabling screening for several target sequences within a single reaction, which is necessary for cases in which sample volume and resources are limited.

  11. 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.

  12. 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

  13. Generation of ultralarge surface enhanced Raman spectroscopy (SERS)-active hot-spot volumes by an array of 2D nano-superlenses.

    PubMed

    Wei, KhoKiang; Shen, ZeXiang; Malini, Olivo

    2012-01-17

    Surface Enhanced Raman Spectroscopy (or SERS) has received tremendous attention in the past three decades. However, the extremely-confined probe volume (1 nm) of the plasmonic hot-spots occurring on a conventional roughened SERS-active metallic surface has limited value in macro-molecular studies. In this article, we show the plausibility of generating large SERS hot-spot volumes on an atomically-flat metal surface based upon a special 3D adiabatic plasmonic nano-focusing effect brought about by an array of nano-scale superlenses. We experimentally demonstrate the feasibility of this particular approach and report, for the first time, the acquisition of whole-protein SERS spectra of a layer of test protein, Cytochrome-c, using a custom-made Otto-Raman spectroscopy system equipped with nano-fluidics. Our study shows the potential of whole-protein SERS spectroscopy as a useful analytical tool that complements surface probe microscopies.

  14. Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Gleeson, Helen F.

    Raman spectroscopy has been used as a tool to study liquid crystals for several decades. There are several features that make Raman spectroscopy an important characterisation method. It is bond-specific, so can provide information about the interaction of liquid crystals with colloidal systems and can offer an insight into phase transitions. The polarization dependence of the scattering can be used to determine order parameters in liquid crystal systems. Finally, the relatively high spatial resolution of the technique (∽1 μm) can be used to explore spatiallydependent order in soft matter systems. This chapter describes the most important ways in which Raman spectroscopy can be used to reveal information about liquid crystal systems, illustrated by examples. Both the theoretical background and experimental considerations are described, providing a comprehensive introduction to anybody interested in using the technique to understand liquid crystal systems.

  15. 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.

  16. Surface-enhanced Raman spectroscopy (SERS) for identifying traces of adenine in different mineral and rock samples

    NASA Astrophysics Data System (ADS)

    Lafuente, B.; Navarro, R.; Sansano, A.; Rull, F.

    2012-09-01

    The aim of this study is to analyze the potentials of SERS as a technique for in-situ identification of life traces in Mars surface explorations using the Raman instrument (RLS), payload of the ESA Mars mission Exomars. This preliminary study focused on detection of adenine on a variety of rocks soils samples using macro-SERS detection.

  17. 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.

  18. 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.

  19. Detection of Genomic DNA Damage from Radiated Nasopharyngeal Carcinoma Cells Using Surface-Enhanced Raman Spectroscopy (SERS).

    PubMed

    Ou, Lin; Chen, Yang; Su, Ying; Zou, Changyan; Chen, Zhong

    2016-11-01

    Structural changes and chemical modifications in DNA during interactions with X-ray radiation are still not clear within 48 h of incubation. We investigate genomic DNA from the radiated CNE2 cell line within 48 h of incubation using surface-enhanced Raman spectroscopy (SERS). Multivariate methods including principal component analysis (PCA) and random forest are proposed to explore the statistical significance before and after radiation. Our results show that intensities of several bands change after radiation, which indicates backbone damage and base-unstacking. Biological effects from DNA damage repairing process may be simultaneously stimulated and different from incubation time. Under doses of 10 Gy (with 24 and 48 h of incubation) and 20 Gy (with 48 h of incubation), the relative contents of C against T and A against G deviate obviously from the control level. Statistical results strengthen significantly the idea that modification in DNA bases is associated with the disruption of base-stacking in the DNA duplex. Our findings provide vital information for radiation-induced the DNA damage at the molecular level, which may provide insight into the effect and mechanism of anticarcinogens in tumor therapy.

  20. 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.

  1. The development of "fab-chips" as low-cost, sensitive surface-enhanced Raman spectroscopy (SERS) substrates for analytical applications.

    PubMed

    Robinson, Ashley M; Zhao, Lili; Shah Alam, Marwa Y; Bhandari, Paridhi; Harroun, Scott G; Dendukuri, Dhananjaya; Blackburn, Jonathan; Brosseau, Christa L

    2015-02-07

    The demand for methods and technologies capable of rapid, inexpensive and continuous monitoring of health status or exposure to environmental pollutants persists. In this work, the development of novel surface-enhanced Raman spectroscopy (SERS) substrates from metal-coated silk fabric, known as zari, presents the potential for SERS substrates to be incorporated into clothing and other textiles for the routine monitoring of important analytes, such as disease biomarkers or environmental pollutants. Characterization of the zari fabric was completed using scanning electron microscopy, energy dispersive X-ray analysis and Raman spectroscopy. Silver nanoparticles (AgNPs) were prepared, characterized by transmission electron microscopy and UV-vis spectroscopy, and used to treat fabric samples by incubation, drop-coating and in situ synthesis. The quality of the treated fabric was evaluated by collecting the SERS signal of 4,4'-bipyridine on these substrates. When AgNPs were drop-coated on the fabric, sensitive and reproducible substrates were obtained. Adenine was selected as a second probe molecule, because it dominates the SERS signal of DNA, which is an important class of disease biomarker, particularly for pathogens such as Plasmodium spp. and Mycobacterium tuberculosis. Excellent signal enhancement could be achieved on these affordable substrates, suggesting that the developed fabric chips have the potential for expanding the use of SERS as a diagnostic and environmental monitoring tool for application in wearable sensor technologies.

  2. Detecting Esophageal Cancer Using Surface-Enhanced Raman Spectroscopy (SERS) of Serum Coupled with Hierarchical Cluster Analysis and Principal Component Analysis.

    PubMed

    Li, Xiaozhou; Yang, Tianyue; Li, Siqi; Wang, Deli; Guan, Dagang

    2015-11-01

    Serum samples taken from healthy individuals and pre- and post-operative esophageal cancer patients were analyzed using surface-enhanced Raman spectroscopy (SERS) to explore the feasibility of diagnosing esophageal cancer using the technique. The serum spectrum data were collected using a He-Ne laser of wavelength 632.8 nm. Differences in peaks assigned to nucleic acids, lipids, and proteins were found to be statistically significant between groups, which implies that corresponding serum alterations occur with the development of esophageal diseases. For quantitative analysis, the chemometric methods of hierarchical clustering analysis and principal component analysis were utilized on the obtained SERS spectra for classification with good results.

  3. Detection of thiopurine methyltransferase activity in lysed red blood cells by means of lab-on-a-chip surface enhanced Raman spectroscopy (LOC-SERS).

    PubMed

    März, Anne; Mönch, Bettina; Rösch, Petra; Kiehntopf, Michael; Henkel, Thomas; Popp, Jürgen

    2011-07-01

    In this contribution, the great potential of surface enhanced Raman spectroscopy (SERS) in a lab-on-a-chip (LOC) device for the detection of analyte molecules in a complex environment is demonstrated. Using LOC-SERS, the enzyme activity of thiopurine S-methyltransferase (TPMT) is analysed and identified in lysed red blood cells. The conversion of 6-mercaptopurine to 6-methylmercaptopurine catalysed by TPMT is observed as it gives evidence for the enzyme activity. Being able to determine the TPMT activity before starting a treatment using 6-mercaptopurine, an optimized dosage can be applied to each patient and serious toxicity appearing within thiopurine treatment will be prevented.

  4. Interaction of TGA@CdTe Quantum Dots with an Extracellular Matrix of Haematococcus pluvialis Microalgae Detected Using Surface-Enhanced Raman Spectroscopy (SERS).

    PubMed

    Cepeda-Pérez, Elisa; Aguilar-Hernández, Iris; López-Luke, Tzarara; Piazza, Valeria; Carriles, Ramón; Ornelas-Soto, Nancy; de la Rosa, Elder

    2016-09-01

    The present study reports the localization and interaction of thioglycolic acid (TGA) capped CdTe quantum dots (TGA@CdTe QDs) within the extracellular matrix (ECM) of Haematococcus pluvialis (Chlorophyceae) microalgae (HPM) after an incubation period of 5 min. Changes in the Raman spectrum of HPM induced by the adsorption of the TGA@CdTe QDs are successfully found by using naked gold anisotropic structures as nano-sensors for surface-enhanced Raman scattering (SERS effect). Raman spectroscopy results show that TGA@CdTe QDs interact with the biomolecules present in the ECM. Sample preparation and characterization by complementary techniques such as confocal and electron microscopy are also used to confirm the presence and localization of the nanoparticles in the algae. This research shows new evidence on early accumulation of QDs in plant cells and would further improve our understanding about their environmental impact. © The Author(s) 2016.

  5. 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

  6. 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.

  7. 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)

  8. 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)

  9. Finite-Difference Time-Domain (FDTD) Modeling of Gold Core-Shell Structures with Different Shell Morphology for Surface-Enhanced Raman Spectroscopy (SERS)

    NASA Astrophysics Data System (ADS)

    Gorunmez, Zohre; Jana, Debrina; He, Jie; Sagle, Laura; Beck, Thomas

    Core-shell (CS) nanostructures have received attention in recent years due to their usefulness in applications ranging from catalysis to cancer treatment. SERS has been shown to be one of the most sensitive techniques for molecular detection, achieving single molecule detection. It has been established that the electromagnetic mechanism (EM) provides the main contribution to SERS enhancement due to the normal Raman spectroscopy arising from coupling of both the incident and re-emitted fields. The FDTD technique has been developed to provide numerical solutions to Maxwell's time-dependent curl equations in order to promise modeling capabilities for EM enhancement of SERS. Herein, we apply this method to the study of three morphologically different gold core-shell nanoparticles to investigate their contributions to SERS. In these structures, the dye/probe molecule resides in between the shell and the core and only the shell morphology is altered. The data shows that the surface plasmon resonances (PRs) influencing the SERS of the probe molecules, due to the coupling of the core and shell, are tunable by changing the shell morphologies and CS structures with sharp features on their surfaces highlight larger enhancements due to stronger localized surface PRs. University of Cincinnati start-up funds, NSF, Ohio Supercomputer Center, and the Ministry of National Education of the Republic of Turkey.

  10. 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.

  11. Sensitive surface-enhanced Raman spectroscopy (SERS) detection of organochlorine pesticides by alkyl dithiol-functionalized metal nanoparticles-induced plasmonic hot spots.

    PubMed

    Kubackova, Jana; Fabriciova, Gabriela; Miskovsky, Pavol; Jancura, Daniel; Sanchez-Cortes, Santiago

    2015-01-06

    In this work, we report the detection of the organochlorine pesticides aldrin, dieldrin, lindane, and α-endosulfan by using surface-enhanced Raman spectroscopy (SERS) and optimization of the SERS-sensing substrate. In order to overcome the inherent problem of the low affinity of the above pesticides, we have developed a strategy consisting of functionalization of the metal surface with alkyl dithiols in order to achieve two different goals: (i) to induce the nanoparticle linkage and create interparticle junctions where sensitive hot spots needed for SERS enhancement are present, and (ii) to create a specific environment in the nanogaps between silver and gold nanoparticles, making them suitable for the assembly and SERS detection of the analyzed pesticides. Afterward, an optimization of the sensing substrate was performed by varying the experimental conditions: type of metal nanoparticles, molecular linker (aromatic versus aliphatic dithiols and the length of the intermediate chain), surface coverage, laser excitation wavelength. From the adsorption isotherms, it was possible to deduce the corresponding adsorption constant and the limit of detection. The present results confirm the high sensitivity of SERS for the detection of the organochlorine pesticides with a limit of detection reaching 10(-8) M, thus providing a solid basis for the construction of suitable nanosensors for the identification and quantitative analysis of this type of chemical.

  12. Using Standing Gold Nanorod Arrays as Surface-Enhanced Raman Spectroscopy (SERS) Substrates for Detection of Carbaryl Residues in Fruit Juice and Milk.

    PubMed

    Alsammarraie, Fouad K; Lin, Mengshi

    2017-01-25

    In recent years, there have been increasing concerns about pesticide residues in various foods. On the other hand, there is growing attention in utilizing novel nanomaterials as highly sensitive, low-cost, and reproducible substrates for surface-enhanced Raman spectroscopy (SERS) applications. The objective of this study was to develop a SERS method for the rapid detection of pesticides that were extracted from different types of food samples (fruit juice and milk). A new SERS substrate was prepared by assembling gold nanorods into standing arrays on a gold-coated silicon slide. The standing nanorod arrays were neatly arranged and were able to generate a strong electromagnetic field in SERS measurement. The as-prepared SERS substrate was utilized to detect carbaryl in acetonitrile/water solution, fruit juices (orange and grapefruit), and milk. The results show that the concentrations of carbaryl spiked in fruit juice and milk were linearly correlated with the concentrations predicted by the partial least-squares (PLS) models with r values of 0.91, 0.88, and 0.95 for orange juice, grapefruit juice, and milk, respectively. The SERS method was able to detect carbaryl that was extracted from fruit juice and milk samples at a 50 ppb level. The detection limits of carbaryl were 509, 617, and 391 ppb in orange juice, grapefruit juice, and milk, respectively. All detection limits are below the maximum residue limits that were set by the U.S. EPA. Moreover, satisfactory recoveries (82-97.5%) were accomplished for food samples using this method. These results demonstrate that SERS coupled with the standing gold nanorod array substrates is a rapid, reliable, sensitive, and reproducible method for the detection of pesticide residues in foods.

  13. Electride Mediated Surface Enhanced Raman Scattering (SERS)

    NASA Technical Reports Server (NTRS)

    Anderson, Mark S. (Inventor)

    2016-01-01

    An electride may provide surface enhanced Raman scattering (SERS). The electride, a compound where the electrons serve as anions, may be a ceramic electride, such as a conductive ceramic derived from mayenite, or an organic electride, for example. The textured electride surface or electride particles may strongly enhance the Raman scattering of organic or other Raman active analytes. This may also provide a sensitive method for monitoring the chemistry and electronic environment at the electride surface. The results are evidence of a new class of polariton (i.e., a surface electride-polariton resonance mechanism) that is analogous to the surface plasmon-polariton resonance that mediates conventional SERS.

  14. Tuning gold nanoparticles interfaces by specific peptide interaction for surface enhanced Raman spectroscopy (SERS) and separation applications.

    PubMed

    Manikas, Anastasios C; Causa, Filippo; Della Moglie, Raffaella; Netti, Paolo A

    2013-08-28

    Surface functionalization and control over nanostructured interfaces represents a key aspect in nanoscience and nanobiotechnology. Nanoplasmonic structures for analyte detection typically require sophisticated nanofabrication techniques, as well as bioactivated nanostructures that need multistep conjugations for chemical ligation. An alternative to such complex processes is to rely on specific biomolecules adsorption for decoration or self-assembly of nanoparticles at solid/liquid interface. In principle, small biomolecules with specific binding properties to nanostructures could control the assembly without modifying the nanoparticle chemistry, pH of the solution or salt concentration. Importantly, such an approach could be direct, robust, and reversible. In this work, we report about the use of a specific peptide for direct and reversible adsorption on gold nanoparticles with tuned interfacial properties just by simply adjusting the ratio between the numbers of peptide molecules to the number of gold nanoparticles. This easy, direct and reversible assembly of gold nanoparticles mediated by the specific peptide makes this platform ideal for small-volume samples and low concentrations detection using surface enhanced Raman Spectroscopy, as well as for the capture or separation of biomolecules in complex mix.

  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.

  16. Utility of surface enhanced Raman spectroscopy (SERS) for elucidation and simultaneous determination of some penicillins and penicilloic acid using hydroxylamine silver nanoparticles.

    PubMed

    El-Zahry, Marwa R; Refaat, Ibrahim H; Mohamed, Horria A; Rosenberg, Erwin; Lendl, Bernhard

    2015-11-01

    Elucidation and quantitative determination of some of commonly used penicillins (ampicillin, penicillin G and carbenicillin) in the presence of their main degradation product (penicilloic acid) were developed. Forced acidic and basic degradation processes were applied at different time intervals. The formed degradation products were elucidated and quantified using surface enhanced Raman spectroscopy (SERS). Silver nanoparticles (AgNPs) prepared by reduction of silver nitrate using hydroxylamine-HCl in alkaline medium were used as SERS substrate. The results obtained in SERS were confirmed by the application of LC/MS method. The concentration range was 100-600 ng/ml in case of the studied penicillins and 100-700 ng/ml in case of penicilloic acid. An excellent correlation coefficient was found in case of ampicillin (r=0.9993) and in the case of penicilloic acid (r=0.9997). Validation procedures were carried out including precision, robustness and accuracy by comparing F- and t-values of both the proposed and reported methods. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. 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.

  18. 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.

  19. 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.

  20. Surface-Enhanced Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Stiles, Paul L.; Dieringer, Jon A.; Shah, Nilam C.; van Duyne, Richard P.

    2008-07-01

    The ability to control the size, shape, and material of a surface has reinvigorated the field of surface-enhanced Raman spectroscopy (SERS). Because excitation of the localized surface plasmon resonance of a nanostructured surface or nanoparticle lies at the heart of SERS, the ability to reliably control the surface characteristics has taken SERS from an interesting surface phenomenon to a rapidly developing analytical tool. This article first explains many fundamental features of SERS and then describes the use of nanosphere lithography for the fabrication of highly reproducible and robust SERS substrates. In particular, we review metal film over nanosphere surfaces as excellent candidates for several experiments that were once impossible with more primitive SERS substrates (e.g., metal island films). The article also describes progress in applying SERS to the detection of chemical warfare agents and several biological molecules.

  1. 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.

  2. 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.

  3. Detection of trace melamine in raw materials used for protein pharmaceutical manufacturing using surface-enhanced Raman spectroscopy (SERS) with gold nanoparticles.

    PubMed

    Wen, Zai-Qing; Li, Guiyang; Ren, Da

    2011-05-01

    Melamine, a nitrogen-rich molecule, was found as an adulterant in pet foods in 2007 in North America and in milk products in 2008 in China. These scandalous abuses of melamine have alarmed the biopharmaceutical industry and the FDA and alerted them to potential adulteration and contamination of melamine in raw materials used to make protein therapeutics. Highly sensitive analytical methods are needed to screen melamine adulteration and contamination in raw materials. We conducted surface-enhanced Raman spectroscopy (SERS) experiments to test trace melamine spiked in three raw materials commonly used for protein pharmaceutical formulation and purification, including sucrose, urea, and arginine, with a portable Raman device and gold nanoparticles. The detection limit of 10 ppb in raw material dissolved in 30:70% water/acetonitrile is equivalent to 0.5 ppm in solid raw material. It has excellent linearity in the concentration range measured. The cross-validation regression coefficient R(2) and the standard error of prediction (SEP) are 0.960 and 7.18 ppb, respectively, in sucrose. The R(2) and SEP are 0.958 and 9.15 ppb in urea. It has a relatively lower R(2) = 0.630 and a SEP of 35.0 ppb in arginine, which could be due to the competitive adsorption of arginine molecules to the surfaces of gold nanoparticles. The detection of melamine using the SERS technique is rapid (within 3 minutes), convenient, and requires no extraction procedure, offering an alternative method for screening melamine in raw materials at biopharmaceutical manufacture sites.

  4. 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.

  5. Ultrafast surface-enhanced Raman spectroscopy.

    PubMed

    Keller, Emily L; Brandt, Nathaniel C; Cassabaum, Alyssa A; Frontiera, Renee R

    2015-08-07

    Ultrafast surface-enhanced Raman spectroscopy (SERS) with pico- and femtosecond time resolution has the ability to elucidate the mechanisms by which plasmons mediate chemical reactions. Here we review three important technological advances in these new methodologies, and discuss their prospects for applications in areas including plasmon-induced chemistry and sensing at very low limits of detection. Surface enhancement, arising from plasmonic materials, has been successfully incorporated with stimulated Raman techniques such as femtosecond stimulated Raman spectroscopy (FSRS) and coherent anti-Stokes Raman spectroscopy (CARS). These techniques are capable of time-resolved measurement on the femtosecond and picosecond time scale and can be used to follow the dynamics of molecules reacting near plasmonic surfaces. We discuss the potential application of ultrafast SERS techniques to probe plasmon-mediated processes, such as H2 dissociation and solar steam production. Additionally, we discuss the possibilities for high sensitivity SERS sensing using these stimulated Raman spectroscopies.

  6. 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.

  7. 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

    2014-05-02

    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. Published by Elsevier B.V.

  8. 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

  9. On-line monitoring of airborne chemistry in levitated nanodroplets: in situ synthesis and application of SERS-active Ag-Sols for trace analysis by FT-Raman spectroscopy.

    PubMed

    Leopold, Nicolae; Haberkorn, Michael; Laurell, Thomas; Nilsson, Johan; Baena, Josefa R; Frank, Johannes; Lendl, Bernhard

    2003-05-01

    We report a new strategy for on-line monitoring of chemical reactions in ultrasonically levitated, nanoliter-sized droplets by Raman spectroscopy. A flow-through microdispenser connected to an automated flow injection system was used to dose picoliter droplets into the node of an ultrasonic trap. Taking advantage of the flow-through characteristics of the microdispenser and the versatility of the automated flow system, a well-defined sequence of reagents could be injected via the microdispenser into the levitated droplet placed in the focus of the collection optics of the Fourier transform Raman spectrometer. In that way, chemical reactions could be carried out and monitored on-line. The developed system was used for fast, reproducible, in situ synthesis of a highly active surface enhanced Raman scattering (SERS) sol resulting from the reduction of silver nitrate with hydroxylamine hydrochloride in basic conditions. With this chemical system, SERS substrate preparation could be achieved at room temperature and in short time. The in situ prepared silver sol was used for trace analysis of several organic test molecules that were injected into the levitated SERS-active droplet again using the microdispenser. The concentration dependence of the SERS spectra was studied using 9-aminoacridine, revealing that down to the femtogram region high-quality SERS spectra could be obtained. Additionally, SERS spectra of 6-mercaptopurine, thiamine, and acridine were recorded in the levitated drop as well.

  10. Raman spectroscopy in graphene

    NASA Astrophysics Data System (ADS)

    Malard, L. M.; Pimenta, M. A.; Dresselhaus, G.; Dresselhaus, M. S.

    2009-04-01

    Recent Raman scattering studies in different types of graphene samples are reviewed here. We first discuss the first-order and the double resonance Raman scattering mechanisms in graphene, which give rise to the most prominent Raman features. The determination of the number of layers in few-layer graphene is discussed, giving special emphasis to the possibility of using Raman spectroscopy to distinguish a monolayer from few-layer graphene stacked in the Bernal (AB) configuration. Different types of graphene samples produced both by exfoliation and using epitaxial methods are described and their Raman spectra are compared with those of 3D crystalline graphite and turbostratic graphite, in which the layers are stacked with rotational disorder. We show that Resonance Raman studies, where the energy of the excitation laser line can be tuned continuously, can be used to probe electrons and phonons near the Dirac point of graphene and, in particular allowing a determination to be made of the tight-binding parameters for bilayer graphene. The special process of electron-phonon interaction that renormalizes the phonon energy giving rise to the Kohn anomaly is discussed, and is illustrated by gated experiments where the position of the Fermi level can be changed experimentally. Finally, we discuss the ability of distinguishing armchair and zig-zag edges by Raman spectroscopy and studies in graphene nanoribbons in which the Raman signal is enhanced due to resonance with singularities in the density of electronic states.

  11. 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.

  12. Genesis of enhanced Raman bands in SERS spectra of 2-mercaptoimidazole: FTIR, Raman, DFT, and SERS.

    PubMed

    Chandra, Subhendu; Chowdhury, Joydeep; Ghosh, Manash; Talapatra, G B

    2012-11-15

    The surface enhanced Raman scattering (SERS) spectra of biologically and industrially significant, 2-mercaptoimidazole (2-MI) molecule have been investigated. The SERS spectra of the molecule at different concentrations of the adsorbate are compared with its Fourier transform infrared (FTIR) and normal Raman spectra (NRS) in varied environments. The optimized molecular structures and vibrational wavenumbers of the various forms (ca. cationic, neutral, ylidic, anionic) of the molecule have been estimated from the density functional theory (DFT). The vibrational signatures of the molecule have been assigned for the first time from the potential energy distributions (PEDs). The analyses of the Raman vibrational signatures reveal the coexistence of all the different forms of the molecule in the solid state and in aqueous solution. Concentration dependent SERS spectra of the molecule at neutral pH of the medium together with the multivariate data analyses techniques also suggest the concomitance of all the probable forms of the molecule in the surface adsorbed state. The genesis of selective enhancements of the Raman bands in the SERS spectra emanating from the cationic, neutral, ylidic and anionic forms of the molecule have been divulged from the view of the Albretcht's "A" and Herzberg-Teller (HT) charge transfer (CT) contribution.

  13. 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.

  14. Surface-enhanced Raman scattering (SERS) spectroscopic analysis of herba houttuyniae decoction (HHD)

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    The normal Raman spectrum and surface-enhanced Raman scattering (SERS) spectrum of herba houttuyniae decoction (HHD) were tested and analyzed. The characteristic SERS bands of HHD were tentatively assigned. There was no Raman signal in normal Raman spectrum of HHD. However, as a result of the silver colloid enhanced effects on the Raman scattering of HHD, we observed that the SERS spectrum of HHD had primary thirteen SERS peaks such as 538, 620, 686, 730, 955, 1030, 1231, 1240, 1325, 1400, 1472, 1564 and 1651 cm-1, and there were six strong signals at 538, 620, 730, 955, 1325 and 1400 cm-1 bands. The results showed that the SERS spectroscopy might provide a new kind of high-sensitive, accurate, easy, and rapid detecting method for traditional Chinese medicine (TCM).

  15. Raman spectroscopy of piezoelectrics

    NASA Astrophysics Data System (ADS)

    Pezzotti, Giuseppe

    2013-06-01

    Raman spectroscopy represents an insightful characterization tool in electronics, which comprehensively suits the technological needs for locally and quantitatively assessing crystal structures, domain textures, crystallographic misalignments, and residual stresses in piezoelectric materials and related devices. Recent improvements in data processing and instrumental screening of large sampling areas have provided Raman spectroscopic evaluations with rejuvenating effectiveness and presently give spin to increasingly wider and more sophisticated experimental explorations. However, the physics underlying the Raman effect represents an issue of deep complexity and its applicative development to non-cubic crystallographic structures can yet be considered in its infancy. This review paper revisits some applicative aspects of the physics governing Raman emission from crystalline matter, exploring the possibility of disentangling the convoluted dependences of the Raman spectrum on crystal orientation and mechanical stress. Attention is paid to the technologically important class of piezoelectric materials, for which working algorithms are explicitly worked out in order to quantitatively extract both structural and mechanical information from polarized Raman spectra. Systematic characterizations of piezoelectric materials and devices are successively presented as applications of the developed equations. The Raman response of complex crystal structures, described here according to a unified formalism, is interpreted as a means for assessing both crystallographic textures and stress-related issues in the three-dimensional space (thus preserving their vectorial and tensorial nature, respectively). Statistical descriptions of domain textures based on orientation distribution functions are also developed in order to provide a link between intrinsic single-crystal data and data collected on polycrystalline (partly textured) structures. This paper aims at providing rigorous

  16. Resonance Raman spectroscopy.

    PubMed

    Robert, Bruno

    2009-01-01

    Resonance Raman spectroscopy may yield precise information on the conformation of, and on the interactions assumed by, the chromophores involved in the first steps of the photosynthetic process, whether isolated in solvents, embedded in soluble or membrane proteins, or, as shown recently, in vivo. By making use of this technique, it is possible, for instance, to relate the electronic properties of these molecules to their structure and/or the physical properties of their environment, or to determine subtle changes of their conformation associated with regulatory processes. After a short introduction to the physical principles that govern resonance Raman spectroscopy, the information content of resonance Raman spectra of chlorophyll and carotenoid molecules is described in this review, together with the experiments which helped in determining which structural parameter each Raman band is sensitive to. A selection of applications of this technique is then presented, in order to give a fair and precise idea of which type of information can be obtained from its use in the field of photosynthesis.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  18. Hollow plasmonic antennas for broadband SERS spectroscopy.

    PubMed

    Messina, Gabriele C; Malerba, Mario; Zilio, Pierfrancesco; Miele, Ermanno; Dipalo, Michele; Ferrara, Lorenzo; De Angelis, Francesco

    2015-01-01

    The chemical environment of cells is an extremely complex and multifaceted system that includes many types of proteins, lipids, nucleic acids and various other components. With the final aim of studying these components in detail, we have developed multiband plasmonic antennas, which are suitable for highly sensitive surface enhanced Raman spectroscopy (SERS) and are activated by a wide range of excitation wavelengths. The three-dimensional hollow nanoantennas were produced on an optical resist by a secondary electron lithography approach, generated by fast ion-beam milling on the polymer and then covered with silver in order to obtain plasmonic functionalities. The optical properties of these structures have been studied through finite element analysis simulations that demonstrated the presence of broadband absorption and multiband enhancement due to the unusual geometry of the antennas. The enhancement was confirmed by SERS measurements, which showed a large enhancement of the vibrational features both in the case of resonant excitation and out-of-resonance excitation. Such characteristics indicate that these structures are potential candidates for plasmonic enhancers in multifunctional opto-electronic biosensors.

  19. [Current views on surface enhanced Raman spectroscopy in microbiology].

    PubMed

    Jia, Xiaoxiao; Li, Jing; Qin, Tian; Deng, Aihua; Liu, Wenjun

    2015-05-01

    Raman spectroscopy has generated many branches during the development for more than 90 years. Surface enhanced Raman spectroscopy (SERS) improves SNR by using the interaction between tested materials and the surface of rough metal, as to quickly get higher sensitivity and precision spectroscopy without sample pretreatment. This article describes the characteristic and classification of SERS, and updates the theory and clinical application of SERS. It also summarizes the present status and progress of SERS in various disciplines and illustrates the necessity and urgency of its research, which provides rationale for the application for SERS in microbiology.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  1. The effect of aqueous solution in Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Kang, Jian; Yuan, Xiaojuan; Dong, Xiao; Gu, Huaimin

    2009-08-01

    In Raman detection, the most popular solution for the samples is tri-distilled water. But the effect of aqueous solution is barely studied in Raman spectroscopy. In fact Raman spectroscopy of solid-state and liquid-state are obvious different. In addition, FWHM of Raman spectral peaks also change evidently. In this paper, several samples were selected for the experiment; including sodium nitrate, sodium nitrite, glucose and caffeine. By comparing the Raman spectroscopy of samples at different concentrations, it is found that the concentration of the sample can affect the strength of Raman spectroscopy, but it can hardly impact FWHM of Raman spectral peaks. By comparing the Raman spectroscopy of liquid-state with the Raman spectroscopy of solid-state, it is observed that the FWHM of some Raman spectral peaks varied obviously; that may be because when the sample was dissolved into the water, the crystal lattice structure was broken, and for some samples atom form became ion form in aqueous solution. Those structural variations caused the variation of the FWHM. The Raman spectroscopy of caffeine aqueous solution at very low concentration was also detected and analyzed. Compared with the Raman spectra of solid-state samples, it is found that some Raman spectral peaks disappeared when the sample was dissolved in water. It is possible that the low concentration of the sample result in the weakening of Raman signals and the disappearing of some weak Raman spectral peaks. Then Ag nanoparticles were added into the caffeine aqueous solution, the results suggest that surface enhanced Raman spectroscopy (SERS) not only can enhance the Raman spectral signal, but also can reduce the effect of aqueous solution. It is concluded that the concentration of sample only affects the strength of Raman spectroscopy; the aqueous solution can affect the FWHM of Raman spectral peaks; and SERS can reduce the effect of aqueous solution.

  2. Surface-Enhanced Femtosecond Stimulated Raman Spectroscopy.

    PubMed

    Frontiera, Renee R; Henry, Anne-Isabelle; Gruenke, Natalie L; Van Duyne, Richard P

    2011-05-19

    Surface-enhanced Raman spectroscopy (SERS) and femtosecond stimulated Raman spectroscopy (FSRS) have revolutionized the Raman spectroscopy field. SERS provides spectroscopic detection of single molecules, and FSRS enables the acquisition of Raman spectra on the ultrafast time scale of molecular motion. Here, we present the first successful combination of these two techniques, demonstrating surface-enhanced femtosecond stimulated Raman spectroscopy (SE-FSRS) using gold nanoantennas with embedded reporter molecules. Using a picosecond Raman and femtosecond probe pulse, the time- and ensemble-averaged enhancement factor is estimated to be in the range of 10(4)-10(6). We report the line shapes, power dependence, and magnitude of the SE-FSRS signal and discuss contributions to sample degradation on the minute time scale. With these first successful proof-of-principle experiments, time-resolved SE-FSRS techniques can now be rationally attempted with the goals of investigating the dynamics of plasmonic materials as well as examining the contributions of environmental heterogeneities by probing more homogeneous molecular subsets.

  3. Raman spectroscopy of oral bacteria

    NASA Astrophysics Data System (ADS)

    Berger, Andrew J.; Zhu, Qingyuan; Quivey, Robert G.

    2003-10-01

    Raman spectroscopy has been employed to measure the varying concentrations of two oral bacteria in simple mixtures. Evaporated droplets of centrifuged mixtures of Streptococcus sanguis and Streptococcus mutans were analyzed via Raman microspectroscopy. The concentration of s. sanguis was determined based upon the measured Raman spectrum, using partial least squares cross-validation, with an r2 value of 0.98.

  4. Industrial applications of Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Grasselli, J. G.; Walder, F.; Petty, C.; Kemeny, G.

    1993-03-01

    In the last two decades, Raman spectroscopy has matured as an important method for the study of molecules and complex molecular systems. This is evident from the number of fine texts and the many review articles which have been published describing theory and applications of Raman spectroscopy over a very broad range of subjects (1-10). Raman spectroscopy is the essential partner to infrared spectroscopy for a complete vibrational analysis of a molecule in structure determinations. From the understanding developed on small molecules, theory was extended to interpret the spectra of larger systems such as polymers, biological molecules, and ordered condensed phases. The contribution of Raman spectroscopy to these areas has been significant. It was the development of commercial lasers in the 1960s which spurred the renewed interest in the Raman technique. But applications were still limited for highly fluorescing or intensely colored systems. In 1986, a breakthrough paper by Hirschfeld and Chase (11) described the use of near-infrared laser excitation and a commercial interferometer-based FT-IR spectrometer to record FT-Raman spectra. Significant advantages included the inherent multiplex, throughput and data processing features of the FT interferometers and the use of a ND:YAG laser (1.064 μm) which dramatically decreased problems with sample fluorescence and decomposition. A deluge of papers describing applications of FT-Raman spectroscopy can be found in the Journal of Raman Spectroscopy, Spectrochimica Acta (special issues 40A ad 47A), and Applied Spectroscopy since then.

  5. 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.

  6. 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. )

  7. Femtosecond Stimulated Raman Spectroscopy.

    PubMed

    Dietze, Daniel R; Mathies, Richard A

    2016-05-04

    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.

  8. 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.

  9. Fabrication of Annealed Gold Nanostructures on Pre-Treated Glow-Discharge Cleaned Glasses and Their Used for Localized Surface Plasmon Resonance (LSPR) and Surface Enhanced Raman Spectroscopy (SERS) Detection of Adsorbed (Bio)molecules

    PubMed Central

    Ionescu, Rodica Elena; Aybeke, Ece Neslihan; Bourillot, Eric; Lacroute, Yvon; Lesniewska, Eric; Adam, Pierre-Michel; Bijeon, Jean-Louis

    2017-01-01

    Metallic nanoparticles are considered as active supports in the development of specific chemical or biological biosensors. Well-organized nanoparticles can be prepared either through expensive (e.g., electron beam lithography) or inexpensive (e.g., thermal synthesis) approaches where different shapes of nanoparticles are easily obtained over large solid surfaces. Herein, the authors propose a low-cost thermal synthesis of active plasmonic nanostructures on thin gold layers modified glass supports after 1 h holding on a hot plate (~350 °C). The resulted annealed nanoparticles proved a good reproducibility of localized surface plasmon resonance (LSPR) and surface enhanced Raman spectroscopy (SERS) optical responses and where used for the detection of low concentrations of two model (bio)chemical molecules, namely the human cytochrome b5 (Cyt-b5) and trans-1,2-bis(4-pyridyl)ethylene (BPE). PMID:28134754

  10. Charge Transfer Effect on Raman and Surface Enhanced Raman Spectroscopy of Furfural Molecules

    PubMed Central

    Wan, Fu; Shi, Haiyang; Chen, Weigen; Gu, Zhaoliang; Du, Lingling; Wang, Pinyi; Wang, Jianxin

    2017-01-01

    The detection of furfural in transformer oil through surface enhanced Raman spectroscopy (SERS) is one of the most promising online monitoring techniques in the process of transformer aging. In this work, the Raman of individual furfural molecules and SERS of furfural-Mx (M = Ag, Au, Cu) complexes are investigated through density functional theory (DFT). In the Raman spectrum of individual furfural molecules, the vibration mode of each Raman peak is figured out, and the deviation from experimental data is analyzed by surface charge distribution. In the SERS of furfural-Mx complexes, the influence of atom number and species on SERS chemical enhancement factors (EFs) are studied, and are further analyzed by charge transfer effect. Our studies strengthen the understanding of charge transfer effect in the SERS of furfural molecules, which is important in the online monitoring of the transformer aging process through SERS. PMID:28767053

  11. Laser sources for Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Kilmer, J.; Iadevaia, A.; Yin, Y.

    2011-06-01

    While conventional Raman Spectroscopy (RS) has predominately used fixed wavelength cw lasers, advanced Raman spectroscopic techniques such as Stimulated Raman and some types of Raman Imaging typically need pulsed lasers with sufficient energy to induce the Raman process. In addition, pulsed lasers are beneficial for the following Raman techniques: Time Resolved Raman (TRR), Resonance Raman (RR), or non linear Raman techniques, such as Coherent anti-Stokes Raman spectroscopy (CARS). Here the naturally narrower linewidth of a ns pulse width laser is advantageous to a broader linewidth ultrafast pulsed laser. In this paper, we report on the development of a compact, highly efficient, high power solid-state Ti: Sapphire laser ideally suited for many Raman spectroscopic techniques. This laser produces nanosecond pulses at kHz repetition rates with a tunable output wavelength from ~1 micron to ~200 nm and pulse energies up to 1 mJ. The narrow bandwidth of this laser (<0.1cm-1) is ideally suited for applications such as Laser-induced fluorescence (LIF) measurement of OH free-radicals concentrations, atmospheric LIDAR and Raman spectroscopy. New KBBF and RBBF deep ultraviolet (DUV) and vacuum ultraviolet (VUV) crystals are now available that enable direct doubling of the SHG output of these tunable Ti: Sapphire lasers to directly achieve wavelengths as short as 175 nm without the need to generate the 3rd harmonic and utilize frequency mixing. This results in a highly efficient output in the DUV/VUV, enabling improved signal to noise ratios (S/N) in these previously difficult wavelength regions. Photonics Industries has recently achieved a few mW of power at 193nm with such direct doubling crystals.

  12. FT-IR, Raman, and SERS spectra of arcaine sulfate

    SciTech Connect

    Eapen, A.; Joe, I.H.; Aruldhas, G.

    1997-11-01

    Vibrational spectral analysis of arcaine sulfate has been carried out using FT-IR, Raman, and SERS spectra. Raman and FT-IR spectra suggest protonation of the imino groups of the arcaine molecule at the expense of the proton from H{sub 2}SO{sub 4}. Analysis of SERS spectra shows that the molecule is adsorbed to the silver surface through the uncharged amino group and oxygen sites of the sulfate groups. The large enhancement observed for the amino group bending vibrations suggests that the molecule is adsorbed perpendicular to the silver surface.

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. Substrate Oxide Layer Thickness Optimization for a Dual-Width Plasmonic Grating for Surface-Enhanced Raman Spectroscopy (SERS) Biosensor Applications

    PubMed Central

    Bauman, Stephen J.; Brawley, Zachary T.; Darweesh, Ahmad A.; Herzog, Joseph B.

    2017-01-01

    This work investigates a new design for a plasmonic SERS biosensor via computational electromagnetic models. It utilizes a dual-width plasmonic grating design, which has two different metallic widths per grating period. These types of plasmonic gratings have shown larger optical enhancement than standard single-width gratings. The new structures have additional increased enhancement when the spacing between the metal decreases to sub-10 nm dimensions. This work integrates an oxide layer to improve the enhancement even further by carefully studying the effects of the substrate oxide thickness on the enhancement and reports ideal substrate parameters. The combined effects of varying the substrate and the grating geometry are studied to fully optimize the device’s enhancement for SERS biosensing and other plasmonic applications. The work reports the ideal widths and substrate thickness for both a standard and a dual-width plasmonic grating SERS biosensor. The ideal geometry, comprising a dual-width grating structure atop an optimal SiO2 layer thickness, improves the enhancement by 800%, as compared to non-optimized structures with a single-width grating and a non-optimal oxide thickness. PMID:28665308

  18. 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.

  19. 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.

  20. Laser crater enhanced Raman spectroscopy.

    PubMed

    Lednev, Vasily N; Sdvizhenskii, Pavel A; Grishin, Mikhail Ya; Filippov, Mikhail N; Shchegolikhin, Alexander N; Pershin, Sergey M

    2017-02-01

    Raman signal enhancement by multiple scattering inside laser crater cones was observed for the first time, to the best of our knowledge. Laser crater enhanced Raman spectroscopy (LCERS) yielded a 14-fold increase in the Raman spectra bands due to efficient multiple scattering of laser irradiation within the laser crater walls. The same pulsed Nd:YAG laser (532 nm, 10 ns) was used for both laser crater formation and Raman scattering experiments by varying the output pulse energy. First, powerful pulses are used to produce the laser crater; then low-energy pulses are used to perform Raman scattering measurements. The laser crater profile and its alignment with the laser beam waist were found to be the key parameters for the optimization of the Raman spectrum intensity enhancement. Raman intensity enhancement resulted from increased surface scattering area at the crater walls, rather than spatially offset Raman scattering. The increased signal-to-noise ratio resulted in limits of detection improvement for quantitative analysis using LCERS.

  1. 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

  2. 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.

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

    SciTech Connect

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

    2016-05-06

    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.

  4. 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.

  5. 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.

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

    PubMed

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

    2016-01-15

    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.

  7. Optimization of surface enhanced Raman scattering (SERS) assay for the transition from benchtop to handheld Raman systems

    NASA Astrophysics Data System (ADS)

    Schechinger, Monika; Marks, Haley; Locke, Andrea; Choudhury, Mahua; Coté, Gerard

    2017-02-01

    Human biomarkers are indicative of the body's relative state prior to the onset of disease, and sometimes before symptoms present. While blood biomarker detection has achieved considerable success in laboratory settings, its clinical application is lagging and commercial point-of-care devices are rare. A physician's ability to detect biomarkers such as microRNA-17, a potential epigenetic indicator of preeclampsia in pregnant woman, could enable early diagnosis and preventive intervention as early as the 1st trimester. One detection approach employing DNA-functionalized nanoparticles to detect microRNA-17, in conjunction with surface-enhanced Raman spectroscopy (SERS), has shown promise but is hindered, in part, by the use of large and expensive benchtop Raman microscopes. However, recent strides have been made in developing portable Raman systems for field applications. Characteristics of the SERS assay responsible for strengthening the assay's plasmonic response were explored, whilst comparing the results from both benchtop and portable Raman systems. The Raman spectra and intensity of three different types of photoactive molecules were compared as potential Raman reporter molecules: chromophores, fluorophores, and highly polarizable small molecules. Furthermore, the plasmonic characteristics governing the formation of SERS colloidal nanoparticle assemblies in response to DNA/miRNA hybridization were investigated. There were significant variations in the SERS enhancement in response to microRNA-17 using our assay depending on the excitation lasers at wavelengths of 532 nm and 785 nm, depending on which of the three different Raman systems were used (benchtop, portable, and handheld), and depending on which of the three different Raman reporters (chromophore, fluorophore, or Raman active molecule) were used. Analysis of data obtained did indicate that signal enhancement was better for the chromophore (MGITC) and Raman active molecule (DTNB) than it was for the

  8. 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.

  9. Raman spectroscopy of advanced materials.

    PubMed

    Huong, P V

    1996-06-01

    Many micro-structural aspects of advanced materials and the incidence on the physical properties have been elucidated by Raman micro-spectroscopy. The potential of this technique is demonstrated with new materials interesting in both academic and industrial developments: new carbons and diamonds, superconductors, semiconductors, superhards.

  10. Surface-enhanced Raman spectroscopy: substrate-related issues.

    PubMed

    Lin, Xiu-Mei; Cui, Yan; Xu, Yan-Hui; Ren, Bin; Tian, Zhong-Qun

    2009-08-01

    After over 30 years of development, surface-enhanced Raman spectroscopy (SERS) is now facing a very important stage in its history. The explosive development of nanoscience and nanotechnology has assisted the rapid development of SERS, especially during the last 5 years. Further development of surface-enhanced Raman spectroscopy is mainly limited by the reproducible preparation of clean and highly surface enhanced Raman scattering (SERS) active substrates. This review deals with some substrate-related issues. Various methods will be introduced for preparing SERS substrates of Ag and Au for analytical purposes, from SERS substrates prepared by electrochemical or vacuum methods, to well-dispersed Au or Ag nanoparticle sols, to nanoparticle thin film substrates, and finally to ordered nanostructured substrates. Emphasis is placed on the analysis of the advantages and weaknesses of different methods in preparing SERS substrates. Closely related to the application of SERS in the analysis of trace sample and unknown systems, the existing cleaning methods for SERS substrates are analyzed and a combined chemical adsorption and electrochemical oxidation method is proposed to eliminate the interference of contaminants. A defocusing method is proposed to deal with the laser-induced sample decomposition problem frequently met in SERS measurement to obtain strong signals. The existing methods to estimate the surface enhancement factor, a criterion to characterize the SERS activity of a substrate, are analyzed and some guidelines are proposed to obtain the correct enhancement factor.

  11. 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.

  12. 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.

