Fluorescence and Fourier Transform surface-enhanced Raman scattering measurements of methylene blue adsorbed onto a sulfur-modified gold electrode

Naujok, Roberta R.; Duevel, Robert V.; Corn, Robert M.

doi:10.1021/la00031a026

Cited by 167 publications

(125 citation statements)

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“…2A). After subtracting the background, the spectra were normalized to the common band at 1;620 cm −1 , assigned to the ring νðC-CÞ vibration mode of both thionin and MB (26,27). The data were fit (Fig.…”

Section: Resultsmentioning

confidence: 99%

Quantitative ratiometric discrimination between noncancerous and cancerous prostate cells based on neuropilin-1 overexpression

Pallaoro

Braun

Moskovits

2011

Proc. Natl. Acad. Sci. U.S.A.

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A multiplexed, ratiometric method is described that can confidently distinguish between cancerous and noncancerous epithelial prostate cells in vitro. The technique is based on bright surfaceenhanced resonance Raman scattering (SERRS) biotags (SBTs) infused with unique Raman reporter molecules, and carrying cellspecific peptides. Two sets of SBTs were used. One targets the neuropilin-1 (NRP-1) receptors of cancer cells through the RPARPAR peptide. The other functions as a positive control (PC) and binds to both noncancerous and cancer cells through the HIV-derived TAT peptide. Point-by-point 2D Raman maps of the spatial distribution of the two tags were constructed with subcellular resolution from cells simultaneously incubated with the two sets of SBTs. Averaging the SERRS signal over a given cell yielded an NRP/PC ratio from which a robust quantitative measure of the overexpression of the NRP-1 by the cancer cell line was extracted. The use of a local, on-cell reference produces quantitative, statistically robust measures of overexpression independent of such sources of uncertainty as variations in the location of the focal plane, the local cell concentration, and turbidity.surface-enhanced Raman spectroscopy biomarker | cancer cell identification | multiplexing | silver nanoparticles E arly and rapid identification of malignant cells [ideally freeflowing in biological fluids such as urine (1) or blood (2-4)] is a central goal in cancer research. Accordingly, seeking improvements in sensitivity and accuracy of detection and quantification through, for example, the development of cell-specific diagnostic tools and biomarkers is an active enterprise. Although it is known that such cells are present in body fluids, concentrating them to levels appropriate for confident identification and quantification is still a serious challenge, despite significant advances that have been made by, for example, using microfluidics (5). Once collected, the cells must be identified as either cancerous or noncancerous within tolerable confidence limits, which may be improved by, for example, using several nonredundant biomarkers. Numerous promising identification methods have been reported using antibodies. In this article, we report a technique based on surface-enhanced Raman spectroscopy (SERS) and biotags that produce bright surface-enhanced resonance Raman scattering (SERRS) signals, comparable to or exceeding the intensities of fluorescent tags. The SERRS biotags (SBTs) used in this study exploit peptides as recognition moieties. We show that using SBTs ratiometrically can provide highly statistically significant, quantitative measures of neuropilin-1 (NRP-1) overexpression insensitive to normal causes of uncertainty in optical measurements such as variations in focal plane, cell concentration, and turbidity.Normal Raman signals from cells and their infrared (FTIR) absorbance patterns have been previously used to differentiate between cancer and normal cells (6-9). SERS has been used as an alternative immunohistochemistry (IH...

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Section: Resultsmentioning

confidence: 99%

Quantitative ratiometric discrimination between noncancerous and cancerous prostate cells based on neuropilin-1 overexpression

Pallaoro

Braun

Moskovits

2011

Proc. Natl. Acad. Sci. U.S.A.

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“…The Raman band at 1620 cm -1 which is assigned to the aromatic C-C stretching vibration is the strongest one [32]. Its intensity overwhelms those of the other modes.…”

