In situ synthesis of Au-shelled Ag nanoparticles on PDMS for flexible, long-life, and broad spectrum-sensitive SERS substrates

Fortuni, Beatrice; Inose, Tomoko; Uezono, S.; Toyouchi, Shuichi; Umemoto, Kazuki; Sekine, Satoshi; Fujita, Yoshihiro; Ricci, Marilena; Lü, Gang; Masuhara, Akito; Hutchison, James A.; Latterini, Loredana; Uji‐i, Hiroshi

doi:10.1039/c7cc05420c

Cited by 60 publications

(48 citation statements)

References 34 publications

(46 reference statements)

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“…It is also noticed that the peaks around 700 and 800 cm −1 undergoes a blueshift as the increasing pH. The theoretically simulated pH‐dependent SERS of PMBA match quite well with experimentally measured results …”

Section: Resultssupporting

confidence: 83%

“…p ‐mercaptobenzoic acid (PMBA) and p ‐mercaptopyridine (PMPY) can be transformed to their corresponding conjugated base and acid during deprotonation and protonation processes. Thus, these two molecules are widely applied as pH sensors to determine the surface pK a by measuring the pH‐dependent SERS . Yu et al reported a SERS method to determine the pK a value by monitoring the SERS spectral changes of PMPY adsorbed on a buffer/gold interface .…”

Section: Introductionmentioning

confidence: 99%

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Simulating pH‐dependent surface‐enhanced Raman spectra by density functional theory calculations

Xiang

Zhang

Gao

et al. 2019

J Raman Spectroscopy

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The pH‐dependent surface‐enhanced Raman spectra of two typical surface sensor molecules p‐mercaptobenzoic acid (PMBA) and p‐mercaptopyridine (PMPY) were simulated by density functional theory calculations. First, the acid dissociation constants and individual surface Raman spectra of PMBA and PMPY were computed and compared with experimental results. It was found that acid dissociation constants calculated by the hybrid implicit‐explicit model and surface‐enhanced Raman scattering (SERS) spectra simulated by the explicit model most closely coincide with experimental results. Then, the pH‐dependent SERS spectra of PMBA and PMPY were obtained by overlaying the SERS of individual acid species and base species multiplied by their molar fractions, which were calculated from the acid dissociation constants. During the deprotonation process of PMBA, the Raman intensity from COOH stretching decreases and the Raman intensity from COO− stretching increases. During the protonation process of PMPY, the ν8a mode undergoes a significant blueshift and the relative Raman intensity of ν7a mode decreases. At last, pH calibration curves of PMBA and PMPY were obtained according to the simulated pH‐dependent Raman spectra, in which the logarithmic value of relative Raman intensity of characteristic peaks varies almost linearly with solution pH.

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Section: Resultssupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Simulating pH‐dependent surface‐enhanced Raman spectra by density functional theory calculations

Xiang

Zhang

Gao

et al. 2019

J Raman Spectroscopy

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“…Surface-enhanced Raman scattering (SERS) is a non-destructive and ultra-sensitive analytical technique, which allows rapid molecular-specific detection of a wide range of targets [1,2]. Since its discovery in 1974, SERS has been applied for the analytical sensing of many molecules of biological interest ranging from small organic molecules [3][4][5], pesticides [6,7] and drugs [8,9] to larger structures such as proteins, nucleic acids and cells [10][11][12][13]. Due to its promptness, high sensitivity and molecular specificity, SERS is particularly useful for drug detection.…”

Section: Introductionmentioning

confidence: 99%

“…The enhancement of Raman signals in SERS depends upon the intensification of the electromagnetic field of both incident and scattered radiation in the proximity of metal plasmon surfaces (electromagnetic enhancement), and/or upon the resonant or non-resonant energy transfer between the metal nanoparticle and the adsorbed molecule (chemical enhancement). Traditionally, silver-based nanomaterials are used in SERS applications, since this metal demonstrated to induce strong enhancement effects [8,9]; however, it has been already reported that silver nanostructures can easily oxidase at room temperature conditions [3] and show a strong tendency to growth and/or reshape upon prolonged irradiation [21,22]. For this reason, in recent years, the attention was focused on hybrid nanomaterials, in which the properties of two or more elements are combined in a single platform [5,7,[23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Multilayer Gold-Silver Bimetallic Nanostructures to Enhance SERS Detection of Drugs

et al. 2020

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Surface-enhanced Raman scattering (SERS) is a widely used technique for drug detection due to high sensitivity and molecular specificity. The applicability and selectivity of SERS in the detection of specific drug molecules can be improved by gathering information on the specific interactions occurring between the molecule and the metal surface. In this work, multilayer gold-silver bimetallic nanorods (Au@Ag@AuNRs) have been prepared and used as platforms for SERS detection of specific drugs (namely promethazine, piroxicam, furosemide and diclofenac). The analysis of SERS spectra provided accurate information on the molecular location upon binding and gave some insight into molecule-surface interactions and selectivity in drug detection through SERS.