  13. Raman spectroscopy of thin films

    NASA Astrophysics Data System (ADS)

    Burgess, James Shaw

    Raman spectroscopy was used in conjunction with x-ray diffraction and x-ray photoelectron spectroscopy to elucidate structural and compositional information on a variety of samples. Raman was used on the unique La 2NiMnO6 mixed double perovskite which is a member of the LaMnO3 family of perovskites and has multiferroic properties. Raman was also used on nanodiamond films as well as some boron-doped carbon compounds. Finally, Raman was used to identify metal-dendrimer bonds that have previously been overlooked. Vibrational modes for La2NiMnO6 were ascribed by comparing spectra with that for LaMnO3 bulk and thin film spectra. The two most prominent modes were labeled as an asymmetric stretch (A g) centered around 535 cm-1 and a symmetric stretch (B g) centered around 678 cm. The heteroepitaxial quality of La2NiMnO 6 films on SrTiO3 (100) and LaAlO3 (100) substrates were examined using the Raman microscope by way of depth profile experiments and by varying the thickness of the films. It was found that thin films (10 nm) had much greater strain on the LaAlO3 substrate than on the SrTiO3 substrate by examining the shifts of the Ag and the Bg modes from their bulk positions. Changes in the unit cell owing to the presence of oxygen defects were also monitored using Raman spectroscopy. It was found that the Ag and Bg modes shifted between samples formed with different oxygen partial pressures. These shifts could be correlated to changes in the symmetry of the manganese centers due to oxygen defects. Raman spectroscopy was used to examine the structural and compositional characteristics of carbon materials. Nanocrystalline diamond coated cutting tools were examined using the Raman Microscope. Impact, abrasion, and depth profile experiments indicated that delamination was the primary cause of film failure in these systems. Boron doped material of interest as catalyst supports were also examined. Monitoring of the G-mode and intensities of the D- and G-modes indicated that

  14. Quantitative fiber-optic Raman spectroscopy for tissue Raman measurements

    NASA Astrophysics Data System (ADS)

    Duraipandian, Shiyamala; Bergholt, Mads; Zheng, Wei; Huang, Zhiwei

    2014-03-01

    Molecular profiling of tissue using near-infrared (NIR) Raman spectroscopy has shown great promise for in vivo detection and prognostication of cancer. The Raman spectra measured from the tissue generally contain fundamental information about the absolute biomolecular concentrations in tissue and its changes associated with disease transformation. However, producing analogues tissue Raman spectra present a great technical challenge. In this preliminary study, we propose a method to ensure the reproducible tissue Raman measurements and validated with the in vivo Raman spectra (n=150) of inner lip acquired using different laser powers (i.e., 30 and 60 mW). A rapid Raman spectroscopy system coupled with a ball-lens fiber-optic Raman probe was utilized for tissue Raman measurements. The investigational results showed that the variations between the spectra measured with different laser powers are almost negligible, facilitating the quantitative analysis of tissue Raman measurements in vivo.

  15. 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.

  16. Theoretical calculation (DFT), Raman and surface-enhanced Raman scattering (SERS) study of ponceau 4R

    NASA Astrophysics Data System (ADS)

    Xie, Yunfei; Li, Yan; Sun, Yingying; Wang, Heya; Qian, He; Yao, Weirong

    2012-10-01

    Ponceau 4R is used as a coloring agent in many different products, such as food, drinks, medicines, cosmetics and tobacco. However, ponceau 4R also shows carcinogenic, teratogenic and mutagenic behavior in high doses. In this work, standard Raman, theoretical Raman and surface-enhanced Raman scattering (SERS) spectra have been used to investigate ponceau 4R. More specifically, density functional theory (DFT) calculations have been used to calculate the optimized Raman spectrum of ponceau 4R at the B3LYP/6-31G(d) level. This has provided a better understanding of the optimized geometry and vibrational frequencies of this dye. In addition, the experimental spectrum of ponceau 4R has been compared with the theoretical spectrum; good agreement was obtained. Finally, it has shown that using SERS the detection limit of the ponceau 4R solution can be as low as 5 μg/mL. This has been achieved by SERS measurements of ponceau 4R on a substrate of gold nanoparticles. The SERS peaks at 1030, 1236, 1356 and 1502 cm-1 were chosen as index for semi-quantitative analysis, showing that the SERS technique provided a useful ultrasensitive method for the detection of ponceau 4R.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Shell-isolated nanoparticle-enhanced Raman spectroscopy.

    PubMed

    Li, Jian Feng; Huang, Yi Fan; Ding, Yong; Yang, Zhi Lin; Li, Song Bo; Zhou, Xiao Shun; Fan, Feng Ru; Zhang, Wei; Zhou, Zhi You; Wu, De Yin; Ren, Bin; Wang, Zhong Lin; Tian, Zhong Qun

    2010-03-18

    Surface-enhanced Raman scattering (SERS) is a powerful spectroscopy technique that can provide non-destructive and ultra-sensitive characterization down to single molecular level, comparable to single-molecule fluorescence spectroscopy. However, generally substrates based on metals such as Ag, Au and Cu, either with roughened surfaces or in the form of nanoparticles, are required to realise a substantial SERS effect, and this has severely limited the breadth of practical applications of SERS. A number of approaches have extended the technique to non-traditional substrates, most notably tip-enhanced Raman spectroscopy (TERS) where the probed substance (molecule or material surface) can be on a generic substrate and where a nanoscale gold tip above the substrate acts as the Raman signal amplifier. The drawback is that the total Raman scattering signal from the tip area is rather weak, thus limiting TERS studies to molecules with large Raman cross-sections. Here, we report an approach, which we name shell-isolated nanoparticle-enhanced Raman spectroscopy, in which the Raman signal amplification is provided by gold nanoparticles with an ultrathin silica or alumina shell. A monolayer of such nanoparticles is spread as 'smart dust' over the surface that is to be probed. The ultrathin coating keeps the nanoparticles from agglomerating, separates them from direct contact with the probed material and allows the nanoparticles to conform to different contours of substrates. High-quality Raman spectra were obtained on various molecules adsorbed at Pt and Au single-crystal surfaces and from Si surfaces with hydrogen monolayers. These measurements and our studies on yeast cells and citrus fruits with pesticide residues illustrate that our method significantly expands the flexibility of SERS for useful applications in the materials and life sciences, as well as for the inspection of food safety, drugs, explosives and environment pollutants.

  2. Study and application of new Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, Qiushi; Zhang, Xiaohua

    2016-03-01

    Spatially Offset Raman Spectroscopy (SORS) is a new type of Raman Spectroscopy technology, which can detect the medium concealed in the opaque or sub-transparent material fast and nondestructively. The article summarized Spatially Offset Raman Spectroscopy`s international and domestic study and application progress on contraband detecting, medical science (bone ingredient, cancer diagnose etc.), agricultural products, historical relic identification etc. and stated the technology would become an effective measurement which had wide application prospect.

  3. 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

  4. Raman spectroscopy: Enhanced by organic surfaces

    NASA Astrophysics Data System (ADS)

    Lombardi, John R.

    2017-09-01

    Nanostructured films of organic semiconductors are now shown to enhance the Raman signal of probe molecules, paving the way to the realization of substrates for Raman spectroscopy with molecular selectivity.

  5. 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.

  6. 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…

  7. 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…

  8. Raman spectroscopy of biomedical polyethylenes.

    PubMed

    Pezzotti, Giuseppe

    2017-06-01

    With the development of three-dimensional Raman algorithms for local mapping of oxidation and plastic strain, and the ability to resolve molecular orientation patterns with microscopic spatial resolution, there is an opportunity to re-examine many of the foundations on which our understanding of biomedical grade ultra-high molecular weight polyethylenes (UHMWPEs) are based. By implementing polarized Raman spectroscopy into an automatized tool with an improved precision in non-destructively resolving Euler angles, oxidation levels, and microscopic strain, we become capable to make accurate and traceable measurements of the in vitro and in vivo tribological responses of a variety of commercially available UHMWPE bearings for artificial hip and knee joints. In this paper, we first review the foundations and the main algorithms for Raman analyses of oxidation and strain of biomedical polyethylene. Then, we critically re-examine a large body of Raman data previously collected on different polyethylene joint components after in vitro testing or in vivo service, in order to shed new light on an area of particular importance to joint orthopedics: the microscopic nature of UHMWPE surface degradation in the human body. A complex scenario of physical chemistry appears from the Raman analyses, which highlights the importance of molecular-scale phenomena besides mere microstructural changes. The availability of the Raman microscopic probe for visualizing oxidation patterns unveiled striking findings related to the chemical contribution to wear degradation: chain-breaking and subsequent formation of carboxylic acid sites preferentially occur in correspondence of third-phase regions, and they are triggered by emission of dehydroxylated oxygen from ceramic oxide counterparts. These findings profoundly differ from more popular (and simplistic) notions of mechanistic tribology adopted in analyzing joint simulator data. Statement of Significance This review was dedicated to the

  9. 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

  10. 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.

  11. Core-Shell Nanoparticle-Enhanced Raman Spectroscopy.

    PubMed

    Li, Jian-Feng; Zhang, Yue-Jiao; Ding, Song-Yuan; Panneerselvam, Rajapandiyan; Tian, Zhong-Qun

    2017-03-08

    Core-shell nanoparticles are at the leading edge of the hot research topics and offer a wide range of applications in optics, biomedicine, environmental science, materials, catalysis, energy, and so forth, due to their excellent properties such as versatility, tunability, and stability. They have attracted enormous interest attributed to their dramatically tunable physicochemical features. Plasmonic core-shell nanomaterials are extensively used in surface-enhanced vibrational spectroscopies, in particular, surface-enhanced Raman spectroscopy (SERS), due to the unique localized surface plasmon resonance (LSPR) property. This review provides a comprehensive overview of core-shell nanoparticles in the context of fundamental and application aspects of SERS and discusses numerous classes of core-shell nanoparticles with their unique strategies and functions. Further, herein we also introduce the concept of shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) in detail because it overcomes the long-standing limitations of material and morphology generality encountered in traditional SERS. We then explain the SERS-enhancement mechanism with core-shell nanoparticles, as well as three generations of SERS hotspots for surface analysis of materials. To provide a clear view for readers, we summarize various approaches for the synthesis of core-shell nanoparticles and their applications in SERS, such as electrochemistry, bioanalysis, food safety, environmental safety, cultural heritage, materials, catalysis, and energy storage and conversion. Finally, we exemplify about the future developments in new core-shell nanomaterials with different functionalities for SERS and other surface-enhanced spectroscopies.

  12. SERS Detection of Biomolecules by Highly Sensitive and Reproducible Raman-Enhancing Nanoparticle Array

    NASA Astrophysics Data System (ADS)

    Chan, Tzu-Yi; Liu, Ting-Yu; Wang, Kuan-Syun; Tsai, Kun-Tong; Chen, Zhi-Xin; Chang, Yu-Chi; Tseng, Yi-Qun; Wang, Chih-Hao; Wang, Juen-Kai; Wang, Yuh-Lin

    2017-05-01

    This paper describes the preparation of nanoarrays composed of silver nanoparticles (AgNPs: 20-50 nm) for use as surface-enhanced Raman scattering (SERS) substrates. The AgNPs were grown on porous anodic aluminum oxide (AAO) templates by electrochemical plating, and the inter-channel gap of AAO channels is between 10 and 20 nm. The size and interparticle gap of silver particles were adjusted in order to achieve optimal SERS signals and characterized by scanning electron microscopy, atomic force microscopy, and Raman spectroscopy. The fluctuation of SERS intensity is about 10-20% when measuring adenine solutions, showing a great reproducible SERS sensing. The nanoparticle arrays offer a large potential for practical applications as shown by the SERS-based quantitative detection and differentiation of adenine (A), thymine (T), cytosine (C), guanine (G), β-carotene, and malachite green. The respective detection limits are <1 ppb for adenine and <0.63 ppm for β-carotene and malachite green, respectively.

  13. Raman spectroscopy peer review report

    SciTech Connect

    Winkelman, W.D.; Eberlein, S.J.

    1994-09-01

    The Hanford Site in eastern Washington includes 177 underground storage tanks (UST), which contain waste materials produced during the production of nuclear fuels. The materials in the tanks must be characterized to support the retrieval, processing, and final disposition of the waste. Characterization is currently performed by removing waste samples for analyses in a hot cell or laboratory. A review of the Hanford Raman Spectroscopy Program was held in Richland on March 23 and 24, 1994. A team of principal investigators and researchers made presentations that covered both technical and programmatic aspects of the Hanford Site Raman work. After these presentations and discussions, the review panel met in a closed session to formalize a list of findings. The reviewers agreed that Raman spectroscopy is an excellent method to attack the tank waste characterization and screening problems that were presented. They agreed that there was a good chance that the method would be successful as presently envisioned. The reviewers provided the following primary recommendations: evaluation a laser with wavelength in the near infrared; provide optical filters at or near the sampling end of the fiber-optic probe; develop and implement a strategy for frequent calibration of the system; do not try to further increase Raman resolution at the expense of wavelength range; clearly identify and differentiate between requirements for providing a short-term operational system and requirements for optimizing a system for long-term field use; and determine the best optical configuration, which may include reduced fiber-optic diameter and/or short focal length and low F-number spectrographs.

  14. Rapid quantitative analysis of Dimethoate pesticide using surface enhanced raman spectroscopy

    USDA-ARS?s Scientific Manuscript database

    A method for rapid quantitative detection of dimethoate pesticide by using surface-enhanced Raman spectroscopy (SERS) has been described. Significantly enhanced Raman signals of pesticide in low concentrations of 0.5 ~ 10 ug/mL were acquired by confocal raman micro-spectrometry with renishaw diagno...

  15. [Surface-enhanced Raman spectroscopy analysis of thiabendazole pesticide].

    PubMed

    Lin, Lei; Wu, Rui-mei; Liu, Mu-hua; Wang, Xiao-bin; Yan, Lin-yuan

    2015-02-01

    Surface-enhanced Raman spectroscopy (SERS) technique was used to analyze the Raman peaks of thiabendazole pesticides in the present paper. Surface enhanced substrates of silver nanoparticle were made based on microwave technology. Raman signals of thiabendazole were collected by laser Micro-Raman spectrometer with 514. 5 and 785 nm excitation wavelengths, respectively. The Raman peaks at different excitation wavelengths were analyzed and compared. The Raman peaks 782 and 1 012 at 785 nm excitation wavelength were stronger, which were C--H out-of-plane vibrations. While 1284, 1450 and 1592 cm(-1) at 514.5 nm excitation wavelength were stronger, which were vng and C==N stretching. The study results showed that the intensity of Raman peak and Raman shift at different excitation wavelengths were different And strong Raman signals were observed at 782, 1012, 1284, 1450 and 1592 cm(-1) at 514.5 and 785 nm excitation wavelengths. These characteristic vibrational modes are characteristic Raman peaks of carbendazim pesticide. The results can provide basis for the rapid screening of pesticide residue in agricultural products and food based on Raman spectrum.

  16. Cysteamine-modified silver nanoparticle aggregates for quantitative SERS sensing of pentachlorophenol with a portable Raman spectrometer.

    PubMed

    Jiang, Xiaohong; Yang, Min; Meng, Yanjing; Jiang, Wei; Zhan, Jinhua

    2013-08-14

    Cysteamine-modified silver nanoparticle aggregates has been fabricated for pentachlorophenol (PCP) sensing by surface-enhanced Raman spectroscopy (SERS) using a portable Raman spectrometer. The cysteamine monolayers could preconcentrate PCP close to the substrate surface through the electrostatic interaction, which makes the SERS detection of PCP possible. Moreover, the Raman bands of cysteamine could be used as the internal spectral reference in the quantitative analysis. Qualitative detection of PCP was carried out by SERS without any sample pretreatment. Quantitative analysis of PCP was further realized based on the prepared substrate, as the log-log plot of normalized SERS intensity of PCP versus its concentrations exhibits a good linear relationship. The SERS signals collected on 20 randomly selected points show that the relative standard deviation of the normalized Raman intensity is 5.8%, which indicates the substrate had good uniformity. The PCP sensor also shows good long-term stability in the analyte solution. The substrate was cyclic immersed into PCP and methanol solution; after several cycles, the sensor still had good adsorption to PCP, which revealed the sensor has good reusability. Coupling with a portable Raman spectrometer, the cysteamine-modified silver nanoparticle aggregates have the potential to be used for in situ and routine SERS analysis of PCP in environmental samples.

  17. 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.

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

    USDA-ARS?s Scientific Manuscript database

    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. Drug analysis by Raman and micro-Raman spectroscopy.

    PubMed

    Huong, P V

    1986-01-01

    The technique of Raman spectroscopy, resonance Raman spectroscopy and micro-Raman spectroscopy is described for application to drug analysis and investigation. Possibilities and limits are mentioned for qualitative and quantitative analyses as well as for studies of structure and interactions. Some principal interaction modes, such as hydrogen bonding, proton transfer, charge transfer and ion-molecule attraction, are shown to explain drug reactivity. Illustrations are given based on several drug families, in particular vitamins, anti-depressants, cardio-active and anticancer drugs.

  20. Raman Plus X: Biomedical Applications of Multimodal Raman Spectroscopy

    PubMed Central

    Das, Nandan K.; Dai, Yichuan; Liu, Peng; Hu, Chuanzhen; Tong, Lieshu; Chen, Xiaoya

    2017-01-01

    Raman spectroscopy is a label-free method of obtaining detailed chemical information about samples. Its compatibility with living tissue makes it an attractive choice for biomedical analysis, yet its translation from a research tool to a clinical tool has been slow, hampered by fundamental Raman scattering issues such as long integration times and limited penetration depth. In this review we detail the how combining Raman spectroscopy with other techniques yields multimodal instruments that can help to surmount the translational barriers faced by Raman alone. We review Raman combined with several optical and non-optical methods, including fluorescence, elastic scattering, OCT, phase imaging, and mass spectrometry. In each section we highlight the power of each combination along with a brief history and presentation of representative results. Finally, we conclude with a perspective detailing both benefits and challenges for multimodal Raman measurements, and give thoughts on future directions in the field. PMID:28686212

  1. Raman Plus X: Biomedical Applications of Multimodal Raman Spectroscopy.

    PubMed

    Das, Nandan K; Dai, Yichuan; Liu, Peng; Hu, Chuanzhen; Tong, Lieshu; Chen, Xiaoya; Smith, Zachary J

    2017-07-07

    Raman spectroscopy is a label-free method of obtaining detailed chemical information about samples. Its compatibility with living tissue makes it an attractive choice for biomedical analysis, yet its translation from a research tool to a clinical tool has been slow, hampered by fundamental Raman scattering issues such as long integration times and limited penetration depth. In this review we detail the how combining Raman spectroscopy with other techniques yields multimodal instruments that can help to surmount the translational barriers faced by Raman alone. We review Raman combined with several optical and non-optical methods, including fluorescence, elastic scattering, OCT, phase imaging, and mass spectrometry. In each section we highlight the power of each combination along with a brief history and presentation of representative results. Finally, we conclude with a perspective detailing both benefits and challenges for multimodal Raman measurements, and give thoughts on future directions in the field.

  2. 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.

  3. Urinalysis by surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Farquharson, Stuart; Lee, Yuan-Hsiang; Kwon, Hyeog; Shahriari, Mahmoud; Rainey, Petrie

    2000-01-01

    The overall objective of this Small Business Technology Transfer Research program is the development of a fiber optic sensor suitable for surface-enhanced Raman spectroscopy that provides reversible, reproducible, quantitative measurements of trace chemicals. The sensor is intended to benefit NASA and the International Space Station in several areas. For example, the sensor could provide real-time measurements for space-based research in the areas of chemistry and biotechnology, it could provide continuous water quality monitoring in the life support systems, or it could provide astronaut health monitoring through urine and blood chemical analysis. This paper describes the development of the SERS based sensor and its application to astronaut health monitoring through urinalysis. .

  4. 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

  5. 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.

  6. Assignment of vibrational spectral bands of kidney tissue by means of low temperature SERS spectroscopy

    NASA Astrophysics Data System (ADS)

    Velicka, M.; Radzvilaite, M.; Ceponkus, J.; Urboniene, V.; Pucetaite, M.; Jankevicius, F.; Steiner, G.; Sablinskas, V.

    2017-02-01

    Surface enhanced Raman scattering (SERS) spectroscopy is a useful method for detection of trace amounts of molecules. It has already been successfully implemented for detection of explosives, food additives, biomarkers in blood or urine, etc. In the last decade, SERS spectroscopy was introduced into the field of health sciences and has been especially focused on early disease detection. In the recent years, application of SERS spectroscopy for detection of various types of human cancerous tissues emerged. Furthermore, SERS spectroscopy of extracellular fluid shows great potential for the differentiation of normal and cancerous tissues; however, due to high variety of molecules present in such biological samples, the experimental spectrum is a combination of many different overlapping vibrational spectral bands. Thus, precise assignment of these bands to the corresponding molecular vibrations is a difficult task. In most cases, researchers try to avoid this task satisfying just with tentative assignment. In this study, low temperature SERS measurements of extracellular fluid of cancerous and healthy kidney tissue samples were carried out in order to get a deeper understanding of the nature of vibrational spectral bands present in the experimental spectrum. The SERS spectra were measured in temperature range from 300 K down to 100 K. SERS method was implemented using silver nanoparticle colloidal solution. The results of the low temperature SERS experiment were analysed and compared with the results of theoretical calculations. The analysis showed that the SERS spectrum of extracellular fluid of kidney tissue is highly influenced by the vibrational bands of adenine and Lcystine molecules.

  7. Development of a rapid macro-Raman spectroscopy system for nasopharyngeal cancer detection based on surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lin, Duo; Chen, Guannan; Feng, Shangyuan; Pan, Jianji; Lin, Juqiang; Huang, Zufang; Chen, Rong

    2015-01-01

    This study aims to evaluate the utility of a home-made surface-enhanced Raman spectroscopy (SERS) system for detection of nasopharyngeal cancer (NPC). A Raman spectral system with a special probe and a millimeter order excitation laser spot size was developed to acquire SERS signals of blood plasma. High quality SERS spectra can be recorded from blood plasma samples belonging to 60 healthy volunteers and 96 NPC patients, and the diagnostic sensitivity and specificity of 95.8% and 91.7%, respectively, can be achieved for classification between normal and cancer blood groups by principal component analysis combined with linear discriminant analysis (PCA-LDA). This exploratory study demonstrates that SERS based on a larger laser spot together with PCA-LDA has the potential for detection of nasopharyngeal cancer, and even for further in vivo cancer detection in the future.

  8. 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.

  9. 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.

  10. Raman spectroscopy of transition metal dichalcogenides.

    PubMed

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

    2016-09-07

    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.

  11. 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.

  12. 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.

  13. Raman spectroscopy and its urological applications

    PubMed Central

    Hanchanale, Vishwanath S.; Rao, Amrith R.; Das, Sakti

    2008-01-01

    Purpose: The Raman spectroscopic technology can be utilized for the detection of changes occurring at the molecular level during the pathological transformation of the tissue. The potential of its use in urology is still in its infancy and increasing utility of this technology will transform noninvasive tissue diagnosis. The Nobel laureate, Sir C.V. Raman is credited for the discovery of the principles of Raman spectroscopy. Materials and Methods: Applications of Raman spectroscopy in the bladder, renal, prostate, and other urological disorders were gathered from Medline and abstracts from recent international urological meetings. Current status and future directions of Raman spectroscopy in urology were also reviewed. Results: Raman spectroscopic technology is used to interrogate biological tissues. The potential use of this technology in urology has shown encouraging results in the in vitro diagnosis and grading of cancers of the bladder and the prostate. Raman microprobes have been used for the characterization and identification of renal lithiasis. Technology may be available for the urologists to determine the margin status intraoperatively during partial nephrectomy and radical prostatectomy. The future would see the development of optical fiber probes to incorporate them into catheters, endoscopes, and laparoscopes that will enable the urologist to obtain information during the operation. Conclusion: Raman spectroscopy is an exciting tool for real-time diagnosis and in vivo evaluation of living tissue. The potential applications of Raman spectroscopy may herald a new future in the management of various malignant, premalignant, and other benign conditions in urology. PMID:19468494

  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. 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.

  16. 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

  17. SERS imaging of cell-surface biomolecules metabolically labeled with bioorthogonal Raman reporters.

    PubMed

    Xiao, Ming; Lin, Liang; Li, Zefan; Liu, Jie; Hong, Senlian; Li, Yaya; Zheng, Meiling; Duan, Xuanming; Chen, Xing

    2014-08-01

    Live imaging of biomolecules with high specificity and sensitivity as well as minimal perturbation is essential for studying cellular processes. Here, we report the development of a bioorthogonal surface-enhanced Raman scattering (SERS) imaging approach that exploits small Raman reporters for visualizing cell-surface biomolecules. The cells were cultured and imaged by SERS microscopy on arrays of Raman-enhancing nanoparticles coated on silicon wafers or glass slides. The Raman reporters including azides, alkynes, and carbondeuterium bonds are small in size and spectroscopically bioorthogonal (background-free). We demonstrated that various cell-surface biomolecules including proteins, glycans, and lipids were metabolically incorporated with the corresponding precursors bearing a Raman reporter and visualized by SERS microscopy. The coupling of SERS microscopy with bioorthogonal Raman reporters expands the capabilities of live-cell microscopy beyond the modalities of fluorescence and label-free imaging. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. 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.

  19. Raman microscopy and surface-enhanced Raman scattering (SERS) for in situ analysis of biofilms.

    PubMed

    Ivleva, Natalia P; Wagner, Michael; Horn, Harald; Niessner, Reinhard; Haisch, Christoph

    2010-08-01

    Biofilms are communities of micro-organisms enclosed in a matrix of extracellular polymeric substances (EPS). They represent a ubiquitous form of microbial life on Earth. Detailed information on chemical composition and structure of the EPS matrix is relevant in medicine, industry and technological processes. Raman microscopy (RM) provides whole-organism fingerprints for biological samples with spatial resolution in the microm range and enables correlations between optical and chemical images to be made. Low water background makes RM beneficial for in situ studies of biofilms, since water is the major component of the biofilm matrix. In this paper we discuss the feasibility of RM for chemical characterization of different structures in a multispecies biofilm matrix, including microbial constituents and EPS. We show that by improving the sensitivity of RM with surface-enhanced Raman scattering (SERS) one can perform rapid biofilm analysis. In particular, by choosing appropriate SERS substrates and solving the problem of SERS measurement reproducibility one can carry out in situ study of different components in the complex biofilm matrix. (c) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Surface enhanced raman spectroscopy studies on triglycine sulphate single crystals

    NASA Astrophysics Data System (ADS)

    Parameswari, A.; Mohamed Asath, R.; Premkumar, R.; Milton Franklin Benial, A.

    2017-01-01

    Adsorption characteristics of triglycine sulphate (TGS) on silver (Ag) surface were investigated based on density functional theory calculations and surface enhanced Raman spectroscopy (SERS) technique. The single crystals of TGS were grown by slow evaporation method. Ag nanoparticles (Ag NPs) were prepared by solution combustion method and characterized. The calculated and observed structural parameters of TGS molecule were compared. Raman and SERS spectra for TGS single crystal were studied experimentally and validated theoretically. Frontier molecular orbitals (FMOs) analysis was carried out for TGS and TGS adsorbed on Ag surface. The second harmonic generation measurements confirm the nonlinear optical (NLO) activity of the TGS molecule. SERS spectral analysis reveals that the TGS adsorbed as tilted orientation on the silver surface. The theoretical and experimental results evidence the suitability of the grown TGS single crystal for optoelectronic applications.

  1. 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

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

    PubMed

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

    2006-06-28

    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.

  3. 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

  4. Stress measurement in MEMS using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Animoto, Sherwin T.; Chang, Dick J.; Birkitt, Andra D.

    1998-09-01

    Raman spectroscopy is used as a non-contact method in measuring stresses at the surface of a crystalline structure or the crystalline-coated surface of an amorphous structure. The stress measurement capability is based on the relative frequency shift of Raman spectra when the crystal lattice is strained. The Raman spectroscopy has a resolution on the order of a few micrometer (micrometers ) which may be used to probe the local non-uniform stress distribution and thus address the material nonhomogeneity. This paper presents the Raman secular equation for general and cubic crystal systems and discusses the stress field effects to Raman frequency shifts and polarization. Experimental testing will include the calibration of the Raman signal versus mechanically applied stresses using single crystal strips, poly-silicon coatings deposited on different specimen configurations, and the stress measurements on a frequently used MEMS structure, cantilever beam, subject to electrostatic forces. Correlation of the experimental results with the analytical prediction will be addressed.

  5. 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).

  6. Surface-enhanced Raman Spectroscopy for Astrobiology Exploration on Mars

    DTIC Science & Technology

    2012-10-01

    oxalates and perhaps acetatemay have been formed on the sur- face of Mars through oxidation of meteorite-delivered organics and these are largely...invisible to the analytic instruments onboard Viking lander. Salts of these or- ganic acids are resistant to further oxidation and may be present in...as described in the following section. Surface enhanced Raman spectroscopy (SERS): The surface-enhancing effect was discovered by Fleischmann et

  7. Surface-enhanced Raman spectroscopy for homeland defense

    NASA Astrophysics Data System (ADS)

    Spencer, Kevin M.; Sylvia, James M.; Marren, Peter J.; Bertone, Jane F.; Christesen, Steven D.

    2004-03-01

    Surface-enhanced Raman spectroscopy (SERS) is a spectroscopic technique that enables trace detection of analytes of relevance using fieldable equipment. SERS uses the enhanced Raman signals observed when an analyte adsorbs to a roughened metal substrate, generally gold, silver, or copper. Coupled to a microscope, single molecule detection has been demonstrated. With a fieldable instrument, enhancements of 108 compared to unenhanced Raman spectroscopy are expected, allowing trace detection in the field. Proper development of the metal substrate will optimize the sensitivity and selectivity towards the analytes of interest. In this presentation, we will discuss applications under development at EIC Laboratories that are of importance to Homeland Defense. We will review the capabilities of SERS to detect buried explosives, explosives associated with nuclear weaponry and chemicals involved in the nuclear enrichment process. We will discuss the detection of chemical and biological warfare agents in the water supply in research performed under the Joint Service Agent Water Monitor. We will demonstrate the current detection limits, the reproducibility of the signal, and results collected using actual chemical warfare agents, and show how the results can be extended to vapor detection. We will also discuss the current state-of-the art for fieldable instrumentation. The emphasis on portability and speed will be stressed; SERS acquisitions are restricted to 30 s or less.

  8. 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.

  9. 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

  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. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Raman spectroscopy in pharmaceutical product design.

    PubMed

    Paudel, Amrit; Raijada, Dhara; Rantanen, Jukka

    2015-07-15

    Almost 100 years after the discovery of the Raman scattering phenomenon, related analytical techniques have emerged as important tools in biomedical sciences. Raman spectroscopy and microscopy are frontier, non-invasive analytical techniques amenable for diverse biomedical areas, ranging from molecular-based drug discovery, design of innovative drug delivery systems and quality control of finished products. This review presents concise accounts of various conventional and emerging Raman instrumentations including associated hyphenated tools of pharmaceutical interest. Moreover, relevant application cases of Raman spectroscopy in early and late phase pharmaceutical development, process analysis and micro-structural analysis of drug delivery systems are introduced. Finally, potential areas of future advancement and application of Raman spectroscopic techniques are discussed.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. Estimating Atomic Sizes with Raman Spectroscopy

    PubMed Central

    Wang, Dingdi; Guo, Wenhao; Hu, Juanmei; Liu, Fang; Chen, Lisheng; Du, Shengwang; Tang, Zikang

    2013-01-01

    We demonstrate a technique to determine the Van der Waals radius of iodine atoms using Raman spectroscopy. The iodine diatomic molecules are diffused into the nano-scale channels of a zeolite single crystal. We found their polarized Raman spectroscopy, which corresponds to iodine molecule's vibrational motion along the direction of molecular axis, is significantly modified by the interaction between the iodine molecules and the rigid frame of the crystal's nano-channels. From the number of excitable vibration quantum states of the confined iodine molecules determined from Raman spectra and the size of the nano-channels, we estimate the iodine atomic radius to be 2.10 ± 0.05 Å. It is the first time that atomic sizes, which are far beyond the optical diffraction limit, have be resolved optically using Raman spectroscopy with the help of nano-scale structures. PMID:23508118

  1. Raman spectroscopy towards clinical application: drug monitoring and pathogen identification.

    PubMed

    Neugebauer, Ute; Rösch, Petra; Popp, Jürgen

    2015-12-01

    Raman spectroscopy is a label-free method that measures quickly and contactlessly, providing detailed information from the sample, and has proved to be an ideal tool for medical and life science research. In this review, recent advances of the technique towards drug monitoring and pathogen identification by the Jena Research Groups are reviewed. Surface-enhanced Raman spectroscopy (SERS) and ultraviolet resonance Raman spectroscopy in hollow-core optical fibres enable the detection of drugs at low concentrations as shown for the metabolites of the immunosuppressive drug 6-mercaptopurine as well as antimalarial agents. Furthermore, Raman spectroscopy can be used to characterise pathogenic bacteria in infectious diseases directly from body fluids, making time-consuming cultivation processes dispensable. Using the example of urinary tract infection, it is shown how bacteria can be identified from patients' urine samples within <1 h. The methods cover both single-cell analysis and dielectrophoretic capturing of bacteria in suspension. The latter method could also be used for fast (<3.5 h) identification of antibiotic resistance as shown exemplarily for vancomycin-resistant enterococci. Copyright © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  2. 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.

  3. Sensitive SERS nanotags for use with a hand-held 1064 nm Raman spectrometer

    NASA Astrophysics Data System (ADS)

    Kearns, Hayleigh; Ali, Fatima; Bedics, Matthew A.; Shand, Neil C.; Faulds, Karen; Detty, Michael R.; Graham, Duncan

    2017-07-01

    This is the first report of the use of a hand-held 1064 nm Raman spectrometer combined with red-shifted surface-enhanced Raman scattering (SERS) nanotags to provide an unprecedented performance in the short-wave infrared (SWIR) region. A library consisting of 17 chalcogenopyrylium nanotags produce extraordinary SERS responses with femtomolar detection limits being obtained using the portable instrument. This is well beyond previous SERS detection limits at this far red-shifted wavelength and opens up new options for SERS sensors in the SWIR region of the electromagnetic spectrum (between 950 and 1700 nm).

  4. 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.

  5. Detection of pathogens and toxins by surface enhanced Raman spectroscopy using silver nanorods array substrates

    USDA-ARS?s Scientific Manuscript database

    Surface enhanced Raman spectroscopy (SERS) offers considerable potential in the area of molecular identification and trace element analysis, which has significant applications in both biological and chemical analysis. We have created a portable SERS probe which can be easily incorporated with a fibe...

  6. 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.

  7. Surface- and Tip-Enhanced Raman Spectroscopy as Operando Probes for Monitoring and Understanding Heterogeneous Catalysis.

    PubMed

    Harvey, Clare E; Weckhuysen, Bert M

    Surface-enhanced Raman spectroscopy (SERS) and tip-enhanced Raman spectroscopy (TERS) were until recently limited in their applicability to the majority of heterogeneous catalytic reactions. Recent developments begin to resolve the conflicting experimental requirements for SERS and TERS on the one hand, and heterogeneous catalysis on the other hand. This article discusses the development and use of SERS and TERS to study heterogeneous catalytic reactions, and the exciting possibilities that may now be within reach thanks to the latest technical developments. This will be illustrated with showcase examples from photo- and electrocatalysis.

  8. Raman and SERS recognition of β-carotene and haemoglobin fingerprints in human whole blood

    NASA Astrophysics Data System (ADS)

    Casella, Michele; Lucotti, Andrea; Tommasini, Matteo; Bedoni, Marzia; Forvi, Elena; Gramatica, Furio; Zerbi, Giuseppe

    2011-09-01

    The present work reports on Raman and Surface Enhanced Raman Scattering (SERS) vibrational fingerprints of β-carotene and haemoglobin in fresh whole blood (i.e. right after blood test) with different laser excitations, i.e. visible (514 nm) and near-infrared (NIR, 785 nm). The use of colloidal silver nanoparticles significantly increases the Raman signal, thus providing a clear SERS spectrum of blood. The collected spectra have been examined and marker bands of β-carotene and of the haem prosthetic group of haemoglobin have been found. In particular, the fundamental features of β-carotene (514 nm excitation), blood proteins and haem molecules (785 nm excitation) were recognized and assigned. Moreover haemoglobin SERS signals can be identified and related with its oxygenation state (oxy-haemoglobin). The data reported show the prospects of Raman and SERS techniques to detect important bio-molecules in a whole blood sample with no pre-treatment.

  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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Esophageal cancer detection based on tissue surface-enhanced Raman spectroscopy and multivariate analysis

    NASA Astrophysics Data System (ADS)

    Feng, Shangyuan; Lin, Juqiang; Huang, Zufang; Chen, Guannan; Chen, Weisheng; Wang, Yue; Chen, Rong; Zeng, Haishan

    2013-01-01

    The capability of using silver nanoparticle based near-infrared surface enhanced Raman scattering (SERS) spectroscopy combined with principal component analysis (PCA) and linear discriminate analysis (LDA) to differentiate esophageal cancer tissue from normal tissue was presented. Significant differences in Raman intensities of prominent SERS bands were observed between normal and cancer tissues. PCA-LDA multivariate analysis of the measured tissue SERS spectra achieved diagnostic sensitivity of 90.9% and specificity of 97.8%. This exploratory study demonstrated great potential for developing label-free tissue SERS analysis into a clinical tool for esophageal cancer detection.

  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. Development of Raman Spectroscopy as a Clinical Diagnostic Tool

    NASA Astrophysics Data System (ADS)

    Borel, Santa

    Raman spectroscopy is the collection of inelastically scattered light in which the spectra contain biochemical information of the probed cells or tissue. This work presents both targeted and untargeted ways that the technique can be exploited in biological samples. First, surface enhanced Raman scattering (SERS) gold nanoparticles conjugated to targeting antibodies were shown to be successful for multiplexed detection of overexpressed surface antigens in lung cancer cell lines. Further work will need to optimize the conjugation technique to preserve the strong binding affinity of the antibodies. Second, untargeted Raman microspectroscopy combined with multivariate statistical analysis was able to successfully differentiate mouse ovarian surface epithelial (MOSE) cells and spontaneously transformed ovarian surface epithelial (STOSE) cells with high accuracy. The differences between the two groups were associated with increased nucleic acid content in the STOSE cells. This shows potential for single cell detection of ovarian cancer.

  13. Comparisons between Surface-Enhanced Raman and Surface Infrared Spectroscopies for Strongly Perturbed Adsorbates: Thiocyanate at Gold Electrodes.

    DTIC Science & Technology

    1986-07-30

    tu. 3. iptt FCSa, s CATALOG NUtof SBetween Surface -Enhanced Raman anj$ YEO EOTI EIDCvfr Surface Infared Spectroscopies for StrongiV Technical Report...REPORT 8 49 0Comparisons Between Surface-Enhanced Raman and Surface Infrared Spectroscopies for Strongly Perturbed Adsorbates: Thiocyanate at Gold...for thiocyanate adsorbed at the gold-aqueous interface is examined by both surface-enhanced Raman spectroscopy (SERS) and subtractively normalized

  14. 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.

  15. Polymorph Discrimination using Low Wavenumber Raman Spectroscopy

    PubMed Central

    Roy, Saikat; Chamberlin, Brianna; Matzger, Adam J.

    2016-01-01

    Characterization of crystalline polymorphs and their quantitation has become an integral part of the pre-clinical drug development process. Raman spectroscopy is a powerful technique for the rapid identification of phases of pharmaceuticals. In the present work we demonstrate the use of low wavenumber Raman vibrational spectroscopy (including phonon measurement) for discrimination among polymorphs. A total of 10 polymorphic pharmaceuticals were employed to conduct a critical assessment. Raman scattering in the low frequency region (10–400 cm−1), which includes crystal lattice vibrations, has been analyzed and the results indicate lattice phonon Raman scattering can be used for rapid discrimination of polymorphic phases with additional discriminating power compared to conventional collection strategies. Moreover structural insight and conformational changes can be detected with this approach. PMID:27642248

  16. Analysing avian eggshell pigments with Raman spectroscopy.

    PubMed

    Thomas, Daniel B; Hauber, Mark E; Hanley, Daniel; Waterhouse, Geoffrey I N; Fraser, Sara; Gordon, Keith C

    2015-09-01

    Avian eggshells are variable in appearance, including coloration. Here, we demonstrate that Raman spectroscopy can provide accurate diagnostic information about major eggshell constituents, including the pigments biliverdin and protoporphyrin IX. Eggshells pigmented with biliverdin showed a series of pigment-diagnostic Raman peaks under 785 nm excitation. Eggshells pigmented with protoporphyrin IX showed strong emission under 1064 nm and 785 nm excitation, whereas resonance Raman spectra (351 nm excitation) showed a set of protoporphyrin IX informative peaks characteristic of protoporphyrin IX. As representative examples, we identified biliverdin in the olive green eggshells of elegant crested tinamous (Eudromia elegans) and in the blue eggshells of extinct upland moa (Megalapteryx didinus). This study encourages the wider use of Raman spectroscopy in pigment and coloration research and highlights the value of this technique for non-destructive analyses of museum eggshell specimens. © 2015. Published by The Company of Biologists Ltd.

  17. 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.

  18. 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.

  19. Doppler-Shifted Raman Spectroscopy Measures Flows

    NASA Technical Reports Server (NTRS)

    Exton, Reginald J.; Hillard, Mervin E., Jr.; Lempert, Walter R.; Covell, Peter F.; Miller, David S.

    1990-01-01

    Technique for measuring velocity, static pressure, and translational temperature of flowing molecules by use of stimulated Raman spectroscopy demonstrated in supersonic wind tunnel at NASA Langley Research Center. Nonintrusive, accurate wind-tunnel measurements obtained without seeding flows. Optical equipment for vibration-free Raman doppler velocimetry in wind tunnel includes specially designed retrometer that reduces sensitivity of system to vibrations. This capability very valuable in aerodynamic testing and proves useful in wide variety of laboratory, industrial, and engineering applications.

  20. Bio-Conjugated Gold Nanoparticle Based SERS Probe for Ultrasensitive Identification of Mosquito-Borne Viruses Using Raman Fingerprinting.

    PubMed

    Paul, Amber M; Fan, Zhen; Sinha, Sudarson S; Shi, Yongliang; Le, Linda; Bai, Fengwei; Ray, Paresh C

    2015-10-15

    Dengue virus (DENV) and West Nile virus (WNV) are two well-documented mosquito-borne flaviviruses that cause significant health problems worldwide. Driven by this need, we have developed a bio-conjugated gold nanoparticle (AuNP)-based surface enhanced Raman spectroscopy (SERS) probe for the detection of both DENV and WNV. Reported data demonstrate anti-flavivirus 4G2 antibody conjugated gold nanoparticle (GNP) SERS probe can be used as a Raman fingerprint for the ultrasensitive detection of DENV and WNV selectively. Experimental data show that due to the plasmon coupling in nano-assembly, antibody conjugated GNP- based SERS is able to detect as low as 10 plaque-forming units (PFU)/ml of DENV-2 and WNV, which is comparable with the sensitivity of quantitative PCR-based assays. Selectivity of our probe was demonstrated using another mosquito-borne chikungunya virus (CHIKV) as a negative control. Experimental data demonstrate a huge enhancement of SERS intensity is mainly due to the strong electric field enhancement, which has been confirmed by the finite-difference time-domain (FDTD) simulation. Reported FDTD simulation data indicate the SERS enhancement factor can be more than 10(4) times, due to the assembled structure. Reported results suggest that bio-conjugated AuNP-4G2 based SERS probes have great potential to be used to screen viral particles in clinical and research-based laboratories.

  1. Surface enhanced Raman scattering (SERS) and FTIR characterization of the sepia melanin pigment used in works of art

    NASA Astrophysics Data System (ADS)

    Centeno, Silvia A.; Shamir, Jacob

    2008-02-01

    Surface enhanced Raman scattering (SERS) and FTIR were used for the vibrational characterization of the sepia melanin pigment extracted from the cuttlefish or Sepia officinalis, a material used in works of art from at least the late 18th century. The heterogeneous polymeric nature of the pigment, together with its fluorescent background, makes its identification by normal Raman spectroscopy difficult. In the present study, SERS and FTIR spectra of sepia were obtained. SERS proved to be suitable to characterize this complex material in micro-samples because of its sensitivity, ability to quench fluorescence, and minimal preparation required. For the SERS measurements, different substrates were tested in contact with the sepia pigment. It was found that a sodium borohydride reduced silver colloid gave the best performance, particularly when applied as a drop on top of a solid sepia sample, and subsequently dried. A larger enhancement was observed in the SERS spectrum of the sepia sample extracted in the laboratory, when compared to the more pure commercial sample, consistently with the higher metal binding capacity of less pure sepia melanin reported by other authors. The FTIR and SERS frequencies observed were found to be consistent with those reported in the literature for closely related compounds, such as indole, pyrrole and substituted pyrroles, and were assigned by comparison with them and with other published data for functional groups in organic chemistry.

  2. Surface enhanced Raman spectroscopy in breast cancer cells

    PubMed Central

    González-Solís, JL; Luévano-Colmenero, GH; Vargas-Mancilla, J

    2013-01-01

    Background and aims: Raman spectroscopy is a vibrational technique which provides information about the chemical structure. Nevertheless, since many chemicals are present in a cell at very low concentration, the Raman signal observed from a single cell is extremely weak. In surface enhanced Raman scattering (SERS), Raman signals can be enhanced by many orders of magnitude when nanoparticles are incorporated into the cell. Materials (subjects) and methods: The tumor biopsies were obtained from 5 patients who were clinically diagnosed with breast cancer. Breast cancer cells isolated from the biopsy were washed, centrifuged and seeded out. Cultivation took place in DMEM at 37°C in a humidified of 5% CO2 in air with addition of colloidal silver nanoparticles of 40 nm into the cell by sonication. Immediately, the washed cells were analyzed in phosphate buffered saline (PBS) at pH 7. Raman analysis was carried out on the Jobin-Yvon LabRAM HR800 microscope system, with a NIR 830 nm laser excitation source. Results: The strongly enhanced Raman signals allow Raman measurements of a single cell in the 200–1800 cm−1 range in relatively short collection times (5 second) using 17 mW near-infrared excitation. Observed spectral features differed across the cell, but chemical constituents in the cell nucleus and cytoplasm, such as DNA, RNA, and amino acids tyrosine and phenylalanine can be identified. Conclusions: Particularly strong field enhancement can be observed when nanoparticles form colloidal clusters. The results suggest that SERS could be a new technique for the identification of breast cancer cell. PMID:24155548

  3. 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.