Section: Resultsmentioning

confidence: 93%

Superhydrophobic SERS substrates based on silicon hierarchical nanostructures

Chen

Wen

Zhou

et al. 2018

J. Opt.

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Silicon nanostructures have been cultivated as promising surface enhanced Raman scattering (SERS) substrates in terms of their low-loss optical resonance modes, facile functionalization, and compatibility with today's state-of-the-art CMOS techniques. However, unlike their plasmonic counterparts, the electromagnetic field enhancements induced by silicon nanostructures are relatively small, which restrict their SERS sensing limit to around 10 -7 M. To tackle this problem, we propose here a strategy for improving the SERS performance of silicon nanostructures by constructing silicon hierarchical nanostructures with a superhydrophobic surface. The hierarchical nanostructures are binary structures consisted of silicon nanowires (NWs) grown on micropyramids (MPs). After being modified with perfluorooctyltriethoxysilane (PFOT), the nanostructure surface shows a stable superhydrophobicity with a high contact angle of ∼160°. The substrate can allow for concentrating diluted analyte solutions into a specific area during the evaporation of the liquid droplet, whereby the analytes are aggregated into a small volume and can be easily detected by the silicon nanostructure SERS substrate. The analyte molecules (methylene blue: MB) enriched from an aqueous solution lower than 10 -8 M can be readily detected. Such a detection limit is ∼100-fold lower than the conventional SERS substrates made of silicon nanostructures. Additionally, the detection limit can be further improved by functionalizing gold nanoparticles onto silicon hierarchical nanostructures, whereby the superhydrophobic characteristics and plasmonic field enhancements can be combined synergistically to give a detection limit down to ∼10 -11 M. A gold nanoparticle-functionalized superhydrophobic substrate was employed to detect the spiked melamine in liquid milk. The results showed that the detection limit can be as low as 10 -5 M, highlighting the potential of the proposed superhydrophobic SERS substrate in practical food safety inspection applications.

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“…5(c), the symmetric stretch of C-N bond occurs in both solid and MB loaded carbon, but the asymmetric stretch of C-N bond has been identified in the solid only. And finally a typical large MB peak was found at 1625 cm -1 for both spectra which is related to the C-C bond stretch of the benzene ring of MB molecule [15][16]. It was considerably more intense in the solid MB spectra.…”

Section: Raman Spectroscopy Analysismentioning

confidence: 88%

“…One peak was identified at 1038 cm -1 , showing low intensity in the solid MB spectra but being quite significant when MB molecules are adsorbed in the Raphanus sativus carbon; the other peak occurred at 1153 cm -1 for both curves with quite similar intensities. Other deformation on the atoms of MB molecules is related to the symmetric and asymmetric stretch of C-N bond that are found at 1390 and 1430 cm -1 , respectively [15]. According to Fig.…”

Section: Raman Spectroscopy Analysismentioning

confidence: 89%

“…5(c). Firstly, peaks related to the CH bond deformation  (C-H) are found at 1030 and 1151 cm -1 [15]. One peak was identified at 1038 cm -1 , showing low intensity in the solid MB spectra but being quite significant when MB molecules are adsorbed in the Raphanus sativus carbon; the other peak occurred at 1153 cm -1 for both curves with quite similar intensities.…”

Section: Raman Spectroscopy Analysismentioning

confidence: 94%

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Characterization of an absorbent based onRaphanus sativus(L. var.), a solid residue from biodiesel production, for the removal of methylene blue

LÁzaro

Caldeira

Dantas

et al. 2010

WIT Transactions on Ecology and the Environment

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In this study, an adsorbent produced from Raphanus sativus (L. var.), a residue from the biodiesel industry, was investigated for the removal of methylene blue (MB) from textile effluents aiming to: (i) obtain physical and textural characteristics of the given carbon, and (ii) understand the MB adsorption mechanism onto such carbonaceous structures. The following methods were employed: SEM-EDS microscopy, gas adsorption and Raman spectroscopy. Physical and textural characteristics of the carbon obtained by classical methodologies such as BET, BJH and SEM analyses were corroborated by the Raman analysis. For the experimental conditions used on the preparation of the activated carbon of Raphanus sativus, the main physical parameters measured were specific surface area (236.3 m 2 .g -1 ), total pore volume (0.06 cm 3 .g -1 ) and average pore size (1.4 nm). SEM and Raman analysis revealed that a microporous structure of carbon was obtained as the ratio between the disorder band and the graphite band was higher than unity, thus indicating that MB adsorption may occur predominantly at the surface of the adsorbent, given that the diameter of MB molecule was estimated to be nearly 1.5 nm. Raman analysis of solid MB revealed that MB molecules are predominantly found as dimmers in the solid however they are adsorbed as monomer in the Raphanus sativus carbon. MB through the central nitrogen atom of its molecule; MB bonding through sulfur atom may also occur but at lesser intensity while MB bonding through amino nitrogen atom does not seem probable.

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Fluorescence and Fourier Transform surface-enhanced Raman scattering measurements of methylene blue adsorbed onto a sulfur-modified gold electrode

Cited by 167 publications

References 0 publications

Quantitative ratiometric discrimination between noncancerous and cancerous prostate cells based on neuropilin-1 overexpression

Quantitative ratiometric discrimination between noncancerous and cancerous prostate cells based on neuropilin-1 overexpression

Superhydrophobic SERS substrates based on silicon hierarchical nanostructures

Characterization of an absorbent based onRaphanus sativus(L. var.), a solid residue from biodiesel production, for the removal of methylene blue

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