Raman spectra of pyridine adsorbed at a silver electrode

Fleischmann, M.; Hendra, P.J.; McQuillan, A. James

doi:10.1016/0009-2614(74)85388-1

Cited by 6,385 publications

(3,815 citation statements)

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“…Finally, we investigated the potential use of chloride-dipped electrodes in MEF, which are widely used in SERS to enhance signal intensities [16,17]. Our findings show no enhancement in fluorescence emission after chloride dipping, which is consistent with MEF being a through-space phenomenon as compared to SERS, which conversely is thought to be a contact (or near contact) interaction with a metallic surface [20,21].…”

Section: Introductionsupporting

confidence: 66%

“…Such a treatment of the electrode typically results in significantly large enhancements in the surface Raman intensities [16,17]. We questioned what would be observed for the fluorescence intensities.…”

Section: Chloride Dipped Electrodesmentioning

confidence: 94%

“…A roughened silver cathode was also dipped in 10 −4 M NaCl for 1 h before being washed and then coated with ICG-HSA, so as to place our findings in context with the huge enhancements in Raman signals, typically obtained after chloride dipping the electrodes [16,17].…”

Section: Roughened Silver Electrodesmentioning

confidence: 94%

“…Localized silver colloid formation has been accomplished with reagents in laminar flow [12], by nanolithography [13,14], and by electroplating on insulators [15]. Given the extensive use of roughened silver electrodes for surface-enhanced Raman scattering (SERS) [16,17], we investigated their use for spatially selective MEF, given the typically high surface areas of fractal-like structures.…”

Section: Introductionmentioning

confidence: 99%

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Untitled

Geddes

Parfenov

Roll

et al. 2003

Journal of Fluorescence

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Substantial increases in fluorescence emission from fluorophore-protein-coated fractal-like silver structures have been observed. We review two methods for silver fractal structure preparation, which have been employed and studied. The first, a roughened silver electrode, typically yielded a 100-fold increase in fluorophore emission, and the second, silver fractal-like structures grown on glass between two silver electrodes, produced a ≈500-fold increase. In addition, significant increases in probe photostability were observed for probes coated on the silver fractal like structures. These results further serve to compliment our recent work on the effects of nobel metal particles with fluorophores, a relatively new phenomenon in fluorescence we have termed both "metal-enhanced fluorescence" [1] and "radiative decay engineering" [2,3]. These results are explained by the metallic surfaces modifying the radiative decay rate (Γ) of the fluorescent labels. We believe that this new silver-surface preparation, which results in ultrabright and photostable fluorophores, offers a new generic technology platform for increased fluorescence signal levels, with widespread potential applications to the analytical sciences, imaging, and medical diagnostics.

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Section: Introductionsupporting

confidence: 66%

Section: Chloride Dipped Electrodesmentioning

confidence: 94%

Section: Roughened Silver Electrodesmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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Untitled

Geddes

Parfenov

Roll

et al. 2003

Journal of Fluorescence

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“…Surface-enhanced Raman spectroscopy (SERS) is an ideal approach for optical label-free sensing because it identifies targeted molecules based on their unique vibrational and rotational signatures. [22][23][24][25][26] Application of SERS for hormone detection appears relatively unexplored due to minimal experimental success: previously reported SERS-based quantitative insulin sensors were limited due to weaklyenhancing substrates made of randomly dispersed nanoparticles resulting in micromolar detection sensitivity, approximately 2 to 4 orders of magnitude larger than clinically-relevant insulin levels. [27][28][29][30] In this study, we report highly sensitive SERS-based insulin sensing at clinically relevant concentrations using a non-resonant SERS substrate with strong signal enhancement and wafer- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 5 scale uniformity.…”

mentioning

confidence: 99%

Surface-Enhanced Raman Spectroscopy-Based Label-Free Insulin Detection at Physiological Concentrations for Analysis of Islet Performance

Cho¹,

Kumar²,

Yang³

et al. 2018

ACS Sens.

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Label-free optical detection of insulin would allow in vitro assessment of pancreatic cell functions in their natural state and expedite diabetes-related clinical research and treatment, however no existing method has met these criteria at physiological concentrations. Using spatially-uniform 3D gold-nanoparticle sensors, we have demonstrated surface-enhanced Raman sensing of insulin in the secretions from human pancreatic islets under low and high glucose environments without the use of labels such as antibodies or aptamers. Label-free measurements of the islet secretions showed excellent correlation among the ambient glucose levels, secreted insulin concentrations, and measured Raman-emission intensities. When excited at 785 nm, plasmonic hotspots of the densely-arranged 3D gold-nanoparticle pillars as well as strong interaction between sulphide linkages of the insulin molecules and the gold nanoparticles produced highly sensitive and reliable insulin measurements down to 100 pM. The sensors exhibited a dynamic range of 100 pM to 50 nM with an estimated detection limit of 35 pM, which covers the reported concentration range of insulin observed in pancreatic cell secretions.The sensitivity of this approach is approximately four orders of magnitude greater than previously reported results using label-free optical approaches, and it is much more costeffective than immunoassay-based insulin detection widely used in clinics and laboratories. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 3 Hormones are chemical messengers that control a wide variety of functions in the human body. Maintaining adequate hormone levels is extremely important for human health and disruption to these levels can result in life-debilitating conditions. Simple and easy measurements of hormonal secretions ex vivo or in vivo are essential for implementing next generation biosensors, allowing convenient monitoring of health and early disease detection.One of the most prevalent diseases resulting from hormonal dysfunction is diabetes, which arises from a disruption in the release of insulin in the body. 1-2 Insulin is a peptide hormone which is secreted by beta cells, one of five primary cell-types which populate pancreatic cellular clusters known as islets. The concentration of insulin secreted from beta cells in plasma has been reported to vary between 100 pM (fasting) and 2 nM (about 1 hour after glucose intake) in non-diabetic individuals. [3][4] In diabetic individuals, functional damage to the beta cells reduces or inhibits their ability to release insulin. One of the leading methodologies for treatment of type-1 diabetes is pancreatic islet transplantation, where healthy islets harvested from deceased donors are transplanted into diabetic patients. [5][6] Since the number of donors is limited, methodologies that can improve the efficiency and succe...

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