  4. Amide I vibrational mode suppression in surface (SERS) and tip (TERS) enhanced Raman spectra of protein specimens.

    PubMed

    Kurouski, Dmitry; Postiglione, Thomas; Deckert-Gaudig, Tanja; Deckert, Volker; Lednev, Igor K

    2013-03-21

    Surface- and tip-enhanced Raman spectroscopy (SERS and TERS) are modern spectroscopic techniques, which are becoming widely used and show a great potential for the structural characterisation of biological systems. Strong enhancement of the Raman signal through localised surface plasmon resonance enables chemical detection at the single-molecule scale. Enhanced Raman spectra collected from biological specimens, such as peptides, proteins or microorganisms, were often observed to lack the amide I band, which is commonly used as a marker for the interpretation of the secondary protein structure. The cause of this phenomenon was unclear for many decades. In this work, we investigated this phenomenon for native insulin and insulin fibrils using both TERS and SERS and compared these spectra to the spectra of well-defined homo peptides. The results indicate that the appearance of the amide I Raman band does not correlate with the protein aggregation state, but is instead determined by the size of the amino acid side chain. For short model peptides, the absence of the amide I band in TERS and SERS spectra correlates with the presence of a bulky side chain. Homo-glycine and -alanine, which are peptides with small side chain groups (H and CH(3), respectively), exhibited an intense amide I band in almost 100% of the acquired spectra. Peptides with bulky side chains, such as tyrosine and tryptophan, exhibited the amide I band in 70% and 31% of the acquired spectra, respectively.

  5. 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.

  6. Process analytical applications of Raman spectroscopy.

    PubMed

    Rantanen, Jukka

    2007-02-01

    There is an increasing demand for new approaches to understand the chemical and physical phenomena that occur during pharmaceutical unit operations. Obtaining real-time information from processes opens new perspectives for safer and more efficient manufacture of pharmaceuticals. Raman spectroscopy provides a molecular level insight into processing, and therefore it is a future process analytical tool. In this review, different applications of Raman spectroscopy in the field of process analysis of pharmaceutical solid dosage forms are summarized. In addition, pitfalls associated with interfacing to the process environment and challenges within data management are discussed.

  7. Ultraviolet surface-enhanced Raman spectroscopy using aluminum plasmonic gratings

    NASA Astrophysics Data System (ADS)

    Roberts, Adam T.; Butun, Serkan; Aydin, Koray; Everitt, Henry O.; Bloemer, Mark; D'Aguanno, Giuseppe; Mattiucci, Nadia

    2013-03-01

    Surface-enhanced Raman scattering (SERS) has been widely studied both theoretically and experimentally for chemical and biological sensing, primarily in the visible and near-infrared wavelengths. Although in the ultraviolet (UV) plasmonic behavior is limited by metallic dampening, we have theoretically shown that SERS enhancement factors as large as 105 can be achieved when the laser is tuned to the plasmonic band edge of an Al metallic grating grown on a sapphire substrate. Using electron beam lithography, aluminum gratings were fabricated whose pitch (150-300 nm), slit widths (64 nm), and thickness (50 nm) were chosen to produce large enhancement factors at wavelengths in the UV. Analytes such as thiophenol were then deposited on the gratings, and UV-SERS spectroscopy was performed to measure the enhancement factors and compare with theoretical estimates. Enhancement factors were measured by comparing the strength of the Raman signal from the grating region with the strength of the Raman signal from adjacent regions without a grating. The dependence of the enhancement factor on laser wavelength relative to the plasmonic band edge for a given grating pitch was explored, as was the effect of using a tapered slit geometry that focuses the local field on the nanoscale.

  8. 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.

  9. Intracellular multiplex detection and imaging of stable chemisorbed labels by SERS spectroscopy

    NASA Astrophysics Data System (ADS)

    Sirimuthu, Narayana M. S.; Syme, Christopher D.; Cooper, Jonathan M.

    2012-03-01

    SERS spectroscopy is currently gaining wider acceptance in biological research due to its ability to obtain signals from very low quantities of material, and to obtain information from within live cells. SERS spectroscopy yields very narrow bands (10-100 times narrower than typical fluorescence bands) and spectra suffer from minimal interference from aqueous media, making SERS spectroscopy ideal for multiplex detection of intracellular components. Typically for sensing, nanoparticles are labelled with suitable sensing molecules such as a dye or thiol. Nanoparticle labelling involves two different types of interaction between the label and the enhancing surface, chemisorption and physisorption. The former is considerably stronger and more stable than the latter and hence chemisorbed labels are more appropriate for intracellular nanosensor design. In this paper, we demonstrate the difference in stability of both types of Raman label inside live cells over periods of time. Chinese hamster ovary (CHO) cells were infused with a mixture of differently labelled stable nanosensors and were imaged using SERS microspectroscopy. We also demonstrate the applicability of SERS mapping for high-throughput multiplex detection using micropatterned cell arrays.

  10. 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.

  11. Surface-Enhanced Raman Spectroscopy with High Spatial Resolution

    SciTech Connect

    Huser, T R

    2003-02-04

    The identification of individual molecules and the determination of how these interact with their local environment are critical steps toward a better understanding of complex organic systems. Optical detection techniques have always played a key role in the nondestructive and noninvasive analysis of complex materials. Until recently, however, optical microscopy has lacked the sensitivity to study processes on the molecular scale. This has changed with the recent development of new schemes that limit the optical detection volume, and the advent of new, highly quantum-efficient photon detectors. These inventions have enabled researchers to optically probe biomolecular processes at the single molecule level by observing the fluorescence of specific marker molecules. The requirement to specifically label biomolecules and the fact, that fluorescence emission is prone to photodecomposition of the marker molecules, however, have limited this approach to a few, well-characterized case studies. Raman scattering, is one of few optical techniques that can identify atomic species and in addition determine their chemical bonds by observing their distinct vibrational fingerprints; but it is orders of magnitude weaker than fluorescence. In this project, we have developed new optical probes that allow for the non-destructive characterization and identification of organic and inorganic matter at the single molecule level by surface-enhanced Raman spectroscopy. Our approach combines confocal Raman microscopy with surface-enhanced Raman spectroscopy (SERS) generated by coating scanning probe microscope (SPM) tips with thin (30-40 nm) gold and silver films. The scanning SERS probe generates an image of the physical structure of a sample together with detailed chemical information about its composition. In a complementary approach, we have also used gold or silver nanoparticles to generate SER spectra from single molecules adsorbed to these particles. This project has led to the

  12. Surface Enhanced Raman Scattering (SERS) Studies of Gold and Silver Nanoparticles Prepared by Laser Ablation

    PubMed Central

    Herrera, Gloria M.; Padilla, Amira C.; Hernandez-Rivera, Samuel P.

    2013-01-01

    Gold and silver nanoparticles (NPs) were prepared in water, acetonitrile and isopropanol by laser ablation methodologies. The average characteristic (longer) size of the NPs obtained ranged from 3 to 70 nm. 4-Aminobenzebethiol (4-ABT) was chosen as the surface enhanced Raman scattering (SERS) probe molecule to determine the optimum irradiation time and the pH of aqueous synthesis of the laser ablation-based synthesis of metallic NPs. The synthesized NPs were used to evaluate their capacity as substrates for developing more analytical applications based on SERS measurements. A highly energetic material, TNT, was used as the target compound in the SERS experiments. The Raman spectra were measured with a Raman microspectrometer. The results demonstrate that gold and silver NP substrates fabricated by the methods developed show promising results for SERS-based studies and could lead to the development of micro sensors.

  13. Theory of femtosecond stimulated Raman spectroscopy

    PubMed Central

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

    2005-01-01

    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 ∼1 – 3 ps Raman pump pulse with a continuum ∼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

  14. Visualizing Cell State Transition Using Raman Spectroscopy

    PubMed Central

    Ichimura, Taro; Chiu, Liang-da; Fujita, Katsumasa; Kawata, Satoshi; Watanabe, Tomonobu M.; Yanagida, Toshio; Fujita, Hideaki

    2014-01-01

    System level understanding of the cell requires detailed description of the cell state, which is often characterized by the expression levels of proteins. However, understanding the cell state requires comprehensive information of the cell, which is usually obtained from a large number of cells and their disruption. In this study, we used Raman spectroscopy, which can report changes in the cell state without introducing any label, as a non-invasive method with single cell capability. Significant differences in Raman spectra were observed at the levels of both the cytosol and nucleus in different cell-lines from mouse, indicating that Raman spectra reflect differences in the cell state. Difference in cell state was observed before and after the induction of differentiation in neuroblastoma and adipocytes, showing that Raman spectra can detect subtle changes in the cell state. Cell state transitions during embryonic stem cell (ESC) differentiation were visualized when Raman spectroscopy was coupled with principal component analysis (PCA), which showed gradual transition in the cell states during differentiation. Detailed analysis showed that the diversity between cells are large in undifferentiated ESC and in mesenchymal stem cells compared with terminally differentiated cells, implying that the cell state in stem cells stochastically fluctuates during the self-renewal process. The present study strongly indicates that Raman spectral morphology, in combination with PCA, can be used to establish cells' fingerprints, which can be useful for distinguishing and identifying different cellular states. PMID:24409302

  15. Surface-enhanced Raman scattering (SERS) imaging of alkyne-tagged small molecule drug in live cells with endocytosed gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Ando, Jun; Sekiya, Takumasa; Ka, Den; Yamakoshi, Hiroyuki; Dodo, Kosuke; Sodeoka, Mikiko; Kawata, Satoshi; Fujita, Katsumasa

    2017-02-01

    We propose the combination of alkyne-tag and surface-enhanced Raman scattering (SERS) spectroscopy to perform highly-sensitive and selective drug imaging in live cells. Gold nanoparticles are introduced in lysosomes through endocytosis as SERS agents, and the alkyne-tagged drugs are subsequently administered in cells. Raman microscopic observation reveals the arrival of drug in lysosome through enhanced Raman signal of alkyne. Since the peak of alkyne appears in Raman-silent region of biomolecules, selective detection of drugs is possible without background signal of endogenous molecules. From endocytosed gold nanoparticles in living HeLa cells, we observed distinct Raman signal from alkyne-tagged inhibitor of lysosomal enzyme.

  16. Quantitative determinations using portable Raman spectroscopy.

    PubMed

    Navin, Chelliah V; Tondepu, Chaitanya; Toth, Roxana; Lawson, Latevi S; Rodriguez, Jason D

    2017-03-20

    A portable Raman spectrometer was used to develop chemometric models to determine percent (%) drug release and potency for 500mg ciprofloxacin HCl tablets. Parallel dissolution and chromatographic experiments were conducted alongside Raman experiments to assess and compare the performance and capabilities of portable Raman instruments in determining critical drug attributes. All batches tested passed the 30min dissolution specification and the Raman model for drug release was able to essentially reproduce the dissolution profiles obtained by ultraviolet spectroscopy at 276nm for all five batches of the 500mg ciprofloxacin tablets. The five batches of 500mg ciprofloxacin tablets also passed the potency (assay) specification and the % label claim for the entire set of tablets run were nearly identical, 99.4±5.1 for the portable Raman method and 99.2±1.2 for the chromatographic method. The results indicate that portable Raman spectrometers can be used to perform quantitative analysis of critical product attributes of finished drug products. The findings of this study indicate that portable Raman may have applications in the areas of process analytical technology and rapid pharmaceutical surveillance. Published by Elsevier B.V.

  17. Raman spectroscopy of proteins and nucleoproteins.

    PubMed

    Nemecek, Daniel; Stepanek, Josef; Thomas, George J

    2013-01-01

    A protein Raman spectrum comprises discrete bands representing vibrational modes of the peptide backbone and its side chains. The spectral positions, intensities, and polarizations of the Raman bands are sensitive to protein secondary, tertiary, and quaternary structures and to side-chain orientations and local environments. In favorable cases, the Raman spectrum serves as an empirical signature of protein three-dimensional structure, intramolecular dynamics, and intermolecular interactions. Quantitative analysis of Raman spectral series can be further boosted by advanced statistical approaches of factor analysis that allow fitting of specific theoretical models while reducing the amount of analyzed data. Here, the strengths of Raman spectroscopy are illustrated by considering recent applications from the authors' work that address (1) subunit folding and recognition in assembly of the icosahedral bacteriophages, (2) orientations of subunit main chains and side chains in native filamentous viruses, (3) roles of cysteine hydrogen bonding in the folding, assembly, and function of virus structural proteins, and (4) structural determinants of protein/DNA recognition in gene regulatory complexes. Conventional Raman and polarized Raman techniques are surveyed.

  18. 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.

  19. Use of Single-Layer g-C3N4/Ag Hybrids for Surface-Enhanced Raman Scattering (SERS)

    NASA Astrophysics Data System (ADS)

    Jiang, Jizhou; Zou, Jing; Wee, Andrew Thye Shen; Zhang, Wenjing

    2016-09-01

    Surface-enhanced Raman scattering (SERS) substrates with high activity and stability are desirable for SERS sensing. Here, we report a new single atomic layer graphitic-C3N4 (S-g-C3N4) and Ag nanoparticles (NPs) hybrid as high-performance SERS substrates. The SERS mechanism of the highly stable S-g-C3N4/Ag substrates was systematically investigated by a combination of experiments and theoretical calculations. From the results of XPS and Raman spectroscopies, it was found that there was a strong interaction between S-g-C3N4 and Ag NPs, which facilitates the uniform distribution of Ag NPs over the edges and surfaces of S-g-C3N4 nanosheets, and induces a charge transfer from S-g-C3N4 to the oxidizing agent through the silver surface, ultimately protecting Ag NPs from oxidation. Based on the theoretical calculations, we found that the net surface charge of the Ag atoms on the S-g-C3N4/Ag substrates was positive and the Ag NPs presented high dispersibility, suggesting that the Ag atoms on the S-g-C3N4/Ag substrates were not likely to be oxidized, thereby ensuring the high stability of the S-g-C3N4/Ag substrate. An understanding of the stability mechanism in this system can be helpful for developing other effective SERS substrates with long-term stability.

  20. Use of Single-Layer g-C3N4/Ag Hybrids for Surface-Enhanced Raman Scattering (SERS).

    PubMed

    Jiang, Jizhou; Zou, Jing; Wee, Andrew Thye Shen; Zhang, Wenjing

    2016-09-30

    Surface-enhanced Raman scattering (SERS) substrates with high activity and stability are desirable for SERS sensing. Here, we report a new single atomic layer graphitic-C3N4 (S-g-C3N4) and Ag nanoparticles (NPs) hybrid as high-performance SERS substrates. The SERS mechanism of the highly stable S-g-C3N4/Ag substrates was systematically investigated by a combination of experiments and theoretical calculations. From the results of XPS and Raman spectroscopies, it was found that there was a strong interaction between S-g-C3N4 and Ag NPs, which facilitates the uniform distribution of Ag NPs over the edges and surfaces of S-g-C3N4 nanosheets, and induces a charge transfer from S-g-C3N4 to the oxidizing agent through the silver surface, ultimately protecting Ag NPs from oxidation. Based on the theoretical calculations, we found that the net surface charge of the Ag atoms on the S-g-C3N4/Ag substrates was positive and the Ag NPs presented high dispersibility, suggesting that the Ag atoms on the S-g-C3N4/Ag substrates were not likely to be oxidized, thereby ensuring the high stability of the S-g-C3N4/Ag substrate. An understanding of the stability mechanism in this system can be helpful for developing other effective SERS substrates with long-term stability.

  1. Use of Single-Layer g-C3N4/Ag Hybrids for Surface-Enhanced Raman Scattering (SERS)

    PubMed Central

    Jiang, Jizhou; Zou, Jing; Wee, Andrew Thye Shen; Zhang, Wenjing

    2016-01-01

    Surface-enhanced Raman scattering (SERS) substrates with high activity and stability are desirable for SERS sensing. Here, we report a new single atomic layer graphitic-C3N4 (S-g-C3N4) and Ag nanoparticles (NPs) hybrid as high-performance SERS substrates. The SERS mechanism of the highly stable S-g-C3N4/Ag substrates was systematically investigated by a combination of experiments and theoretical calculations. From the results of XPS and Raman spectroscopies, it was found that there was a strong interaction between S-g-C3N4 and Ag NPs, which facilitates the uniform distribution of Ag NPs over the edges and surfaces of S-g-C3N4 nanosheets, and induces a charge transfer from S-g-C3N4 to the oxidizing agent through the silver surface, ultimately protecting Ag NPs from oxidation. Based on the theoretical calculations, we found that the net surface charge of the Ag atoms on the S-g-C3N4/Ag substrates was positive and the Ag NPs presented high dispersibility, suggesting that the Ag atoms on the S-g-C3N4/Ag substrates were not likely to be oxidized, thereby ensuring the high stability of the S-g-C3N4/Ag substrate. An understanding of the stability mechanism in this system can be helpful for developing other effective SERS substrates with long-term stability. PMID:27687573

  2. Raman spectroscopy of newberyite, hannayite and struvite

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Weier, Matt L.; Martens, Wayde N.; Henry, Dermot A.; Mills, Stuart J.

    2005-11-01

    The phosphate minerals hannayite, newberyite and struvite have been studied by Raman spectroscopy using a thermal stage. Hannayite and newberyite are characterised by an intense band at around 980 cm -1 assigned to the v symmetric stretching vibration of the HPO 4 units. In contrast the symmetric stretching mode is observed at 942 cm -1 for struvite. The Raman spectra are characterised by multiple v anti-symmetric stretching bands and v and v bending modes indicating strong distortion of the HPO 4 and PO 4 units. Hannayite and newberyite are defined by bands at 3382 and 3350 cm -1 attributed to HOPO 3 vibrations and hannayite and struvite by bands at 2990, 2973 and 2874 assigned to NH 4+ bands. Raman spectroscopy has proven most useful for the analysis of these 'cave' minerals where complex paragenetic relationships exist between the minerals.

  3. 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.

  4. 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.

  5. Monitoring Early-Stage Nanoparticle Assembly in Microdroplets by Optical Spectroscopy and SERS.

    PubMed

    Salmon, Andrew R; Esteban, Ruben; Taylor, Richard W; Hugall, James T; Smith, Clive A; Whyte, Graeme; Scherman, Oren A; Aizpurua, Javier; Abell, Chris; Baumberg, Jeremy J

    2016-04-06

    Microfluidic microdroplets have increasingly found application in biomolecular sensing as well as nanomaterials growth. More recently the synthesis of plasmonic nanostructures in microdroplets has led to surface-enhanced Raman spectroscopy (SERS)-based sensing applications. However, the study of nanoassembly in microdroplets has previously been hindered by the lack of on-chip characterization tools, particularly at early timescales. Enabled by a refractive index matching microdroplet formulation, dark-field spectroscopy is exploited to directly track the formation of nanometer-spaced gold nanoparticle assemblies in microdroplets. Measurements in flow provide millisecond time resolution through the assembly process, allowing identification of a regime where dimer formation dominates the dark-field scattering and SERS. Furthermore, it is shown that small numbers of nanoparticles can be isolated in microdroplets, paving the way for simple high-yield assembly, isolation, and sorting of few nanoparticle structures.

  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. 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.

  8. Bacillus spore classification via surface-enhanced Raman spectroscopy and principal component analysis.

    PubMed

    Guicheteau, J; Argue, L; Emge, D; Hyre, A; Jacobson, M; Christesen, S

    2008-03-01

    Surface-enhanced Raman spectroscopy (SERS) can provide rapid fingerprinting of biomaterial in a nondestructive manner. The adsorption of colloidal silver to biological material suppresses native biofluorescence while providing electromagnetic surface enhancement of the normal Raman signal. This work validates the applicability of qualitative SER spectroscopy for analysis of bacterial species by utilizing principal component analysis (PCA) to show discrimination of biological threat simulants, based upon multivariate statistical confidence limits bounding known data clusters. Gram-positive Bacillus spores (Bacillus atrophaeus, Bacillus anthracis, and Bacillus thuringiensis) are investigated along with the Gram-negative bacterium Pantoea agglomerans.

  9. Raman spectroscopy - in situ characterization of growth and surface processes

    NASA Astrophysics Data System (ADS)

    Perkins, James Robert

    The goal of this thesis is to expand on the usefulness of Raman spectroscopy as an in situ probe to aid in the growth and implementation of electronic, optical, and biodetection materials. We accomplish this goal by developing two diverse optical characterization projects. In the first project, an autoclave similar to those used in solvothermal growth which has been outfitted with an optical window is used to collect vibrational spectra of solvents and mineralizers commonly used in the ammonothermal growth of gallium nitride. Secondly, novel silver nanowires created by ferroelectric lithography are evaluated by surface enhanced micro-Raman spectroscopy for use as surface enhanced substrates for low detection limit or single molecule bio-detectors. Raman spectroscopy is already a widely accepted method to characterize and identify a wide variety of materials. Vibrational spectra can yield much information on the presence of chemical species as well as information regarding the phase and interactive properties. Because Raman spectroscopy is a generally non-intrusive technique it is ideal for analysis of hazardous or far-from-ambient liquids, gases, or solids. This technique is used in situ to characterize crystal growth and surface enhanced photochemistry. The phenomenon of Surface Enhanced Raman Spectroscopy (SERS) has been observed in many systems but some fundamental understanding is still lacking and the technique has been slow to transition from the laboratory to the industry. Aggregated colloids and lithographically created islands have shown the best success as reproducible substrates for SERS detection. These techniques, however, lack control over shape, size, and position of the metal nanoparticles which leave them reliant on hotspots. Because of the potential for control of the position of aggregates, ferroelectric lithographically created silver nanowires are evaluated as a potential SERS substrate using pyridine, benzoic acid, and Rhodamine 6g. Surface

  10. 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

  11. 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

    2014-12-22

    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.

  12. 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

  13. Blood proteins analysis by Raman spectroscopy method

    NASA Astrophysics Data System (ADS)

    Artemyev, D. N.; Bratchenko, I. A.; Khristoforova, Yu. A.; Lykina, A. A.; Myakinin, O. O.; Kuzmina, T. P.; Davydkin, I. L.; Zakharov, V. P.

    2016-04-01

    This work is devoted to study the possibility of plasma proteins (albumin, globulins) concentration measurement using Raman spectroscopy setup. The blood plasma and whole blood were studied in this research. The obtained Raman spectra showed significant variation of intensities of certain spectral bands 940, 1005, 1330, 1450 and 1650 cm-1 for different protein fractions. Partial least squares regression analysis was used for determination of correlation coefficients. We have shown that the proposed method represents the structure and biochemical composition of major blood proteins.

  14. 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.

  15. Detection of Pesticide Residues in Food Using Surface-Enhanced Raman Spectroscopy: A Review.

    PubMed

    Xu, Meng-Lei; Gao, Yu; Han, Xiao Xia; Zhao, Bing

    2017-08-16

    Pesticides directly pollute the environment and contaminate foods ultimately being absorbed by the human body. Their residues contain highly toxic substances that have been found to cause serious problems to human health even at very low concentrations. The gold standard method, gas/liquid chromatography combined with mass spectroscopy, has been widely used for the detection of pesticide residues. However, these methods have some drawbacks such as complicated pretreatment and cleanup steps. Recent technological advancements of surface-enhanced Raman spectroscopy (SERS) have promoted the creation of alternative detection techniques. SERS is a useful detection tool with ultrasensitivity and simpler protocols. Present SERS-based pesticide residue detection often uses standard solutions of target analytes in conjunction with theoretical Raman spectra calculated by density functional theory (DFT) and actual Raman spectra detected by SERS. SERS is quite a promising technique for the direct detection of pesticides at trace levels in liquid samples or on the surface of solid samples following simple extraction to increase the concentration of analytes. In this review, we highlight recent studies on SERS-based pesticide detection, including SERS for pesticide standard solution detection and for pesticides in/on food samples. Moreover, in-depth analysis of pesticide chemical structures, structural alteration during food processing, interaction with SERS substrates, and selection of SERS-active substrates is involved.

  16. Biomarkers of cigarette smoking and DNA methylating agents: Raman, SERS and DFT study of 3-methyladenine and 7-methyladenine

    NASA Astrophysics Data System (ADS)

    Harroun, Scott G.; Zhang, Yaoting; Chen, Tzu-Heng; Ku, Ching-Rong; Chang, Huan-Tsung

    2017-04-01

    3-Methyladenine and 7-methyladenine are biomarkers of DNA damage from exposure to methylating agents. For example, the concentration of 3-methyladenine increases significantly in the urine of cigarette smokers. Surface-enhanced Raman spectroscopy (SERS) has shown much potential for detection of biomolecules, including DNA. Much work has been dedicated to the canonical nucleobases, with comparatively fewer investigations of modified DNA and modified DNA nucleobases. Herein, Raman spectroscopy and SERS are used to examine the adsorption orientations of 3-methyladenine and 7-methyladenine on Ag nanoparticles. Density functional theory (DFT) calculations at the B3LYP level are used to support the conclusions via simulated spectra of the nucleobases and of Ag+/nucleobase complexes. The results herein show that 7-methyladenine adsorbs upright via its N3 and N9 atoms side, similarly to adenine. 3-Methyladenine adsorbs in a very tilted or flat orientation on the Ag nanoparticles. These findings will be useful for future SERS or other nanoparticle-based bioanalytical assays for detection of these methyladenines or other modified nucleobases.

  17. SERS spectroscopy of kaempferol and galangin under the interaction of human serum albumin with adsorbed silver nanoparticles.

    PubMed

    Zhang, Wei; Bai, Xueyuan; Wang, Yingping; Zhao, Bing; Zhao, Daqing; Zhao, Yu

    2012-06-15

    Raman and surface-enhanced Raman scattering (SERS) spectroscopy were employed to probe the interaction of the flavonol drugs, kaempferol and galangin, with human serum albumin (HSA). SERS spectra of both flavonol derivatives were obtained from a colloidal silver surface in physiological condition, based on the high performance of the enhanced substrate, the most enhanced modes of kaempferol and galangin were those with certain motions perpendicular to the metal surface. The SERS spectra were allowed to predict similar orientation geometry for both of the drugs on the colloidal surface with minor difference. In addition, both flavonols-HSA complexes were prepared in different concentration ratios and the orientated differences between kaempferol and galangin were investigated by SERS.

  18. SERS spectroscopy of kaempferol and galangin under the interaction of human serum albumin with adsorbed silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Bai, Xueyuan; Wang, Yingping; Zhao, Bing; Zhao, Daqing; Zhao, Yu

    Raman and surface-enhanced Raman scattering (SERS) spectroscopy were employed to probe the interaction of the flavonol drugs, kaempferol and galangin, with human serum albumin (HSA). SERS spectra of both flavonol derivatives were obtained from a colloidal silver surface in physiological condition, based on the high performance of the enhanced substrate, the most enhanced modes of kaempferol and galangin were those with certain motions perpendicular to the metal surface. The SERS spectra were allowed to predict similar orientation geometry for both of the drugs on the colloidal surface with minor difference. In addition, both flavonols-HSA complexes were prepared in different concentration ratios and the orientated differences between kaempferol and galangin were investigated by SERS.

  19. 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.

  20. 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.

  1. 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

  2. Drug stability analysis by Raman spectroscopy.

    PubMed

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

    2014-12-22

    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.

  3. Measurement of lactose crystallinity using Raman spectroscopy.

    PubMed

    Murphy, Bridget M; Prescott, Stuart W; Larson, Ian

    2005-06-01

    Raman spectroscopy (RS) was used to determine the crystallinity of lactose (a commonly used carrier in dry powder inhaler (DPI) formulations). Samples of alpha-lactose monohydrate and amorphous lactose were prepared using ethanol precipitation and lyophilisation respectively. The anomeric forms were confirmed using DSC at a rate of 10 degrees C/min and heated to 250 degrees C. The Raman spectra of both alpha-lactose monohydrate and amorphous lactose were obtained. Distinguishable differences were seen between the two spectra including peak areas and intensities. Depolarisation ratios (rho) of each form were then determined to identify the crystallinity of the lactose carrier samples. At the prominent Raman bands 865 and 1082 cm-1, significant differences in rho values were observed for crystalline (0.80+/-0.07, 0.89+/-0.06 respectively) and amorphous samples (0.44+/-0.07, 0.51+/-0.10).

  4. Remote Adjustable focus Raman Spectroscopy Probe

    SciTech Connect

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

    1998-07-28

    A remote adjustable focus Raman spectroscopy probe allows for analyzing Raman scattered light from a point of interest external to the 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 along 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 translate the probe 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.

  5. Inkjet printed surface enhanced Raman spectroscopy array on cellulose paper.

    PubMed

    Yu, Wei W; White, Ian M

    2010-12-01

    A novel, ultra low-cost surface enhanced Raman spectroscopy (SERS) substrate has been developed by modifying the surface chemistry of cellulose paper and patterning nanoparticle arrays, all with a consumer inkjet printer. Micro/nanofabrication of SERS substrates for on-chip chemical and biomolecular analysis has been under intense investigation. However, the high cost of producing these substrates and the limited shelf life severely limit their use, especially for routine laboratory analysis and for point-of-sample analysis in the field. Paper-based microfluidic biosensing systems have shown great potential as low-cost disposable analysis tools. In this work, this concept is extended to SERS-based detection. Using an inexpensive consumer inkjet printer, cellulose paper substrates are modified to be hydrophobic in the sensing regions. Synthesized silver nanoparticles are printed onto this hydrophobic paper substrate with microscale precision to form sensing arrays. The hydrophobic surface prevents the aqueous sample from spreading throughout the paper and thus concentrates the analyte within the sensing region. A SERS fingerprint signal for Rhodamine 6G dye was observed for samples with as low as 10 femtomoles of analyte in a total sample volume of 1 μL. This extraordinarily simple technique can be used to construct SERS microarrays immediately before sample analysis, enabling ultra low-cost chemical and biomolecular detection in the lab as well as in the field at the point of sample collection.

  6. Characterization method for relative Raman enhancement for surface-enhanced Raman spectroscopy using gold nanoparticle dimer array

    NASA Astrophysics Data System (ADS)

    Sugano, Koji; Ikegami, Kohei; Isono, Yoshitada

    2017-06-01

    In this paper, a characterization method for Raman enhancement for highly sensitive and quantitative surface-enhanced Raman spectroscopy (SERS) is reported. A particle dimer shows a marked electromagnetic enhancement when the particle connection direction is matched to the polarization direction of incident light. In this study, dimers were arrayed by nanotrench-guided self-assembly for a marked total Raman enhancement. By measuring acetonedicarboxylic acid, the fabricated structures were characterized for SERS depending on the polarization angle against the particle connection direction. This indicates that the fabricated structures cause an effective SERS enhancement, which is dominated by the electromagnetic enhancement. Then, we measured 4,4‧-bipyridine, which is a pesticide material, for quantitative analysis. In advance, we evaluated the enhancement of the particle structure by the Raman measurement of acetonedicarboxylic acid. Finally, we compared the Raman intensities of acetonedicarboxylic acid and 4,4‧-bipyridine. Their intensities showed good correlation. The advantage of this method for previously evaluating the enhancement of the substrate was demonstrated. This developed SERS characterization method is expected to be applied to various quantitative trace analyses of molecules with high sensitivity.

  7. 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

  8. Detecting Chemically Modified DNA Bases Using Surface Enhanced Raman Spectroscopy.

    PubMed

    Barhoumi, Aoune; Halas, Naomi J

    2011-12-15

    Post-translational modifications of DNA- changes in the chemical structure of individual bases that occur without changes in the DNA sequence- are known to alter gene expression. They are believed to result in frequently deleterious phenotypic changes, such as cancer. Methylation of adenine, methylation and hydroxymethylation of cytosine, and guanine oxidation are the primary DNA base modifications identified to date. Here we show it is possible to use surface enhanced Raman spectroscopy (SERS) to detect these primary DNA base modifications. SERS detection of modified DNA bases is label-free and requires minimal additional sample preparation, reducing the possibility of additional chemical modifications induced prior to measurement. This approach shows the feasibility of DNA base modification assessment as a potentially routine analysis that may be further developed for clinical diagnostics.

  9. 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.

  10. 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.

  11. 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.

  12. Raman spectroscopy system with hollow fiber probes

    NASA Astrophysics Data System (ADS)

    Liu, Bing-hong; Shi, Yi-Wei

    2012-11-01

    A Raman remote spectroscopy system was realized using flexible hollow optical fiber as laser emittion and signal collection probes. A silver-coated hollow fiber has low-loss property and flat transmission characteristics in the visible wavelength regions. Compared with conventional silica optical fiber, little background fluorescence noise was observed with optical fiber as the probe, which would be of great advantages to the detection in low frequency Raman shift region. The complex filtering and focusing system was thus unnecessary. The Raman spectra of CaCO3 and PE were obtained by using the system and a reasonable signal to noise ratio was attained without any lens. Experiments with probes made of conventional silica optical fibers were also conducted for comparisons. Furthermore, a silver-coated hollow glass waveguide was used as sample cell to detect liquid phase sample. We used a 6 cm-long hollow fiber as the liquid cell and Butt-couplings with emitting and collecting fibers. Experiment results show that the system obtained high signal to noise ratio because of the longer optical length between sample and laser light. We also give the elementary theoretical analysis for the hollow fiber sample cell. The parameters of the fiber which would affect the system were discussed. Hollow fiber has shown to be a potential fiber probe or sample cell for Raman spectroscopy.

  13. Raman Spectroscopy for Analysis of Thorium Compounds

    SciTech Connect

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

    2016-05-12

    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 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Detection and Analysis of Cyclotrimethylenetrinitramine (RDX) in Environmental Samples by Surface-Enhanced Raman Spectroscopy

    DTIC Science & Technology

    2010-01-01

    the detection and analysis of RDX is con- ducted primarily via high-performance liquid chromatography ( HPLC ) (USEPA Method 8330), which requires... fingerprint ’ of the chemical composition of each agent. In addition, SERS is often more sensitive than traditional Raman spectroscopy because the...Hatab et al. nondestructive, and most analytes can be analyzed directly in water. The availability of portable Raman spectrometers also makes it

  19. 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

  20. Perspective: Two-dimensional resonance Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Molesky, Brian P.; Guo, Zhenkun; Cheshire, Thomas P.; Moran, Andrew M.

    2016-11-01

    Two-dimensional resonance Raman (2DRR) spectroscopy has been developed for studies of photochemical reaction mechanisms and structural heterogeneity in complex systems. The 2DRR method can leverage electronic resonance enhancement to selectively probe chromophores embedded in complex environments (e.g., a cofactor in a protein). In addition, correlations between the two dimensions of the 2DRR spectrum reveal information that is not available in traditional Raman techniques. For example, distributions of reactant and product geometries can be correlated in systems that undergo chemical reactions on the femtosecond time scale. Structural heterogeneity in an ensemble may also be reflected in the 2D spectroscopic line shapes of both reactive and non-reactive systems. In this perspective article, these capabilities of 2DRR spectroscopy are discussed in the context of recent applications to the photodissociation reactions of triiodide and myoglobin. We also address key differences between the signal generation mechanisms for 2DRR and off-resonant 2D Raman spectroscopies. Most notably, it has been shown that these two techniques are subject to a tradeoff between sensitivity to anharmonicity and susceptibility to artifacts. Overall, recent experimental developments and applications of the 2DRR method suggest great potential for the future of the technique.

  1. Electromagnetic theories of surface-enhanced Raman spectroscopy.

    PubMed

    Ding, Song-Yuan; You, En-Ming; Tian, Zhong-Qun; Moskovits, Martin

    2017-07-07

    Surface-enhanced Raman spectroscopy (SERS) and related spectroscopies are powered primarily by the concentration of the electromagnetic (EM) fields associated with light in or near appropriately nanostructured electrically-conducting materials, most prominently, but not exclusively high-conductivity metals such as silver and gold. This field concentration takes place on account of the excitation of surface-plasmon (SP) resonances in the nanostructured conductor. Optimizing nanostructures for SERS, therefore, implies optimizing the ability of plasmonic nanostructures to concentrate EM optical fields at locations where molecules of interest reside, and to enhance the radiation efficiency of the oscillating dipoles associated with these molecules and nanostructures. This review summarizes the development of theories over the past four decades pertinent to SERS, especially those contributing to our current understanding of SP-related SERS. Special emphasis is given to the salient strategies and theoretical approaches for optimizing nanostructures with hotspots as efficient EM near-field concentrating and far-field radiating substrates for SERS. A simple model is described in terms of which the upper limit of the SERS enhancement can be estimated. Several experimental strategies that may allow one to approach, or possibly exceed this limit, such as cascading the enhancement of the local and radiated EM field by the multiscale EM coupling of hierarchical structures, and generating hotspots by hybridizing an antenna mode with a plasmonic waveguide cavity mode, which would result in an increased local field enhancement, are discussed. Aiming to significantly broaden the application of SERS to other fields, and especially to material science, we consider hybrid structures of plasmonic nanostructures and other material phases and strategies for producing strong local EM fields at desired locations in such hybrid structures. In this vein, we consider some of the numerical

  2. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Multiple myeloma detection based on blood plasma surface-enhanced Raman spectroscopy using a portable Raman spectrometer

    NASA Astrophysics Data System (ADS)

    Chen, Jie; Huang, Meizhen; Zou, Ye; Song, Biao; Wang, Yang; Wang, Kehui; Li, Xia; Liu, Xi; Chen, Xiaofan; Li, Feng; Zhan, Yanxia

    2016-10-01

    The feasibility of surface enhanced Raman spectroscopy (SERS) for multiple myeloma (MM) detection is investigated in this work. SERS measurements of silver nanoparticle mixed blood plasma samples are performed using a low-cost and portable Raman spectrometer. The tentative assignment of Raman peaks indicates an increase in amino acids, nucleic acid base content and a decrease in cholesterol ester in the MM group. Combined with the multivariate analysis method of principle component analysis (PCA) and linear discriminate analysis (LDA), a diagnosis result for 32 samples with a sensitivity of 93.75% and specificity of 87.5% is achieved. The performance of the corresponding receiver operating characteristic (ROC) curve is 0.957. It is a potential rapid and non-invasive method for preliminary MM screening.

  4. 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.

  5. Raman and SERS recognition of β-carotene and haemoglobin fingerprints in human whole blood.

    PubMed

    Casella, Michele; Lucotti, Andrea; Tommasini, Matteo; Bedoni, Marzia; Forvi, Elena; Gramatica, Furio; Zerbi, Giuseppe

    2011-09-01

    The present work reports on Raman and Surface Enhanced Raman Scattering (SERS) vibrational fingerprints of β-carotene and haemoglobin in fresh whole blood (i.e. right after blood test) with different laser excitations, i.e. visible (514 nm) and near-infrared (NIR, 785 nm). The use of colloidal silver nanoparticles significantly increases the Raman signal, thus providing a clear SERS spectrum of blood. The collected spectra have been examined and marker bands of β-carotene and of the haem prosthetic group of haemoglobin have been found. In particular, the fundamental features of β-carotene (514 nm excitation), blood proteins and haem molecules (785 nm excitation) were recognized and assigned. Moreover haemoglobin SERS signals can be identified and related with its oxygenation state (oxy-haemoglobin). The data reported show the prospects of Raman and SERS techniques to detect important bio-molecules in a whole blood sample with no pre-treatment. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Non-Destructive Characterization of Polymer/Metal Interfaces Using Surface-Enhanced Raman Scattering (SERS)

    DTIC Science & Technology

    1990-06-01

    an acrylic monomer and a cure system consisting of cumene hydroperoxide (CHP), acetylphenylhydrazine (APH) and saccharin . SERS spectra obtained from...films of t1he adhesive spin-coated onto silver island films were similar to normal Raman spectra of salts of saccharin , indicating that saccharin had

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

    USDA-ARS?s Scientific Manuscript database

    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 ...

  8. Raman and infrared spectroscopy of selected vanadates.

    PubMed

    Frost, Ray L; Erickson, Kristy L; Weier, Matt L; Carmody, Onuma

    2005-03-01

    Raman and infrared spectroscopy has been used to study the structure of selected vanadates including pascoite, huemulite, barnesite, hewettite, metahewettite, hummerite. Pascoite, rauvite and huemulite are examples of simple salts involving the decavanadates anion (V10O28)6-. Decavanadate consists of four distinct VO6 units which are reflected in Raman bands at the higher wavenumbers. The Raman spectra of these minerals are characterised by two intense bands at 991 and 965 cm(-1). Four pascoite Raman bands are observed at 991, 965, 958 and 905 cm(-1) and originate from four distinct VO6 sites. The other minerals namely barnesite, hewettite, metahewettite and hummerite have similar layered structures to the decavanadates but are based upon (V5O14)3- units. Barnesite is characterised by a single Raman band at 1010 cm(-1), whilst hummerite has Raman bands at 999 and 962 cm(-1). The absence of four distinct bands indicates the overlap of the vibrational modes from two of the VO6 sites. Metarossite is characterised by a strong band at 953 cm(-1). These bands are assigned to nu1 symmetric stretching modes of (V6O16)2- units and terminal VO3 units. In the infrared spectra of these minerals, bands are observed in the 837-860 cm(-1) and in the 803-833 cm(-1) region. In some of the Raman spectra bands are observed for pascoite, hummerite and metahewettite in similar positions. These bands are assigned to nu3 antisymmetric stretching of (V10O28)6- units or (V5O14)3- units. Because of the complexity of the spectra in the low wavenumber region assignment of bands is difficult. Bands are observed in the 404-458 cm(-1) region and are assigned to the nu2 bending modes of (V10O28)6- units or (V5O14)3- units. Raman bands are observed in the 530-620 cm(-1) region and are assigned to the nu4 bending modes of (V10O28)6- units or (V5O14)3- units. The Raman spectra of the vanadates in the low wavenumber region are complex with multiple overlapping bands which are probably due to VO

  9. Raman and infrared spectroscopy of selected vanadates

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Erickson, Kristy L.; Weier, Matt L.; Carmody, Onuma

    2005-03-01

    Raman and infrared spectroscopy has been used to study the structure of selected vanadates including pascoite, huemulite, barnesite, hewettite, metahewettite, hummerite. Pascoite, rauvite and huemulite are examples of simple salts involving the decavanadates anion (V 10O 28) 6-. Decavanadate consists of four distinct VO 6 units which are reflected in Raman bands at the higher wavenumbers. The Raman spectra of these minerals are characterised by two intense bands at 991 and 965 cm -1. Four pascoite Raman bands are observed at 991, 965, 958 and 905 cm -1 and originate from four distinct VO 6 sites. The other minerals namely barnesite, hewettite, metahewettite and hummerite have similar layered structures to the decavanadates but are based upon (V 5O 14) 3- units. Barnesite is characterised by a single Raman band at 1010 cm -1, whilst hummerite has Raman bands at 999 and 962 cm -1. The absence of four distinct bands indicates the overlap of the vibrational modes from two of the VO 6 sites. Metarossite is characterised by a strong band at 953 cm -1. These bands are assigned to ν1 symmetric stretching modes of (V 6O 16) 2- units and terminal VO 3 units. In the infrared spectra of these minerals, bands are observed in the 837-860 cm -1 and in the 803-833 cm -1 region. In some of the Raman spectra bands are observed for pascoite, hummerite and metahewettite in similar positions. These bands are assigned to ν 3 antisymmetric stretching of (V 10O 28) 6- units or (V 5O 14) 3- units. Because of the complexity of the spectra in the low wavenumber region assignment of bands is difficult. Bands are observed in the 404-458 cm -1 region and are assigned to the ν2 bending modes of (V 10O 28) 6- units or (V 5O 14) 3- units. Raman bands are observed in the 530-620 cm -1 region and are assigned to the ν4 bending modes of (V 10O 28) 6- units or (V 5O 14) 3- units. The Raman spectra of the vanadates in the low wavenumber region are complex with multiple overlapping bands which are

  10. 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.

  11. 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.

  12. Poly(ethylene glycol)-stabilized silver nanoparticles for bioanalytical applications of SERS spectroscopy.

    PubMed

    Shkilnyy, Andriy; Soucé, Martin; Dubois, Pierre; Warmont, Fabienne; Saboungi, Marie-Louise; Chourpa, Igor

    2009-09-01

    The present work depicts the efficient one-step synthesis and detailed evaluation of stable aqueous colloids of silver nanoparticles (NPs) coated with poly(ethylene glycol) (PEG) covalently attached to their surface. Due to steric repulsion between polymer-modified surfaces, the stability of the nanoparticle suspension was preserved even at high ionic strength (0.1 M NaCl). At the same time, the PEG coating remains sufficiently permeable to allow surface-enhanced Raman scattering (SERS) from micromolar concentrations of small molecules such as the anticancer drug mitoxantrone (MTX). The enhancement efficiency of the hot spot-free Ag-PEG was compared to that of citrate-stabilized Ag colloids used after pre-aggregation. The potential of the polymer-stabilized colloids developed in this study is discussed in terms of bioanalytical applications of SERS spectroscopy.

  13. 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.

  14. Surface-enhanced Raman spectroscopy of dyes: from single molecules to the artists' canvas.

    PubMed

    Wustholz, Kristin L; Brosseau, Christa L; Casadio, Francesca; Van Duyne, Richard P

    2009-09-14

    This perspective presents recent surface-enhanced Raman spectroscopy (SERS) studies of dyes, with applications to the fields of single-molecule spectroscopy and art conservation. First we describe the development and outlook of single-molecule SERS (SMSERS). Rather than providing an exhaustive review of the literature, SMSERS experiments that we consider essential for its future development are emphasized. Shifting from single-molecule to ensemble-averaged experiments, we describe recent efforts toward SERS analysis of colorants in precious artworks. Our intention is to illustrate through these examples that the forward development of SERS is dependent upon both fundamental (e.g., SMSERS) and applied (e.g., on-the-specimen SERS of historical art objects) investigations and that the future of SERS is very bright indeed.

  15. 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

  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. Infrared, Polarized Raman, and SERS Spectra of Betaine Hydrogen Oxalate Monohydrate

    NASA Astrophysics Data System (ADS)

    Philip, Daizy; Aruldhas, G.

    1995-01-01

    Infrared and polarized Raman spectra of betaine hydrogen oxalate monohydrate are recorded and analyzed. The observed bands are assigned on the basis of vibrations due to oxalic acid, betaine, and water molecules. In the crystal it is found that oxalic acid molecules occupy a lower site and that betaine exists in zwitterionic form. Oxalic acid and water molecules are involved in strong hydrogen bending. Band assignments are confirmed by deuteration. Surface enhanced Raman scattering (SERS) spectra recorded in two silver colloids reveal chemisorption through different adsorption sites. The observed SERS spectra are interpreted on the basis of different adsorption sites, geometries, and adsorbate conformation/orientation. The change of the SERS spectrum with time is due to the different stabilities of the adsorbed states. The oxalic acid molecules of the compound are likely to be in a tilted orientation with respect to the silver surface.