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“…Raman spectra are then collected after a period of mixing, which is crucial for the metal-analyte interaction, as well as for the difficulty to guarantee the colloidal stability upon mixing with high ionic strength bio solutions [9]. Fortuni et al described a protocol for in situ growth of Au shelled Ag-NPs on polidymethylsiloxane (PDMS), which led to great polydispersity of NPs with consequent low reproducible fabrication of SERS-substrates [14]. Moreover, most of the SERS-microfluidic POC devices described, are coupled with Raman microscopes, which are expensive bench-top bulky instruments not always compatible with measurements in a clinical scenario [15][16][17].…”

mentioning

confidence: 99%

Nanostars—decorated microfluidic sensors for surface enhanced Raman scattering targeting of biomolecules

et al. 2020

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Novel localised surface plasmon resonance-based sensors exploitable as diagnostic devices through surface enhanced Raman scattering (SERS) represent a powerful solution for the analysis of liquid samples. In this work, we developed a rapid, versatile, low-cost and time-saving strategy combining advanced (3D-printing) and traditional manufacturing (replica molding) processes to prototype polymeric microfluidic devices, integrating all the components into a single portable platform. Microfluidics provide multiplexed capability, adequate miniaturization and robustness, handling simplicity, reliability, as well as low sample and reagents consumption, while the use of polydimethylsiloxane as supporting substrate drastically reduces the final cost. To introduce SERS capability, plasmonic features were incorporated functionalizing substrates with gold nanoparticles (NPs), engineered in terms of shape, size and surface chemistry to play with plasmonic properties as well as to guarantee reproducibility to the NPs immobilization step and consequently to the SERS effect for signal enhancing. To assess the feasibility of the measurements for molecules optical targeting, SERS-microfluidic systems were synergically coupled with a portable fiber-based set-up and Raman spectra of rhodamine 6 G at different concentrations were acquired. To further demonstrate the potentiality of developed SERS-based substrates as point-of-care devices, Raman analysis were successfully implemented on aqueous solutions of amyloid-β 1-42 (Aβ), considered the main biomarkers for Alzheimer's disease.© 2020 The Author(s). Published by IOP Publishing Ltd J. Phys. Photonics 2 (2020) 024008 C Dallari et al enhance the Raman signal of several order of magnitude (typically 10 6 -10 7 ) and to probe low concentration analytes localized onto or near the surface of metallic nanostructures [6,7]. The main points to be addressed when fabricating SERS-based surfaces are represented by the morphology and design of resonant metallic nanostructures and their relative distance from the target analytes. For analytical applications as well as for biosensors fabrication, the preparation of these structures has to be (i) straightforward, (ii) reproducible and (iii) cost effective to consequently (iv) guarantee a robust SERS signal [8]. To this aim, microfluidic platforms are expected to provide reproducibility of SERS analysis of liquid samples because measurements could be finely controlled on a large scale, when prone to human errors, as well as exploited when samples volumes are reduced to micron or sub-micron scale [9]. Besides this, microfluidic chips as lab-on-chip devices (LoC) can reduce the assay cost in terms of consumption of reagents, sample volumes and time. Moreover, the real possibility to perform analysis in parallel speeds up the operations while allowing the identification of multiple target analytes, avoiding cross-contamination [10,11]. In many ways, LoCs fulfil the requirements for point-of-care (POC) diagnostic device [12]. The promising future pers...

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In situ synthesis of Au-shelled Ag nanoparticles on PDMS for flexible, long-life, and broad spectrum-sensitive SERS substrates

Cited by 60 publications

References 34 publications

Simulating pH‐dependent surface‐enhanced Raman spectra by density functional theory calculations

Simulating pH‐dependent surface‐enhanced Raman spectra by density functional theory calculations

Multilayer Gold-Silver Bimetallic Nanostructures to Enhance SERS Detection of Drugs

Nanostars—decorated microfluidic sensors for surface enhanced Raman scattering targeting of biomolecules

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