  18. Hotspot-engineered 3D multipetal flower assemblies for surface-enhanced Raman spectroscopy.

    PubMed

    Jung, Kinam; Hahn, Jungsuk; In, Sungjun; Bae, Yongjun; Lee, Heechul; Pikhitsa, Peter V; Ahn, Kwangjun; Ha, Kyungyeon; Lee, Jong-Kwon; Park, Namkyoo; Choi, Mansoo

    2014-09-10

    Novel 3D metallic structures composed of multipetal flowers consisting of nanoparticles are presented. The control of surface plasmon hotspots is demonstrated in terms of location and intensity as a function of petal number for uniform and reproducible surfaceenhanced Raman spectroscopy (SERS) with high field enhancement.

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. Polarised Raman spectroscopy on a single class of single-wall nanotubes by nano surface-enhanced scattering

    NASA Astrophysics Data System (ADS)

    Azoulay, J.; Débarre, A.; Richard, A.; Tchénio, P.; Bandow, S.; Iijima, S.

    2000-12-01

    We report on the opportunity of performing polarised Raman spectroscopy on nanotubes by using surface-enhanced Raman scattering (SERS) mechanisms at the scale of a single hot site. In conjunction with the opportunity of selecting a single class of single wall nanotubes (SWNTs), it opens the way to fine spectroscopic studies of carbon nanotubes. Results obtained on a single class of nanotubes demonstrate first that polarised Raman spectroscopy is possible when a single hot site of a SERS substrate is selected and second that in this situation, unambiguous assignment of the modes is possible.

  6. 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

  7. 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.

  8. Raman Spectroscopy of Blood and Blood Components.

    PubMed

    Atkins, Chad G; Buckley, Kevin; Blades, Michael W; Turner, Robin F B

    2017-05-01

    Blood is a bodily fluid that is vital for a number of life functions in animals. To a first approximation, blood is a mildly alkaline aqueous fluid (plasma) in which a large number of free-floating red cells (erythrocytes), white cells (leucocytes), and platelets are suspended. The primary function of blood is to transport oxygen from the lungs to all the cells of the body and move carbon dioxide in the return direction after it is produced by the cells' metabolism. Blood also carries nutrients to the cells and brings waste products to the liver and kidneys. Measured levels of oxygen, nutrients, waste, and electrolytes in blood are often used for clinical assessment of human health. Raman spectroscopy is a non-destructive analytical technique that uses the inelastic scattering of light to provide information on chemical composition, and hence has a potential role in this clinical assessment process. Raman spectroscopic probing of blood components and of whole blood has been on-going for more than four decades and has proven useful in applications ranging from the understanding of hemoglobin oxygenation, to the discrimination of cancerous cells from healthy lymphocytes, and the forensic investigation of crime scenes. In this paper, we review the literature in the field, collate the published Raman spectroscopy studies of erythrocytes, leucocytes, platelets, plasma, and whole blood, and attempt to draw general conclusions on the state of the field.

  9. Confocal Raman spectroscopy of whole hairs.

    PubMed

    Pudney, Paul D A; Bonnist, Eleanor Y M; Mutch, Kevin J; Nicholls, Rachel; Rieley, Hugh; Stanfield, Samuel

    2013-12-01

    This paper describes the application of Raman spectroscopy to whole hair fibers. Previously this has proved difficult because the hairs are relatively opaque, and spatial resolution diminishes with depth because of the change in refractive index. A solution is to couple confocal Raman with multivariate curve resolution (MCR) data analysis, which separates spectral differences with depth despite this reduction in resolution. Initially, it is shown that the cuticle can be separated from the cortex, showing the differences in the proteins, which can then be plotted as a function of depth, with the cuticle factor being seen only at the surface as expected. Hairs that had been treated in different ways, e.g., by bleaching, treatment with the active molecule resorcinol followed by rinsing and treatment with a full hair care product, were also examined. In all cases, changes to the hair are identified and are associated with specific parts of the fiber. Since the hair fiber is kept intact, it can be repeatedly treated and measured, hence multistep treatment processes can be followed. This method expands the potential use of Raman spectroscopy in hair research.

  10. 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.

  11. 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

  12. Visible wavelength surface-enhanced Raman spectroscopy from In-InP nanopillars for biomolecule detection

    NASA Astrophysics Data System (ADS)

    Murdoch, B. J.; Portoles, J. F.; Tardio, S.; Barlow, A. J.; Fletcher, I. W.; Cumpson, P. J.

    2016-12-01

    Visible wavelength surface-enhanced Raman spectroscopy (SERS) has been observed from bovine serum albumin (BSA) using In-InP nanopillars synthesised by Ar gas cluster ion beam sputtering of InP wafers. InP provides a high local refractive index for plasmonic In structures, which increases the wavelength of the In surface plasmon resonance. The Raman scattering signal was determined to be up to 285 times higher for BSA deposited onto In-InP nanopillars when compared with Si wafer substrates. These substrates demonstrate the label-free detection of biomolecules by visible wavelength SERS, without the use of noble metal particles.

  13. 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.

  14. Thyroid tissue analysis through Raman spectroscopy.

    PubMed

    Teixeira, Caroline S B; Bitar, Renata A; Martinho, Herculano S; Santos, André B O; Kulcsar, Marco A V; Friguglietti, Celso U M; da Costa, Ricardo B; Arisawa, Emilia A L; Martin, Airton A

    2009-11-01

    The diagnosis of thyroid pathologies is usually made by cytologic analysis of the fine needle aspiration (FNA) material. However, this procedure has a low sensitivity at times, presenting a variation of 2-37%. The application of optical spectroscopy in the characterization of alterations could result in the development of a minimally invasive and non-destructive method for the diagnosis of thyroid diseases. Thus, the objective of this work was to study the biochemical alterations of tissues and hormones (T3 and T4) of the thyroid gland by means of molecular vibrations probed by FT-Raman spectroscopy. Through the discriminative linear analysis of the Raman spectra of the tissue, it was possible to establish (in percentages) the correct classification index among the groups: goitre adjacent tissue, goitre nodular region, follicular adenoma, follicular carcinoma and papillary carcinoma. As a result of the comparison between the groups goitre adjacent tissue versus goitre nodular region, an index of 58.3% of correct classification was obtained; this percentage was considered low, and it was not possible to distinguish the Raman spectra of these groups. Between goitre (nodular region and adjacent tissue) versus papillary carcinoma, the index of correct classification was 64.9%, which was considered good. A relevant result was obtained in the analysis of the benign tissues (goitre and follicular adenoma) versus malignant tissues (papillary and follicular carcinomas), for which the index was 72.5% and considered good. It was also possible, by means of visual observation, to find similar vibrational modes in the hormones and pathologic tissues. In conclusion, some biochemical alterations, represented by the FT-Raman spectra, were identified that could possibly be used to classify histologic groups of the thyroid. However, more studies are necessary due to the difficulty in setting a standard for pathologic groups.

  15. Combining immunolabeling and surface-enhanced Raman spectroscopy on cell membranes.

    PubMed

    Hodges, Matthew D; Kelly, Jemma G; Bentley, Adam J; Fogarty, Simon; Patel, Imran I; Martin, Francis L; Fullwood, Nigel J

    2011-12-27

    We applied surface-enhanced Raman spectroscopy (SERS) to immunolabeled endothelial cells to derive enhanced spectra of the biomolecular makeup of the cellular surface. A two-step immunolabeling protocol with gold-conjugated antibodies coupled with silver enhancement to attach silver nanoparticles to the cell surface was employed. This approach generated ∼50-fold SERS enhancement of spectral signals. The SERS spectra exhibited several SERS-enhanced peaks associated with cell membrane components. The SERS detection of silver nanoparticles proved more far more sensitive than conventional light microscopy techniques. The SERS enhancement allowed us to carry out spectral mapping using wavenumbers associated with membrane components that correlated directly with the distribution of silver nanoparticles. SERS has the potential to detect immunolabeling at lower levels than is possible using conventional immunolabeling methods while simultaneously providing unique, spatially defined, biochemical information.

  16. 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.

  17. 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

  18. Noise autocorrelation spectroscopy with coherent Raman scattering

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoji G.; Konorov, Stanislav O.; Hepburn, John W.; Milner, Valery

    2008-02-01

    Coherent anti-Stokes Raman scattering (CARS) with femtosecond laser pulses has become a widespread method in nonlinear optical spectroscopy and microscopy. As a third-order nonlinear process, femtosecond CARS exhibits high efficiency at low average laser power. High sensitivity to molecular structure enables detection of small quantities of complex molecules and non-invasive biological imaging. Temporal and spectral resolution of CARS is typically limited by the duration of the excitation pulses and their frequency bandwidth, respectively. Broadband femtosecond pulses are advantageous for time-resolved CARS spectroscopy, but offer poor spectral resolution. The latter can be improved by invoking optical or quantum interference at the expense of increasing complexity of instrumentation and susceptibility to noise. Here, we present a new approach to coherent Raman spectroscopy in which high resolution is achieved by means of deliberately introduced noise. The proposed method combines the efficiency of a coherent process with the robustness of incoherent light. It does require averaging over different noise realizations, but no temporal scanning or spectral pulse shaping as commonly used by frequency-resolved spectroscopic methods with ultrashort pulses.

  19. Exploring many body interactions with Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Tian, Yao

    Many-body interactions are cornerstones of contemporary solid state physics research. Especially, phonon related interactions such as phonon-phonon coupling, spin-phonon coupling and electron-phonon coupling constantly present new challenges. To study phonon related many-body interactions, temperature dependent Raman spectroscopy is employed. Firstly, a new design and construction of a Raman microscope aimed at high collection eciency, positional and thermal stability is discussed. The application of the home-built Raman microscope is shown in the context of two types of novel materials; Cr2Ge2Te6 (spin-phonon coupling) and Bi2Te3-xSex (phonon-phonon coupling). Cr2Ge2Te6 is one of the rare class of ferromagnetic semiconductors and recent thermal transport studies suggest the spin and lattice are strongly coupled in its cousin compound Cr2Si2Te6. In this work, the spin-phonon coupling in Cr2Ge2Te6 has been revealed in multiple ways: we observed a split of two phonon modes due to the breaking of time reversal symmetry; the anomalous hardening of an additional three modes; and a dramatic enhancement of the phonon lifetimes. It is well-known that the phonon-phonon interaction plays a signicant role in determining the thermal transport properties of thermoelectrics. A comprehensive study of the phonon dynamics of Bi2Te3-xSex has been performed. We found that the unusual temperature dependence of dierent phonon modes originates from both cubic and quartic anharmonicity. These results are consistent with the resonance bonding mechanism, suggesting that the resonance bonding may be a common feature for conventional thermoelectrics. In the Raman spectra of Bi2Te2Se, the origin of the extra Raman feature has been debated for decades. Through a temperature dependent Raman study, we were able to prove the feature is generated by a Te-Se antisite induced local mode. The anomalous linewidth of the local mode as well as the anharmonic behavior were explained through a statistical

  20. Measuring Rocket Engine Temperatures with Hydrogen Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Wehrmeyer, Joseph A.

    2002-01-01

    Laser-based combustion diagnostics, such as single-pulse UV Raman spectroscopy and visible Raman spectroscopy, have been successfully applied to optically-accessible rocket-like test articles. If an independent pressure measurement is available, Raman major species concentration measurements can also provide a temperature measurement. However it is desirable to obtain a Raman-derived temperature measurement without the need for simultaneous pressure measurement, especially when chamber pressure may vary spatially. This report describes Raman temperature measurements obtained by exploiting the variation in shape of the H2 Raman spectrum. Hydrogen is advantageous since it is ubiquitous in H2-O2 systems and its Raman spectrum is simpler than for other diatomics. However the influence of high pressure on the H2 Raman spectrum must be investigated. At moderate pressures, well below those of rocket engines, the Raman spectra of O2 and N2 are known to become featureless due to collisional broadening.

  1. Measuring Rocket Engine Temperatures with Hydrogen Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Wehrmeyer, Joseph A.

    2002-01-01

    Laser-based combustion diagnostics, such as single-pulse UV Raman spectroscopy and visible Raman spectroscopy, have been successfully applied to optically-accessible rocket-like test articles. If an independent pressure measurement is available, Raman major species concentration measurements can also provide a temperature measurement. However it is desirable to obtain a Raman-derived temperature measurement without the need for simultaneous pressure measurement, especially when chamber pressure may vary spatially. This report describes Raman temperature measurements obtained by exploiting the variation in shape of the H2 Raman spectrum. Hydrogen is advantageous since it is ubiquitous in H2-O2 systems and its Raman spectrum is simpler than for other diatomics. However the influence of high pressure on the H2 Raman spectrum must be investigated. At moderate pressures, well below those of rocket engines, the Raman spectra of O2 and N2 are known to become featureless due to collisional broadening.

  2. 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.

  3. Characterization of amino acids using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Jenkins, Amanda L.; Larsen, Richard A.; Williams, Timothy B.

    2005-05-01

    A key process in the development of new drugs is elucidation of the interaction between the drug molecule and the target protein. Such knowledge then makes it possible to make systematic structural modifications of the drug molecule to optimize the interaction. Many analytical techniques can be applied to proteins in solution such as circular dichroism, ultraviolet, and fluorescence spectroscopy but these all have limitations. In this paper, we investigate the feasibility of using relatively simple, visible light Raman spectroscopic methods to investigate amino acids and related biopolymers.

  4. Raman Spectroscopy Of Glass-Crystalline Transformations

    NASA Astrophysics Data System (ADS)

    Haro, E.; Balkanski, M.

    1988-01-01

    Glass-crystalline transition is induced by laser irradiation on a GeSe bulk glass sample. The structural changes are detected by Raman spectroscopy. The speed of the crystallization process depends on the laser irradiation intensity. We have studied this crystallization process for three different powers of irradiation. It is found that the speed of crystallization increases with power. Stokes and anti-Stokes spectra were recorded during the transformation. From this data temperature was inferred at different stages of crystallization. The significance of this temperature is discussed.

  5. 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.

  6. 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.

  7. Sensitive detection of nucleic acids with rolling circle amplification and surface-enhanced Raman scattering spectroscopy.

    PubMed

    Hu, Juan; Zhang, Chun-yang

    2010-11-01

    Detection of specific DNA sequences is important to molecular biology research and clinical diagnostics. To improve the sensitivity of surface-enhanced Raman scattering spectroscopy (SERS), a variety of signal amplification methods has been developed, including Raman-active-dye, polymerase chain reaction (PCR) technology, molecular beacon, SERS-active substrates, and SERS-tag. However, the combination of rolling circle amplification (RCA) with SERS for nucleic acid detection has not been reported. Herein, we describe a new approach for nucleic acid detection by the combination of RCA reaction with SERS. Because of the binding of abundance repeated sequences of RCA products with gold nanoparticle (Au NP) and Rox-modified detection probes, SERS signal is significantly amplified and the detection limit of 10.0 pM might be achieved. The sensitivity of RCA-based SERS has increased by as much as 3 orders of magnitude as compared to PCR-based SERS and is also comparable with or even exceeds that of both RCA-based electrochemical and RCA-based fluorescent methods. This RCA-based SERS might discriminate perfect matched target DNA from 1-base mismatched DNA with high selectivity. The high sensitivity and selectivity of RCA-based SERS makes it a potential tool for early diagnosis of gene-related disease and also offers a great promise for multiplexed assays with DNA microarrays.

  8. Spontaneous transient ultrafast coherent raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Meiselman, Seth

    I explore the application of Transient Coherent Ultrafast Phonon Spectroscopy (TCUPS) to the measurement of vibrational coherence dynamics of liquid alcohols. The demonstrated technique is complementary to and, in some cases, simpler than traditional stimulated spectroscopy techniques in that it does not require more than one laser and is free of non-resonant background. I demonstrate coherence measurements of single-photon-level collective excitations: a single vibrational state at 1033 (1/cm) in; a pair of simultaneous excited vibrational states at 2834 and 2944 (1/cm) in methanol; and three simultaneous excited states at 2885, ˜2930, and 2976 (1/cm) in isopropanol. I develop a Fourier-transform-based analysis of the TCUPS data that overcomes poor signal-to-noise ratio and signal degradation due to etaloning and fluorescence. The coherence lifetimes and oscillation frequencies agree with frequency-domain line-shape measurements and femtosecond Coherent anti-Stokes Raman Scattering (CARS) measurements.

  9. 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

  10. Characterization and identification of contraband using UV resonant Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lacey, Richard J.; Hayward, Ian P.; Sands, H. S.; Batchelder, David N.

    1997-02-01

    A range of explosives and narcotics have been examined using Raman spectroscopy with 244 nm excitation. This wavelength of excitation eliminates the fluorescence problems associated with excitation at visible wavelengths. Comparison with spectra obtained using visible excitation reveals that resonance Raman scattering is occurring. This results in simplified spectra, and enhanced Raman scattering efficiencies.

  11. In vivo Raman spectroscopy of cervix cancers

    NASA Astrophysics Data System (ADS)

    Rubina, S.; Sathe, Priyanka; Dora, Tapas Kumar; Chopra, Supriya; Maheshwari, Amita; Krishna, C. Murali

    2014-03-01

    Cervix-cancer is the third most common female cancer worldwide. It is the leading cancer among Indian females with more than million new diagnosed cases and 50% mortality, annually. The high mortality rates can be attributed to late diagnosis. Efficacy of Raman spectroscopy in classification of normal and pathological conditions in cervix cancers on diverse populations has already been demonstrated. Our earlier ex vivo studies have shown the feasibility of classifying normal and cancer cervix tissues as well as responders/non-responders to Concurrent chemoradiotherapy (CCRT). The present study was carried out to explore feasibility of in vivo Raman spectroscopic methods in classifying normal and cancerous conditions in Indian population. A total of 182 normal and 132 tumor in vivo Raman spectra, from 63 subjects, were recorded using a fiberoptic probe coupled HE-785 spectrometer, under clinical supervision. Spectra were acquired for 5 s and averaged over 3 times at 80 mW laser power. Spectra of normal conditions suggest strong collagenous features and abundance of non-collagenous proteins and DNA in case of tumors. Preprocessed spectra were subjected to Principal Component-Linear Discrimination Analysis (PCLDA) followed by leave-one-out-cross-validation. Classification efficiency of ~96.7% and 100% for normal and cancerous conditions respectively, were observed. Findings of the study corroborates earlier studies and suggest applicability of Raman spectroscopic methods in combination with appropriate multivariate tool for objective, noninvasive and rapid diagnosis of cervical cancers in Indian population. In view of encouraging results, extensive validation studies will be undertaken to confirm the findings.

  12. [Study of aspirin and its interaction with DNA by Raman and UV spectroscopies].

    PubMed

    Kang, Qian-qian; Zhou, Guang-ming

    2012-03-01

    Normal Raman spectroscopy and surface-enhanced Raman spectroscopy of aspirin and aspirin tablet were reported, and the vibrational and enhanced peaks were assigned; the interaction of aspirin with DNA was investigated by SERS and UV. The results showed that NRS and SERS of aspirin and aspirin tablet were consistent basically, which indicated that excipient hardly affected the detection of aspirin; in SERS, aspirin was absorbed perpendicularly on silver colloid through the carboxyl group and the benzene ring; The interaction was mainly caused by the inserting-action mode between aspirin and DNA, and the benzene ring and C=O of aspirin were inserted between the base pair of the double helix structure of DNA, which provided important information and useful reference for understanding deeply the mechanism of action of this kind of drug.

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

    PubMed

    Wang, Yuling; Irudayaraj, Joseph

    2013-02-05

    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.

  14. Gated Raman Spectroscopy of Twisted Bilayer Graphene

    NASA Astrophysics Data System (ADS)

    Huang, Shengqiang; Chattrakun, Kanokporn; Yankowitz, Matthew; Sandhu, Arvinder; Leroy, Brian

    2014-03-01

    The interaction of charge carriers with lattice vibrations in graphene exhibits many intriguing physical phenomena. Raman spectroscopy is a powerful non-destructive technique to probe these interactions. In twisted bilayer graphene, the electronic band structure and phonon dispersion depend on the rotation angle between the layers. Here we present a systematic Raman spectroscopy study of twisted bilayer graphene, using a 532 nm laser, with controllable charge densities up to 2 ×1013cm-2. The twist angle is first identified by the observation of a moire pattern in STM measurements. In the angle range between 5 and 8 degrees, the R' peak softens and weakens with increasing charge density. Near 12 degrees, the G peak is enhanced due to the increased density of states in twisted bilayer graphene. However, the G peak area quickly decreases with increasing charge density. Lastly, we observed several unusual effects for the G peak for all angles from 2 to 10 degrees as a function of increasing charge density. We found that the G peak broadened, split and oscillated in position. All these results demonstrate that twisted bilayer graphene has rich optoelectronic properties.

  15. Resonant Raman spectroscopy of twisted multilayer graphene

    NASA Astrophysics Data System (ADS)

    Wu, Jiang-Bin; Zhang, Xin; Ijäs, Mari; Han, Wen-Peng; Qiao, Xiao-Fen; Li, Xiao-Li; Jiang, De-Sheng; Ferrari, Andrea C.; Tan, Ping-Heng

    2014-11-01

    Graphene and other two-dimensional crystals can be combined to form various hybrids and heterostructures, creating materials on demand with properties determined by the interlayer interaction. This is the case even for a single material, where multilayer stacks with different relative orientation have different optical and electronic properties. Probing and understanding the interface coupling is thus of primary importance for fundamental science and applications. Here we study twisted multilayer graphene flakes with multi-wavelength Raman spectroscopy. We find a significant intensity enhancement of the interlayer coupling modes (C peaks) due to resonance with new optically allowed electronic transitions, determined by the relative orientation of the layers. The interlayer coupling results in a Davydov splitting of the C peak in systems consisting of two equivalent graphene multilayers. This allows us to directly quantify the interlayer interaction, which is much smaller compared with Bernal-stacked interfaces. This paves the way to the use of Raman spectroscopy to uncover the interface coupling of two-dimensional hybrids and heterostructures.

  16. 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.

  17. Combined fiber probe for fluorescence lifetime and Raman spectroscopy

    PubMed Central

    Dochow, Sebastian; Ma, Dinglong; Latka, Ines; Bocklitz, Thomas; Hartl, Brad; Bec, Julien; Fatakdawala, Hussain; Marple, Eric; Urmey, Kirk; Wachsmann-Hogiu, Sebastian; Schmitt, Michael; Marcu, Laura; Popp, Jürgen

    2016-01-01

    In this contribution we present a dual modality fiber optic probe combining fluorescence lifetime imaging (FLIm) and Raman spectroscopy for in vivo endoscopic applications. The presented multi-spectroscopy probe enables efficient excitation and collection of fluorescence lifetime signals for FLIm in the UV/visible wavelength region, as well as of Raman spectra in the near-IR for simultaneous Raman/FLIm imaging. The probe was characterized in terms of its lateral resolution and distance dependency of the Raman and FLIm signals. In addition, the feasibility of the probe for in vivo FLIm and Raman spectral characterization of tissue was demonstrated. PMID:26093843

  18. 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.

  19. 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.

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

    PubMed

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

    2015-08-09

    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.

  1. Determining the Authenticity of Gemstones Using Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Aponick, Aaron; Marchozzi, Emedio; Johnston, Cynthia R.; Wigal, Carl T.

    1998-04-01

    The benefits of laser spectroscopy in the undergraduate curriculum have been the focus of several recent articles in this journal. Raman spectroscopy has been of particular interest since the similarities of Raman to conventional infrared spectroscopy make the interpretation of spectral data well within undergraduate comprehension. In addition, the accessibility to this technology is now within the reach of most undergraduate institutions. This paper reports the development of an experiment using Raman spectroscopy which determines the authenticity of both diamonds and pearls. The resulting spectra provide an introduction to vibrational spectroscopy and can be used in a variety of laboratory courses ranging from introductory chemistry to instrumental analysis.

  2. Chemical analysis in vivo and in vitro by Raman spectroscopy – from single cells to humans

    PubMed Central

    Wachsmann-Hogiu, Sebastian; Weeks, Tyler

    2009-01-01

    Summary The gold standard for clinical diagnostics of tissues is immunofluorescence staining. Toxicity of many fluorescent dyes precludes their application in vivo. Raman spectroscopy, a chemically specific, label-free diagnostic technique, is rapidly gaining in acceptance as a powerful alternative. It has the ability to probe the chemical composition of biological materials in a nondestructive and mostly non-perturbing manner. We review the most recent developments in Raman spectroscopy in the life sciences, detailing advances in technology that have improved the ability to screen for diseases. Its role in the monitoring of biological function and mapping the intracellular chemical microenvironment will be discussed. Applications including endoscopy, surface-enhanced Raman scattering (SERS), and coherent Raman scattering (CRS) will be reviewed. PMID:19268566

  3. 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.

  4. 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.

  5. In-line interferometric femtosecond stimulated Raman scattering spectroscopy.

    PubMed

    Dobner, Sven; Groß, Petra; Fallnich, Carsten

    2013-06-28

    We present in-line interferometric femtosecond stimulated Raman scattering (II-FSRS), a new method to measure the spectral Raman intensity and phase over a broad spectral range, potentially in a single shot. An analytic model is developed, that excellently reproduces the measured spectra. Additionally, the performance of II-FSRS is directly compared in experiments to two established techniques, namely femtosecond stimulated Raman scattering and femtosecond Raman induced Kerr-effect spectroscopy.

  6. Nanoparticle-nanoparticle vs. nanoparticle-substrate hot spot contributions to the SERS signal: studying Raman labelled monomers, dimers and trimers.

    PubMed

    Sergiienko, Sergii; Moor, Kamila; Gudun, Kristina; Yelemessova, Zarina; Bukasov, Rostislav

    2017-02-08

    We used a combination of Raman microscopy, AFM and TEM to quantify the influence of dimerization on the surface enhanced Raman spectroscopy (SERS) signal for gold and silver nanoparticles (NPs) modified with Raman reporters and situated on gold, silver, and aluminum films and a silicon wafer. The overall increases in the mean SERS enhancement factor (EF) upon dimerization (up by 43% on average) and trimerisation (up by 96% on average) of AuNPs and AgNPs on the studied metal films are within a factor of two, which is moderate when compared to most theoretical models. However, the maximum ratio of EFs for some dimers to the mean EF of monomers can be as high as 5.5 for AgNPs on a gold substrate. In contrast, for dimerization and trimerization of gold and silver NPs on silicon, the mean EF increases by 1-2 orders of magnitude relative to the mean EF of single NPs. Therefore, hot spots in the interparticle gap between gold nanoparticles rather than hot spots between Au nanoparticles and the substrate dominate SERS enhancement for dimers and trimers on a silicon substrate. However, Raman labeled noble metal nanoparticles on plasmonic metal films generate on average SERS enhancement of the same order of magnitude for both types of hot spot zones (e.g. NP/NP and NP/metal film).

  7. Evaluating internal maturity of tomatoes using spatially offset Raman spectroscopy

    USDA-ARS?s Scientific Manuscript database

    Spatially offset Raman spectroscopy technique was investigated for evaluating internal maturity of intact tomatoes. A Raman spectroscopy system was assembled to acquire spatially offset spectra in the wavenumber range of 200–2500 cm–1. A 785-nm laser was used as the excitation source and the measure...

  8. Investigating Nanoscale Electrochemistry with Surface- and Tip-Enhanced Raman Spectroscopy.

    PubMed

    Zaleski, Stephanie; Wilson, Andrew J; Mattei, Michael; Chen, Xu; Goubert, Guillaume; Cardinal, M Fernanda; Willets, Katherine A; Van Duyne, Richard P

    2016-09-20

    The chemical sensitivity of surface-enhanced Raman spectroscopy (SERS) methodologies allows for the investigation of heterogeneous chemical reactions with high sensitivity. Specifically, SERS methodologies are well-suited to study electron transfer (ET) reactions, which lie at the heart of numerous fundamental processes: electrocatalysis, solar energy conversion, energy storage in batteries, and biological events such as photosynthesis. Heterogeneous ET reactions are commonly monitored by electrochemical methods such as cyclic voltammetry, observing billions of electrochemical events per second. Since the first proof of detecting single molecules by redox cycling, there has been growing interest in examining electrochemistry at the nanoscale and single-molecule levels. Doing so unravels details that would otherwise be obscured by an ensemble experiment. The use of optical spectroscopies, such as SERS, to elucidate nanoscale electrochemical behavior is an attractive alternative to traditional approaches such as scanning electrochemical microscopy (SECM). While techniques such as single-molecule fluorescence or electrogenerated chemiluminescence have been used to optically monitor electrochemical events, SERS methodologies, in particular, have shown great promise for exploring electrochemistry at the nanoscale. SERS is ideally suited to study nanoscale electrochemistry because the Raman-enhancing metallic, nanoscale substrate duly serves as the working electrode material. Moreover, SERS has the ability to directly probe single molecules without redox cycling and can achieve nanoscale spatial resolution in combination with super-resolution or scanning probe microscopies. This Account summarizes the latest progress from the Van Duyne and Willets groups toward understanding nanoelectrochemistry using Raman spectroscopic methodologies. The first half of this Account highlights three techniques that have been recently used to probe few- or single-molecule electrochemical

  9. Electrochemical tip-enhanced Raman spectroscopy (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Zeng, Zhicong; Huang, Shengchao; Huang, Tengxiang; Li, Maohua; Ren, Bin

    2015-08-01

    Tip-enhanced Raman spectroscopy (TERS) can not only provide very high sensitivity but also high spatial resolution, and has found applications in various fields, including surface science, materials, and biology. Most of previous TERS studies were performed in air or in the ultrahigh vacuum. If TERS study can be performed in the electrochemical environment, the electronic properties of the surface can be well controlled so that the interaction of the molecules with the substrate and the configuration of the molecules on the surface can also be well controlled. However, the EC-TERS is not just a simple combination of electrochemistry with TERS, or the combination of EC-STM with Raman. It is a merge of STM, electrochemistry and Raman spectroscopy, and the mutual interference among these techniques makes the EC-TERS particularly challenge: the light distortion in EC system, the sensitivity, the tip coating to work under EC-STM and retain the TERS activity and cleanliness. We designed a special spectroelectrochemical cell to eliminate the distortion of the liquid layer to the optical path and obtain TER spectra of reasonably good signal to noise ratio for surface adsorbed molecules under electrochemical potential control. For example, potential dependent TERS signal have been obtained for adsorbed aromatic thiol molecule, and much obvious signal change compared with SERS has been found, manifesting the importance of EC-TERS to reveal the interfacial structure of an electrochemical system. We further extended EC-TERS to electrochemical redox system, and clear dependence of the species during redox reaction can be identified.

  10. The hallmarks of breast cancer by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Abramczyk, H.; Surmacki, J.; Brożek-Płuska, B.; Morawiec, Z.; Tazbir, M.

    2009-04-01

    This paper presents new biological results on ex vivo breast tissue based on Raman spectroscopy and demonstrates its power as diagnostic tool with the key advantage in breast cancer research. The results presented here demonstrate the ability of Raman spectroscopy to accurately characterize cancer tissue and distinguish between normal, malignant and benign types. The goal of the paper is to develop the diagnostic ability of Raman spectroscopy in order to find an optical marker of cancer in the breast tissue. Applications of Raman spectroscopy in breast cancer research are in the early stages of development in the world. To the best of our knowledge, this paper is one of the most statistically reliable reports (1100 spectra, 99 patients) on Raman spectroscopy-based diagnosis of breast cancers among the world women population.

  11. Surface enhanced Raman spectroscopy and quantum chemical studies on glycine single crystal

    NASA Astrophysics Data System (ADS)

    Parameswari, A.; Premkumar, S.; Premkumar, R.; Milton Franklin Benial, A.

    2016-07-01

    Adsorption characteristics of glycine (Gly) on silver surface were investigated based on density functional theory calculations and surface enhanced Raman spectroscopy (SERS) technique. The single crystals of Gly were grown by slow evaporation method and characterized by single crystal X-ray diffraction (XRD) technique. Silver nanoparticles (Ag NPs) were prepared by solution combustion method using Gly as fuel. The Ag NPs were characterized by XRD, ultraviolet-visible spectroscopy and high-resolution transmission electron microscopy techniques. The calculated structural parameters of Gly molecule were compared with the experimental observed single crystal XRD data. The structural parameters of Gly after adsorption on silver surface show the slight deviation, which indicates the interaction between the Gly and Ag3 cluster. Raman and SERS spectra for Gly single crystal were studied experimentally. Raman frequencies were calculated for Gly and Gly adsorbed on a silver surface. Raman and SERS frequencies were assigned on the basis of potential energy distribution calculation and compared with the experimental values. Frontier molecular orbital analysis was carried out for Gly and Gly adsorbed on a silver surface. The band gap value was significantly reduced for Gly after adsorption on the silver surface. The reduction in band gap indicates the delocalization of electrons, which leads to the higher bioactivity of the title molecule. SERS spectral analysis reveals that the Gly adsorbed as a stand-on orientation on the silver surface. Hence, the present investigation has been developed as a model system to understand the interaction of Ag NPs with amino acids.

  12. Enhanced Raman Spectroscopy via Plasmonic and Carbonaceous Nanostructures for the Detection, Diagnosis and Treatment of Cancer Part 1: Diagnosis.

    PubMed

    Darrigues, Emilie; Nima, Zeid A; Majeed, Waquar; Vang, Kieng Bao; Dantuluri, Vijayalakshmi; Biris, Alexandru R; Zharov, Vladimir; Griffin, Robert J; Biris, Alexandru S

    2017-03-07

    Spectroscopic techniques including Raman, photothermal, photoacoustic, have been intensively studied for the accurate and fast detection of diseases, such as cancer. Additionally, due to the drastic, rapid advances in computer science and the intense use of various multifunctional nanosystems in the medical field, surface-enhanced Raman scattering (SERS) and Raman spectroscopy have developed quickly as new tools for fundamental analysis in biochemical science and as a new imaging method to aid in early, efficient cancer diagnosis. This review focuses on the major recent advances in Raman instrumentation and the improvement of Raman and SERS substrates that have moved this technology from a proof-of-concept tool to a viable technique. The translation, dissemination, and validation of future Raman and nanosubstrate developments are also discussed, with a focus on their role in cancer diagnostics improvement.

  13. Nasopharyngeal cancer detection based on blood plasma surface-enhanced Raman spectroscopy and multivariate analysis.

    PubMed

    Feng, Shangyuan; Chen, Rong; Lin, Juqiang; Pan, Jianji; Chen, Guannan; Li, Yongzeng; Cheng, Min; Huang, Zufang; Chen, Jiesi; Zeng, Haishan

    2010-07-15

    A surface-enhanced Raman spectroscopy (SERS) method was developed for blood plasma biochemical analysis for the first time with the aim to develop a simple blood test for non-invasive nasopharyngeal cancer detection. Silver nanoparticles (Ag NP) as the SERS-active nanostructures were directly mixed with blood plasma to enhance the Raman scattering signals of various biomolecular constituents such as proteins, lipids, and nucleic acids. High quality SERS spectrum from blood plasma-Ag NP mixture can be obtained within 10s using a Renishaw micro-Raman system. SERS measurements were performed on two groups of blood plasma samples: one group from patients (n=43) with pathologically confirmed nasopharyngeal carcinomas (WHO type I, II, and III) and the other group from healthy volunteers (control subjects, n=33). Tentative assignments of the Raman bands in the measured SERS spectra suggest interesting cancer specific biomolecular differences, including an increase in the relative amounts of nucleic acid, collagen, phospholipids and phenylalanine and a decrease in the percentage of amino acids and saccharide contents in the blood plasma of nasopharyngeal cancer patients as compared to that of healthy subjects. Principal component analysis (PCA) of the measured SERS spectra separated the spectral features of the two groups into two distinct clusters with little overlaps. Linear discriminate analysis (LDA) based on the PCA generated features differentiated the nasopharyngeal cancer SERS spectra from normal SERS spectra with high sensitivity (90.7%) and specificity (100%). The results from this exploratory study demonstrated great potentials for developing SERS blood plasma analysis into a novel clinical tool for non-invasive detection of nasopharyngeal cancers.

  14. Raman spectroscopy explores molecular structural signatures of hidden materials in depth: Universal Multiple Angle Raman Spectroscopy

    PubMed Central

    Sil, Sanchita; Umapathy, Siva

    2014-01-01

    Non-invasive 3D imaging in materials and medical research involves methodologies such as X-ray imaging, MRI, fluorescence and optical coherence tomography, NIR absorption imaging, etc., providing global morphological/density/absorption changes of the hidden components. However, molecular information of such buried materials has been elusive. In this article we demonstrate observation of molecular structural information of materials hidden/buried in depth using Raman scattering. Typically, Raman spectroscopic observations are made at fixed collection angles, such as, 90°, 135°, and 180°, except in spatially offset Raman scattering (SORS) (only back scattering based collection of photons) and transmission techniques. Such specific collection angles restrict the observations of Raman signals either from or near the surface of the materials. Universal Multiple Angle Raman Spectroscopy (UMARS) presented here employs the principle of (a) penetration depth of photons and then diffuse propagation through non-absorbing media by multiple scattering and (b) detection of signals from all the observable angles. PMID:24930768

  15. Breast cancer detection based on serum sample surface enhanced Raman spectroscopy.

    PubMed

    Vargas-Obieta, Enrique; Martínez-Espinosa, Juan Carlos; Martínez-Zerega, Brenda Esmeralda; Jave-Suárez, Luis Felipe; Aguilar-Lemarroy, Adriana; González-Solís, José Luis

    2016-09-01

    Raman spectroscopy is a vibrational technique which provides information about the chemical structure. Nevertheless, since many chemicals are present in a sample at very low concentration, the Raman signal observed is extremely weak. In surface enhanced Raman scattering (SERS), Raman signals can be enhanced by many orders of magnitude when nanoparticles are used. To the best of our knowledge, this is the first report in the breast cancer detection based on serum SERS. The serum samples were obtained from 12 patients who were clinically diagnosed with advanced breast cancer and 15 controls. In the same proportion, the serum samples were mixed with colloidal gold nanoparticles of 40 nm using sonication. At least 10 spectra were collected of each serum sample using a Jobin-Yvon LabRAM Raman Spectrometer with a laser of 830 nm. Raw spectra were processed by carrying baseline correction, smoothing, and normalization and then analyzed using principle component analysis (PCA) and linear discriminant analysis (LDA). Raman spectra showed strongly enhanced bands in the 600-1800 cm (-1) range due to the nanoparticle colloidal clusters observed. These Raman bands allowed identifying biomolecules present at low concentration as amide I and III, β carotene, glutathione, tryptophan, tyrosine, and phenylalanine. Preliminary results demonstrated that SERS and PCA-LDA can be used to discriminate between control and cancer samples with high sensitivity and specificity. SERS allowed short exposures and required a minimal sample preparation. The preliminary results suggest that SERS and PCA-LDA could be an excellent support technique for the breast cancer detection using serum samples.

  16. DNA-guided assembly of three-dimensional nanostructures for surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Wu, Li-An; Lin, Yu-Ting; Chen, Yih-Fan

    2015-03-01

    Surface enhancement Raman spectroscopy (SERS) has drawn much attention in recent years because its ability to greatly enhance Raman signals to allow for the detection of molecules at low concentration. When using metallic nanoparticles as SERS substrates, many studies have shown that the size of the interparticle gap significantly affects the enhancement of the Raman signals. Given that the optimal interparticle gap is as small as a few nanometers, fabricating sensitive, uniform, and reproducible SERS substrates remains challenging. Here we report a three-dimensional SERS substrate created through the assembly of core-shell nanoparticles using DNA. By using DNA of appropriate sequence and length, DNA-functionalized nanoparticles were assembled into ordered and highly packed nanostructures. The interparticle distance was precisely controlled by adjusting the design of the DNA and the thickness of the silver shell coated on the gold nanoparticles. Compared with randomly aggregated nanoparticles, the interparticle distance in the synthesized nanostructures can be more uniform and better controlled. In addition, the DNA-guided assembly process allows us to create precise nanostructures without using complex and expensive fabrication methods. The study demonstrates that the synthesized nanostructures can be used as effective SERS substrates to successfully measure the Raman signals of malachite green, a toxic compound that is sometimes illegally used on fish, as well as Fluorescein isothiocyanate (FITC) at low concentrations.

  17. Raman spectroscopy of ion irradiated diamond

    NASA Astrophysics Data System (ADS)

    Brunetto, R.; Baratta, G. A.; Strazzulla, G.

    2004-07-01

    Ion irradiation experiments of diamond samples at room temperature have been performed by using in situ Raman spectroscopy as diagnostic technique. Different ions are used with energies of 200 or 400 keV. The area of virgin diamond Raman band (at 1332 cm-1) decreases exponentially as the ion fluence increases. This is due to changes in the optical properties of the damaged samples in the visible spectral range. Results from different ions demonstrate that this effect is correlated with the number of displacements/cm2, i.e., with the energy lost by ions through elastic collisions with target nuclei. Amorphous carbon (sp2) is formed after a threshold of about 2×1022 vacancies/cm3, or about 16 eV/C-atom deposited by elastic collisions. The peak position and full width at half maximum of the D line and G line of the synthesized amorphous carbon are studied. In particular, the G-line peak position shifts from the initial 1545 cm-1 to about 1515 cm-1 at the higher doses. The results are also discussed in view of their relevance in astrophysical environments.

  18. Measurement of clathrate hydrates via Raman spectroscopy

    USGS Publications Warehouse

    Sum, A.K.; Burruss, R.C.; Sloan, E.D.

    1997-01-01

    Raman spectra of clathrate hydrate guest molecules are presented for three known structures (I (sI), II (sII), and H (sH)) in the following systems: CH4 (sI), CO2 (sI), C3H8 (sII), CH4 + CO2 (sI), CD4 + C3H8 (sII), CH4 + N2 (sI), CH4 + THF-d8 (sII), and CH4 + C7D14 (sH). Relative occupancy of CH4 in the large and small cavities of sI were determined by deconvoluting the ??1 symmetric bands, resulting in hydration numbers of 6.04 ?? 0.03. The frequency of the ??1 bands for CH4 in structures I, II, and H differ statistically, so that Raman spectroscopy is a potential tool to identify hydrate crystal structure. Hydrate guest compositions were also measured for two vapor compositions of the CH4 + CO2 system, and they compared favorably with predictions. The large cavities were measured to be almost fully occupied by CH4 and CO2, whereas only a small fraction of the small cavities are occupied by CH4. No CO2 was found in the small cavities. Hydration numbers from 7.27 to 7.45 were calculated for the mixed hydrate.

  19. Raman spectroscopy of hypersonic shock waves

    PubMed

    Ramos; Mate; Tejeda; Fernandez; Montero

    2000-10-01

    Raman spectroscopy is shown to be an efficient diagnostic methodology for the study of hypersonic shock waves. As a test, absolute density and rotational population profiles have been measured across five representative normal shock waves of N2 generated in a free jet, spanning the Mach number range 7.7

  20. Surface-enhanced Raman spectroscopy on engineered plasmonic metamaterials for "label free" biosensing

    NASA Astrophysics Data System (ADS)

    Rippa, Massimo; Capasso, Rossella; Pannico, Marianna; La Manna, Pietro; Musto, Pellegrino; Bobeico, Eugenia; Zhou, Jun; Petti, Lucia

    2015-08-01

    The last decade has been characterized by artificial electromagnetic (EM) materials, including photonic crystals (PCs) and photonic quasi-crystals (PQCs), making these very attractive given that there are new possibilities to control the EM field in innovative way. Quasiperiodic crystals (QCs) are a new class of materials that have fascinating optical properties lying somewhere between those of disordered and period structures. With the use of PCs and PQCs, it is possible to synthesize novel artificial structures characterized by selective EM responses, which, in turn, undergo significant frequency shifts, in presence of biological material. In the present work we studied artificial EM nanomaterials to develop innovative plasmonic nanobiosensors based on Surface Enhanced Raman Scattering (SERS) substrates and working in the visible and NIR frequency bands. A fabricated gold PQC in a Thue Morse arrangement is proposed for the engineering of reproducible SERS substrates. Structural characterization of this surface is performed by SEM and AFM. Optical properties of this plasmonic nanostructure are evaluated via UV/ Vis absorption spectroscopy and surface-enhanced Raman spectroscopy (SERS). Using a molecular monolayer of pMA (p-mercaptoaniline) as a Raman reporter, we show that a high value of SERS enhancement factor (measured up to 1.4 x 107) can be achieved in a properly optimized photonic structure, in good agreement with FDTD calculations. SERS enhancement factor is dependent on the plasmon absorption wavelength and laser wavelength used in these experiments.

  1. Combined fiber probe for fluorescence lifetime and Raman spectroscopy.

    PubMed

    Dochow, Sebastian; Ma, Dinglong; Latka, Ines; Bocklitz, Thomas; Hartl, Brad; Bec, Julien; Fatakdawala, Hussain; Marple, Eric; Urmey, Kirk; Wachsmann-Hogiu, Sebastian; Schmitt, Michael; Marcu, Laura; Popp, Jürgen

    2015-11-01

    In this contribution we present a dual modality fiber optic probe combining fluorescence lifetime imaging (FLIm) and Raman spectroscopy for in vivo endoscopic applications. The presented multi-spectroscopy probe enables efficient excitation and collection of fluorescence lifetime signals for FLIm in the UV/visible wavelength region, as well as of Raman spectra in the near-IR for simultaneous Raman/FLIm imaging. The probe was characterized in terms of its lateral resolution and distance dependency of the Raman and FLIm signals. In addition, the feasibility of the probe for in vivo FLIm and Raman spectral characterization of tissue was demonstrated. Graphical Abstract An image comparison between FLIm and Raman spectroscopy acquired with the bimodal probe onseveral tissue samples.

  2. A Nanosensor for Explosives Detection Based on Molecularly Imprinted Polymers (MIPs) and Surfaced-enhanced Raman Scattering (SERS)

    DTIC Science & Technology

    2010-03-01

    Imprinted Polymers ( MIPs ) and Surfaced- enhanced Raman Scattering (SERS) Ellen Holthoff and Dimitra Stratis-Cullum Sensors and Electron Devices...for target chemical analytes of interest. Essentially, one creates a molecular “memory” within the imprinted polymer matrix. In a sensor format, the...A Nanosensor for Explosives Detection Based on Molecularly Imprinted Polymers ( MIPs ) and Surfaced- enhanced Raman Scattering (SERS) by Ellen

  3. Large-area, uniform and low-cost dual-mode plasmonic naked-eye colorimetry and SERS sensor with handheld Raman spectrometer

    NASA Astrophysics Data System (ADS)

    Xu, Zhida; Jiang, Jing; Wang, Xinhao; Han, Kevin; Ameen, Abid; Khan, Ibrahim; Chang, Te-Wei; Liu, Gang Logan

    2016-03-01

    We demonstrated a highly-sensitive, wafer-scale, highly-uniform plasmonic nano-mushroom substrate based on plastic for naked-eye plasmonic colorimetry and surface-enhanced Raman spectroscopy (SERS). We gave it the name FlexBrite. The dual-mode functionality of FlexBrite allows for label-free qualitative analysis by SERS with an enhancement factor (EF) of 108 and label-free quantitative analysis by naked-eye colorimetry with a sensitivity of 611 nm RIU-1. The SERS EF of FlexBrite in the wet state was found to be 4.81 × 108, 7 times stronger than in the dry state, making FlexBrite suitable for aqueous environments such as microfluid systems. The label-free detection of biotin-streptavidin interaction by both SERS and colorimetry was demonstrated with FlexBrite. The detection of trace amounts of the narcotic drug methamphetamine in drinking water by SERS was implemented with a handheld Raman spectrometer and FlexBrite. This plastic-based dual-mode nano-mushroom substrate has the potential to be used as a sensing platform for easy and fast analysis in chemical and biological assays.We demonstrated a highly-sensitive, wafer-scale, highly-uniform plasmonic nano-mushroom substrate based on plastic for naked-eye plasmonic colorimetry and surface-enhanced Raman spectroscopy (SERS). We gave it the name FlexBrite. The dual-mode functionality of FlexBrite allows for label-free qualitative analysis by SERS with an enhancement factor (EF) of 108 and label-free quantitative analysis by naked-eye colorimetry with a sensitivity of 611 nm RIU-1. The SERS EF of FlexBrite in the wet state was found to be 4.81 × 108, 7 times stronger than in the dry state, making FlexBrite suitable for aqueous environments such as microfluid systems. The label-free detection of biotin-streptavidin interaction by both SERS and colorimetry was demonstrated with FlexBrite. The detection of trace amounts of the narcotic drug methamphetamine in drinking water by SERS was implemented with a handheld Raman

  4. Raman spectroscopy of human saliva for acute myocardial infarction detection

    NASA Astrophysics Data System (ADS)

    Chen, Maowen; Chen, Yuanxiang; Wu, Shanshan; Huang, Wei; Lin, Jinyong; Weng, Guo-Xing; Chen, Rong

    2014-09-01

    Raman spectroscopy is a rapidly non-invasive technique with great potential for biomedical research. The aim of this study was to evaluate the feasibility of using Raman spectroscopy of human saliva for acute myocardial infarction (AMI) detection. Raman spectroscopy measurements were performed on two groups of saliva samples: one group from patients (n=30) with confirmed AMI and the other group from healthy controls (n=31). The diagnostic performance for differentiating AMI saliva from normal saliva was evaluated by multivariate statistical analysis. The combination of principal component analysis (PCA) and linear discriminate analysis (LDA) of the measured Raman spectra separated the spectral features of the two groups into two distinct clusters with little overlaps, rendering the sensitivity of 80.0% and specificity of 80.6%. The results from this exploratory study demonstrated that Raman spectroscopy of human saliva can serve as a potentially clinical tool for rapid AMI detection and screening.

  5. Raman Spectroscopy of Optically Trapped Single Biological Micro-Particles

    PubMed Central

    Redding, Brandon; Schwab, Mark J.; Pan, Yong-le

    2015-01-01

    The combination of optical trapping with Raman spectroscopy provides a powerful method for the study, characterization, and identification of biological micro-particles. In essence, optical trapping helps to overcome the limitation imposed by the relative inefficiency of the Raman scattering process. This allows Raman spectroscopy to be applied to individual biological particles in air and in liquid, providing the potential for particle identification with high specificity, longitudinal studies of changes in particle composition, and characterization of the heterogeneity of individual particles in a population. In this review, we introduce the techniques used to integrate Raman spectroscopy with optical trapping in order to study individual biological particles in liquid and air. We then provide an overview of some of the most promising applications of this technique, highlighting the unique types of measurements enabled by the combination of Raman spectroscopy with optical trapping. Finally, we present a brief discussion of future research directions in the field. PMID:26247952

  6. Raman Spectroscopy of Optically Trapped Single Biological Micro-Particles.

    PubMed

    Redding, Brandon; Schwab, Mark; Pan, Yong-le

    2015-08-04

    The combination of optical trapping with Raman spectroscopy provides a powerful method for the study, characterization, and identification of biological micro-particles. In essence, optical trapping helps to overcome the limitation imposed by the relative inefficiency of the Raman scattering process. This allows Raman spectroscopy to be applied to individual biological particles in air and in liquid, providing the potential for particle identification with high specificity, longitudinal studies of changes in particle composition, and characterization of the heterogeneity of individual particles in a population. In this review, we introduce the techniques used to integrate Raman spectroscopy with optical trapping in order to study individual biological particles in liquid and air. We then provide an overview of some of the most promising applications of this technique, highlighting the unique types of measurements enabled by the combination of Raman spectroscopy with optical trapping. Finally, we present a brief discussion of future research directions in the field.

  7. Blood surface-enhanced Raman spectroscopy based on Ag and Au nanoparticles for nasopharyngeal cancer detection

    NASA Astrophysics Data System (ADS)

    Lin, Duo; Ge, Xiaosong; Lin, Xueliang; Chen, Guannan; Chen, Rong

    2016-05-01

    This study aims to evaluate and compare the utility of blood surface-enhanced Raman spectroscopy (SERS) based on Au or Ag nanoparticles (NPs), respectively, for detection of nasopharyngeal cancer (NPC). A rapid home-made Raman system was employed for SERS measurement, and high quality SERS spectra can be recorded from blood plasma samples belonging to 60 healthy volunteers and 100 NPC patients, using both metallic NPs. The spectral differences under Ag-SERS measurement between the normal and cancer groups are more significant than Au-SERS. Principal component analysis combined with linear discriminant analysis (PCA-LDA) was used for differentiating the two blood groups with a diagnostic sensitivity and specificity of 90% and 95%, respectively, using Ag-SERS method, which has almost a 20% improvement in diagnostic specificity in comparison to Au-SERS. This exploratory study demonstrates that blood SERS based on Ag NPs is capable of achieving a better diagnostic performance for NPC detection, and has promising potential for improving NPC screening.

  8. Raman spectroscopy for optical diagnosis of laryngeal cancer

    NASA Astrophysics Data System (ADS)

    Teh, Seng Khoon; Zheng, Wei; Lau, David P.; Huang, Zhiwei

    2008-02-01

    In this report, the diagnostic ability of near-infrared (NIR) Raman spectroscopy for identifying the malignant tumors from normal tissues in the larynx was studied. A rapid NIR Raman system was utilized. Multivariate statistical techniques were employed to develop effective diagnostic algorithms. Raman spectra in the range of 800-1,800 cm-1 differed significantly between normal and malignant tumor tissues. The diagnostic algorithms can yielded a diagnostic sensitivity of 92.9% and specificity 83.3% for separating malignant tumors from normal laryngeal tissues. NIR Raman spectroscopy with multivariate statistical techniques has a potential for the non-invasive detection of malignant tumors in the larynx.

  9. In situ cellular level Raman spectroscopy of the thyroid

    PubMed Central

    Law, Alan Wing Lun; Ahmed, Rafay; Cheung, Tsz Wing; Mak, Chun Yu; Lau, Condon

    2017-01-01

    We report a novel Raman spectroscopy method for in situ cellular level analysis of the thyroid. Thyroids are harvested from control and lithium treated mice. Lithium is used to treat bipolar disorder, but affects thyroid function. Raman spectra are acquired with a confocal setup (514 nm laser, 20 µm spot) focused on a follicular lumen. Raman peaks are observed at 1440, 1656, and 1746 cm−1, corresponding to tyrosine, an important amino acid for protein synthesis. Peaks are also observed at 563, 1087, 1265 and 1301 cm−1. With lithium, the tyrosine peaks increase, indicating tyrosine buildup. Raman spectroscopy can study the impact of many exogenous treatments on thyroid biochemistry. PMID:28270975

  10. In situ cellular level Raman spectroscopy of the thyroid.

    PubMed

    Law, Alan Wing Lun; Ahmed, Rafay; Cheung, Tsz Wing; Mak, Chun Yu; Lau, Condon

    2017-02-01

    We report a novel Raman spectroscopy method for in situ cellular level analysis of the thyroid. Thyroids are harvested from control and lithium treated mice. Lithium is used to treat bipolar disorder, but affects thyroid function. Raman spectra are acquired with a confocal setup (514 nm laser, 20 µm spot) focused on a follicular lumen. Raman peaks are observed at 1440, 1656, and 1746 cm(-1), corresponding to tyrosine, an important amino acid for protein synthesis. Peaks are also observed at 563, 1087, 1265 and 1301 cm(-1). With lithium, the tyrosine peaks increase, indicating tyrosine buildup. Raman spectroscopy can study the impact of many exogenous treatments on thyroid biochemistry.

  11. Photoacoustic imaging and surface-enhanced Raman spectroscopy using dual modal contrast agents

    NASA Astrophysics Data System (ADS)

    Park, Sungjo; Lee, Seunghyun; Cha, Myeonggeun; Jeong, Cheolhwan; Kang, Homan; Park, So Yeon; Lee, Yoon-sik; Jeong, Daehong; Kim, Chulhong

    2016-03-01

    Recently, photoacoustic tomography (PAT) has emerged as a remarkable non-invasive imaging modality that provides a strong optical absorption contrast, high ultrasonic resolution, and great penetration depth. Thus, PAT has been widely used as an in vivo preclinical imaging tool. Surface-enhanced Raman spectroscopy (SERS) is another attractive sensing technology in biological research because it offers highly sensitive chemical analyses and multiplexed detection. By performing dual-modal imaging of SERS and PAT, high-resolution structural PAT imaging and high-sensitivity SERS sensing can be achieved. At the same time, it is equally important to develop a dual modal contrast agent for this purpose. To perform both PAT and SERS, we synthesized PEGylated silver bumpy nanoshells (AgBSs). The AgBSs generate strong PA signals owing to their strong optical absorption properties as well as sensitive SERS signals because of the surface plasmon resonance effect. Then, multiplexed Raman chemicals were synthesized to enhance the sensitivity of Raman. We have photoacoustically imaged the sentinel lymph nodes of small animals after intradermal injection of multiplexed agents. Furthermore, the chemical composition of each agent has been distinguished through SERS.

  12. Near-infrared excited surface-enhanced Raman spectroscopy of rhodamine 6G on colloidal silver

    NASA Astrophysics Data System (ADS)

    Kneipp, K.; Roth, E.; Engert, C.; Kiefer, W.

    1993-05-01

    1064 nm excited surface-enhanced Raman spectroscopy (SERS) of rhodamine 6G (Rh 6G) on NaCl-activated silver sol is reported performed with a scanning Raman spectrometer. The present study gives the opportunity to compare directly the enhancement factors for excitation in the near-infrared (NIR) and in the visible region and shows that for the case of Rh 6G these factors are of the same order of magnitude. This result can be explained by a growing electromagnetic contribution to the enhancement at 1064 nm which compensates the loss of resonance Raman enhancement by the change of excitation wavelength from about 500 to 1064 nm. An additional enhancement factor ascribed to the local mechanism of a Rh 6G-adatom—anion surface complex gives an essential contribution to SERS. This specific enhancement due to Cl-activated sites results in similar contributions in the visible and in the NIR.

  13. Structure fits the purpose: photonic crystal fibers for evanescent-field surface-enhanced Raman spectroscopy.

    PubMed

    Khaing Oo, Maung Kyaw; Han, Yun; Kanka, Jiri; Sukhishvili, Svetlana; Du, Henry

    2010-02-15

    We report numerical simulation and hyperspectral Raman imaging of three index-guiding solid-core photonic crystal fibers (PCFs) of different air-cladding microstructures to assess their respective potential for evanescent-field Raman spectroscopy, with an emphasis on achieving surface-enhanced Raman scattering (SERS) over the entire fiber length. Suspended-core PCF consisting of a silica core surrounded by three large air channels conjoined by a thin silica web is the most robust of the three SERS-active PCFs, with a demonstrated detection sensitivity of 1x10(-10) M R6G in an aqueous solution of only approximately 7.3 microL sampling volume.

  14. Surface-Enhanced Raman Scattering (SERS) for Detection in Immunoassays. Applications, fundamentals, and optimization

    SciTech Connect

    Driskell, Jeremy Daniel

    2006-08-09

    Immunoassays have been utilized for the detection of biological analytes for several decades. Many formats and detection strategies have been explored, each having unique advantages and disadvantages. More recently, surface-enhanced Raman scattering (SERS) has been introduced as a readout method for immunoassays, and has shown great potential to meet many key analytical figures of merit. This technology is in its infancy and this dissertation explores the diversity of this method as well as the mechanism responsible for surface enhancement. Approaches to reduce assay times are also investigated. Implementing the knowledge gained from these studies will lead to a more sensitive immunoassay requiring less time than its predecessors. This dissertation is organized into six sections. The first section includes a literature review of the previous work that led to this dissertation. A general overview of the different approaches to immunoassays is given, outlining the strengths and weaknesses of each. Included is a detailed review of binding kinetics, which is central for decreasing assay times. Next, the theoretical underpinnings of SERS is reviewed at its current level of understanding. Past work has argued that surface plasmon resonance (SPR) of the enhancing substrate influences the SERS signal; therefore, the SPR of the extrinsic Raman labels (ERLs) utilized in our SERS-based immunoassay is discussed. Four original research chapters follow the Introduction, each presented as separate manuscripts. Chapter 2 modifies a SERS-based immunoassay previously developed in our group, extending it to the low-level detection of viral pathogens and demonstrating its versatility in terms of analyte type, Chapter 3 investigates the influence of ERL size, material composition, and separation distance between the ERLs and capture substrate on the SERS signal. This chapter links SPR with SERS enhancement factors and is consistent with many of the results from theoretical treatments

  15. Surface-enhanced vibrational spectroscopy of B vitamins: what is the effect of SERS-active metals used?

    PubMed

    Kokaislová, A; Matějka, P

    2012-05-01

    Surface-enhanced Raman scattering (SERS) spectroscopy and surface-enhanced infrared absorption (SEIRA) spectroscopy are analytical tools suitable for the detection of small amounts of various analytes adsorbed on metal surfaces. During recent years, these two spectroscopic methods have become increasingly important in the investigation of adsorption of biomolecules and pharmaceuticals on nanostructured metal surfaces. In this work, the adsorption of B-group vitamins pyridoxine, nicotinic acid, folic acid and riboflavin at electrochemically prepared gold and silver substrates was investigated using Fourier transform SERS spectroscopy at an excitation wavelength of 1,064 nm. Gold and silver substrates were prepared by cathodic reduction on massive platinum targets. In the case of gold substrates, oxidation-reduction cycles were applied to increase the enhancement factor of the gold surface. The SERS spectra of riboflavin, nicotinic acid, folic acid and pyridoxine adsorbed on silver substrates differ significantly from SERS spectra of these B-group vitamins adsorbed on gold substrates. The analysis of near-infrared-excited SERS spectra reveals that each of B-group vitamin investigated interacts with the gold surface via a different mechanism of adsorption to that with the silver surface. In the case of riboflavin adsorbed on silver substrate, the interpretation of surface-enhanced infrared absorption (SEIRA) spectra was also helpful in investigation of the adsorption mechanism.

  16. From Femtosecond Dynamics to Breast Cancer Diagnosis by Raman Spectroscopy

    SciTech Connect

    Abramczyk, H.; Placek, I.; Brozek-Pluska, B.; Kurczewski, K.; Morawiec, Z.; Tazbir, M.

    2007-12-26

    This paper presents new results based on Raman spectroscopy and demonstrates its utilisation as a diagnostic and development tool with the key advantage in breast cancer research. Applications of Raman spectroscopy in cancer research are in the early stages of development. However, research presented here as well as performed in a few other laboratories demonstrate the ability of Raman spectroscopy to accurately characterize cancer tissue and distinguish between normal, malignant and benign types. The main goals of bio-Raman spectroscopy at this stage are threefold. Firstly, the aim is to develop the diagnostic ability of Raman spectroscopy so it can be implemented in a clinical environment, producing accurate and rapid diagnoses. Secondly, the aim is to optimize the technique as a diagnostic tool for the non-invasive real time medical applications. Thirdly, the aim is to formulate some hypothesis based on Raman spectroscopy on the molecular mechanism which drives the transformation of normal human cells into highly malignant derivatives. To the best of our knowledge, this is the most statistically reliable report on Raman spectroscopy-based diagnosis of breast cancers among the world women population.

  17. Time-correlated Raman and fluorescence spectroscopy based on a silicon photomultiplier and time-correlated single photon counting technique.

    PubMed

    Zhang, Chunling; Zhang, Liying; Yang, Ru; Liang, Kun; Han, Dejun

    2013-02-01

    We report a time-correlated Raman spectroscopy technique based on a silicon photomultiplier (SiPM) and a time-correlated single photon counting (TCSPC) technique to exploit the natural temporal separation between Raman and fluorescence phenomena to alleviate the high fluorescence background with conventional Raman detection. The TCSPC technique employed can greatly reduce the effect of high dark count rate (DCR) and crosstalk of SiPM that seriously hinder its application in low light level detection. The operating principle and performance of the 400 ps time resolution system are discussed along with the improvement of the peak-to-background ratio (PBR) for bulk trinitrotoluene (TNT) Raman spectrum relative to a commercial Raman spectrometer with charge coupled device (CCD). The fluorescence lifetime for solid TNT and Surface Enhanced Raman Scattering (SERS) spectrum for 10(-6) mol/L trace TNT have also been obtained by this system, showing excellent versatility and convenience in spectroscopy measurement.

  18. Surface-enhanced Raman scattering (SERS) detection for chemical and biological agents

    NASA Astrophysics Data System (ADS)

    Yan, Fei; Stokes, David L.; Wabuyele, Musundi B.; Griffin, Guy D.; Vass, Arpad A.; Vo-Dinh, Tuan

    2004-07-01

    Surface-enhanced Raman scattering (SERS) spectra of chemical agent simulants such as dimethyl methylphonate (DMMP), pinacolyl methylphosphonate (PMP), diethyl phosphoramidate (DEPA), and 2-chloroethyl ethylsulfide (CEES), and biological agent simulants such as bacillus globigii (BG), erwinia herbicola (EH), and bacillus thuringiensis (BT) were obtained from silver oxide film-deposited substrates. Thin AgO films ranging in thickness from 50 nm to 250 nm were produced by chemical bath deposition onto glass slides. Further Raman intensity enhancements were noticed in UV irradiated surfaces due to photo-induced Ag nanocluster formation, which may provide a possible route to producing highly useful plasmonic sensors for the detection of chemical and biological agents upon visible light illumination.

  19. Surface enhanced Raman spectroscopy on the tip of a plastic optical fiber

    NASA Astrophysics Data System (ADS)

    Taguenang, J. M.; Kassu, A.; Sharma, A.; Diggs, D.

    2007-09-01

    Surface Enhanced Raman Spectroscopy is a powerful analytical technique capable of single molecule detection sensitivity. We have detected SERS on the tip of a 3 mm-core diameter PMMA plastic optical fiber. The technique involves deposition of 30 nm gold nanoparticles followed by deposition of sample of interest to be analyzed. SERS enhancement has been demonstrated for several chemicals like glycerin and dye Rhodamine 6G as well biological molecules like Acetaminophen, aspirin and Streptavidin and poly-L-Lysine. It is shown that interfering spectrum of PMMA can be subtracted to reveal the SERS spectrum of molecule of interest. The technique can simplify SERS detection by connecting the other end of fiber directly to a spectrometer. SERS was recorded for various concentrations of analytes. Using a focused 633 nm laser, a detection sensitivity of 0.1picogram was established.

  20. Laser writing of single-crystalline gold substrates for surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Singh, Astha; Sharma, Geeta; Ranjan, Neeraj; Mittholiya, Kshitij; Bhatnagar, Anuj; Singh, B. P.; Mathur, Deepak; Vasa, Parinda

    2017-07-01

    Surface enhanced Raman scattering (SERS) spectroscopy, a powerful contemporary tool for studying low-concentration analytes via surface plasmon induced enhancement of local electric field, is of utility in biochemistry, material science, threat detection, and environmental studies. We have developed a simple, fast, scalable, and relatively low-cost optical method of fabricating and characterizing large-area, reusable and broadband SERS substrates with long storage lifetime. We use tightly focused, intense infra-red laser pulses to write gratings on single-crystalline, Au (1 1 1) gold films on mica which act as SERS substrates. Our single-crystalline SERS substrates compare favourably, in terms of surface quality and roughness, to those fabricated in poly-crystalline Au films. Tests show that our SERS substrates have the potential of detecting urea and 1,10-phenantroline adulterants in milk and water, respectively, at 0.01 ppm (or lower) concentrations.

  1. Using Ambient Ion Beams to Write Nanostructured Patterns for Surface Enhanced Raman Spectroscopy

    SciTech Connect

    Li, Anyin; Baird, Zane; Bag, Soumabha; Sarkar, Depanjan; Prabhath, Anupama; Pradeep, Thalappil; Cooks, Robert G.

    2014-11-10

    Electrolytic spray deposition was used to pattern surfaces with 2D metallic nanostructures. Spots that contain silver nanoparticles (AgNP) were created by landing solvated silver ions at desired locations using electrically floated masks to focus the metal ions to an area as little as 20 mm in diameter. The AgNPs formed are unprotected and their aggregates can be used for surface-enhanced Raman spectroscopy (SERS). The morphology and SERS activity of the NP structures were controlled by the surface coverage of landed silver ions. The NP structures created could be used as substrates onto which SERS samples were deposited or prepared directly on top of predeposited samples of interest. The evenly distributed hot spots in the micron-sized aggregates had an average SERS enhancement factor of 108. The surfaces showed SERS activity when using lasers of different wavelengths (532, 633, and 785 nm) and were stable in air.

  2. Gold nanodome-patterned microchips for intracellular surface-enhanced Raman spectroscopy.

    PubMed

    Wuytens, Pieter C; Subramanian, Ananth Z; De Vos, Winnok H; Skirtach, Andre G; Baets, Roel

    2015-12-21

    While top-down substrates for surface-enhanced Raman spectroscopy (SERS) offer outstanding control and reproducibility of the gold nanopatterns and their related localized surface plasmon resonance, intracellular SERS experiments heavily rely on gold nanoparticles. These nanoparticles often result in varying and uncontrollable enhancement factors. Here we demonstrate the use of top-down gold-nanostructured microchips for intracellular sensing. We develop a tunable and reproducible fabrication scheme for these microchips. Furthermore we observe the intracellular uptake of these structures, and find no immediate influence on cell viability. Finally, we perform a proof-of-concept intracellular SERS experiment by the label-free detection of extraneous molecules. By bringing top-down SERS substrates to the intracellular world, we set an important step towards time-dependent and quantitative intracellular SERS.

  3. Surface-Enhanced Raman Spectroscopy: A New Modality for Cancer Imaging

    PubMed Central

    Andreou, Chrysafis; Kishore, Sirish A.; Kircher, Moritz F.

    2015-01-01

    While surface-enhanced Raman scattering (SERS) spectroscopy has traditionally been employed as an in vitro analytical tool, in the past few years the first reports of the feasibility of in vivo imaging of cancer with biocompatible SERS probes have emerged. SERS imaging has great potential in the field of medical imaging because it offers several major theoretical advantages over other molecular imaging methods. Medical imaging using SERS nanoprobes can yield higher sensitivity and higher signal specificity than other imaging modalities while also offering multiplexing capabilities that allow for unique applications. This review article explains the principles of SERS and highlights recent advances for in vivo cancer imaging. In order to present the abilities of the method as accurate as possible, the discussion is limited to studies in which the imaging data were confirmed by histological correlation. PMID:26182971

  4. Spectral analysis of human saliva for detection of lung cancer using surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Xiaozhou; Yang, Tianyue; Lin, Junxiu

    2012-03-01

    Surface-enhanced Raman spectroscopy (SERS) has been shown to be able to detect low-concentration biofluids. Saliva SERS readings of 21 lung cancer patients and 20 normal people were measured and differentiated. Most of the Raman peak intensities decrease for lung cancer patients compared with that of normal people. Those peaks were assigned to proteins and nucleic acids, which indicate a corresponding decrease of those substances in saliva. Principal component analysis (PCA) and linear discriminant analysis (LDA) were used to reduce and discriminate between the two groups of data, and the study resulted in accuracy, sensitivity, and specificity being 80%, 78%, and 83%, respectively. In conclusion, SERS of saliva showed the ability to predict lung cancer in our experiment.

  5. Boron Nitride Nanosheets Improve Sensitivity and Reusability of Surface-Enhanced Raman Spectroscopy.

    PubMed

    Cai, Qiran; Mateti, Srikanth; Yang, Wenrong; Jones, Rob; Watanabe, Kenji; Taniguchi, Takashi; Huang, Shaoming; Chen, Ying; Li, Lu Hua

    2016-07-11

    Surface enhanced Raman spectroscopy (SERS) is a useful multidisciplinary analytic technique. However, it is still a challenge to produce SERS substrates that are highly sensitive, reproducible, stable, reusable, and scalable. Herein, we demonstrate that atomically thin boron nitride (BN) nanosheets have many unique and desirable properties to help solve this challenge. The synergic effect of the atomic thickness, high flexibility, stronger surface adsorption capability, electrical insulation, impermeability, high thermal and chemical stability of BN nanosheets can increase the Raman sensitivity by up to two orders, and in the meantime attain long-term stability and extraordinary reusability not achievable by other materials. These advances will greatly facilitate the wider use of SERS in many fields.

  6. Gold nanotags for combined multi-colored Raman spectroscopy and x-ray computed tomography.

    PubMed

    Xiao, Ming; Nyagilo, James; Arora, Veera; Kulkarni, Padmakar; Xu, Dongsheng; Sun, Xiankai; Davé, Digant P

    2010-01-22

    Multi-color gold-nanoparticle-based tags (nanotags) are synthesized for combined surface-enhanced Raman spectroscopy (SERS) and x-ray computed tomography (CT). The nanotags are synthesized with quasi-spherical gold nanoparticles encoded with a reporter dye (color), each with a unique Raman spectrum. A library of nanotags with six different colors were synthesized for a range of gold nanoparticle sizes and an optimum size has been established to yield the largest SERS intensity and x-ray attenuation that is higher than the iodinated CT contrast agents used in clinics. Proof-of-principle in vivo imaging results with nanotags are presented that, for the first time, demonstrates the combined in vivo dual modality imaging capability of SERS and CT with a single nanoparticle probe.

  7. Polytetrafluorethylene-Au as a substrate for surface-enhanced Raman spectroscopy

    PubMed Central

    2011-01-01

    This study deals with preparation of substrates suitable for surface-enhanced Raman spectroscopy (SERS) applications by sputtering deposition of gold layer on the polytetrafluorethylene (PTFE) foil. Time of sputtering was investigated with respect to the surface properties. The ability of PTFE-Au substrates to enhance Raman signals was investigated by immobilization of biphenyl-4,4'-dithiol (BFD) from the solutions with various concentrations. BFD was also used for preparation of sandwich structures with Au or Ag nanoparticles by two different procedures. Results showed that PTFE can be used for fabrication of SERS active substrate with easy handle properties at low cost. This substrate was sufficient for the measurement of SERS spectrum of BFD even at 10-8 mol/l concentration. PMID:21711893

  8. Raman spectroscopy for cancer detection and characterization in metastasis models

    NASA Astrophysics Data System (ADS)

    Koga, Shigehiro; Oshima, Yusuke; Sato, Mitsunori; Ishimaru, Kei; Yoshida, Motohira; Yamamoto, Yuji; Matsuno, Yusuke; Watanabe, Yuji

    2017-02-01

    Raman spectroscopy provides a wealth of diagnostic information to the surgeon with in situ cancer detection and label-free histopathology in clinical practice. Raman spectroscopy is a developing optical technique which can analyze biological tissues with light scattering. The difference in frequencies between the incident light and the scattering light are called Raman shifts, which correspond to the vibrational energy of the molecular bonds. Raman spectrum gives information about the molecular structure and composition in biological specimens. We had been previously reported that Raman spectroscopy could distinguish various histological types of human lung cancer cells from normal cells in vitro. However, to identify and detect cancer diagnostic biomarkers in vivo on Raman spectroscopy is still challenging, because malignancy can be characterized not only by the cancer cells but also by the environmental factors including immune cells, stroma cells, secretion vesicles and extracellular matrix. Here we investigate morphological and molecular dynamics in both cancer cells and their environment in xenograft models and spontaneous metastasis models using Raman spectroscopy combined with fluorescence microscopy and photoluminescence imaging. We are also constructing a custom-designed Raman spectral imaging system for both in vitro and in vivo assay of tumor tissues to reveal the metastasis process and to evaluate therapeutic effects of anti-cancer drugs and their drug delivery toward the clinical application of the technique.

  9. Forensic and homeland security applications of modern portable Raman spectroscopy.

    PubMed

    Izake, Emad L

    2010-10-10

    Modern detection and identification of chemical and biological hazards within the forensic and homeland security contexts may well require conducting the analysis in field while adapting a non-contact approach to the hazard. Technological achievements on both surface and resonance enhancement Raman scattering re-developed Raman spectroscopy to become the most adaptable spectroscopy technique for stand-off and non-contact analysis of hazards. On the other hand, spatially offset Raman spectroscopy proved to be very valuable for non-invasive chemical analysis of hazards concealed within non-transparent containers and packaging. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  10. Periodontitis diagnostics using resonance Raman spectroscopy on saliva

    NASA Astrophysics Data System (ADS)

    Gonchukov, S.; Sukhinina, A.; Bakhmutov, D.; Biryukova, T.; Tsvetkov, M.; Bagratashvily, V.

    2013-07-01

    In view of its wealth of molecular information, Raman spectroscopy has been the subject of active biomedical research. The aim of this work is Raman spectroscopy (RS) application for the determination of molecular biomarkers in saliva with the objective of early periodontitis detection. As was shown in our previous study, carotenoids contained in saliva can be molecular fingerprint information for the periodontitis level. It is shown here that the carotenoid RS lines at wavenumbers of 1156 and 1524 cm-1 can be easily detected and serve as reliable biomarkers of periodontitis using resonance Raman spectroscopy of dry saliva.

  11. Raman spectroscopy of gliomas: an exploratory study

    NASA Astrophysics Data System (ADS)

    Shenoy, Mahesh; Hole, Arti R.; Shridhar, E.; Moiyadi, Aliasgar V.; Krishna, C. Murali

    2014-03-01

    Gliomas are extremely infiltrative type of brain cancers, the borders of which are difficult to locate. Gliomas largely consist of tumors of astrocytic or oligodendroglial lineage. Usually stereotactic surgery is performed to obtain tumor tissue sample. Complete excision of these tumors with preservation of uninvolved normal areas is important during brain tumor surgeries. The present study was undertaken to explore feasibility of classifying abnormal and normal glioma tissues with Raman spectroscopy (RS). RS is a nondestructive vibrational spectroscopic technique, which provides information about molecular composition, molecular structures and molecular interactions in tissue. Postoperated 33 (20-abnormal and 13-normal) gliomas tissue samples of different grades were collected under clinical supervision. Five micron section from tissue sample was used for confirmatory histopathological diagnosis while the remaining tissue was placed on CaF2 window and spectra were acquired using a fiberoptic-probe-coupled HE-785 Raman-spectrometer. Spectral acquisition parameters were laser power-80mW, integration-20s and averaged over 3 accumulations. Spectra were pre-processed and subjected to unsupervised Principal-Component Analysis (PCA) to identify trends of classification. Supervised PC-LDA (Principal-Component-Linear-Discriminant Analysis) was used to develop standard-models using spectra of 12 normal and abnormal specimens each. Leave-one-out crossvalidation yielded classification-efficiency of 90% and 80% for normal and abnormal conditions, respectively. Evaluation with an independent-test data-set comprising of 135 spectra of 9 samples provided sensitivity of 100% and specificity of 70%. Findings of this preliminary study may pave way for objective tumor margin assessment during brain surgery.

  12. New Insight of Tetraphenylethylene-based Raman Signatures for Targeted SERS Nanoprobe Construction Toward Prostate Cancer Cell Detection.

    PubMed

    Ramya, Adukkadan N; Joseph, Manu M; Nair, Jyothi B; Karunakaran, Varsha; Narayanan, Nisha; Maiti, Kaustabh Kumar

    2016-04-27

    We have designed and synthesized novel tetraphenylethylene (TPE) appended organic fluorogens and unfold their unique Raman fingerprinting reflected by surface-enhanced Raman scattering (SERS) upon adsorption on nanoroughened gold surface as a new insight in addition to their prevalent aggregation-induced emission (AIE) and aggregation-caused quenching (ACQ) phenomena. A series of five TPE analogues has been synthesized consisting of different electron donors such as (1) indoline with propyl (TPE-In), (2) indoline with lipoic acid (TPE-In-L), (3) indoline with Boc-protected propyl amine (TPE-In-Boc), (4) benzothaizole (TPE-B), and (5) quinaldine (TPE-Q). Interestingly, all five TPE analogues produced multiplexing Raman signal pattern, out of which TPE-In-Boc showed a significant increase in signal intensity in the fingerprint region. An efficient SERS nanoprobe has been constructed using gold nanoparticles as SERS substrate, and the TPE-In as the Raman reporter, which conjugated with a specific peptide substrate, Cys-Ser-Lys-Leu-Gln-OH, well-known for the recognition of prostate-specific antigen (PSA). The designated nanoprobe TPE-In-PSA@Au acted as SERS "ON/OFF" probe in peace with the vicinity of PSA protease, which distinctly recognizes PSA expression with a limit of detection of 0.5 ng in SERS platform. Furthermore, TPE-In-PSA@Au nanoprobe was efficiently recognized the overexpressed PSA in human LNCaP cells, which can be visualized through SERS spectral analysis and SERS mapping.

  13. Performance characteristics of bio-inspired metal nanostructures as surface-enhanced Raman scattered (SERS) substrates

    SciTech Connect

    Areizaga-Martinez, Hector I.; Kravchenko, Ivan; Lavrik, Nickolay V.; Sepaniak, Michael J.; Hernandez-Rivera, Samuel P.; De Jesus, Marco A.

    2016-08-26

    The fabrication of high-performance plasmonic nanomaterials for bio-sensing and trace chemical detection is a field of intense theoretical and experimental research. The use of metal-silicon nanopillar arrays as analytical sensors has been reported with reasonable results in recent years. The use of bio-inspired nanocomposite structures that follow the Fibonacci numerical architecture offers the opportunity to develop nanostructures with theoretically higher and more reproducible plasmonic fields over extended areas. The work presented here describes the nanofabrication process for a series of 40 µm × 40 µm bio-inspired arrays classified as asymmetric fractals (sunflower seeds and romanesco broccoli), bilaterally symmetric (acacia leaves and honeycombs), and radially symmetric (such as orchids and lily flowers) using electron beam lithography. In addition, analytical capabilities were evaluated using surface-enhanced Raman scattering (SERS). Here, the substrate characterization and SERS performance of the developed substrates as the strategies to assess the design performance are presented and discussed.

  14. Performance characteristics of bio-inspired metal nanostructures as surface-enhanced Raman scattered (SERS) substrates

    SciTech Connect

    Areizaga-Martinez, Hector I.; Kravchenko, Ivan; Lavrik, Nickolay V.; Sepaniak, Michael J.; Hernandez-Rivera, Samuel P.; De Jesus, Marco A.

    2016-08-26

    The fabrication of high-performance plasmonic nanomaterials for bio-sensing and trace chemical detection is a field of intense theoretical and experimental research. The use of metal-silicon nanopillar arrays as analytical sensors has been reported with reasonable results in recent years. The use of bio-inspired nanocomposite structures that follow the Fibonacci numerical architecture offers the opportunity to develop nanostructures with theoretically higher and more reproducible plasmonic fields over extended areas. The work presented here describes the nanofabrication process for a series of 40 µm × 40 µm bio-inspired arrays classified as asymmetric fractals (sunflower seeds and romanesco broccoli), bilaterally symmetric (acacia leaves and honeycombs), and radially symmetric (such as orchids and lily flowers) using electron beam lithography. In addition, analytical capabilities were evaluated using surface-enhanced Raman scattering (SERS). Here, the substrate characterization and SERS performance of the developed substrates as the strategies to assess the design performance are presented and discussed.

  15. Application of Raman spectroscopy and surface-enhanced Raman scattering to the analysis of synthetic dyes found in ballpoint pen inks.

    PubMed

    Geiman, Irina; Leona, Marco; Lombardi, John R

    2009-07-01

    The applicability of Raman spectroscopy and surface-enhanced Raman scattering (SERS) to the analysis of synthetic dyes commonly found in ballpoint inks was investigated in a comparative study. Spectra of 10 dyes were obtained using a dispersive system (633 nm, 785 nm lasers) and a Fourier transform system (1064 nm laser) under different analytical conditions (e.g., powdered pigments, solutions, thin layer chromatography [TLC] spots). While high fluorescence background and poor spectral quality often characterized the normal Raman spectra of the dyes studied, SERS was found to be generally helpful. Additionally, dye standards and a single ballpoint ink were developed on a TLC plate following a typical ink analysis procedure. SERS spectra were successfully collected directly from the TLC plate, thus demonstrating a possible forensic application for the technique.

  16. Sensitivity of Raman spectroscopy to normal patient variability

    NASA Astrophysics Data System (ADS)

    Vargis, Elizabeth; Byrd, Teresa; Logan, Quinisha; Khabele, Dineo; Mahadevan-Jansen, Anita

    2011-11-01

    Many groups have used Raman spectroscopy for diagnosing cervical dysplasia; however, there have been few studies looking at the effect of normal physiological variations on Raman spectra. We assess four patient variables that may affect normal Raman spectra: Race/ethnicity, body mass index (BMI), parity, and socioeconomic status. Raman spectra were acquired from a diverse population of 75 patients undergoing routine screening for cervical dysplasia. Classification of Raman spectra from patients with a normal cervix is performed using sparse multinomial logistic regression (SMLR) to determine if any of these variables has a significant effect. Results suggest that BMI and parity have the greatest impact, whereas race/ethnicity and socioeconomic status have a limited effect. Incorporating BMI and obstetric history into classification algorithms may increase sensitivity and specificity rates of disease classification using Raman spectroscopy. Studies are underway to assess the effect of these variables on disease.

  17. Real-time in vivo cancer diagnosis using Raman spectroscopy.

    PubMed

    Wang, Wenbo; Zhao, Jianhua; Short, Michael; Zeng, Haishan

    2015-07-01

    Raman spectroscopy has becoming a practical tool for rapid in vivo tissue diagnosis. This paper provides an overview on the latest development of real-time in vivo Raman systems for cancer detection. Instrumentation, data handling, as well as oncology applications of Raman techniques were covered. Optic fiber probes designs for Raman spectroscopy were discussed. Spectral data pre-processing, feature extraction, and classification between normal/benign and malignant tissues were surveyed. Applications of Raman techniques for clinical diagnosis for different types of cancers, including skin cancer, lung cancer, stomach cancer, oesophageal cancer, colorectal cancer, cervical cancer, and breast cancer, were summarized. Schematic of a real-time Raman spectrometer for skin cancer detection. Without correction, the image captured on CCD camera for a straight entrance slit has a curvature. By arranging the optic fiber array in reverse orientation, the curvature could be effectively corrected. © 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Sensitivity of Raman spectroscopy to normal patient variability

    PubMed Central

    Vargis, Elizabeth; Byrd, Teresa; Logan, Quinisha; Khabele, Dineo; Mahadevan-Jansen, Anita

    2011-01-01

    Many groups have used Raman spectroscopy for diagnosing cervical dysplasia; however, there have been few studies looking at the effect of normal physiological variations on Raman spectra. We assess four patient variables that may affect normal Raman spectra: Race/ethnicity, body mass index (BMI), parity, and socioeconomic status. Raman spectra were acquired from a diverse population of 75 patients undergoing routine screening for cervical dysplasia. Classification of Raman spectra from patients with a normal cervix is performed using sparse multinomial logistic regression (SMLR) to determine if any of these variables has a significant effect. Results suggest that BMI and parity have the greatest impact, whereas race/ethnicity and socioeconomic status have a limited effect. Incorporating BMI and obstetric history into classification algorithms may increase sensitivity and specificity rates of disease classification using Raman spectroscopy. Studies are underway to assess the effect of these variables on disease. PMID:22112136

  19. Intracellularly grown gold nanoislands as SERS substrates for monitoring chromate, sulfate and nitrate localization sites in remediating bacteria biofilms by Raman chemical imaging

    PubMed Central

    Ravindranath, Sandeep P.; Kadam, Ulhas S.; Thompson, Dorothea K.; Irudayaraj, Joseph

    2012-01-01

    Understanding the chemical composition of biofilm matrices is vital in different fields of biology such as surgery, dental medicine, synthetic grafts and bioremediation. The knowledge of biofilm development, composition, active reduction sites and remediation efficacy will help in the development of effective solutions and evaluation of remediating approaches prior to implementation. Surface-enhanced Raman spectroscopy (SERS) based imaging is an invaluable tool to obtain an understanding of the remediating efficacy of microorganisms and its role in the formation of organic and inorganic compounds in biofilms. We demonstrate for the first time, the presence of chromate, sulfate, nitrate and reduced trivalent chromium in soil biofilms. In addition, we demonstrate that SERS imaging was able to validate two observations made by previous studies on chromate/sulfate and chromate/nitrate interactions in Shewanella oneidensis MR-1 biofilms. Additionally, we show a detailed Raman mapping based evidence of the existence of chromate-sulfate competition for cellular entry. Subsequently, we use Raman mapping to study the effect of nitrate on chromate reduction. The findings presented in this paper are among the first to report- detection of multiple metallic ions in bacterial biofilms using intracellular SERS substrates. Such a detailed characterization of biofilms using gold nanoislands based SERS mapping substrate can be extended to study cellular localization of other metallic ions and chemical species of biological and toxicological significance and their effect on reduction reactions in bacterial biofilms. PMID:22938600

  20. Plasmonic-enhanced Raman scattering of graphene on growth substrates and its application in SERS

    NASA Astrophysics Data System (ADS)

    Zhao, Yuan; Chen, Guanxiong; Du, Yuanxin; Xu, Jin; Wu, Shuilin; Qu, Yan; Zhu, Yanwu

    2014-10-01

    We detail a facile method for enhancing the Raman signals of as-grown graphene on Cu foils by depositing gold nanoislands (Au Nis) onto the surface of graphene. It is found that an enhancement of up to 49 fold in the graphene Raman signal has been achieved by depositing a 4 nm thick Au film. The enhancement is considered to be related to the coupling between graphene and the plasmon modes of Au Nis, as confirmed by the finite element simulations. The plasmonic effect of the Au/graphene/Cu hybrid platform leads to a strong absorption at the resonant wavelength whose position shifts from visible light (640 nm) to near-infrared (1085 nm) when the thickness of Au films is increased from 2 nm to 18 nm. Finally, we demonstrate that hybrid substrates are reliable surface-enhanced Raman scattering (SERS) systems, showing an enhancement factor of ~106 for dye molecules Rhodamine B and Rhodamine 6G with uniform and stable response and a detection limit of as low as 0.1 nM for Sudan III and Sudan IV.We detail a facile method for enhancing the Raman signals of as-grown graphene on Cu foils by depositing gold nanoislands (Au Nis) onto the surface of graphene. It is found that an enhancement of up to 49 fold in the graphene Raman signal has been achieved by depositing a 4 nm thick Au film. The enhancement is considered to be related to the coupling between graphene and the plasmon modes of Au Nis, as confirmed by the finite element simulations. The plasmonic effect of the Au/graphene/Cu hybrid platform leads to a strong absorption at the resonant wavelength whose position shifts from visible light (640 nm) to near-infrared (1085 nm) when the thickness of Au films is increased from 2 nm to 18 nm. Finally, we demonstrate that hybrid substrates are reliable surface-enhanced Raman scattering (SERS) systems, showing an enhancement factor of ~106 for dye molecules Rhodamine B and Rhodamine 6G with uniform and stable response and a detection limit of as low as 0.1 nM for Sudan III and

  1. Investigation of biomineralization by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Fatscher, Robert William

    Biomineralization is a process in which living organism grow composite materials consisting of inorganic and organic materials. This produces a composite material consisting of both inorganic and organic components, with superior mechanical properties. In the human body bone and dentin are both examples of biominerals. In this research Raman spectroscopy was used to characterize dentin from mice and human teeth, to determine composition. In the mouse tooth samples areas of irregular dentin were found, along the inside of the tooth, to be in the process of mineralization. By analyzing the samples along these areas we were able to determine the composition of dentin and track how it changed in these area. By analysis of the mineral to matrix ratio the areas of irregular dentin were determined to have less mineral present. Observations of other organic components and collagen in increased concentrations in this area suggested these area were in the process of biomineralization. The understanding of the structure of dentin and its biomineralization process is of crucial importance when trying reproduce dentin. Scientists and engineers are able to produce dentin minerals in vitro by culturing various dental stem cells. The ability to create dentin mineral from cells could lead to methods of repairing dentin in patients, or even lead to the creation of a completely engineered tooth. While dentin-like materials can be produced in a laboratory environment, analysis and comparison of the composition of these materials must be performed to ensure the mineral produced is consistent with dentin. Mineralized nodules from six different dental stem cell lines were cultured to produce a mineralized deposit. Utilizing Raman spectroscopy, we were able to determine cell source dependent differences in a variety of dental stem cells, and compare the mineral produced to native dentin. Orthopedic implants are implants used to replace damaged bone, examples include knee, hip and dental

  2. Raman Spectroscopy as a Probe of Surface Oxides and Hydrides on Niobium

    SciTech Connect

    J. Zasadzinski, B. Albee, S. Bishnoi, C. Cao, G. Ciovati, L.D. Cooley, D.C. Ford, Th. Proslier

    2011-07-01

    Raman microscopy/spectroscopy has been used in conjunction with AFM, tunneling and magnetic susceptibility to identify surface oxides and hydrides on annealed, recrystallized foils of high purity Nb and on single crystals of cavity grade Nb. Cold worked regions of the Nb foil as well as rough regions near grain boundaries showed clear evidence of ordered hydride phases which were identified by VASP phonon calculations. Cold worked regions also displayed enhanced surface paramagnetism. Surface enhanced Raman spectra have also been obtained using 1.0 nm Au depositon. The SERS spectra reveal hydride molecular species which are not observable by conventional Raman. These results indicate that Raman is a useful probe of Nb surfaces relevant for cavity performance

  3. In Vivo and Ex Vivo Transcutaneous Glucose Detection Using Surface-Enhanced Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ma, Ke

    Diabetes mellitus is widely acknowledged as a large and growing health concern. The lack of practical methods for continuously monitoring glucose levels causes significant difficulties in successful diabetes management. Extensive validation work has been carried out using surface-enhanced Raman spectroscopy (SERS) for in vivo glucose sensing. This dissertation details progress made towards a Raman-based glucose sensor for in vivo, transcutaneous glucose detection. The first presented study combines spatially offset Raman spectroscopy (SORS) with SERS (SESORS) to explore the possibility of in vivo, transcutaneous glucose sensing. A SERS-based glucose sensor was implanted subcutaneously in Sprague-Dawley rats. SERS spectra were acquired transcutaneously and analyzed using partial least-squares (PLS). Highly accurate and consistent results were obtained, especially in the hypoglycemic range. Additionally, the sensor demonstrated functionality at least17 days after implantation. A subsequent study further extends the application of SESORS to the possibility of in vivo detection of glucose in brain through skull. Specifically, SERS nanoantennas were buried in an ovine tissue behind a bone with 8 mm thickness and detected by using SESORS. In addition, quantitative detection through bones by using SESORS was also demonstrated. A device that could measure glucose continuously as well as noninvasively would be of great use to patients with diabetes. The inherent limitation of the SESORS approach may prevent this technique from becoming a noninvasive method. Therefore, the prospect of using normal Raman spectroscopy for glucose detection was re-examined. Quantitative detection of glucose and lactate in the clinically relevant range was demonstrated by using normal Raman spectroscopy with low power and short acquisition time. Finally, a nonlinear calibration method called least-squares support vector machine regression (LS-SVR) was investigated for analyzing spectroscopic

  4. Application of Raman spectroscopy to forensic fibre cases.

    PubMed

    Lepot, L; De Wael, K; Gason, F; Gilbert, B

    2008-09-01

    Five forensic fibre cases in which Raman spectroscopy proved to be a good complementary method for microspectrophotometry (MSP) are described. Absorption spectra in the visible range are indeed sometimes characteristic ofa certain dye but this one can be subsequently identified unambiguously by Raman spectroscopy using a spectral library. In other cases the comparison of Raman spectra of reference fibres and suspect fibres led to an improvement of the discrimination power. The Raman measurements have been performed directly on mounted fibres and the spectra showed only little interference from the mounting resin and glass. Raman spectroscopy is therefore a powerful method that can be applied in routine fibre analysis following optical microscopy and MSP measurements.

  5. Application of Raman Spectroscopy for Nondestructive Evaluation of Composite Materials

    NASA Technical Reports Server (NTRS)

    Washer, Glenn A.; Brooks, Thomas M. B.; Saulsberry, Regor

    2007-01-01

    This paper will present an overview of efforts to investigate the application of Raman spectroscopy for the characterization of Kevlar materials. Raman spectroscopy is a laser technique that is sensitive to molecular interactions in materials such as Kevlar, graphite and carbon used in composite materials. The overall goal of this research reported here is to evaluate Raman spectroscopy as a potential nondestructive evaluation (NDE) tool for the detection of stress rupture in Kevlar composite over-wrapped pressure vessels (COPVs). Characterization of the Raman spectra of Kevlar yarn and strands will be presented and compared with analytical models provided in the literature. Results of testing to investigate the effects of creep and high-temperature aging on the Raman spectra will be presented.

  6. Profiling the near field of nanoshells using surface enhanced Raman spectroscopy and fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Lal, Surbhi

    Plasmon resonances in metal nanoparticles control the far field and near field optical properties of these metallic structures. The enhanced electromagnetic near field is strongest at the surface of the nanoparticles and rapidly decays away from the surface. This enhanced near field is exploited in surface enhanced spectroscopies including Surface Enhanced Raman Spectroscopy (SERS) and Metal Enhanced Fluorescence Spectroscopy (MEFS). A measurement of the decay profile of the fringing field is important both for further development of surface enhanced spectroscopy for sensor device application, and for understanding from a fundamental physics point of view. Gold nanoshells are spherical colloidal nanoparticles with a silica core covered by a thin gold shell. The plasmon resonance of nanoshells can be controllably tuned in the visible and infrared parts of the spectrum. The near field profile of nanoshells can be theoretically calculated on the basis of Mie scattering theory. The thesis describes a series of experiments designed to experimentally verify the near field profile of nanoshells. A scaffold of ss-DNA is used to place a fluorescein dye molecule at varying distances from the nanoshell surface. The SERS intensity from both the scaffold molecules and the fluorescein placed at the end of the tether is measured simultaneously and self consistently. The fluorescein-ss-DNA nanoshell conjugate structures are also used to study the distance dependence of the fluorescence emission from fluorescein. The thesis discusses the results of the SERS intensity profile agreement with the intensity profile calculated using Mie scattering theory. The quenching and enhancement of the fluorescence emission at varying distances from the nanoshell surface are also discussed.

  7. Rapid and label-free screening and identification of Anthrax simulants by Surface Enhanced Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Lai, Antonia; Almaviva, Salvatore; Spizzichino, Valeria; Palucci, Antonio; Addari, Lorella; Luciani, Domenico; Mengali, Sandro; Marquette, Christophe; Berthuy, Ophélie; Jankiewicz, Bartlomiej; Pierno, Luigi

    2014-10-01

    In the framework of RAMBO (Rapid-Air Monitoring particle against biological threats) project of the European Defense Agency (EDA), the feasibility of an unattended Surface Enhanced Raman Spectroscopy (SERS) sensor for biological threats detection was investigated. Its main goal concern Bacillus anthrax detection, both as vegetative cells and endospores. However since such bacteria are classified in Risk Group 3 (very dangerous microorganism), Bacillus thuringiensis and Bacillus atrophaeus were used as simulants. In order to bind selectively the target bacilli, Phages properly selected were immobilized on an active commercially available SERS substrate (functionalization). The Phages are a type of virus that infect selectively, by means of receptors, specific bacteria. Moreover they can resist on water or air environments without losing their binding capabilities. The sensing surface was characterized by standard micro-Raman equipments to assess the background Raman features. The Raman measurements have been carried out from 10X to 100X of magnification to differentiate between average and local features. Moreover the fast response was acquired by limiting the measure time at less than 1 minute. Samples of vegetative cells and endospores of Bacilli were randomly dispersed on the functionalized SERS substrates. The results obtained are promising: samples with and without bacilli could be distinguished one from the other. This is a step toward the use of SERS as an effective and fast technique for early warning of biological threats.

  8. Trace detection of explosives and their precursors by surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Almaviva, S.; Botti, S.; Cantarini, L.; Palucci, A.; Puiu, A.; Rufoloni, A.; Landstrom, L.; Romolo, F. S.

    2012-10-01

    Surface Enhanced Raman Spectroscopy measurements on some common military explosives were performed with a table-top micro-Raman system integrated with a Serstech R785 minispectrometer. Serstech R785 is a miniaturised spectrometer suitable for Raman and NIR measurements. Integration of R785 in our table-top system aims to the realization of a portable SERS detector, able to perform in-situ measurements. SERS Spectra were obtained exciting the substance of interest with a 785 nm diode-laser, while these substances were deposited starting from commercial solutions on commercial SERS substrates, to improve the detection sensitivity. The amount of the sampled substance was determined through the analysis of images of the substrate covered with the residue of explosive. In fact, once the solvent is completely evaporated, the residue of explosive was observed to be uniformly distributed on the substrate surface. Images acquired with a Scanning Electron Microscope provided further details of the deposition process showing that a fraction of the active SERS sites are completely covered with the analyte while other sites appear to be empty; from the analysis of the images the sampled quantity was estimated to be about 200 pg. The main Raman features of each substance were clearly identified, the spectral resolution was sufficiently high to clearly distinguish spectra belonging to different substances.

  9. Ultrasensitive and selective homogeneous sandwich immunoassay detection by Surface Enhanced Raman Scattering (SERS).

    PubMed

    Pekdemir, Mustafa Ersin; Ertürkan, Deniz; Külah, Haluk; Boyacı, Ismail H; Ozgen, Canan; Tamer, Uğur

    2012-10-21

    In this report, a simple and highly selective homogeneous sandwich immunoassay was developed for ultrasensitive detection of Staphylococcal Enterotoxin B (SEB) using Surface Enhanced Raman Scattering (SERS). The assay uses polyclonal-antibody functionalized magnetic gold nanorod particles as capture probes for SEB, which can be collected via a simple magnet. After separating SEB from the sample matrix, they are sandwiched by using binding-specific antibody-antigen pairs with the help of gold nanorod particles. Gold nanorod particles are bifunctional by design and contain self-assembled monolayers (SAMs) of a SERS tag molecule (5,5-dithiobis (2-nitrobenzoic acid), DTNB) and carboxylic functionalities of DTNB for coupling with a suitable antibody. The correlation between the SEB concentration and SERS signal was found to be linear within the range of 3 fM to 0.3 μM. The limit of detection for the assay was determined to be 768 aM (ca., 9250 SEB molecules per 20 μL sample volume). The gold heterogeneous assay system for SEB detection was also compared with the same SERS probes and gold-coated surfaces as capture substrates. The developed method was further evaluated for detecting SEB in artificially contaminated milk. Finally, the method was used for investigating the SEB specificity on bovine serum albumin (BSA) and avidin.

  10. Identification of aqueous pollen extracts using surface enhanced Raman scattering (SERS) and pattern recognition methods.

    PubMed

    Seifert, Stephan; Merk, Virginia; Kneipp, Janina

    2016-01-01

    Aqueous pollen extracts of varying taxonomic relations were analyzed with surface enhanced Raman scattering (SERS) by using gold nanoparticles in aqueous suspensions as SERS substrate. This enables a selective vibrational characterization of the pollen water soluble fraction (mostly cellular components) devoid of the spectral contributions from the insoluble sporopollenin outer layer. The spectra of the pollen extracts are species-specific, and the chemical fingerprints can be exploited to achieve a classification that can distinguish between different species of the same genus. In the simple experimental procedure, several thousands of spectra per species are generated. Using an artificial neural network (ANN), it is demonstrated that analysis of the intrinsic biochemical information of the pollen cells in the SERS data enables the identification of pollen from different plant species at high accuracy. The ANN extracts the taxonomically-relevant information from the data in spite of high intra-species spectral variation caused by signal fluctuations and preparation specifics. The results show that SERS can be used for the reliable characterization and identification of pollen samples. They have implications for improved investigation of pollen physiology and for allergy warning.

  11. Capillary-driven surface-enhanced Raman scattering (SERS)-based microfluidic chip for abrin detection

    NASA Astrophysics Data System (ADS)

    Yang, Hao; Deng, Min; Ga, Shan; Chen, Shouhui; Kang, Lin; Wang, Junhong; Xin, Wenwen; Zhang, Tao; You, Zherong; An, Yuan; Wang, Jinglin; Cui, Daxiang

    2014-03-01

    Herein, we firstly demonstrate the design and the proof-of-concept use of a capillary-driven surface-enhanced Raman scattering (SERS)-based microfluidic chip for abrin detection. The micropillar array substrate was etched and coated with a gold film by microelectromechanical systems (MEMS) process to integrate into a lateral flow test strip. The detection of abrin solutions of various concentrations was performed by the as-prepared microfluidic chip. It was shown that the correlation between the abrin concentration and SERS signal was found to be linear within the range of 0.1 ng/mL to 1 μg/mL with a limit of detection of 0.1 ng/mL. Our microfluidic chip design enhanced the operability of SERS-based immunodiagnostic techniques, significantly reducing the complication and cost of preparation as compared to previous SERS-based works. Meanwhile, this design proved the superiority to conventional lateral flow test strips in respect of both sensitivity and quantitation and showed great potential in the diagnosis and treatment for abrin poisoning as well as on-site screening of abrin-spiked materials.

  12. Clinical instrumentation and applications of Raman spectroscopy.

    PubMed

    Pence, Isaac; Mahadevan-Jansen, Anita

    2016-04-07

    Clinical diagnostic devices provide new sources of information that give insight about the state of health which can then be used to manage patient care. These tools can be as simple as an otoscope to better visualize the ear canal or as complex as a wireless capsule endoscope to monitor the gastrointestinal tract. It is with tools such as these that medical practitioners can determine when a patient is healthy and to make an appropriate diagnosis when he/she is not. The goal of diagnostic medicine then is to efficiently determine the presence and cause of disease in order to provide the most appropriate intervention. The earliest form of medical diagnostics relied on the eye - direct visual observation of the interaction of light with the sample. This technique was espoused by Hippocrates in his 5th century BCE work Epidemics, in which the pallor of a patient's skin and the coloring of the bodily fluids could be indicative of health. In the last hundred years, medical diagnosis has moved from relying on visual inspection to relying on numerous technological tools that are based on various types of interaction of the sample with different types of energy - light, ultrasound, radio waves, X-rays etc. Modern advances in science and technology have depended on enhancing technologies for the detection of these interactions for improved visualization of human health. Optical methods have been focused on providing this information in the micron to millimeter scale while ultrasound, X-ray, and radio waves have been key in aiding in the millimeter to centimeter scale. While a few optical technologies have achieved the status of medical instruments, many remain in the research and development phase despite persistent efforts by many researchers in the translation of these methods for clinical care. Of these, Raman spectroscopy has been described as a sensitive method that can provide biochemical information about tissue state while maintaining the capability of delivering

  13. Clinical instrumentation and applications of Raman spectroscopy

    PubMed Central

    Pence, Isaac

    2016-01-01

    Clinical diagnostic devices provide new sources of information that give insight about the state of health which can then be used to manage patient care. These tools can be as simple as an otoscope to better visualize the ear canal or as complex as a wireless capsule endoscope to monitor the gastrointestinal tract. It is with tools such as these that medical practitioners can determine when a patient is healthy and to make an appropriate diagnosis when he/she is not. The goal of diagnostic medicine then is to efficiently determine the presence and cause of disease in order to provide the most appropriate intervention. The earliest form of medical diagnostics relied on the eye – direct visual observation of the interaction of light with the sample. This technique was espoused by Hippocrates in his 5th century BCE work Epidemics, in which the pallor of a patient’s skin and the coloring of the bodily fluids could be indicative of health. In the last hundred years, medical diagnosis has moved from relying on visual inspection to relying on numerous technological tools that are based on various types of interaction of the sample with different types of energy – light, ultrasound, radio waves, X-rays etc. Modern advances in science and technology have depended on enhancing technologies for the detection of these interactions for improved visualization of human health. Optical methods have been focused on providing this information in the micron to millimeter scale while ultrasound, X-ray, and radio waves have been key in aiding in the millimeter to centimeter scale. While a few optical technologies have achieved the status of medical instruments, many remain in the research and development phase despite persistent efforts by many researchers in the translation of these methods for clinical care. Of these, Raman spectroscopy has been described as a sensitive method that can provide biochemical information about tissue state while maintaining the capability of

  14. Geometry of GLP on silver surface by surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Bao, PeiDi; Bao, Lang; Huang, TianQuan; Liu, XinMing; Wu, GuoFeng

    2000-05-01

    Leptospirosis is one of the most harmful zoonosis, it is a serious public health issue in some area of Sichuan province. Surface-Enhance Raman Scattering (SERS) Spectroscopy is an effective approach for the study of biomolecular adsorption on metal surface and provides information about the adsorbed species. Two samples of Leptospiral Glycolipoprotein (GLP-1) and GLP-2 which have different toxic effects have been obtained and investigated.

  15. Isotopic hydrogen analysis via conventional and surface-enhanced fiber optic Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lascola, Robert; Zeigler, Kristine E.; McWhorter, C. Scott; Villa-Aleman, Eliel; Tovo, Laura L.; Ward, April E.

    2004-12-01

    This report describes laboratory development and process plant applications of Raman spectroscopy for detection of hydrogen isotopes in the Tritium Facilities at the Savannah River Site (SRS), a U.S. Department of Energy complex. Raman spectroscopy provides a lower-cost, in situ alternative to mass spectrometry techniques currently employed at SRS. Using conventional Raman and fiber optics, we have measured, in the production facility glove boxes, process mixtures of protium and deuterium at various compositions and total pressures ranging from 1000 - 4000 torr, with detection limits ranging from 1-2% for as low as 3-second integration times. We are currently investigating fabrication techniques for SERS surfaces in order to measure trace (0.01-0.1%) amounts of one isotope in the presence of the other. These efforts have concentrated on surfaces containing palladium, which promotes hydrogen dissociation and forms metal hydride bonds, essentially providing a chemical enhancement mechanism.

  16. Applications of spatially offset Raman spectroscopy to defense and security

    NASA Astrophysics Data System (ADS)

    Guicheteau, Jason; Hopkins, Rebecca

    2016-05-01

    Spatially offset Raman spectroscopy (SORS) allows for sub-surface and through barrier detection and has applications in drug analysis, cancer detection, forensic science, as well as defense and security. This paper reviews previous efforts in SORS and other through barrier Raman techniques and presents a discussion on current research in defense and security applications.

  17. Raman spectroscopy of CNC-and CNF-based nanocomposites

    Treesearch

    Umesh P. Agarwal

    2017-01-01

    In this chapter, applications of Raman spectroscopy to nanocelluloses and nanocellulose composites are reviewed, and it is shown how use of various techniques in Raman can provide unique information. Some of the most important uses consisted of identification of cellulose nanomaterials, estimation of cellulose crystallinity, study of dispersion of cellulose...

  18. Continuous gradient temperature Raman spectroscopy of unsaturated fatty acids

    USDA-ARS?s Scientific Manuscript database

    A new innovative technique gradient temperature, Raman spectroscopy (GTRS), identifies Raman frequency shifts in solid or liquid samples, and correlates them with specific temperature ranges within which flexible structures absorb heat. GTRS can easily detect changes that occur within one celcius te...

  19. IR, Raman and SERS spectral analysis and DFT calculations on the Herbicide O,S-Dimethyl phosphoramidothioate, metamidophos

    NASA Astrophysics Data System (ADS)

    Fleming, Guillermo Diaz; Villagrán, Joao; Koch, Rainer

    2013-10-01

    Infrared, Raman and SERS spectra of O,S-Dimethyl phosphoramidothioate, metamidophos, MAP, have been recorded. Density Functional Theory, DFT, with the B3LYP functional was used for the optimization of the ground state geometry and simulation of the infrared and Raman spectra of this molecule. Calculated geometrical parameters fit very well with the experimental ones. Combining the recorded data, the DFT results and a Normal Coordinate Analysis based on a scaled quantum mechanical (SQM) force field approach, a complete vibrational assignment was made for the first time. The comparison of SERS spectra obtained by using colloidal silver nanoparticles, with the corresponding Raman spectrum reveals enhancement and shifts in bands as well as information about the orientation of MAP on the nm-sized metal structures and the importance of the S atom on the SERS effect. DFT modelling of the SERS effect and Molecular Electrostatic Potentials (MEP) confirms the experimental information.

  20. Drop coating deposition Raman spectroscopy of proteinogenic amino acids compared with their solution and crystalline state

    NASA Astrophysics Data System (ADS)

    Pazderka, Tomáš; Kopecký, Vladimír

    2017-10-01

    The Raman spectra of 20 proteinogenic amino acids were recorded in the solution, glass phase (as drop coating deposition Raman (DCDR) samples) and crystalline forms in the wide spectral range of 200-3200 cm- 1. The most apparent spectral differences between the Raman spectra of the crystalline forms, glass phases and aqueous solutions of amino acids were briefly discussed and described in the frame of published works. The possible density dependencies of spectral bands were noted. In some cases, a strong influence of the sample density, as well as of the organization of the water envelope, was observed. The most apparent changes were observed for Ser and Thr. Nevertheless, for the majority of amino acids, the DCDR sample form is an intermediate between the solution and crystalline forms. In contrast, aromatic amino acids have only a small sensitivity to the form of the sample. Our reference set of Raman spectra is useful for revealing discrepancies between the SERS and solid/solution spectra of amino acids. We also found that some previously published Raman spectra of polycrystalline samples resemble glassy state rather than crystalline spectra. Therefore, this reference set of spectra will find application in every branch of Raman spectroscopy where the spectra of biomolecules are collected from coatings.

  1. Drop coating deposition Raman spectroscopy of proteinogenic amino acids compared with their solution and crystalline state.

    PubMed

    Pazderka, Tomáš; Kopecký, Vladimír

    2017-10-05

    The Raman spectra of 20 proteinogenic amino acids were recorded in the solution, glass phase (as drop coating deposition Raman (DCDR) samples) and crystalline forms in the wide spectral range of 200-3200cm(-1). The most apparent spectral differences between the Raman spectra of the crystalline forms, glass phases and aqueous solutions of amino acids were briefly discussed and described in the frame of published works. The possible density dependencies of spectral bands were noted. In some cases, a strong influence of the sample density, as well as of the organization of the water envelope, was observed. The most apparent changes were observed for Ser and Thr. Nevertheless, for the majority of amino acids, the DCDR sample form is an intermediate between the solution and crystalline forms. In contrast, aromatic amino acids have only a small sensitivity to the form of the sample. Our reference set of Raman spectra is useful for revealing discrepancies between the SERS and solid/solution spectra of amino acids. We also found that some previously published Raman spectra of polycrystalline samples resemble glassy state rather than crystalline spectra. Therefore, this reference set of spectra will find application in every branch of Raman spectroscopy where the spectra of biomolecules are collected from coatings. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. On-chip SERS analysis for single mimic pathogen detection using Raman-labeled nanoaggregate-embedded beads with a dielectrophoretic chip

    NASA Astrophysics Data System (ADS)

    Huang, Chen-Han; Lin, Hsing-Ying; Kuo, I.-Ting; Hsieh, Wen-Hsin; Huang, Ping-Ji; Yang, Tzyy-Schiuan; Chau, Lai-Kwan

    2012-02-01

    The integration of Raman-labeled nanoaggregate-embedded beads (NAEBs) for high performance SERS analysis of single mimic pathogen on a self-designed dielectrophoretic chip is demonstrated. The Raman tags called NAEBs are silica-coated, dye-induced aggregates of a small number of gold nanoparticles (AuNPs). In this work, NAEBs consisting of a Raman dye tetramethyl-rhodamine-5-isothiosyanate (TRITC) are chemically functionalized with streptavidin to detect biotin-functionalized polystyrene (PS) microspheres which mimic as pathogens. The sample solution of completely mixed streptavidin-functionalized NAEBs and biotin-functionalized PS microspheres is pumped into the microfluidic channel of a dielectrophoretic chip. By giving an AC voltage on the embedded electrodes, a single mimic pathogen can be caught via the non-contact dielectrophoretic force and suspended at the central cross of four aluminum electrodes for subsequent Raman spectroscopic detection. The SERS signal of TRITC is used as a spectral signature of specific mimic pathogen recognition, otherwise only the background Raman signal of a PS microsphere is observed. A pathogen-specific biosensor based on the dielectrophoresis-Raman spectroscopy system is developed, and the proof-ofconcept is confirmed by the specific molecular interaction model of streptavidin with biotin. Therefore, the on-chip multiplex SERS analysis of pathogens can be anticipated by employing different dye-tagged NAEBs simultaneously in a sample solution. We believe this bioassay has the ability to screen and detect multiple pathogens with minimal sample processing and handling even a small number of pathogens is present.

  3. Raman Spectroscopy for the Investigation of Carbon Based Black Pigments

    NASA Astrophysics Data System (ADS)

    Coccato, A.; Jehlicka, J.; Moens, L.; Vandenabeele, P.

    2014-06-01

    Carbon based black pigments play an important role among artists' materials. The disordered structure of these materials is investigated by means of Raman spectroscopy, which helps in the comprehension of their production processes.

  4. Characterization and noninvasive diagnosis of bladder cancer with serum surface enhanced Raman spectroscopy and genetic algorithms

    NASA Astrophysics Data System (ADS)

    Li, Shaoxin; Li, Linfang; Zeng, Qiuyao; Zhang, Yanjiao; Guo, Zhouyi; Liu, Zhiming; Jin, Mei; Su, Chengkang; Lin, Lin; Xu, Junfa; Liu, Songhao

    2015-05-01

    This study aims to characterize and classify serum surface-enhanced Raman spectroscopy (SERS) spectra between bladder cancer patients and normal volunteers by genetic algorithms (GAs) combined with linear discriminate analysis (LDA). Two group serum SERS spectra excited with nanoparticles are collected from healthy volunteers (n = 36) and bladder cancer patients (n = 55). Six diagnostic Raman bands in the regions of 481-486, 682-687, 1018-1034, 1313-1323, 1450-1459 and 1582-1587 cm-1 related to proteins, nucleic acids and lipids are picked out with the GAs and LDA. By the diagnostic models built with the identified six Raman bands, the improved diagnostic sensitivity of 90.9% and specificity of 100% were acquired for classifying bladder cancer patients from normal serum SERS spectra. The results are superior to the sensitivity of 74.6% and specificity of 97.2% obtained with principal component analysis by the same serum SERS spectra dataset. Receiver operating characteristic (ROC) curves further confirmed the efficiency of diagnostic algorithm based on GA-LDA technique. This exploratory work demonstrates that the serum SERS associated with GA-LDA technique has enormous potential to characterize and non-invasively detect bladder cancer through peripheral blood.

  5. Nanostructured organic semiconductor films for molecular detection with surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Yilmaz, Mehmet; Babur, Esra; Ozdemir, Mehmet; Gieseking, Rebecca L.; Dede, Yavuz; Tamer, Ugur; Schatz, George C.; Facchetti, Antonio; Usta, Hakan; Demirel, Gokhan

    2017-09-01

    π-Conjugated organic semiconductors have been explored in several optoelectronic devices, yet their use in molecular detection as surface-enhanced Raman spectroscopy (SERS)-active platforms is unknown. Herein, we demonstrate that SERS-active, superhydrophobic and ivy-like nanostructured films of a molecular semiconductor, α,ω-diperfluorohexylquaterthiophene (DFH-4T), can be easily fabricated by vapour deposition. DFH-4T films without any additional plasmonic layer exhibit unprecedented Raman signal enhancements up to 3.4 × 103 for the probe molecule methylene blue. The combination of quantum mechanical computations, comparative experiments with a fluorocarbon-free α,ω-dihexylquaterthiophene (DH-4T), and thin-film microstructural analysis demonstrates the fundamental roles of the π-conjugated core fluorocarbon substitution and the unique DFH-4T film morphology governing the SERS response. Furthermore, Raman signal enhancements up to ~1010 and sub-zeptomole (<10-21 mole) analyte detection were accomplished by coating the DFH-4T films with a thin gold layer. Our results offer important guidance for the molecular design of SERS-active organic semiconductors and easily fabricable SERS platforms for ultrasensitive trace analysis.

  6. Characterization and noninvasive diagnosis of bladder cancer with serum surface enhanced Raman spectroscopy and genetic algorithms.

    PubMed

    Li, Shaoxin; Li, Linfang; Zeng, Qiuyao; Zhang, Yanjiao; Guo, Zhouyi; Liu, Zhiming; Jin, Mei; Su, Chengkang; Lin, Lin; Xu, Junfa; Liu, Songhao

    2015-05-07

    This study aims to characterize and classify serum surface-enhanced Raman spectroscopy (SERS) spectra between bladder cancer patients and normal volunteers by genetic algorithms (GAs) combined with linear discriminate analysis (LDA). Two group serum SERS spectra excited with nanoparticles are collected from healthy volunteers (n = 36) and bladder cancer patients (n = 55). Six diagnostic Raman bands in the regions of 481-486, 682-687, 1018-1034, 1313-1323, 1450-1459 and 1582-1587 cm(-1) related to proteins, nucleic acids and lipids are picked out with the GAs and LDA. By the diagnostic models built with the identified six Raman bands, the improved diagnostic sensitivity of 90.9% and specificity of 100% were acquired for classifying bladder cancer patients from normal serum SERS spectra. The results are superior to the sensitivity of 74.6% and specificity of 97.2% obtained with principal component analysis by the same serum SERS spectra dataset. Receiver operating characteristic (ROC) curves further confirmed the efficiency of diagnostic algorithm based on GA-LDA technique. This exploratory work demonstrates that the serum SERS associated with GA-LDA technique has enormous potential to characterize and non-invasively detect bladder cancer through peripheral blood.

  7. Wavelength dependent resonance Raman band intensity of broadband stimulated Raman spectroscopy of malachite green in ethanol

    NASA Astrophysics Data System (ADS)

    Cen, Qiongyan; He, Yuhan; Xu, Mei; Wang, Jingjing; Wang, Zhaohui

    2015-03-01

    Resonance broadband stimulated Raman spectroscopy of malachite green in ethanol has been performed. With a tuning picosecond visible laser source and a broadband Raman probe, the Raman gain and loss spectra have been measured simultaneously. By scanning the Raman pump across the first absorption band of the molecule, we found that the resonant Raman bands could be only seen when the pump laser tuned in the range of the red edge of the S1←S0 transition. Dispersive lineshapes of resonant Raman bands have been observed in the Raman loss spectra, while the line shape is normal (same as spontaneous Raman) in the Raman gain spectra. Although, the resonant bands in the loss spectrum are usually stronger than that in the gain spectrum, the band intensities of both loss and gain linearly increase with the pump energy. The relative magnitude of each corresponding resonant band in the Raman loss and gain varies with the pump wavelength. Mode specified Raman excitation profiles have been obtained through broadband stimulated Raman measurement.

  8. Single Bacterium Detection Using Sers

    NASA Astrophysics Data System (ADS)

    Gonchukov, S. A.; Baikova, T. V.; Alushin, M. V.; Svistunova, T. S.; Minaeva, S. A.; Ionin, A. A.; Kudryashov, S. I.; Saraeva, I. N.; Zayarny, D. A.

    2016-02-01

    This work is devoted to the study of a single Staphylococcus aureus bacterium detection using surface-enhanced Raman spectroscopy (SERS) and resonant Raman spectroscopy (RS). It was shown that SERS allows increasing sensitivity of predominantly low frequency lines connected with the vibrations of Amide, Proteins and DNA. At the same time the lines of carotenoids inherent to this kind of bacterium are well-detected due to the resonance Raman scattering mechanism. The reproducibility and stability of Raman spectra strongly depend on the characteristics of nanostructured substrate, and molecular structure and size of the tested biological object.

  9. Research on identification and determination of mixed pesticides in apples using surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhai, Chen; Li, Yongyu; Peng, Yankun; Xu, Tianfeng; Dhakal, Sagar; Chao, Kuanglin; Qin, Jianwei

    2015-05-01

    Residual pesticides in fruits and vegetables have become one of the major food safety concerns around the world. At present, routine analytical methods used for the determination of pesticide residue on the surface of fruits and vegetables are destructive, complex, time-consuming, high cost and not environmentally friendly. In this study, a novel Surface Enhanced Raman Spectroscopy (SERS) method with silver colloid was developed for fast and sensitive nondestructive detection of residual pesticides in fruits and vegetables by using a self-developed Raman system. SERS technology is a combination of Raman spectroscopy and nanotechnology. SERS can greatly enhance the Raman signal intensity, achieve single-molecule detection, and has a simple sample pre-treatment characteristic of high sensitivity and no damage; in recent years it has begun to be used in food safety testing research. In this study a rapid and sensitive method was developed to identify and analyze mixed pesticides of chlorpyrifos, deltamethrin and acetamiprid in apple samples by SERS. Silver colloid was used for SERS measurement by hydroxylamine hydrochloride reduced. The advantages of this method are seen in its fast preparation at room temperature, good reproducibility and immediate applicability. Raman spectrum is highly interfered by noise signals and fluorescence background, which make it too complex to get good result. In this study the noise signals and fluorescence background were removed by Savitzky-Golay filter and min-max signal adaptive zooming method. Under optimal conditions, pesticide residues in apple samples can be detected by SERS at 0.005 μg/cm2 and 0.002 μg/cm2 for individual acetamiprid and thiram, respectively. When mixing the two pesticides at low concentrations, their characteristic peaks can still be identified from the SERS spectrum of the mixture. Based on the synthesized material and its application in SERS operation, the method represents an ultrasensitive SERS performance

  10. [Identification of B jade by Raman spectroscopy].

    PubMed

    Zu, En-dong; Chen, Da-peng; Zhang, Peng-xiang

    2003-02-01

    Raman spectroscopy has been found to be a useful tool for identification of bleached and polymer-impregnated jadeites (so-called B jade). The major advantage of this system over classical methods of gem testing is the non-destructive identification of inclusions in gemstones and the determination of organic fracture filling in jade. Fissures in jadeites have been filled with oils and various resins to enhance their clarity, such as paraffin wax, paraffin oil, AB glue and epoxy resins. They show different peaks depending on their chemical composition. The characteristic spectrum ranges from 1,200-1,700 cm-1 to 2,800-3,100 cm-1. The spectra of resins show that they all have four strongest peaks related with phenyl: two C-C stretching modes at 1,116 and 1,609 cm-1, respectively, one C-H stretching mode at 3,069 cm-1, and a in-plane C-H bending mode at 1,189 cm-1. In addition, other two -CH2, -CH3 stretching modes at 2,906 and 2,869 cm-1, respectively, are very similar to paraffin. Therefore, the peaks at 1,116, 1,609, 1,189 and 3,069 cm-1 are important in distinguishing resin from paraffin, and we can identify B jade depending on them.

  11. Spatially offset Raman spectroscopy based on a line-scan hyperspectral Raman system

    USDA-ARS?s Scientific Manuscript database

    Spatially offset Raman spectroscopy (SORS) is a technique that can obtain subsurface layered information by collecting Raman spectra from a series of surface positions laterally offset from the excitation laser. The current methods of SORS measurement are typically either slow due to mechanical move...

  12. Adsorption study of antibiotics on silver nanoparticle surfaces by surface-enhanced Raman scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Filgueiras, Aline Luciano; Paschoal, Diego; Dos Santos, Hélio F.; Sant'Ana, Antonio C.

    2015-02-01

    In this work the adsorption of the antibiotics levofloxacin (LV), tetracycline (TC) and benzylpenicillin (BP) on the surface of silver nanoparticles (AgNP) have been investigated through both surface-enhanced Raman scattering (SERS) and UV-VIS-NIR spectroscopies. The SERS spectra were obtained using 1064 nm exciting radiation. Theoretical models for the antibiotic molecules were obtained from DFT calculations, and used in the vibrational assignment. The adsorption geometries were proposed based on the changes in the spectral patterns. The LV compound adsorbs through carboxylate group, TC compound interacts with silver atoms through carbonyl from intermediate ring, and BP compound adsorbs by carbonyl moieties from carboxylate and acyclic amide.

  13. Approximate chemical analysis of volcanic glasses using Raman spectroscopy

    PubMed Central

    Morgavi, Daniele; Hess, Kai‐Uwe; Neuville, Daniel R.; Borovkov, Nikita; Perugini, Diego; Dingwell, Donald B.

    2015-01-01

    The effect of chemical composition on the Raman spectra of a series of natural calcalkaline silicate glasses has been quantified by performing electron microprobe analyses and obtaining Raman spectra on glassy filaments (~450 µm) derived from a magma mingling experiment. The results provide a robust compositionally‐dependent database for the Raman spectra of natural silicate glasses along the calcalkaline series. An empirical model based on both the acquired Raman spectra and an ideal mixing equation between calcalkaline basaltic and rhyolitic end‐members is constructed enabling the estimation of the chemical composition and degree of polymerization of silicate glasses using Raman spectra. The model is relatively insensitive to acquisition conditions and has been validated using the MPI‐DING geochemical standard glasses1 as well as further samples. The methods and model developed here offer several advantages compared with other analytical and spectroscopic methods such as infrared spectroscopy, X‐ray fluorescence spectroscopy, electron and ion microprobe analyses, inasmuch as Raman spectroscopy can be performed with a high spatial resolution (1 µm2) without the need for any sample preparation as a nondestructive technique. This study represents an advance in efforts to provide the first database of Raman spectra for natural silicate glasses and yields a new approach for the treatment of Raman spectra, which allows us to extract approximate information about the chemical composition of natural silicate glasses using Raman spectroscopy. We anticipate its application in handheld in situ terrestrial field studies of silicate glasses under extreme conditions (e.g. extraterrestrial and submarine environments). © 2015 The Authors Journal of Raman Spectroscopy Published by John Wiley & Sons Ltd PMID:27656038

  14. Surface enhanced Raman scattering (SERS) with biopolymer encapsulated silver nanosubstrates for rapid detection of foodborne pathogens.

    PubMed

    Sundaram, Jaya; Park, Bosoon; Kwon, Yongkuk; Lawrence, Kurt C

    2013-10-01

    A biopolymer encapsulated with silver nanoparticles was prepared using silver nitrate, polyvinyl alcohol (PVA) solution, and trisodium citrate. It was deposited on a mica sheet to use as SERS substrate. Fresh cultures of Salmonella Typhimurium, Escherichia coli, Staphylococcus aureus and Listeria innocua were washed from chicken rinse and suspended in 10 ml of sterile deionized water. Approximately 5 μl of the bacterial suspensions was placed on the substrate individually and exposed to 785 nm HeNe laser excitation. SERS spectral data were recorded over the Raman shift between 400 and 1800 cm(-1) from 15 different spots on the substrate for each sample; and three replicates were done on each bacteria type. Principal component analysis (PCA) model was developed to classify foodborne bacteria types. PC1 identified 96% of the variation among the given bacteria specimen, and PC2 identified 3%, resulted in a total of 99% classification accuracy. Soft Independent Modeling of Class Analogies (SIMCA) of validation set gave an overall correct classification of 97%. Comparison of the SERS spectra of different types of gram-negative and gram-positive bacteria indicated that all of them have similar cell walls and cell membrane structures. Conversely, major differences were noted around the nucleic acid and amino acid structure information between 1200 cm(-1) and 1700 cm(-1) and at the finger print region between 400 cm(-1) and 700 cm(-1). Silver biopolymer nanoparticle substrate could be a promising SERS tool for pathogen detection. Also this study indicates that SERS technology could be used for reliable and rapid detection and classification of food borne pathogens. Published by Elsevier B.V.

  15. Rapid monitoring of benzylpenicillin sodium using Raman and surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Jiang, Xin; Qin, Xiaoyu; Yin, Di; Gong, Mengdi; Yang, Libin; Zhao, Bing; Ruan, Weidong

    2015-04-01

    At present, fluorescence spectroscopy, ultraviolet spectroscopy and infrared spectroscopy are usually used to detect drug molecules, however the information about using Raman spectroscopy to detect drug molecules is very few. In this work normal Raman spectroscopy and surface-enhanced Raman spectroscopy were utilized to study benzylpenicillin sodium (NaBP). The results show that NaBP is close to the surface of silver substrate through the carboxyl group, and the detection limit of NaBP is reduced to 1 × 10-7 mol/L. Accordingly, the quantitative analysis of NaBP can be carried out in the range of 1 × 10-4-1 × 10-7 mol/L concentration. And it is proved that NaBP is not stable in acid and alkali conditions and the decomposition reaction is very complex.

  16. Rapid monitoring of benzylpenicillin sodium using Raman and surface enhanced Raman spectroscopy.

    PubMed

    Jiang, Xin; Qin, Xiaoyu; Yin, Di; Gong, Mengdi; Yang, Libin; Zhao, Bing; Ruan, Weidong

    2015-04-05

    At present, fluorescence spectroscopy, ultraviolet spectroscopy and infrared spectroscopy are usually used to detect drug molecules, however the information about using Raman spectroscopy to detect drug molecules is very few. In this work normal Raman spectroscopy and surface-enhanced Raman spectroscopy were utilized to study benzylpenicillin sodium (NaBP). The results show that NaBP is close to the surface of silver substrate through the carboxyl group, and the detection limit of NaBP is reduced to 1×10(-7) mol/L. Accordingly, the quantitative analysis of NaBP can be carried out in the range of 1×10(-4)-1×10(-7) mol/L concentration. And it is proved that NaBP is not stable in acid and alkali conditions and the decomposition reaction is very complex. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Raman and SERS study on atrazine, prometryn and simetryn triazine herbicides

    NASA Astrophysics Data System (ADS)

    Bonora, Sergio; Benassi, Enrico; Maris, Assimo; Tugnoli, Vitaliano; Ottani, Stefano; Di Foggia, Michele

    2013-05-01

    In the present study, we considered the Raman spectra of atrazine, prometryn and simetryn, in the solid form and in polar and apolar solvents, extending the investigation in the very diluted aqueous solutions (ppm) range by using the SERS technique. We performed theoretical calculations at the B3LYP/aug-cc-pVQZ level on the three triazines, alone and in solution with polar and apolar solvents. An excellent agreement between theoretical and experimental frequencies was reached, with differences lying within few wavenumbers. The small differences observed can be ascribed to the solid crystalline phase and can be caused by local deviations in the uniformity of the crystalline field or to a coupling with lattice vibrations. Also the theoretical and experimental peak intensities well agreed and in most cases lied within ±10%, the differences being ascribed to the local non-homogeneity of dielectric properties in the crystal. Moreover, this behavior confirmed the rigidity of the molecules and that their structure was not involved during the solution process. The theoretical SERS spectra at B3LYP/6-311+G(d,p) level of triazines bound to an Ag2 metal cluster offered an acceptable qualitative agreement with the experimental ones, suggesting that the stronger interaction site of triazines with Ag2 was on the less sterical hindered aromatic nitrogen atom, namely forming the N6⋯Ag2 molecular complex with atrazine, and the N2⋯Ag2 or N4⋯Ag2 molecular complexes with simetryn and prometryn. The agreement between calculated and experimental SERS spectra was not as good as that observed for the Raman spectra of pure compounds, but the trend of the theoretical spectra offered a useful guideline for the comprehension of the interaction sites and of the structural modification after adsorption on silver particles.

  18. Raman spectroscopy characterization of uranium hydride and deuteride

    NASA Astrophysics Data System (ADS)

    Zhang, Guangfeng; Wang, Xiaolin; Lv, Junbo

    2015-03-01

    Raman spectroscopy has been used to characterize uranium hydride and deuteride. Raman shifts of UH3 and UD3 are evident to be inversely proportional to the square root of the mass of hydrogen isotope. The typical Raman peaks of UH3 and UD3 can be characterized by the mass difference of hydrogen isotope for one another. In addition, Raman peaks of uranium hydride and deuteride are identified to be at 725 and 938 cm-1 for UH3 and 518 and 669 cm-1 for UD3, respectively.

  19. Determination of nanotubes properties by Raman spectroscopy.

    PubMed

    Jorio, A; Saito, R; Dresselhaus, G; Dresselhaus, M S

    2004-11-15

    The basic concepts and characteristics of Raman spectra from single-wall carbon nanotubes (SWNTs, both isolated and bundled) are presented. The physical properties of the SWNTs are introduced, followed by the conceptual framework and characteristics of their Raman spectra. Each Raman feature, namely the radial breathing mode, the tangential G band, combination modes and disorder-induced bands are discussed, addressing their physical origin, as well as their capability for characterizing SWNT properties.

  20. Ultra-broadband plasmonic super absorbers for universal surface enhanced Raman spectroscopy substrate (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Zhang, Nan; Liu, Kai; Song, Haomin; Zeng, Xie; Ji, Dengxin; Gan, Qiaoqiang

    2015-08-01

    Although Raman spectroscopy has been commercialized, low-cost and large-area surface enhanced Raman spectroscopy (SERS) substrates with localized enhanced field are heavily required. However, currently dominant manufacturing techniques are expensive and complicated for large-area fabrication. Furthermore, most SERS substrates can only be used for individual excitation wavelengths. In this work, we will report an ultra-broadband super absorbing metasurface to enhance SERS signals in a broadband region (i.e. from 450 nm to 1000 nm). The design consisting of an Ag ground plate, a SiO2 spacer, and a layer of Ag nanoparticles was fabricated using simple film deposition and thermal annealing techniques. A broadband absorption over 80% from 414 nm to 956 nm was obtained, resulting in localized field enhancement between adjacent nanoparticles. We employed this metasurface to test its broadband SERS signal by adsorbing 1,2-Bis(4-pyridyl)-ethylene (BPE) molecules on top of it. We employed 5 laser lines (i.e., 514, 532, 633, 671 and 785 nm) to excite the sample and observed fingerprint signature of BPE molecules under all 5 excitation wavelengths with the average enhancement factor up to 5.3×107. Therefore, the designed SERS substrate can work for almost "all" available excitation wavelengths over a broadband, which is particularly useful for sensing a broad spectrum of chemicals on the same chip.

  1. Spectroscopic characterization of sixteenth century panel painting references using Raman, surface-enhanced Raman spectroscopy and helium-Raman system for in situ analysis of Ibero-American Colonial paintings.

    PubMed

    García-Bucio, María Angélica; Casanova-González, Edgar; Ruvalcaba-Sil, José Luis; Arroyo-Lemus, Elsa; Mitrani-Viggiano, Alejandro

    2016-12-13

    Colonial panel paintings constitute an essential part of Latin-American cultural heritage. Their study is vital for understanding the manufacturing process, including its evolution in history, as well as its authorship, dating and other information significant to art history and conservation purposes. Raman spectroscopy supplies a non-destructive characterization tool, which can be implemented for in situ analysis, via portable equipment. Specific methodologies must be developed, comprising the elaboration of reference panel paintings using techniques and materials similar to those of the analysed period, as well as the determination of the best analysis conditions for different pigments and ground preparations. In order to do so, Raman spectroscopy at 532, 785 and 1064 nm, surface-enhanced Raman spectroscopy (SERS) and a helium-Raman system were applied to a panel painting reference, in combination with X-ray fluorescence analysis. We were able to establish the analysis conditions for a number of sixteenth century pigments and dyes, and other relevant components of panel paintings from this period, 1064 nm Raman and SERS being the most successful. The acquired spectra contain valuable specific information for their identification and they conform a very useful database that can be applied to the analysis of Ibero-American Colonial paintings.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'. © 2016 The Author(s).

  2. Spectroscopic characterization of sixteenth century panel painting references using Raman, surface-enhanced Raman spectroscopy and helium-Raman system for in situ analysis of Ibero-American Colonial paintings

    NASA Astrophysics Data System (ADS)

    García-Bucio, María Angélica; Casanova-González, Edgar; Ruvalcaba-Sil, José Luis; Arroyo-Lemus, Elsa; Mitrani-Viggiano, Alejandro

    2016-12-01

    Colonial panel paintings constitute an essential part of Latin-American cultural heritage. Their study is vital for understanding the manufacturing process, including its evolution in history, as well as its authorship, dating and other information significant to art history and conservation purposes. Raman spectroscopy supplies a non-destructive characterization tool, which can be implemented for in situ analysis, via portable equipment. Specific methodologies must be developed, comprising the elaboration of reference panel paintings using techniques and materials similar to those of the analysed period, as well as the determination of the best analysis conditions for different pigments and ground preparations. In order to do so, Raman spectroscopy at 532, 785 and 1064 nm, surface-enhanced Raman spectroscopy (SERS) and a helium-Raman system were applied to a panel painting reference, in combination with X-ray fluorescence analysis. We were able to establish the analysis conditions for a number of sixteenth century pigments and dyes, and other relevant components of panel paintings from this period, 1064 nm Raman and SERS being the most successful. The acquired spectra contain valuable specific information for their identification and they conform a very useful database that can be applied to the analysis of Ibero-American Colonial paintings. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

  3. Facing Challenges in Real-Life Application of Surface-Enhanced Raman Scattering (SERS): Design and Nanofabrication of SERS Substrates for Rapid Field Test of Food Contaminants.

    PubMed

    Shi, Ruyi; Liu, Xiangjiang; Ying, Yibin

    2017-09-18

    Surface-enhanced Raman scattering (SERS) is capable of detecting single molecule with high specificity and has become a promising technique for rapid chemical analysis of agricultural products and foods. With a deeper understanding of the SERS effect and advances in nanofabrication technology, SERS is now on the edge of going out of the laboratory and becoming a sophisticated analytical tool to fulfill various real-world tasks. This review focuses on the challenges that SERS has met in this progress, such as how to obtain a reliable SERS signal, improve the sensitivity and specificity in a complex sample matrix, develop simple and user-friendly practical sensing approach, reduce the running cost, etc. This review highlights the new thoughts on design and nanofabrication of SERS-active substrates for solving these challenges and introduces the recent advances of SERS applications in this area. We hope that our discussion will encourage more researches to address these challenges and eventually help to bring SERS technology out of the laboratory.

  4. [Quantitative Analysis of Dimethoate Pesticide Residues in Honey by Surface-Enhanced Raman Spectroscopy].

    PubMed

    Sun, Xu-dong; Dong, Xiao-ling

    2015-06-01

    The feasibility of a combination method of surface-enhanced Raman spectroscopy (SERS) technology and linear regression algorithm was investigated for rapid quantitative analysis of pesticide residues in honey. The total of 30 samples was applied in the experiment with dimethoate pesticide residues range from 1 ppm to 10 ppm. The samples were divided into calibration set (20) and prediction set (10). The substrate of Klarite with an inverted pyramidal structure was adopted for improvement of the relative intensity of the majority of Raman shift peaks. The comparative analysis was carried out between SERS spectra of dimethoate pesticide residues in honey samples and conventional Raman spectra of dimethoate standard sample. And four characteristic Raman shift peaks at the wavenumbers of 867, 1 065, 1 317 and 1 453 cm(-1) were found, which were related with the vibrational information of dimethoate molecule. The relationship was developed by linear regression algorithm between the intensity of Raman shift and the concentration of dimethoate pesticide residues. The 10 new samples in the prediction set were applied to evaluate the performance of the models. By comparison, the optimal model was obtained with the characteristic Raman shift peak of 867 cm(-1). The higher correlation coefficient of prediction of 0.984 and lower root mean square error of prediction of 0.663 ppm were obtained. The detection limit of this method was 2 ppm, which was close to the maximum levels of pesticide residue detection limits. Experimental results showed that it was feasible to rapidly analyze quantitative of pesticide residues in honey with the combination method of SERS technology and linear regression algorithm. Compared with the conventional method coupled with the suitable pretreatment, the combination method of SERS technology and linear regression method could analyze the dimethoate pesticide residues in honey, and it also provided an optional method for rapid quantitative analysis

  5. Micro-Raman spectroscopy for meat type detection

    NASA Astrophysics Data System (ADS)

    De Biasio, M.; Stampfer, P.; Leitner, R.; Huck, C. W.; Wiedemair, V.; Balthasar, D.

    2015-06-01

    The recent horse meat scandal in Europe increased the demand for optical sensors that can identify meat type. Micro-Raman spectroscopy is a promising technique for the discrimination of meat types. Here, we present micro-Raman measurements of chicken, pork, turkey, mutton, beef and horse meat test samples. The data was analyzed with different combinations of data normalization and classification approaches. Our results show that Raman spectroscopy can discriminate between different meat types. Red and white meat are easily discriminated, however a sophisticated chemometric model is required to discriminate species within these groups.

  6. On the Contribution of Raman Spectroscopy to Forensic Science

    NASA Astrophysics Data System (ADS)

    Buzzini, Patrick; Massonnet, Genevieve

    2010-08-01

    Raman spectroscopy has only recently sparked interest from forensic laboratories. The Raman technique has demonstrated important advantages such as its nondestructive nature, its fast analysis time, and especially the possibility of performing microscopical in situ analyses. In forensic applications, it is a versatile technique that covers a wide spectrum of substances such as trace evidence, illicit drugs and inks. An overview of the recent developments of Raman spectroscopy in forensic science will be discussed. Also, the requirements for an analytical technique for the examination of physical evidence will be described. Examples of casework will be depicted.

  7. Gaseous trace analysis using pulsed photoacoustic Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Siebert, D. R.; West, G. A.; Barrett, J. J.

    1980-01-01

    The paper describes a method for the trace analysis of gases, based on the pulsed photoacoustic Raman spectroscopy (PARS) technique. It is reported that the method has been applied to the analysis of mixtures of CH4 in N2, CO2 in N2, and N2O in N2 at concentrations near 1 ppm. Attention is given to the apparatus used and means of improving the method's sensitivity as well as sensitivity-limiting processes are evaluated. Finally, the analytical capabilities of this technique are compared with both direct (IR) absorption and other Raman techniques such as CARS and stimulated Raman gain spectroscopy (SRGS).

  8. Raman spectroscopy in the analysis of food and pharmaceutical nanomaterials.

    PubMed

    Li, Ying-Sing; Church, Jeffrey S

    2014-03-01

    Raman scattering is an inelastic phenomenon. Although its cross section is very small, recent advances in electronics, lasers, optics, and nanotechnology have made Raman spectroscopy suitable in many areas of application. The present article reviews the applications of Raman spectroscopy in food and drug analysis and inspection, including those associated with nanomaterials. Brief overviews of basic Raman scattering theory, instrumentation, and statistical data analysis are also given. With the advent of Raman enhancement mechanisms and the progress being made in metal nanomaterials and nanoscale metal surfaces fabrications, surface enhanced Raman scattering spectroscopy has become an extra sensitive method, which is applicable not only for analysis of foods and drugs, but also for intracellular and intercellular imaging. A Raman spectrometer coupled with a fiber optics probe has great potential in applications such as monitoring and quality control in industrial food processing, food safety in agricultural plant production, and convenient inspection of pharmaceutical products, even through different types of packing. A challenge for the routine application of surface enhanced Raman scattering for quantitative analysis is reproducibility. Success in this area can be approached with each or a combination of the following methods: (1) fabrication of nanostructurally regular and uniform substrates; (2) application of statistic data analysis; and (3) isotopic dilution.

  9. Raman Spectroscopy as an Accurate Probe of Defects in Graphene

    NASA Astrophysics Data System (ADS)

    Rodriguez-Nieva, Joaquin; Barros, Eduardo; Saito, Riichiro; Dresselhaus, Mildred

    2014-03-01

    Raman Spectroscopy has proved to be an invaluable non-destructive technique that allows us to obtain intrinsic information about graphene. Furthermore, defect-induced Raman features, namely the D and D' bands, have previously been used to assess the purity of graphitic samples. However, quantitative studies of the signatures of the different types of defects on the Raman spectra is still an open problem. Experimental results already suggest that the Raman intensity ratio ID /ID' may allow us to identify the nature of the defects. We study from a theoretical point of view the power and limitations of Raman spectroscopy in the study of defects in graphene. We derive an analytic model that describes the Double Resonance Raman process of disordered graphene samples, and which explicitly shows the role played by both the defect-dependent parameters as well as the experimentally-controlled variables. We compare our model with previous Raman experiments, and use it to guide new ways in which defects in graphene can be accurately probed with Raman spectroscopy. We acknowledge support from NSF grant DMR1004147.

  10. Study on nasopharyngeal cancer tissue using surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Ge, Xiaosong; Lin, Xueliang; Xu, Zhihong; Wei, Guoqiang; Huang, Wei; Lin, Duo

    2016-10-01

    Surface-enhanced Raman spectroscopy (SERS) can provide detailed molecular structure and composition information, and has demonstrated great potential in biomedical filed. This spectroscopy technology has become one of the most important optical techniques in the early diagnosis of cancer. Nasopharyngeal cancer (NPC) is a malignant neoplasm arising in the nasopharyngeal epithelial lining, which has relatively high incidence and death rate in Southeast Asia and southern China. This paper reviews the current progress of SERS in the field of cancer diagnostics, including gastric cancer, colorectal cancer, cervical cancer and nasopharyngeal cancer. In addition to above researches, we recently develop a novel NPC detection method based on tissue section using SERS, and obtain primary results. The proposed method has promising potential for the detection of nasopharyngeal carcinoma.

  11. Noninvasive noble metal nanoparticle arrays for surface-enhanced Raman spectroscopy of proteins

    NASA Astrophysics Data System (ADS)

    Inya-Agha, Obianuju; Forster, Robert J.; Keyes, Tia E.

    2007-02-01

    Noble metal nanoparticles arrays are well established substrates for surface enhanced Raman spectroscopy (SERS). Their ability to enhance optical fields is based on the interaction of their surface valence electrons with incident electromagnetic radiation. In the array configuration, noble metal nanoparticles have been used to produce SER spectral enhancements of up to 10 8 orders of magnitude, making them useful for the trace analysis of physiologically relevant analytes such as proteins and peptides. Electrostatic interactions between proteins and metal surfaces result in the preferential adsorption of positively charged protein domains onto metal surfaces. This preferential interaction has the effect of disrupting the native conformation of the protein fold, with a concomitant loss of protein function. A major historic advantage of Raman microspectroscopy has been is its non-invasive nature; protein denaturation on the metal surfaces required for SER spectroscopy renders it a much more invasive technique. Further, part of the analytical power of Raman spectroscopy lies in its use as a secondary conformation probe. The protein structural loss which occurs on the metal surface results in secondary conformation readings which are not true to the actual native state of the analyte. This work presents a method for chemical fabrication of noble metal SERS arrays with surface immobilized layers which can protect protein native conformation without excessively mitigating the electromagnetic enhancements of spectra. Peptide analytes are used as model systems for proteins. Raman spectra of alpha lactalbumin on surfaces and when immobilized on these novel arrays are compared. We discuss the ability of the surface layer to protect protein structure whilst improving signal intensity.

  12. Snapshot depth sensitive Raman spectroscopy in layered tissues.

    PubMed

    Liu, Wei; Ong, Yi Hong; Yu, Xiao Jun; Ju, Jian; Perlaki, Clint Michael; Liu, Lin Bo; Liu, Quan

    2016-12-12

    Depth sensitive Raman spectroscopy has been shown effective in the detection of depth dependent Raman spectra in layered tissues. However, the current techniques for depth sensitive Raman measurements based on fiber-optic probes suffer from poor depth resolution and significant variation in probe-sample contact. In contrast, those lens based techniques either require the change in objective-sample distance or suffer from slow spectral acquisition. We report a snapshot depth-sensitive Raman technique based on an axicon lens and a ring-to-line fiber assembly to simultaneously acquire Raman signals emitted from five different depths in the non-contact manner without moving any component. A numerical tool was developed to simulate ray tracing and optimize the snapshot depth sensitive setup to achieve the tradeoff between signal collection efficiency and depth resolution for Raman measurements in the skin. Moreover, the snapshot system was demonstrated to be able to acquire depth sensitive Raman spectra from not only transparent and turbid skin phantoms but also from ex vivo pork tissues and in vivo human thumbnails when the excitation laser power was limited to the maximum permissible exposure for human skin. The results suggest the great potential of snapshot depth sensitive Raman spectroscopy in the characterization of the skin and other layered tissues in the clinical setting or other similar applications such as quality monitoring of tablets and capsules in pharmaceutical industry requiring the rapid measurement of depth dependent Raman spectra.

  13. Surface-enhanced Raman spectroscopy and homeland security: a perfect match?

    PubMed

    Golightly, Rebecca S; Doering, William E; Natan, Michael J

    2009-10-27

    This Nano Focus article reviews recent developments in surface-enhanced Raman spectroscopy (SERS) and its application to homeland security. It is based on invited talks given at the "Nanorods and Microparticles for Homeland Security" symposium, which was organized by one of the authors and presented at the 238th ACS National Meeting and Exhibition in Washington, DC. The three-day symposium included approximately 25 experts from academia, industry, and national laboratories and included both SERS and non-SERS approaches to detection of chemical and biological substances relevant to homeland security, as well as fundamental advances. Here, we focus on SERS and how it is uniquely positioned to have an impact in a field whose importance is increasing rapidly. We describe some technical challenges that remain and offer a glimpse of what form solutions might take.

  14. Surface-enhanced Raman spectroscopy for differentiation between benign and malignant thyroid tissues

    NASA Astrophysics Data System (ADS)

    Li, Zuanfang; Li, Chao; Lin, Duo; Huang, Zufang; Pan, Jianji; Chen, Guannan; Lin, Juqiang; Liu, Nenrong; Yu, Yun; Feng, Shangyuan; Chen, Rong

    2014-04-01

    The aim of this study was to evaluate the potential of applying silver nano-particle based surface-enhanced Raman scattering (SERS) to discriminate different types of human thyroid tissues. SERS measurements were performed on three groups of tissue samples including thyroid cancers (n = 32), nodular goiters (n = 20) and normal thyroid tissues (n = 25). Tentative assignments of the measured tissue SERS spectra suggest interesting cancer specific biomolecular differences. The principal component analysis (PCA) and linear discriminate analysis (LDA) together with the leave-one-out, cross-validated technique yielded diagnostic sensitivities of 92%, 75% and 87.5%; and specificities of 82.6%, 89.4% and 84.4%, respectively, for differentiation among normal, nodular and malignant thyroid tissue samples. This work demonstrates that tissue SERS spectroscopy associated with multivariate analysis diagnostic algorithms has great potential for detection of thyroid cancer at the molecular level.

  15. Ag-modified silicon nanowires substrate for ultrasensitive surface-enhanced raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Shao, Ming-Wang; Zhang, Ming-Liang; Wong, Ning-Bew; Ma, Dorothy Duo-duo; Wang, Hui; Chen, Weiwei; Lee, Shuit-Tong

    2008-12-01

    We report a unique substrate for surface-enhanced raman spectroscopy (SERS) based on silver nanoparticles-embedded silicon nanowires (SiNWs). The SiNWs were prepared by thermal evaporation of SiO powder via oxide-assisted growth, oxide removed with HF, and then used to reduce silver ions to form a highly decorated Ag-embedded surface. Such modified SiNWs substrates yielded ultrahigh SERS sensitivity, which could detect 25μl of 1×10-16M Rhodamine 6G, 1×10-16M crystal violet, and 1×10-14M nicotine in methanol solutions. An Ag-modified SiNW strand could also enable SERS detection of 25μl of 1×10-8mg/ml calf thymus DNA. The possible mechanisms for the ultrahigh SERS sensitivity were discussed.

  16. Coherent anti-Stokes Raman spectroscopy: Understanding the essentials

    NASA Astrophysics Data System (ADS)

    Ariunbold, Gombojav O.; Altangerel, Narangerel

    2016-12-01

    This paper is a brief overview to coherent anti- Stokes Raman spectroscopic technique and introduces the strengths and barriers to its use all based on the interpretation of simple theoretical formulae. The use of the Gaussian ultrashort pulses is highlighted as a practical elucidatory reconstruction tool of coherent Raman spectra. The paper presents the integral formulae for coherent anti-Stokes and Stokes Raman scattering, and discusses the closed-form solutions, its complex error function, and the delay time formula for enhancement of the inferred pure coherent Raman spectra. As an example, the timeresolved coherent Stokes Raman scattering experimental observations are quantitatively elucidated.Understanding the essentials of coherent Raman spectroscopy, therefore, promotes the importance of a number of experiments including the ones utilizing a broadband excitation with a narrowband delayed probing for successful background suppression.

  17. Label-free surface-enhanced Raman spectroscopy for detection of colorectal cancer and precursor lesions using blood plasma.

    PubMed

    Feng, Shangyuan; Wang, Wenbo; Tai, Isabella T; Chen, Guannan; Chen, Rong; Zeng, Haishan

    2015-09-01

    Fecal based tests have limited diagnostic values in detecting adenomatous polyps, the precursor lesions to colorectal cancer (CRC). Surface enhanced Raman spectroscopy (SERS) using silver nanoparticles as substrate is a multiplexed analytical technique capable of detecting biomolecules with high sensitivity. This study utilizes SERS to analyze blood plasma for detecting both CRC and adenomatous polyps for the first time. Blood plasma samples are collected from healthy control subjects and patients diagnosed with adenomas and CRC. Using a real-time Raman system, SERS spectra for blood plasma samples are measured in 1 s. The collected SERS spectra are analyzed with partial least squares-discriminant analysis. Classification of normal versus CRC plus adenomatous polyps achieved diagnostic sensitivity of 86.4% and specificity of 80%. The results suggest that blood plasma SERS analysis could be a potential screening test to detect both CRC and adenomas.

  18. Label-free surface-enhanced Raman spectroscopy for detection of colorectal cancer and precursor lesions using blood plasma

    PubMed Central

    Feng, Shangyuan; Wang, Wenbo; Tai, Isabella T.; Chen, Guannan; Chen, Rong; Zeng, Haishan

    2015-01-01

    Fecal based tests have limited diagnostic values in detecting adenomatous polyps, the precursor lesions to colorectal cancer (CRC). Surface enhanced Raman spectroscopy (SERS) using silver nanoparticles as substrate is a multiplexed analytical technique capable of detecting biomolecules with high sensitivity. This study utilizes SERS to analyze blood plasma for detecting both CRC and adenomatous polyps for the first time. Blood plasma samples are collected from healthy control subjects and patients diagnosed with adenomas and CRC. Using a real-time Raman system, SERS spectra for blood plasma samples are measured in 1 s. The collected SERS spectra are analyzed with partial least squares-discriminant analysis. Classification of normal versus CRC plus adenomatous polyps achieved diagnostic sensitivity of 86.4% and specificity of 80%. The results suggest that blood plasma SERS analysis could be a potential screening test to detect both CRC and adenomas. PMID:26417518

  19. Gold/Silicon nanowire arrays modified by Gold nanosphere as the surface-enhanced Raman spectroscopy substrate

    NASA Astrophysics Data System (ADS)

    Zhou, Long; Li, Mingyu; Tang, Longhua; He, Jian-Jun

    2016-01-01

    Fabrication of gold coated silicon nanowires (AuSiNW) substrate is introduced in detail and A hybrid substrate is designed for surface-enhanced Raman spectroscopy (SERS). The SERS behaviors are discussed and compared by the detection of 4, 4’-Bipyridine. Gold nanoparicles is modified on the surface of AuSiNW to form the “hot gap”. Molecules captured in these “hot gap” can generate huge Raman signal. Double-fold enhancement of SERS signal has been achieved comparing with AuSiNW. The as-fabricated hybrid substrate exhibit high SERS sensitivity, long-term stability, and consistent reproducibility, highly potential for realizing a rapid, cost-effective, and label-free SERS-based biosensor.

  20. Use of Surface-Enhanced Raman Spectroscopy in Inorganic Syntheses for an Upper-Level Exploratory Lab

    ERIC Educational Resources Information Center

    Seney, Caryn S.; Yelverton, Joshua C.; Eanes, Sharon; Patel, Vikas; Riggs, Julia; Wright, Sarah; Bright, Robin M.

    2007-01-01

    An experiment is designed where students will be using both gold and silver nanoparticles to study the enhancement factors of organic molecules adsorbed to the surface of the nanoparticles during or after synthesis by using surface-enhanced Raman spectroscopy (SERS). The experiment has helped students learn about the theory and experimental…

  1. Use of Surface-Enhanced Raman Spectroscopy in Inorganic Syntheses for an Upper-Level Exploratory Lab

    ERIC Educational Resources Information Center

    Seney, Caryn S.; Yelverton, Joshua C.; Eanes, Sharon; Patel, Vikas; Riggs, Julia; Wright, Sarah; Bright, Robin M.

    2007-01-01

    An experiment is designed where students will be using both gold and silver nanoparticles to study the enhancement factors of organic molecules adsorbed to the surface of the nanoparticles during or after synthesis by using surface-enhanced Raman spectroscopy (SERS). The experiment has helped students learn about the theory and experimental…

  2. Applications of Raman spectroscopy in copper-CMP and in BEOL cleaning chemistries

    NASA Astrophysics Data System (ADS)

    Kondoju, Siddartha

    (<50 mum), continuous flow of the slurry, and dynamics of the film removal process pose a great challenge to the monitoring of slurry components between the pad and the wafer. The slurry constituents such as oxidants and corrosion inhibitors have unique signatures that can be detected using spectroscopic techniques. In this study Raman spectroscopy was used to detect and quantify chemical species such as hydroxylamine, benzotriazole and hydrogen peroxide in-situ. A more detailed study pertaining to the protonation of hydroxylamine with respect to the pH was also performed. Finally, surface enhanced Raman spectroscopy (SERS) was also investigated to improve the detection of pyridine and benzotriazole at low concentrations (<100 ppm).

  3. Raman and surface-enhanced Raman spectroscopy for renal condition monitoring

    NASA Astrophysics Data System (ADS)

    Li, Jingting; Li, Ming; Du, Yong; Santos, Greggy M.; Mohan, Chandra; Shih, Wei-Chuan

    2016-03-01

    Non- and minimally-invasive techniques can provide advantages in the monitoring and clinical diagnostics in renal diseases. Although renal biopsy may be useful in establishing diagnosis in several diseases, it is an invasive approach and impractical for longitudinal disease monitoring. To address this unmet need, we have developed two techniques based on Raman spectroscopy. First, we have investigated the potential of diagnosing and staging nephritis by analyzing kidney tissue Raman spectra using multivariate techniques. Secondly, we have developed a urine creatinine sensor based on surface-enhanced Raman spectroscopy with performance near commercial assays which require relatively laborious sample preparation and longer time.

  4. Non-invasive detection of nasopharyngeal carcinoma using saliva surface-enhanced Raman spectroscopy.

    PubMed

    Qiu, Sufang; Xu, Yuanji; Huang, Lingling; Zheng, Wei; Huang, Chaobin; Huang, Shaohua; Lin, Jinyong; Lin, Duo; Feng, Shangyuan; Chen, Rong; Pan, Jianji

    2016-01-01

    The present study evaluated the use of saliva surface-enhanced Raman spectroscopy (SERS) for the detection of non-invasive nasopharyngeal carcinoma (NPC). SERS measurements were taken from 62 saliva samples, of which 32 were from NPC patients and 30 from healthy volunteers. Notable biochemical Raman bands in the SERS spectra were tentatively assigned to various saliva components. The saliva SERS spectra obtained from the NPC patients and the healthy volunteers were also analyzed by multivariate statistical techniques based on principal component analysis and linear discriminant analysis (PCA-LDA). Significant differences were observed between the saliva SERS spectral intensities for NPC patients and healthy volunteers, particularly at 447, 496, 635, 729, 1134, 1270 and 1448 cm(-1), which primarily contained signals associated with proteins, nucleic acids, fatty acids, glycogen and collagen. The classification results based on the PCA-LDA method provided a relatively high diagnostic sensitivity of 86.7%, specificity of 81.3% and diagnostic accuracy of 83.9% for NPC identification. The results from the present study demonstrate that saliva SERS analysis used in conjunction with PCA-LDA diagnostic algorithms possesses a promising clinical application for the non-invasive detection of NPC.

  5. Surface-enhanced Raman spectroscopy in the structural studies of biomolecules: the state of the art

    NASA Astrophysics Data System (ADS)

    Nabiev, Igor R.; Sokolov, Konstantin V.; Efremov, R. G.; Chumanov, George D.

    1991-05-01

    It has been recently demonstrated'3 that very large (in some cases up to iOn) enhancement of Raman crosssection for molecules in the close vicinity of a metal surface results from superposition of two main mechanisms: electromagnetic and so-called molecular (or "chemical"). Enhancement of the local electromagnetic field near a "rough" metal surface induces the electromagnetic mechanism, while the "molecular" mechanism is connected with the appearance of new excited states for the molecule/metal complexes in the process of chemisorption. The techniques of surface-enhanced Raman (SER) and surface-enhanced resonance Raman (SERR) spectroscopy are based on these mechanisms and widely used in investigations ofbiological molecules.27 The three main questions of applicability of SERS and SERRS for resolving sophisticated problems in molecular biology, bioorganic and physical chemistry are the following: (i) What are the molecular mechanisms of interaction of the biomolecules with a metal surface in the experimental conditions typical of SERS appearance and is it possible to take measurements while preserving the native conformation of the molecule? (ii) What is the exact relationship between the Raman cross-section enhancement and the distance between the metal and the molecule? Is the mechanism for enhancement short-range or long-range and is it be possible to detect all normal vibrations of macromolecules or only vibrations of groups which directly contact the surface? (iii) What are the lowest concentrations for the detection of SER spectra of biomolecules in different experimental systems (electrodes, hydrosols, surfaces with regular roughness)? Is it possible to detect high-quality SER spectra of subpicogram amounts of different classes of biomolecules for successful competition with the traditional techniques in biotechnology and genetic engineering? This paper deals with applications of SERS to the study of membrane proteins and nucleic acids.

  6. Micro-Raman spectroscopy on oral tissues

    NASA Astrophysics Data System (ADS)

    Zenone, F.; Lepore, M.; Perna, G.; Carmone, P.; Riccio, R.; Gaeta, G. M.; Capozzi, V.

    2006-02-01

    Micro-Raman Spectroscopy (μ-RS) provides a unique tool in medicine for a not invasive and real time analysis of biological tissue for biopsy and "in vivo" investigation. Based on the evaluation of molecular vibration frequencies, the μ-RS is able to detect the main molecular bonds of protein constituents, as the C-H and C-C ones. Changes in frequency or in the relative intensity of the vibration modes revealed by μ-RS can be related to changes of chemical bond and of protein structure induced by pathology. The μ-RS has been performed on samples of oral tissue from informed patients, affected by pemphigus vulgaris (an oral pathology) in an advanced regression state. The biopsies were thin slices (about 1mm thick) with 6mm diameter. The sample was measured through a 170 μm thick cover-glass. The experimental set-up was mainly composed by a He-Ne laser and a monochromator equipped with a Peltier cell and with a grating of 1800 grooves/mm. The laser light was focused on the sample surface by means of a long focal length 50X optical objective. The main protein bonds are clearly detectable in the considered samples and this give important information on the integrity and on the state of tissue components (lipids and proteins), and consequently on the occurrence of pathology. The potential application of this method for in vivo analysis is an invaluable alternative to biopsy and pathological examinations for many medical application as screening diagnostic, therapy progress examination, and surgical support.

  7. Shell-isolated nanoparticle-enhanced Raman spectroscopy: principle and applications (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Li, Jian-Feng; Tian, Zhong-Qun

    2015-08-01

    Surface-enhanced Raman spectroscopy (SERS) is a powerful technique that yields fingerprint vibrational information with ultra-high sensitivity. However, only roughened Ag, Au and Cu surfaces can generate strong SERS effect. The lack of materials and morphology generality has severely limited the breadth of SERS practical applications on surface science, electrochemistry and catalysis. Shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) was therefore invented to break the long-standing limitation of SERS. In SHINERS, Au@SiO2 core-shell nanoparticles were rationally designed. The gold core acts as plasmonic antenna and encapsulated by an ultra-thin, uniform and pinhole-free silica shell, can provide high electromagnetic field to enhance the Raman signals of probed molecules. The inert silica shell acts as tunneling barrier prevents the core from interacting with the environment. SHINERS has already been applied to a number of challenging systems, such as hydrogen and CO on Pt(hkl) and Rh(hkl), which can't be realized by traditional SERS. Combining with electrochemical methods, we has investigated the adsorption processes of pyridine at the Au(hkl) single crystal/solution interface, and in-situ monitored the surface electro-oxidation at Au(hkl) electrodes. These pioneering studies demonstrate convincingly the ability of SHINERS in exploring correlations between structure and reactivity as well as in monitoring intermediates at the interfaces. SHINERS was also explored from semiconductor surface for industry, to living bacteria for life science, and to pesticide residue detection for food safety. The concept of shell-isolated nanoparticle-enhancement is being applied to other spectroscopies such as infrared absorption, sum frequency generation and fluorescence. Jian-Feng Li et al., Nature, 2010, 464, 392-395.

  8. Simultaneous rotational coherent anti-Stokes Raman spectroscopy and coherent Stokes Raman spectroscopy with arbitrary pump-Stokes spectral separation.

    PubMed

    Eckbreth, A C; Anderson, T J

    1986-08-01

    A new approach to pure rotational coherent anti-Stokes Raman spectroscopy (CARS) and coherent Stokes Raman spectroscopy (CSRS) is demonstrated in which the pump and broadband Stokes lasers that are mixed have a large and arbitrary spectral separation. In this method, the rotational Raman coherences are established by different frequency components within the single, broadband Stokes source. The narrow band then scatters from the excited coherences, producing CARS and CSRS simultaneously. We discuss phase matching for this new technique and its inherent advantages relative to pure rotational CARS as normally implemented.

  9. Boron nitride nanosheets as improved and reusable substrates for gold nanoparticles enabled surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Cai, Qiran; Li, Lu Hua; Yu, Yuanlie; Liu, Yun; Huang, Shaoming; Chen, Ying; Watanabe, Kenji; Taniguchi, Takashi

    Atomically thin boron nitride (BN) nanosheets have been found an excellent substrate for noble metal particles enabled surface enhanced Raman spectroscopy (SERS), thanks to their good adsorption of aromatic molecules, high thermal stability and weak Raman scattering. Faceted gold (Au) nanoparticles have been synthesized on BN nanosheets by a simple but controllable and reproducible sputtering and annealing method. The size and density of the Au particles can be controlled by sputtering time, current and annealing temperature etc. Under the same sputtering and annealing conditions, the Au particles on BN of different thicknesses show various sizes because the surface diffusion coefficients of Au depends on the thickness of BN. Intriguingly, decorated with similar morphology and distribution of Au particles, BN nanosheets exhibit better Raman enhancements than silicon substrate as well as bulk BN crystals. Additionally, BN nanosheets show no noticeable SERS signal and hence cause no interference to the Raman signal of analyte. The Au/BN substrates can be reused by heating in air to remove adsorbed analyte without loss of SERS enhancement.

  10. Boron nitride nanosheets as improved and reusable substrates for gold nanoparticles enabled surface enhanced Raman spectroscopy.

    PubMed

    Cai, Qiran; Li, Lu Hua; Yu, Yuanlie; Liu, Yun; Huang, Shaoming; Chen, Ying; Watanabe, Kenji; Taniguchi, Takashi

    2015-03-28

    Atomically thin boron nitride (BN) nanosheets have been found to be excellent substrates for noble metal particles enabled surface enhanced Raman spectroscopy (SERS), thanks to their good adsorption of aromatic molecules, high thermal stability and weak Raman scattering. Faceted gold (Au) nanoparticles have been synthesized on BN nanosheets using a simple but controllable and reproducible sputtering and annealing method. The size and density of the Au particles can be controlled by sputtering time, current and annealing temperature etc. Under the same sputtering and annealing conditions, the Au particles on BN of different thicknesses show various sizes because the surface diffusion coefficients of Au depend on the thickness of BN. Intriguingly, decorated with similar morphology and distribution of Au particles, BN nanosheets exhibit better Raman enhancements than silicon substrates as well as bulk BN crystals. Additionally, BN nanosheets show no noticeable SERS signal and hence cause no interference to the Raman signal of the analyte. The Au/BN substrates can be reused by heating in air to remove the adsorbed analyte without loss of SERS enhancement.

  11. Detection of liver cancer tissue using silver nanoparticles-based surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lin, Juqiang; Liao, Fadian; Ruan, Qiuyong; Zeng, Yongyi; Li, Ling; Huang, Zufang; Lu, Peng; Chen, Rong

    2014-11-01

    Early detection of hepatocellular carcinoma is difficult due to the absence of recognizable physical symptoms. In this study, Raman spectra of liver normal tissues and hepatocellular carcinoma tissues were measured by using silver nanoparticles based surface enhanced Raman spectroscopy (SERS), respectively. The mean Raman spectra of two groups are roughly similar. But the peaks intensity of hepatocellular carcinoma tissues at 722 cm-1 and 1049 cm-1 are obviously higher than those of normal tissues. Some peaks of hepatocellular carcinoma tissues have shifted by different degree. Besides, Raman peaks at 1004cm-1 had disappeared in normal tissue. The result suggested that SERS spectra can feature liver normal tissue and hepatocellular carcinoma tissue. Principal component analysis (PCA) coupled with linear discriminant analysis (LDA) was performed on the measured spectra. There were three most diagnostically significant PCs (PC3, PC9, and PC15, p<0.05) for discriminating these two groups. The diagnostic sensitivity and specificity both were 84.6%. The whole analysis of each sample needs less time-consumed and cost than other traditional methods in detecting and diagnosing HCC. The preliminary result suggests that SERS spectra can be a potential medical technology to detect and diagnose HCC.

  12. Time-dependent picture of the charge-transfer contributions to surface enhanced Raman spectroscopy.

    PubMed

    Lombardi, John R; Birke, Ronald L

    2007-06-28

    We reexamine the Herzberg-Teller theory of charge-transfer contributions to the theory of surface enhanced Raman scattering (SERS). In previous work, the Kramers-Heisenberg-Dirac framework was utilized to explain many of the observed features in SERS. However, recent experimental and theoretical developments suggest that we revise the theory to take advantage of the time-dependent picture of Raman scattering. Results are obtained for molecular adsorption on nanoparticles in both the strong confinement limit and the weak confinement limit. We show that the Herzberg-Teller contributions to the charge-transfer effect in SERS display a resonance at the molecule-to-metal or metal-to-molecule transition while retaining the selection rules associated with normal Raman spectroscopy (i.e., harmonic oscillator, as opposed to Franck-Condon overlaps). The charge-transfer contribution to the enhancement factor scales as Gamma(-4), where Gamma is the homogeneous linewidth of the charge-transfer transition, and thus is extremely sensitive to the magnitude of this parameter. We show that the Herzberg-Teller coupling term may be associated with the polaron-coupling constant of the surface phonon-electron interaction. A time-dependent expression for the Raman amplitude is developed, and we discuss the implications of these results for both metal and semiconductor nanoparticle surfaces.

  13. Mode-dependent dispersion in Raman line shapes: Observation and implications from ultrafast Raman loss spectroscopy

    SciTech Connect

    Umapathy, S.; Mallick, B.; Lakshmanna, A.

    2010-07-14

    Ultrafast Raman loss spectroscopy (URLS) enables one to obtain the vibrational structural information of molecular systems including fluorescent materials. URLS, a nonlinear process analog to stimulated Raman gain, involves a narrow bandwidth picosecond Raman pump pulse and a femtosecond broadband white light continuum. Under nonresonant condition, the Raman response appears as a negative (loss) signal, whereas, on resonance with the electronic transition the line shape changes from a negative to a positive through a dispersive form. The intensities observed and thus, the Franck-Condon activity (coordinate dependent), are sensitive to the wavelength of the white light corresponding to a particular Raman frequency with respect to the Raman pump pulse wavelength, i.e., there is a mode-dependent response in URLS.

  14. Raman spectroscopy for planetary exploration and characterization of extraterrestrial materials

    NASA Astrophysics Data System (ADS)

    Acosta-Maeda, Tayro E.

    The sharp spectral features of Raman spectra are widely recognized to provide unequivocal and accurate chemical characterization of organic and inorganic compounds. Therefore Raman spectroscopy can be used to detect minerals, water bearing minerals, organic and biological materials and biomarkers in the context of planetary science. This dissertation extends the applicability of the Raman technique both laboratory based micro-Raman and remote Raman sensing ahead of planetary exploration missions to Mars employing Raman spectrometers. The interpretation of Raman imaging from a meteorite taken with a micro-Raman system revealed a close correlation between the blue color in natural ringwoodite and a new observed Raman peak that shows strong resonance Raman enhancement. The data suggest that ringwoodite exists both in the spinel structure and in the partially inverse spinel structure. In the field of remote Raman, this dissertation provides carefully derived Raman cross-section values for various organic liquids and inorganic polyatomic ions in aqueous solutions that will be useful for estimating detection capabilities of 532 nm excitation remote Raman systems for planetary exploration. Suitability of remote 532 nm Raman systems for future applications is explored. A portable, compact time-resolved instrument using a 3-inch diameter telescope is used it to demonstrate daytime detection of amino acids and nucleobases from a distance of 8 m. The measurements with a larger 8-inch Raman system demonstrate that it is possible to acquire good quality Raman spectra of various materials from a 430 meter remote distance during daylight with detection times of 10 seconds, and in some cases as short as 1 second, during daylight and in a realistic outdoor context. To my knowledge, these are the only remote Raman spectra at this distance that provide unambiguous detection of compounds important for planetary science, such as water and water ice, dry ice, sulfur, sulfates, various

  15. Aggregation of nanoparticles in endosomes and lysosomes produces surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lucas, Leanne J.; Chen, Xiaoke K.; Smith, Aaron J.; Korbelik, Mladen; Zeng, Haishan; Lee, Patrick W. K.; Hewitt, Kevin Cecil

    2015-01-01

    The purpose of this study was to explore the use of 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) were incubated with cells (106 per mL) of the A431 human epidermoid carcinoma and normal human bronchial epithelial cell lines. Using the 632.8-nm excitation line of a He-Ne laser, Raman spectroscopy measurements were performed using a point mapping scheme. Normal cells show little to no enhancement. SERS signals were observed inside the cytoplasm of A431 cells with an overall enhancement of 4 to 7 orders of magnitude. Raman intensity maps of the 1450 and 1583 cm-1 peaks correlate well with the expected distribution of EGFR and AuNPs, aggregated following uptake by endosomes and lysosomes. Spectral features from tyrosine and tryptophan residues dominate the SERS signals.

  16. Application of Raman spectroscopy technology to studying Sudan I

    NASA Astrophysics Data System (ADS)

    Li, Gang; Zhang, Guoping; Chen, Chen

    2006-06-01

    Being an industrial dye, the Sudan I may have a toxic effect after oral intake on the body, and has recently been shown to cause cancer in rats, mice and rabbits. Because China and some other countries have detected the Sudan I in samples of the hot chilli powder and the chilli products, it is necessary to study the characteristics of this dye. As one kind of molecule scattering spectroscopy, Raman spectroscopy is characterized by the frequency excursion caused by interactions of molecules and photons. The frequency excursion reflects the margin between certain two vibrational or rotational energy states, and shows the information of the molecule. Because Raman spectroscopy can provides quick, easy, reproducible, and non-destructive analysis, both qualitative and quantitative, with no sample preparation required, Raman spectroscopy has been a particularly promising technique for analyzing the characteristics and structures of molecules, especially organic ones. Now, it has a broad application in biological, chemical, environmental and industrial applications. This paper firstly introduces Sudan I dye and the Raman spectroscopy technology, and then describes its application to the Sudan I. Secondly, the fingerprint spectra of the Sudan I are respectively assigned and analyzed in detail. Finally, the conclusion that the Raman spectroscopy technology is a powerful tool to determine the Sudan I is drawn.

  17. Broadband coherent anti-Stokes Raman spectroscopy characterization of polymer thin films.

    PubMed

    Schultz, Zachary D; Gurau, Marc C; Richter, Lee J

    2006-10-01

    Broadband coherent anti-Stokes Raman spectroscopy (CARS) is demonstrated as an effective probe of polymer thin film materials. A simple modification to a 1 kHz broad bandwidth sum frequency generation (SFG) spectrometer permits acquisition of CARS spectra for polymer thin films less than 100 nm thick, a dimension relevant to organic electronic device applications. CARS spectra are compared to the conventional Raman spectra of polystyrene and the resonance-enhanced Raman spectra of poly(3-hexylthiophene). The CARS spectra obtained under these conditions consistently demonstrate enhanced signal-to-noise ratio compared to the spontaneous Raman scattering. The sensitivity of the CARS measurement is limited by the damage threshold of the samples. The dielectic properties of the substrate have a dramatic effect on the detected signal intensity. For ultrathin films, the strongest signals are obtained from fused silica surfaces. Similar to surface-enhanced Raman scattering (SERS), Au also gives a large signal, but contrary to SERS, no surface roughening is necessary.

  18. Recent Progress in SERS Biosensing

    PubMed Central

    Bantz, Kyle C.; Meyer, Audrey F.; Wittenberg, Nathan J.; Im, Hyungsoon; Kurtuluş, Özge; Lee, Si Hoon; Lindquist, Nathan C.

    2011-01-01

    This perspective gives an overview of recent developments in surface-enhanced Raman scattering (SERS) for biosensing. We focus this review on SERS papers published in the last 10 years and to specific applications of detecting biological analytes. Both intrinsic and extrinsic SERS biosensing schemes have been employed to detect and identify small molecules, nucleic acids, lipids, peptides, and proteins, as well as for in vivo and cellular sensing. Current SERS substrate technologies along with a series of advancements in surface chemistry, sample preparation, intrinsic/extrinsic signal transduction schemes, and tip-enhanced Raman spectroscopy are discussed. The progress covered herein shows great promise for widespread adoption of SERS biosensing. PMID:21509385

  19. Distinction of gastric cancer tissue based on surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Ma, Jun; Zhou, Hanjing; Gong, Longjing; Liu, Shu; Zhou, Zhenghua; Mao, Weizheng; Zheng, Rong-er

    2012-12-01

    Gastric cancer is one of the most common malignant tumors with high recurrence rate and mortality rate in China. This study aimed to evaluate the diagnostic capability of Surface-enhanced Raman spectroscopy (SERS) based on gold colloids for distinguishing gastric tissues. Gold colloids were directly mixed with the supernatant of homogenized tissues to heighten the Raman signal of various biomolecule. A total of 56 samples were collected from normal (30) and cancer (26). Raman spectra were obtained with a 785nm excitation in the range of 600-1800 cm-1. Significant spectral differences in SERS mainly belong to nucleic acid, proteins and lipids, particularly in the range of 653, 726, 828, 963, 1004, 1032, 1088, 1130, 1243, 1369, 1474, 1596, 1723 cm-1. PCA-LDA algorithms with leave-one-patient-out cross validation yielded diagnostic sensitivities of 90% (27/30), specificities of 88.5% (23/26), and accuracy of 89.3% (50/56), for classification of normal and cancer tissues. The receiver operating characteristic (ROC) surface is 0.917, illustrating the diagnostic utility of SERS together with PCA-LDA to identify gastric cancer from normal tissue. This work demonstrated the SERS techniques can be useful for gastric cancer detection, and it is also a potential technique for accurately identifying cancerous tumor, which is of considerable clinical importance to real-time diagnosis.

  20. Shining light on neurosurgery diagnostics using Raman spectroscopy.

    PubMed

    Broadbent, Brandy; Tseng, James; Kast, Rachel; Noh, Thomas; Brusatori, Michelle; Kalkanis, Steven N; Auner, Gregory W

    2016-10-01

    Surgical excision of brain tumors provides a means of cytoreduction and diagnosis while minimizing neurologic deficit and improving overall survival. Despite advances in functional and three-dimensional stereotactic navigation and intraoperative magnetic resonance imaging, delineating tissue in real time with physiological confirmation is challenging. Raman spectroscopy is a promising investigative and diagnostic tool for neurosurgery, which provides rapid, non-destructive molecular characterization in vivo or in vitro for biopsy, margin assessment, or laboratory uses. The Raman Effect occurs when light temporarily changes a bond's polarizability, causing change in the vibrational frequency, with a corresponding change in energy/wavelength of the scattered photon. The recorded inelastic scattering results in a "fingerprint" or Raman spectrum of the constituent under investigation. The amount, location, and intensity of peaks in the fingerprint vary based on the amount of vibrational bonds in a molecule and their ensemble interactions with each other. Distinct differences between various pathologic conditions are shown as different intensities of the same peak, or shifting of a peak based on the binding conformation. Raman spectroscopy has potential for integration into clinical practice, particularly in distinguishing normal and diseased tissue as an adjunct to standard pathologic diagnosis. Further, development of fiber-optic Raman probes that fit through the instrument port of a standard endoscope now allows researchers and clinicians to utilize spectroscopic information for evaluation of in vivo tissue. This review highlights the need for such an instrument, summarizes neurosurgical Raman work performed to date, and discusses the future applications of neurosurgical Raman spectroscopy.

  1. Resonance Raman spectroscopy study of protonated porphyrin

    NASA Astrophysics Data System (ADS)

    Gorski, A.; Starukhin, A.; Stavrov, S.; Gawinkowski, S.; Waluk, J.

    2017-02-01

    Resonance Raman microscopy was used to study the resonance Raman scattering of the diacid (diprotonated form) of free-base porphyrin (21H,23H-porphine) in a crystal powder and KBr pellets. Intensive lines in the spectral range between 100 ÷ 1000 cm- 1 have been detected and assigned as spectral manifestation of out-of-plane modes. The Raman spectra were simulated by means of DFT methods and compared with the experimental data. It is evident from experimental and theoretical results that the activation of out-of-plane modes arises from saddle distortion of the porphyrin macrocycle upon formation of its diprotonated form.

  2. Approximate chemical analysis of volcanic glasses using Raman spectroscopy.

    PubMed

    Di Genova, Danilo; Morgavi, Daniele; Hess, Kai-Uwe; Neuville, Daniel R; Borovkov, Nikita; Perugini, Diego; Dingwell, Donald B

    2015-12-01

    The effect of chemical composition on the Raman spectra of a series of natural calcalkaline silicate glasses has been quantified by performing electron microprobe analyses and obtaining Raman spectra on glassy filaments (~450 µm) derived from a magma mingling experiment. The results provide a robust compositionally-dependent database for the Raman spectra of natural silicate glasses along the calcalkaline series. An empirical model based on both the acquired Raman spectra and an ideal mixing equation between calcalkaline basaltic and rhyolitic end-members is constructed enabling the estimation of the chemical composition and degree of polymerization of silicate glasses using Raman spectra. The model is relatively insensitive to acquisition conditions and has been validated using the MPI-DING geochemical standard glasses1 as well as further samples. The methods and model developed here offer several advantages compared with other analytical and spectroscopic methods such as infrared spectroscopy, X-ray fluorescence spectroscopy, electron and ion microprobe analyses, inasmuch as Raman spectroscopy can be performed with a high spatial resolution (1 µm(2)) without the need for any sample preparation as a nondestructive technique. This study represents an advance in efforts to provide the first database of Raman spectra for natural silicate glasses and yields a new approach for the treatment of Raman spectra, which allows us to extract approximate information about the chemical composition of natural silicate glasses using Raman spectroscopy. We anticipate its application in handheld in situ terrestrial field studies of silicate glasses under extreme conditions (e.g. extraterrestrial and submarine environments).

  3. Raman and surface enhanced Raman spectroscopic investigation on Lamiaceae plants

    NASA Astrophysics Data System (ADS)

    Rösch, P.; Popp, J.; Kiefer, W.

    1999-05-01

    The essential oils of Thymus vulgaris and Origanum vulgaris are studied by means of micro-Raman spectroscopy. The containing monoterpenes can be identified by their Raman spectra. Further the essential oils are investigated in their natural environment, the so-called oil cells of these Lamiaceae plants, with surface enhanced Raman spectroscopy (SERS). This method has the advantage to enhance Raman signals and furthermore the SERS effect leads to fluorescence quenching.

  4. PCR-free Quantification of Multiple Splice Variants in Cancer Gene by Surface Enhanced Raman Spectroscopy

    PubMed Central

    Sun, Lan; Irudayaraj, Joseph

    2009-01-01

    We demonstrate a surface enhanced Raman spectroscopy (SERS) based array platform to monitor gene expression in cancer cells in a multiplex and quantitative format without amplification steps. A strategy comprising of DNA/RNA hybridization, S1 nuclease digestion, and alkaline hydrolysis was adopted to obtain DNA targets specific to two splice junction variants Δ(9, 10) and Δ(5) of the breast cancer susceptibility gene 1 (BRCA1) from MCF-7 and MDA-MB-231 breast cancer cell lines. These two targets were identified simultaneously and their absolute quantities were estimated by a SERS strategy utilizing the inherent plasmon-phonon Raman mode of gold nanoparticle probes as a self-referencing standard to correct for variability in surface enhancement. Results were then validated by reverse transcription PCR (RT-PCR). Our proposed methodology could be expanded to a higher level of multiplexing for quantitative gene expression analysis of any gene without any amplification steps. PMID:19780515

  5. Surface enhanced Raman spectroscopy substrates with advanced spectral sensitivity prepared from five years old silver nanoplatelets

    NASA Astrophysics Data System (ADS)

    Semenova, Anna A.; Goodilin, Eugene A.

    A new simple approach is suggested to prepare surface enhanced Raman spectroscopy (SERS) substrates with high effectiveness for various laser excitation wavelengths and analytes with different light absorption features by impregnation of porous cellulose materials by a mixture of silver nanoplatelets with a wide range of sizes and anisotropy. The suggested route provides a much better spectral sensitivity and flexible applications since SERS as a phenomenon is essential on the nanometer scale only. The mixing provides always a proper fraction of silver nanoparticles deposited onto the substrate thus guaranteeing the enhancement of Raman signals under given excitation conditions for a wider set of given analytes. The substrates were successfully prepared for the first time from silver nanoplatelets aged for five years. This confirms high chemical and morphological stability of stabilized silver nanoparticles and the ability to use them as precursors for application - ready materials.

  6. Surface-enhanced Raman spectroscopy on a surface plasmon resonance biosensor platform for gene diagnostics

    NASA Astrophysics Data System (ADS)

    Yuan, W.; Ho, H. P.; Suen, Y. K.; Kong, S. K.; Lin, Chinlon; Prasad, Paras N.; Li, J.; Ong, Daniel H. C.

    2008-02-01

    We propose to integrate the surface-enhanced Raman spectroscopy (SERS) detection capability with a surface plasmon resonance (SPR) biosensor platform. As a demonstration setup, the experimental scheme is built from a Total Internal Reflection Fluorescence (TIRF) microscope. The sample surface is a gold-coated plasmonic crystal substrate. Two oligonucleotide (ODN) probes that have been labeled with two different Raman active dyes are used to achieve a sandwich assay of target ODNs or polynucleotide. Upon complementary hybridizations between the target and probe ODNs, the target can be identified by detecting the narrow-band spectroscopic fingerprints of the Raman tags. This concept has high potential for achieving multiplexed detection of ODN targets because a very large number of probes can be incorporated to the plasmonic crystal substrate, which may find applications in gene based diseases diagnostics. We also explored the detection of single molecules and achieved some preliminary results.

  7. Unveiling NIR Aza-Boron-Dipyrromethene (BODIPY) Dyes as Raman Probes: Surface-Enhanced Raman Scattering (SERS)-Guided Selective Detection and Imaging of Human Cancer Cells.

    PubMed

    Adarsh, Nagappanpillai; Ramya, Adukkadan N; Maiti, Kaustabh Kumar; Ramaiah, Danaboyina

    2017-08-10

    The development of new Raman reporters has attracted immense attention in diagnostic research based on surface enhanced Raman scattering (SERS) techniques, which is a well established method for ultrasensitive detection through molecular fingerprinting and imaging. Herein, for the first time, we report the unique and efficient Raman active features of the selected aza-BODIPY dyes 1-6. These distinctive attributes could be extended at the molecular level to allow detection through SERS upon adsorption onto nano-roughened gold surface. Among the newly revealed Raman reporters, the amino substituted derivative 4 showed high signal intensity at very low concentrations (ca. 0.4 μm for 4-Au). Interestingly, an efficient nanoprobe has been constructed by using gold nanoparticles as SERS substrate, and 4 as the Raman reporter (4-Au@PEG), which unexpectedly showed efficient recognition of three human cancer cells (lung: A549, cervical: HeLa, Fibrosarcoma: HT-1080) without any specific surface marker. We observed well reflected and resolved Raman mapping and characteristic signature peaks whereas, such recognition was not observed in normal fibroblast (3T3L1) cells. To confirm these findings, a SERS nanoprobe was conjugated with a specific tumour targeting marker, EGFR (Epidermal Growth Factor Receptor), a well known targeted agent for Human Fibrosarcoma (HT1080). This nanoprobe efficiently targeted the surface marker of HT1080 cells, threreby demonstrating its use as an ultrasensitive Raman probe for detection and targeted imaging, leaving normal cells unaffected. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Performance Characteristics of Bio-Inspired Metal Nanostructures as Surface-Enhanced Raman Scattered (SERS) Substrates.

    PubMed

    Areizaga-Martinez, Hector I; Kravchenko, Ivan; Lavrik, Nickolay V; Sepaniak, Michael J; Hernández-Rivera, Samuel P; De Jesús, Marco A

    2016-09-01

    The fabrication of high-performance plasmonic nanomaterials for bio-sensing and trace chemical detection is a field of intense theoretical and experimental research. The use of metal-silicon nanopillar arrays as analytical sensors has been reported with reasonable results in recent years. The use of bio-inspired nanocomposite structures that follow the Fibonacci numerical architecture offers the opportunity to develop nanostructures with theoretically higher and more reproducible plasmonic fields over extended areas. The work presented here describes the nanofabrication process for a series of 40 µm × 40 µm bio-inspired arrays classified as asymmetric fractals (sunflower seeds and romanesco broccoli), bilaterally symmetric (acacia leaves and honeycombs), and radially symmetric (such as orchids and lily flowers) using electron beam lithography. In addition, analytical capabilities were evaluated using surface-enhanced Raman scattering (SERS). The substrate characterization and SERS performance of the developed substrates as the strategies to assess the design performance are presented and discussed. © The Author(s) 2016.

  9. In vitro detection of beta amyloid exploiting surface enhanced Raman scattering (SERS) using a nanofluidic biosensor

    NASA Astrophysics Data System (ADS)

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

    2008-02-01

    Alzheimer's disease (AD), a neurodegenerative disease and the most common cause of dementia, affects 4.5 million people according to the 2000 US census and is expected to triple to 13.2 million by the year 2050. Since no definitive pre-mortem tests exist to distinguish AD from mild cognitive impairment due to the natural aging process, we focus on detecting the beta amyloid (Aβ) protein, the primary component of the senile plaques characteristic of AD. We specifically detect cytotoxic species of Aβ by exploiting surface enhanced Raman scattering (SERS). Using a nanofluidic device with a bottleneck shape (a microchannel leading into a nanochannel); we trapped gold colloid particles (60 nm) at the entrance to the nanochannel, with Aβ restricted within the interstices between the aggregated nanoparticles. The continuous flow generated from pumping the solution into the device produced size-dependent trapping of the gold colloid particles, resulting in a high density of aggregated nanoparticles at this precise region, creating localized "hot spots" in the interstitial region between nanoparticles, and shifting the plasmon resonance to the near infrared region, in resonance with incident laser wavelength. With this robust sensing platform, we were able to obtain concentration-dependent SERS spectra of Aβ and of different proteins present in the cerebrospinal fluid of healthy people and people with Alzheimer's disease.

  10. Performance characteristics of bio-inspired metal nanostructures as surface-enhanced Raman scattered (SERS) substrates

    DOE PAGES

    Areizaga-Martinez, Hector I.; Kravchenko, Ivan; Lavrik, Nickolay V.; ...

    2016-08-26

    The fabrication of high-performance plasmonic nanomaterials for bio-sensing and trace chemical detection is a field of intense theoretical and experimental research. The use of metal-silicon nanopillar arrays as analytical sensors has been reported with reasonable results in recent years. The use of bio-inspired nanocomposite structures that follow the Fibonacci numerical architecture offers the opportunity to develop nanostructures with theoretically higher and more reproducible plasmonic fields over extended areas. The work presented here describes the nanofabrication process for a series of 40 µm × 40 µm bio-inspired arrays classified as asymmetric fractals (sunflower seeds and romanesco broccoli), bilaterally symmetric (acacia leavesmore » and honeycombs), and radially symmetric (such as orchids and lily flowers) using electron beam lithography. In addition, analytical capabilities were evaluated using surface-enhanced Raman scattering (SERS). Here, the substrate characterization and SERS performance of the developed substrates as the strategies to assess the design performance are presented and discussed.« less

  11. Characterization and Detection of Uranyl Ion Sorption on Silver Surfaces using Surface Enhanced Raman Spectroscopy

    SciTech Connect

    Retterer, Scott T; Wells, Sabrina M; Sepaniak, Michael

    2009-01-01

    The study of the chemical behavior of uranyl species and its rapid detection is of primary environmental and non-proliferation concern. Herein we report on a surface enhanced Raman spectroscopic study of uranyl ion (UO22+) sorption onto the thermally vapor deposited silver particle surface. The ability of vibrational spectroscopy to characterize surface phenomenon and the remarkable sensitivity of the surface enhanced Raman spectroscopy (SERS) have been introduced as an appropriate combination for the surface characterization and detection of UO22+ onto the silver surface. The appearance of symmetric stretching frequency of UO22+ around 700 cm-1 and the disappearance of the 854 cm-1 band is attributed to the development of a chemical bond between silver surface and uranyl species. The effects of temperature, solute-surface interaction time, and pH have been studied using silver modified polypropylene filter (PPF) substrates. Results show that under appropriate conditions, the concentration of uranyl ion as low as 20 ng/mL can be easily detected using the discussed SERS approach without any surface modification of silver nanoparticles. Moreover, an alteranative SERS approach of uranyl detection is demonstrated using nano-lithographically fabricated SERS substrates.

  12. Surface enhanced Raman spectroscopy as a point-of-care diagnostic for infection in wound effluent

    NASA Astrophysics Data System (ADS)

    Ghebremedhin, Meron; Yesupriya, Shubha; Crane, Nicole J.

    2016-03-01

    In military medicine, one of the challenges in dealing with large combat-related injuries is the prevalence of bacterial infection, including multidrug resistant organisms. This can prolong the wound healing process and lead to wound dehiscence. Current methods of identifying bacterial infection rely on culturing microbes from patient material and performing biochemical tests, which together can take 2-3 days to complete. Surface Enhanced Raman Spectroscopy (SERS) is a powerful vibrational spectroscopy technique that allows for highly sensitive structural detection of analytes adsorbed onto specially prepared metal surfaces. In the past, we have been able to discriminate between bacterial isolates grown on solid culture media using standard Raman spectroscopic methods. Here, SERS is utilized to assess the presence of bacteria in wound effluent samples taken directly from patients. To our knowledge, this is the first attempt for the application of SERS directly to wound effluent. The utilization of SERS as a point-of-care diagnostic tool would enable physicians to determine course of treatment and drug administration in a matter of hours.

  13. Evaluation of thyroid tissue by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Teixeira, C. S. B.; Bitar, R. A.; Santos, A. B. O.; Kulcsar, M. A. V.; Friguglietti, C. U. M.; Martinho, H. S.; da Costa, R. B.; Martin, A. A.

    2010-02-01

    Thyroid gland is a small gland in the neck consisting of two lobes connected by an isthmus. Thyroid's main function is to produce the hormones thyroxine (T4), triiodothyronine (T3) and calcitonin. Thyroid disorders can disturb the production of these hormones, which will affect numerous processes within the body such as: regulating metabolism and increasing utilization of cholesterol, fats, proteins, and carbohydrates. The gland itself can also be injured; for example, neoplasias, which have been considered the most important, causing damage of to the gland and are difficult to diagnose. There are several types of thyroid cancer: Papillary, Follicular, Medullary, and Anaplastic. The occurrence rate, in general is between 4 and 7%; which is on the increase (30%), probably due to new technology that is able to find small thyroid cancers that may not have been found previously. The most common method used for thyroid diagnoses are: anamnesis, ultrasonography, and laboratory exams (Fine Needle Aspiration Biopsy- FNAB). However, the sensitivity of those test are rather poor, with a high rate of false-negative results, therefore there is an urgent need to develop new diagnostic techniques. Raman spectroscopy has been presented as a valuable tool for cancer diagnosis in many different tissues. In this work, 27 fragments of the thyroid were collected from 18 patients, comprising the following histologic groups: goitre adjacent tissue, goitre nodular tissue, follicular adenoma, follicular carcinoma, and papillary carcinoma. Spectral collection was done with a commercial FTRaman Spectrometer (Bruker RFS100/S) using a 1064 nm laser excitation and Ge detector. Principal Component Analysis, Cluster Analysis, and Linear Discriminant Analysis with cross-validation were applied as spectral classification algorithm. Comparing the goitre adjacent tissue with the goitre nodular region, an index of 58.3% of correct classification was obtained. Between goitre (nodular region and

  14. Analysis of low active-pharmaceutical-ingredient signal drugs based on thin layer chromatography and surface-enhanced Raman spectroscopy.

    PubMed

    Li, Xiao; Chen, Hui; Zhu, Qingxia; Liu, Yan; Lu, Feng

    2016-11-30

    Active pharmaceutical ingredients (API) embedded in the excipients of the formula can usually be unravelled by normal Raman spectroscopy (NRS). However, more and more drugs with low API content and/or low Raman scattering coefficient were insensitive to NRS analysis, which was for the first time defined as Low API-Signal Drugs (LASIDs) in this paper. The NRS spectra of these LASIDs were similar to their dominant excipients' profiles, such as lactose, starch, microcrystalline cellulose (MCC), etc., and were classified into three types as such. 21 out of 100 kinds of drugs were screened as LASIDs and characterized further by Raman microscopic mapping. Accordingly, we proposed a tailored solution to the qualitation and quantitation problem of these LASIDs, using surface-enhanced Raman spectroscopic (SERS) detection on the thin layer chromatographic (TLC) plate both in situ and after-separation. Experimental conditions and parameters including TLC support matrix, SERS substrate, detection mode, similarity threshold, internal standard, etc., were optimized. All LASIDs were satisfactorily identified and the quantitation results agreed well with those of high performance liquid chromatography (HPLC). For some structural analogues of LASIDs, although they presented highly similar SERS spectra and were tough to distinguish even with Raman microscopic mapping, they could be successfully discriminated from each other by coupling SERS (with portable Raman spectrometer) with TLC. These results demonstrated that the proposed solution could be employed to detect the LASIDs with high accuracy and cost-effectiveness. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Raman spectroscopy of shocked gypsum from a meteorite impact crater

    NASA Astrophysics Data System (ADS)

    Brolly, Connor; Parnell, John; Bowden, Stephen

    2017-07-01

    Impact craters and associated hydrothermal systems are regarded as sites within which life could originate on Earth, and on Mars. The Haughton impact crater, one of the most well preserved craters on Earth, is abundant in Ca-sulphates. Selenite, a transparent form of gypsum, has been colonized by viable cyanobacteria. Basement rocks, which have been shocked, are more abundant in endolithic organisms, when compared with un-shocked basement. We infer that selenitic and shocked gypsum are more suitable for microbial colonization and have enhanced habitability. This is analogous to many Martian craters, such as Gale Crater, which has sulphate deposits in a central layered mound, thought to be formed by post-impact hydrothermal springs. In preparation for the 2020 ExoMars mission, experiments were conducted to determine whether Raman spectroscopy can distinguish between gypsum with different degrees of habitability. Ca-sulphates were analysed using Raman spectroscopy and results show no significant statistical difference between gypsum that has experienced shock by meteorite impact and gypsum, which has been dissolved and re-precipitated as an evaporitic crust. Raman spectroscopy is able to distinguish between selenite and unaltered gypsum. This shows that Raman spectroscopy can identify more habitable forms of gypsum, and demonstrates the current capabilities of Raman spectroscopy for the interpretation of gypsum habitability.

  16. Developing fibre optic Raman probes for applications in clinical spectroscopy.

    PubMed

    Stevens, Oliver; Iping Petterson, Ingeborg E; Day, John C C; Stone, Nick

    2016-04-07

    Raman spectroscopy has been shown by various groups over the last two decades to have significant capability in discriminating disease states in bodily fluids, cells and tissues. Recent development in instrumentation, optics and manufacturing approaches has facilitated the design and demonstration of various novel in vivo probes, which have applicability for myriad of applications. This review focusses on key considerations and recommendations for application specific clinical Raman probe design and construction. Raman probes can be utilised as clinical tools able to provide rapid, non-invasive, real-time molecular analysis of disease specific changes in tissues. Clearly the target tissue location, the significance of spectral changes with disease and the possible access routes to the region of interest will vary for each clinical application considered. This review provides insight into design and construction considerations, including suitable probe designs and manufacturing materials compatible with Raman spectroscopy.

  17. Histochemical analysis of biological tissues using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Manoharan, Ramasamy; Wang, Yang; Feld, Michael S.

    1996-02-01

    This paper reviews the application of the Raman spectroscopic technique for analysis of biological tissue. The advantages and disadvantages of visible, near-IR and UV excitations are described, and the problems and prospects of using these methodologies for disease diagnosis are addressed. In situ analysis of tissue proteins, lens, cornea, blood constituents, biological stones and several hard tissues is reviewed, and the potentials for diagnosing arterial disease, and cancer in gynecological tissues, soft tissues, breast, colon, bladder and brain are also presented. Recent technological advances in instrumentation allow the use of Raman spectroscopy for real time histochemical analysis of tissues. The capability of Raman microspectroscopy for providing spatial information about the distribution of biochemical constituents in tissues has been demonstrated. The work reviewed indicates the promise of Raman spectroscopy for endoscopic imaging and real-time quantitation of biochemical constituents in clinical situations.

  18. Remote cure monitoring of polymeric resins by laser Raman spectroscopy

    SciTech Connect

    Hong, K.C.; Vess, T.M.; Lyon, R.E.; Myrick, M.L.

    1993-05-01

    The validity of using Raman spectroscopy to monitor the cure chemistries of amine-cured epoxy is demonstrated by correlating NIR absorbance measurements with Raman measurements for a concentration series of bisphenol-A diglycidylether in its own reaction product with diethylamine. The intensity of a normalized Raman peak at 1240 cm{sup {minus}l}, assigned to the epoxide functionality, was found to be linearly related to the concentration of epoxide groups in the resin mixtures. Also, it is shown that the Ciba-Geigy Matrimid 5292 system can be monitored by ex-situ FT-Raman spectroscopy by observing changes in the carbonyl stretching (1773 cm{sup {minus}1}) or the C=C stretching of maleimide (1587 cm{sup {minus}1}) during the cure reaction.

  19. Surface Raman spectroscopy as a probe of surface chemistry

    NASA Astrophysics Data System (ADS)

    Child, Craig M.; Foster, Michelle; Ivanecky, J. E., III; Perry, Scott S.; Campion, Alan

    1995-09-01

    Unenhanced surface Raman spectroscopy has been used to study the chemistry of polymers adsorbed on solid surfaces and the chemical enhancement mechanism of surface-enhanced Raman scattering. The adsorption and reactions of the polyimide monomers pyromellitic dianhydride (PMDA) and oxydianiline on silver, copper and silicon surfaces under ultrahigh vacuum have been investigated. These include both nondissociative physisorption and dissociative chemisorption of the monomers, and the condensation polymerization to form adsorbed polyimide. The intermediate polyamic acid is detected for the first time in a surface experiment. PMDA adsorbed on Cu(111) shows chemical enhancement in the absence of electromagnetic enhancement. High resolution electron energy loss spectroscopy has revealed a strong charge transfer absorption near the Raman excitation frequency. This observation provides strong support for a proposed resonance Raman chemical enhancement mechanism.

  20. Monitoring the influence of antibiotic exposure using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Samek, Ota; Zemanek, Pavel; Bernatova, Silvie; Jezek, Jan; Sery, Mojmir; Jakl, Petr; Siler, Martin; Ruzicka, Filip

    2014-03-01

    Here we report on combination of the data obtained from MICs (minimum inhibitory concentrations) with infor- mation of microoragnisms fingerprint provided by Raman spectroscopy. In our feasibility study we could follow mechanisms of the bacteriostatic versus bactericidal action on biofilm-positive Staphylococcus epidermidis simply by monitoring Raman bands corresponding to DNA translating the changes introduced by selected antibiotics. The Raman spectra of Staphylococcus epidermidis treated with a bacteriostatic agent show little effect on DNA which is in contrast with the action of a bactericidal agent where decreased in dedicated Raman spectra signal strength suggests DNA fragmentation. Moreover, we demonstrate that Raman tweezers are indeed able to distinguish strains of biofilm-forming (biofilm-positive) and biofilm-negative Staphylococcus epidermidis strains using principal component analysis (PCA).

  1. Remote Raman spectroscopy for planetary exploration: a review.

    PubMed

    Angel, S Michael; Gomer, Nathaniel R; Sharma, Shiv K; McKay, Chris

    2012-02-01

    In this review, we discuss the current state of standoff Raman spectroscopy as it applies to remote planetary applications, including standoff instrumentation, the technique's ability to identify biologically and geologically important analytes, and the feasibility to make standoff Raman measurements under various planetary conditions. This is not intended to be an exhaustive review of standoff Raman and many excellent papers are not mentioned. Rather it is intended to give the reader a quick review of the types of standoff Raman systems that are being developed and that might be suitable for astrospectroscopy, a look at specific analytes that are of interest for planetary applications, planetary measurement opportunities and challenges that need to be solved, and a brief discussion of the feasibility of making surface and plume planetary Raman measurements from an orbiting spacecraft.

  2. Proximal and point detection of contaminated surfaces using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Guicheteau, Jason A.; Christesen, Steven D.; Tripathi, Ashish; Emmons, Erik D.; Wilcox, Phillip G.; Emge, Darren K.; Pardoe, Ian J.; Fountain, Augustus W., III

    2011-11-01

    We are actively investigating the use of Raman spectroscopy for proximal standoff detection of chemicals and explosive materials on surfaces. These studies include Raman Chemical Imaging of contaminated fingerprints for forensic attribution and the assessments of commercial handheld or portable Raman instruments operating with near-infrared (IR) as well as ultraviolet (UV) laser excitation specifically developed for on-the-move reconnaissance of chemical contamination. As part of these efforts, we have measured the Raman cross sections of chemical agents, toxic industrial chemicals, and explosives from the UV to NIR. We have also measured and modeled the effect interrogation angle has on the Raman return from droplets on man-made surfaces. Realistic droplet distributions have been modeled and tested against variations in surface scan patterns and laser spot size for determining the optimum scan characteristics for detection of relevant surface contamination.

  3. Flexible Microsphere-Embedded Film for Microsphere-Enhanced Raman Spectroscopy.

    PubMed

    Xing, Cheng; Yan, Yinzhou; Feng, Chao; Xu, Jiayu; Dong, Peng; Guan, Wei; Zeng, Yong; Zhao, Yan; Jiang, Yijian

    2017-09-27

    Dielectric microspheres with extraordinary microscale optical properties, such as photonic nanojets, optical whispering-gallery modes (WGMs), and directional antennas, have drawn interest in many research fields. Microsphere-enhanced Raman spectroscopy (MERS) is an alternative approach for enhanced Raman detection by dielectric microstructures. Unfortunately, fabrication of microsphere monolayer arrays is the major challenge of MERS for practical applications on various specimen surfaces. Here we report a microsphere-embedded film (MF) by immersing a highly refractive microsphere monolayer array in the poly(dimethylsiloxane) (PDMS) film as a flexible MERS sensing platform for one- to three-dimensional (1D to 3D) specimen surfaces. The directional antennas and wave-guided whispering-gallery modes (WG-WGMs) contribute to the majority of Raman enhancement by the MFs. Moreover, the MF can be coupled with surface-enhanced Raman spectroscopy (SERS) to provide an extra >10-fold enhancement. The limit of detection is therefore improved for sensing of crystal violet (CV) and Sudan I molecules in aqueous solutions at concentrations down to 10(-7) M. A hybrid dual-layer microsphere enhancer, constructed by depositing a MF onto a microsphere monolayer array, is also demonstrated, wherein the WG-WGMs become dominant and boost the enhancement ratio >50-fold. The present work opens up new opportunities for design of cost-effective and flexible MERS sensing platforms as individual or associated techniques toward practical applications in ultrasensitive Raman detection.

  4. Identification and discrimination of polycyclic aromatic hydrocarbons using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Cloutis, Edward; Szymanski, Paul; Applin, Daniel; Goltz, Douglas

    2016-08-01

    Polycyclic aromatic hydrocarbons (PAHs) are widely present throughout the Solar System and beyond. They have been implicated as a contributor to unidentified infrared emission bands in the interstellar medium, comprise a substantial portion of the insoluble organic matter in carbonaceous chondrites, are expected stable components of organic matter on Mars, and are present in a wide range of terrestrial hydrocarbons and as components of biomolecules. However, PAH structures can be very complicated, making their identification challenging. Raman spectroscopy is known to be especially sensitive to the highly polarizable C-C and C=C bonds found in PAHs, and therefore, can be a powerful tool for PAH structural and compositional elucidation. This study examined Raman spectra of 48 different PAHs to determine the degree to which Raman spectroscopy could be used to uniquely identify different species, factors that control the positions of major Raman peaks, the degree to which induced fluorescence affects the intensity of Raman peaks, its usefulness for PAH discrimination, and the effects of varying excitation wavelength on some PAH Raman spectra. It was found that the arrangement and composition of phenyl (benzene) rings, and the type and position of functional groups can greatly affect fluorescence, positions and intensities of Raman peaks associated with the PAH backbone, and the introduction of new Raman peaks. Among the functional groups found on many of the PAHs that were analyzed, only a few Raman peaks corresponding to the molecular vibrations of these groups could be clearly distinguished. Comparison of the PAH Raman spectra that were acquired with both 532 and 785 nm excitation found that the longer wavelength resulted in reduced fluorescence, consistent with previous studies.

  5. Single bacteria identification by Raman spectroscopy.

    PubMed

    Strola, Samy Andrea; Baritaux, Jean-Charles; Schultz, Emmanuelle; Simon, Anne Catherine; Allier, Cédric; Espagnon, Isabelle; Jary, Dorothée; Dinten, Jean-Marc

    2014-01-01

    We report on rapid identification of single bacteria using a low-cost, compact, Raman spectroscope. We demonstrate that a 60-s procedure is sufficient to acquire a comprehensive Raman spectrum in the range of 600 to 3300 cm⁻¹. This time includes localization of small bacteria aggregates, alignment on a single individual, and spontaneous Raman scattering signal collection. Fast localization of small bacteria aggregates, typically composed of less than a dozen individuals, is achieved by lensfree imaging over a large field of view of 24 mm². The lensfree image also allows precise alignment of a single bacteria with the probing beam without the need for a standard microscope. Raman scattered light from a 34-mW continuous laser at 532 nm was fed to a customized spectrometer (prototype Tornado Spectral Systems). Owing to the high light throughput of this spectrometer, integration times as low as 10 s were found acceptable. We have recorded a total of 1200 spectra over seven bacterial species. Using this database and an optimized preprocessing, classification rates of ~90% were obtained. The speed and sensitivity of our Raman spectrometer pave the way for high-throughput and nondestructive real-time bacteria identification assays. This compact and low-cost technology can benefit biomedical, clinical diagnostic, and environmental applications.

  6. Single bacteria identification by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Strola, Samy Andrea; Baritaux, Jean-Charles; Schultz, Emmanuelle; Simon, Anne Catherine; Allier, Cédric; Espagnon, Isabelle; Jary, Dorothée; Dinten, Jean-Marc

    2014-11-01

    We report on rapid identification of single bacteria using a low-cost, compact, Raman spectroscope. We demonstrate that a 60-s procedure is sufficient to acquire a comprehensive Raman spectrum in the range of 600 to 3300. This time includes localization of small bacteria aggregates, alignment on a single individual, and spontaneous Raman scattering signal collection. Fast localization of small bacteria aggregates, typically composed of less than a dozen individuals, is achieved by lensfree imaging over a large field of view of 24. The lensfree image also allows precise alignment of a single bacteria with the probing beam without the need for a standard microscope. Raman scattered light from a 34-mW continuous laser at 532 nm was fed to a customized spectrometer (prototype Tornado Spectral Systems). Owing to the high light throughput of this spectrometer, integration times as low as 10 s were found acceptable. We have recorded a total of 1200 spectra over seven bacterial species. Using this database and an optimized preprocessing, classification rates of ˜90% were obtained. The speed and sensitivity of our Raman spectrometer pave the way for high-throughput and nondestructive real-time bacteria identification assays. This compact and low-cost technology can benefit biomedical, clinical diagnostic, and environmental applications.

  7. Single Molecule Raman Spectroscopy Under High Pressure

    NASA Astrophysics Data System (ADS)

    Fu, Yuanxi; Dlott, Dana

    2014-06-01

    Pressure effects on surface-enhanced Raman scattering spectra of Rhdoamine 6G adsorbed on silver nanoparticle surfaces was studied using a confocal Raman microscope. Colloidal silver nanoparticles were treated with Rhodamine 6G (R6G) and its isotopically substituted partner, R6G-d4. Mixed isotopomers let us identify single-molecule spectra, since multiple-molecule spectra would show vibrational transitions from both species. The nanoparticles were embedded into a poly vinyl alcohol film, and loaded into a diamond anvil cell for the high-pressure Raman scattering measurement. Argon was the pressure medium. Ambient pressure Raman scattering spectra showed few single-molecule spectra. At moderately high pressure ( 1GPa), a surprising effect was observed. The number of sites with observable spectra decreased dramatically, and most of the spectra that could be observed were due to single molecules. The effects of high pressure suppressed the multiple-molecule Raman sites, leaving only the single-molecule sites to be observed.

  8. Raman spectroscopy of polyhedral carbon nano-onions

    NASA Astrophysics Data System (ADS)

    Codorniu Pujals, Daniel; Arias de Fuentes, Olimpia; Desdín García, Luis F.; Cazzanelli, Enzo; Caputi, Lorenzo S.

    2015-09-01

    The Raman spectra of polyhedral carbon nano-onions (PCO), obtained by underwater arc discharge of graphite electrodes, are studied. While the general Raman spectrum of PCO is very similar to those of other carbon nanostructures, including spherical nano-onions, the fine structure of the G and 2D bands gives valuable information that allows using Raman spectroscopy for differentiating the PCO from other carbon structures. The interpretation of the features of the fine structure of the spectra is supported by evidences obtained by TEM.

  9. Time-resolved Raman spectroscopy for in situ planetary mineralogy.

    PubMed

    Blacksberg, Jordana; Rossman, George R; Gleckler, Anthony

    2010-09-10

    Planetary mineralogy can be revealed through a variety of remote sensing and in situ investigations that precede any plans for eventual sample return. We briefly review those techniques and focus on the capabilities for on-surface in situ examination of Mars, Venus, the Moon, asteroids, and other bodies. Over the past decade, Raman spectroscopy has continued to develop as a prime candidate for the next generation of in situ planetary instruments, as it provides definitive structural and compositional information of minerals in their natural geological context. Traditional continuous-wave Raman spectroscopy using a green laser suffers from fluorescence interference, which can be large (sometimes saturating the detector), particularly in altered minerals, which are of the greatest geophysical interest. Taking advantage of the fact that fluorescence occurs at a later time than the instantaneous Raman signal, we have developed a time-resolved Raman spectrometer that uses a streak camera and pulsed miniature microchip laser to provide picosecond time resolution. Our ability to observe the complete time evolution of Raman and fluorescence spectra in minerals makes this technique ideal for exploration of diverse planetary environments, some of which are expected to contain strong, if not overwhelming, fluorescence signatures. We discuss performance capability and present time-resolved pulsed Raman spectra collected from several highly fluorescent and Mars-relevant minerals. In particular, we have found that conventional Raman spectra from fine grained clays, sulfates, and phosphates exhibited large fluorescent signatures, but high quality spectra could be obtained using our time-resolved approach.

  10. Fiber-optic Raman Spectroscopy of Joint Tissues

    PubMed Central

    Esmonde-White, Karen A.; Esmonde-White, Francis W.L.; Morris, Michael D.

    2011-01-01

    In this study, we report adaptation of Raman spectroscopy for arthroscopy of joint tissues using a custom-built fiber optic probe. Differentiation of healthy and damaged tissue or examination of subsurface tissue, such as subchondral bone, is a challenge in arthroscopy because visual inspection may not provide sufficient contrast. Discrimination of healthy versus damaged tissue may be improved by incorporating point spectroscopy or hyperspectral imaging into arthroscopy where contrast is based on molecular structure or chemical composition. Articular joint surfaces of knee cadaveric human tissue and tissue phantoms were examined using a custom-designed Raman fiber optic probe. Fiber-optic Raman spectra were compared against reference spectra of cartilage, subchondral bone and cancellous bone collected using Raman microspectroscopy. In fiber-optic Raman spectra of the articular surface, there was an effect of cartilage thickness on recovery of signal from subchondral bone. At sites with intact cartilage, the bone mineralization ratio decreased but there was a minimal effect in the bone mineral chemistry ratios. Tissue phantoms were prepared as experimental models of the osteochondral interface. Raman spectra of tissue phantoms suggested that optical scattering of cartilage has a large effect on the relative cartilage and bone signal. Finite element analysis modeling of light fluence in the osteochondral interface confirmed experimental findings in human cadaveric tissue and tissue phantoms. These first studies demonstrate proof of principle for Raman arthroscopic measurement of joint tissues and provide a basis for future clinical or animal model studies. PMID:21359366

  11. Surface-enhanced Raman spectroscopy of semiconductor nanostructures

    NASA Astrophysics Data System (ADS)

    Milekhin, A. G.; Sveshnikova, L. L.; Duda, T. A.; Yeryukov, N. A.; Rodyakina, E. E.; Gutakovskii, A. K.; Batsanov, S. A.; Latyshev, A. V.; Zahn, D. R. T.

    2016-01-01

    We review our recent results concerning surface-enhanced Raman scattering (SERS) by confined optical and surface optical phonons in semiconductor nanostructures including CdS, CuS, GaN, and ZnO nanocrystals, GaN and ZnO nanorods, and AlN nanowires. Enhancement of Raman scattering by confined optical phonons as well as appearance of new Raman modes with the frequencies different from those in ZnO bulk attributed to surface optical modes is observed in a series of nanostructures having different morphology located in the vicinity of metal nanoclusters (Ag, Au, and Pt). Assignment of surface optical modes is based on calculations performed in the frame of the dielectric continuum model. It is established that SERS by phonons has a resonant character. A maximal enhancement by optical phonons as high as 730 is achieved for CdS nanocrystals in double resonant conditions at the coincidence of laser energy with that of electronic transitions in semiconductor nanocrystals and localized surface plasmon resonance in metal nanoclusters. Even a higher enhancement is observed for SERS by surface optical modes in ZnO nanocrystals (above 104). Surface enhanced Raman scattering is used for studying phonon spectrum in nanocrystal ensembles with an ultra-low areal density on metal plasmonic nanostructures.

  12. Potential of Raman and Infrared Spectroscopy for Plant Analysis

    NASA Astrophysics Data System (ADS)

    Schulz, H.

    2008-11-01

    Various mid-infrared (MIR) and Raman spectroscopic methods applied to the analysis of valuable plant substances or quality parameters in selected horticultural and agricultural crops are presented. Generally, both spectroscopy techniques allow to identify simultaneously characteristic key bands of individual plant components (e.g. carotenoids, alkaloids, polyacetylenes, fatty acids, amino acids, terpenoids). In contrast to MIR methods Raman spectroscopy mostly does not need any sample pre-treatment; even fresh plant material can be analysed without difficulty because water shows only weak Raman scattering properties. In some cases a significant sensivity enhancement of Raman signals can be achieved if the exciting laser wavelength is adjusted to the absorption range of particular plant chromophores such as carotenoids (Resonance Raman effect). Applying FT-IR or FT Raman micro-spectroscopy the distribution of certain plant constituents in the cell wall can be identified without the need for any physical separation. Furthermore it is also possible to analyse secondary metabolites occurring in the cell vacuoles if significant key bands do not coincide with the spectral background of the plant matrix.

  13. The substrate matters in the Raman spectroscopy analysis of cells.

    PubMed

    Mikoliunaite, Lina; Rodriguez, Raul D; Sheremet, Evgeniya; Kolchuzhin, Vladimir; Mehner, Jan; Ramanavicius, Arunas; Zahn, Dietrich R T

    2015-08-27

    Raman spectroscopy is a powerful analytical method that allows deposited and/or immobilized cells to be evaluated without complex sample preparation or labeling. However, a main limitation of Raman spectroscopy in cell analysis is the extremely weak Raman intensity that results in low signal to noise ratios. Therefore, it is important to seize any opportunity that increases the intensity of the Raman signal and to understand whether and how the signal enhancement changes with respect to the substrate used. Our experimental results show clear differences in the spectroscopic response from cells on different surfaces. This result is partly due to the difference in spatial distribution of electric field at the substrate/cell interface as shown by numerical simulations. We found that the substrate also changes the spatial location of maximum field enhancement around the cells. Moreover, beyond conventional flat surfaces, we introduce an efficient nanostructured silver substrate that largely enhances the Raman signal intensity from a single yeast cell. This work contributes to the field of vibrational spectroscopy analysis by providing a fresh look at the significance of the substrate for Raman investigations in cell research.

  14. The substrate matters in the Raman spectroscopy analysis of cells

    NASA Astrophysics Data System (ADS)

    Mikoliunaite, Lina; Rodriguez, Raul D.; Sheremet, Evgeniya; Kolchuzhin, Vladimir; Mehner, Jan; Ramanavicius, Arunas; Zahn, Dietrich R. T.

    2015-08-01

    Raman spectroscopy is a powerful analytical method that allows deposited and/or immobilized cells to be evaluated without complex sample preparation or labeling. However, a main limitation of Raman spectroscopy in cell analysis is the extremely weak Raman intensity that results in low signal to noise ratios. Therefore, it is important to seize any opportunity that increases the intensity of the Raman signal and to understand whether and how the signal enhancement changes with respect to the substrate used. Our experimental results show clear differences in the spectroscopic response from cells on different surfaces. This result is partly due to the difference in spatial distribution of electric field at the substrate/cell interface as shown by numerical simulations. We found that the substrate also changes the spatial location of maximum field enhancement around the cells. Moreover, beyond conventional flat surfaces, we introduce an efficient nanostructured silver substrate that largely enhances the Raman signal intensity from a single yeast cell. This work contributes to the field of vibrational spectroscopy analysis by providing a fresh look at the significance of the substrate for Raman investigations in cell research.

  15. The substrate matters in the Raman spectroscopy analysis of cells

    PubMed Central

    Mikoliunaite, Lina; Rodriguez, Raul D.; Sheremet, Evgeniya; Kolchuzhin, Vladimir; Mehner, Jan; Ramanavicius, Arunas; Zahn, Dietrich R.T.

    2015-01-01

    Raman spectroscopy is a powerful analytical method that allows deposited and/or immobilized cells to be evaluated without complex sample preparation or labeling. However, a main limitation of Raman spectroscopy in cell analysis is the extremely weak Raman intensity that results in low signal to noise ratios. Therefore, it is important to seize any opportunity that increases the intensity of the Raman signal and to understand whether and how the signal enhancement changes with respect to the substrate used. Our experimental results show clear differences in the spectroscopic response from cells on different surfaces. This result is partly due to the difference in spatial distribution of electric field at the substrate/cell interface as shown by numerical simulations. We found that the substrate also changes the spatial location of maximum field enhancement around the cells. Moreover, beyond conventional flat surfaces, we introduce an efficient nanostructured silver substrate that largely enhances the Raman signal intensity from a single yeast cell. This work contributes to the field of vibrational spectroscopy analysis by providing a fresh look at the significance of the substrate for Raman investigations in cell research. PMID:26310910

  16. Raman spectroscopy in the diagnosis of ulcerative colitis.

    PubMed

    Veenstra, Michelle Anne; Palyvoda, Olena; Alahwal, Hazem; Jovanovski, Marko; Reisner, Luke Anthony; King, Brady; Poulik, Janet; Klein, Michael D

    2015-02-01

    At present, the diagnosis of ulcerative colitis (UC) requires the histologic demonstration of characteristic mucosal inflammatory changes. A rapid and noninvasive diagnosis would be of value, especially if it could be adapted to a simple rectal probe. Raman spectroscopy creates a molecular fingerprint of substances by detecting laser light scattered from asymmetric, vibrating, and chemical bonds. We hypothesize that Raman spectroscopy can distinguish UC from non-UC colon tissue rapidly and accurately. Colon tissue specimens were obtained from patients operated at the Children's Hospital of Michigan, United States, including UC colon and non-UC colon. The samples were examined with a Renishaw inVia Raman microscope (Gloucestershire, United Kingdom) with a 785 nm laser. Principal component analysis and discriminant function analysis were used to classify groups. Final classification was evaluated against histologic diagnoses using leave-one-out cross-validation at a spectral level. We compared Raman spectroscopy examination of colon specimens from four patients with UC and four patients without UC. A total of 801 spectra were recorded from colon specimens. We evaluated 100 spectra each from the mucosal and serosal surfaces of patients with UC and 260 spectra from the mucosal surface and 341 spectra from the serosal surface of the patients who did not have UC. For samples from the mucosal surface, the Raman analysis had a sensitivity of 82% and a specificity of 89%. For samples from the serosal surface, Raman spectroscopy had a sensitivity of 87% and a specificity of 93%. When considering each tissue sample and deciding the diagnosis based on the majority of spectra from that sample, there were no errors in the diagnosis. Raman spectroscopy can distinguish UC from normal colon tissue rapidly and accurately. This technology offers the possibility of real-time diagnosis as well as the ability to study changes in UC-afflicted colon tissue that do not appear

  17. Phytic acid adsorption on the copper surface: Observation of electrochemistry and Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Shen, Shu; Guo, Xiao-yu; Song, Ping; Pan, Ying-Cheng; Wang, Hao-qiong; Wen, Ying; Yang, Hai-Feng

    2013-07-01

    The adsorption of phytic acid (PA) on copper was investigated using electrochemical impedance spectroscopy (EIS), electrochemical polarization measurement and surface-enhanced Raman scattering (SERS) spectroscopy. Electrochemical results indicated that inhibition efficiency of PA film for copper from corrosion in 3 wt% NaCl solution was beyond 80% at an optimum self-assembly concentration of 0.1 mM for 6 h. Electrochemical polarization indicated that PA functioned as a cathodic inhibitor. In addition, Raman studies showed that PA adsorbed on the copper surface formed via P-O groups. Finally, the value of ΔGads (-39.96 kJ mol-1) was close to -40 kJ mol-1, suggesting that the adsorption of PA on the copper surface was the chemical adsorption.

  18. Low-concentration chemical sensing using surface-enhanced coherent anti-Stokes Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Hua, Xia; Sinyukov, Alexander; Traverso, Andrew; Veronine, Dmitri; Wang, Kai; Xia, Hui; Yang, Wenlong; Yuan, Luqi; Sokolov, Alexei; Scully, Marlan

    2010-10-01

    Measurements of surface enhanced coherent anti-Stokes Raman spectra (CARS) of cyclohexane are carried out. Random aggregates of gold nanoparticles for field enhancement were deposited on a glass substrate and were characterized using atomic force microscopy (AFM). Surface enhancement of the CARS signal by gold nanoparticles is observed. This technique can be used to detect low amounts of chemicals with a higher sensitivity compared to the conventional surface-enhanced Raman spectroscopy (SERS). The lowest detected concentration of cyclohexane in a thin film of methanol was 1%. However, it was not possible to detect any signal from the same sample of cyclohexane without gold nanoparticles using conventional CARS technique. Therefore, surface enhancement is necessary to achieve higher spectroscopy sensitivity. Further studies of nanostructure-enhanced electrical fields are required to quantitatively understand the observed effects and will be performed in the future.

  19. Raman spectroscopy of blood in-vitro

    NASA Astrophysics Data System (ADS)

    Villanueva-Luna, A. E.; Castro-Ramos, J.; Vazquez-Montiel, S.; Flores-Gil, A.; Ortiz-Lima, C. M.; Delgado-Atencio, J. A.

    2012-03-01

    We present Raman spectra from a sample of 8 volunteers that have different type of blood. The experimental data were carried out using a 785 nm excitation laser and an ocean optics spectrometer of 6 cm-1 resolution, with a used spectral region from 1000 to 1800 cm-1. We find Raman features at 1000 and 1542 cm-1 regarded with hemoglobin and its derivatives. Also we find Raman features at 1248 and 1342 cm-1 that are now regarded with pure fibrin. In this work, we use Principal Component analysis (PCA) to determine all variations of our samples, which allows us to define a classification of the influence of the blood type. Finally, we found vibrational lines of cholesterol, glucose and triglycerides that are reported in literature.