Gold nanostars as SERS-active substrates for FT-Raman spectroscopy

Zoppi, Angela; Trigari, Silvana; Margheri, Giancarlo; Muniz‐Miranda, Maurizio; Giorgetti, E.

doi:10.1039/c4ra13830a

Cited by 11 publications

(8 citation statements)

References 55 publications

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“…In general, EF can be obtained by Raman measurements by considering the first factor in Eqn , along with a correction through a shielding coefficient K shielding , which takes into account the propagation of incident and scattered radiations through the colloid (second factor in Eqn ):

E F = ([], \frac{I_{italicSERS} C_{italicsol}}{I_{italicRaman} C_{italicsurf}}) \cdot \frac{1}{K_{shielding} ((), λ_{i n c})}

…”

Section: Resultsmentioning

confidence: 99%

Ag nanoparticles obtained by pulsed laser ablation in water: surface properties and SERS activity

Giorgetti

Marsili

Giammanco

et al. 2015

J Raman Spectroscopy

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We studied the surface properties and reactivity of silver nanoparticles obtained by picosecond or nanosecond pulsed laser ablation in water and with 1064-nm wavelength. Ultraviolet-visible spectroscopy results and subsequent modelling by Mie theory indicated the presence of an oxide layer on the nanoparticle surface, which favours the colloidal stability, but reduces the interaction with the environment. The oxide layer is also responsible for the reduced surface enhanced Raman spectroscopy (SERS) activity of these colloids with respect to those obtained by chemical reduction. However, SERS activation can be efficiently obtained by addition of chloride ions to the colloids, leading to SERS enhancement factors that are comparable with those of the chemically prepared counterparts.

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E F = ([], \frac{I_{italicSERS} C_{italicsol}}{I_{italicRaman} C_{italicsurf}}) \cdot \frac{1}{K_{shielding} ((), λ_{i n c})}

…”

Section: Resultsmentioning

confidence: 99%

Ag nanoparticles obtained by pulsed laser ablation in water: surface properties and SERS activity

Giorgetti

Marsili

Giammanco

et al. 2015

J Raman Spectroscopy

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“…As a result, the peak average dimension of the obtained nanoparticles is ≈130.3 nm [see the scanning electron microscope (SEM) image in the central panel of Figure 1 e]. As shown by the solid blue curve in Figure 1 b, a strong absorption peak of 96.2% was obtained at the wavelength of 661 nm with the 80% absorption band from 414 to 956 nm (or 70% absorption band from 407 to 1083 nm, demonstrating its potential application for SERS up to 1064 nm [41][42][43] , which is signifi cantly broader than the previous report. [ 24 ] It has been reported that by manipulating the effective optical constants of ultrathin vanadium dioxide layer on sapphire, perfect optical absorption can be obtained with a given layered thin-fi lm interferometer structure.…”

Section: Resultsmentioning

confidence: 90%

Ultrabroadband Metasurface for Efficient Light Trapping and Localization: A Universal Surface‐Enhanced Raman Spectroscopy Substrate for “All” Excitation Wavelengths

Zhang

Liu

et al. 2015

Adv Materials Inter

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nanoporous lithography methods, [18][19][20][21] etc. However, these techniques are still expensive and complicated for the fabrication of high quality SERS substrates over large areas, thus resulting in high prices for commercial SERS substrates. Furthermore, most commercial SERS substrates can only work for individual excitation wavelengths, i.e., one particular product works at one or two excitation wavelengths only. [22][23][24][25][26][27][28] When one wants to identify anonymous trace molecules or mixed samples, multiple excitation wavelengths will be required. [29][30][31] In this case, different substrates have to be used for different wavelength excitation, which consumes more biological/chemical materials, substrates, and measurement time. This is an obvious disadvantage for conventional SERS substrates. On the contrary, the SERS EF is proportional to the product of the fi eld intensity enhancements at both excitation and Raman scattering wavelengths. It was predicted that the maximum SERS enhancement can be achieved when localized surface plasmon resonance is located between the excitation and Raman scattering wavelengths. [ 32 ] To realize higher EF, double-resonance SERS substrates were proposed to realize strong enhancements for excitation and Raman scattered signals simultaneously using expensive e-beam lithography processes. [ 23 ] Due to the narrowband absorption spectra for both resonant bands, the enhanced SERS signal is still limited within narrow spectral regions. To address this problem, broadband resonant nanostructures are highly desired. For instance, a relatively broadband 1D metal-dielectric-metal metasurface (i.e., ≈70% optical absorption from 420 to 550 nm) was fabricated using e-beam lithography to realize uniform enhancement for SERS sensing. [ 24 ] However, the top-down lithography technique imposed a signifi cant fabrication cost barrier for large-scale practical applications. In addition, 1D grating structures are polarization dependent which can only work for given polarization states (usually transverse magnetic polarization). To overcome these limitations, here we report an ultrabroadband super absorbing metasurface substrate that can enhance the SERS signal for excitation wavelengths in a broad spectral region using lithography-free processes. [ 33 ] Most frequently used excitation wavelengths for SERS (e.g., from 450 to 1100 nm [23][24][25][26][27][28]34 ] are all covered due to the broadband light trapping and fi eld concentration within deep subwavelength Most reported surface-enhanced Raman spectroscopy (SERS) substrates can work for individual excitation wavelengths only. Therefore, different substrates have to be used for different excitation wavelengths, which consumes more biological/chemical materials, substrates, and measurement time. Here, an ultrabroadband super absorbing metasurface that can work as a universal substrate for low cost and high performance SERS sensing is reported. Due to broadband light trapping and localized fi eld enhancement, this structure can...

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“…Raman spectroscopic analysis was performed on the electrodeposited electrodes, and the resulting spectra are shown in Figure 3 b,c. Generally, the intensity of Raman signals is positively dependent on particle size [ 33 ], specific surface area [ 34 ], and the probability of SERS-active sites [ 35 ]. The spectrum of AgNF/ITO electrodes displayed peaks at 642.7, 741.2, 930.7, 1058.59, 1380, 1587, 1774, 2124.25, and 2439 cm −1 .…”

Section: Resultsmentioning

confidence: 99%

Bioelectrocatalysis of Hemoglobin on Electrodeposited Ag Nanoflowers toward H2O2 Detection

Yagati

Cho

2020

Nanomaterials

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Hydrogen peroxide (H2O2) is a partially reduced metabolite of oxygen that exerts a diverse array of physiological and pathological activities in living organisms. Therefore, the accurate quantitative determination of H2O2 is crucial in clinical diagnostics, the food industry, and environmental monitoring. Herein we report the electrosynthesis of silver nanoflowers (AgNFs) on indium tin oxide (ITO) electrodes for direct electron transfer of hemoglobin (Hb) toward the selective quantification of H2O2. After well-ordered and fully-grown AgNFs were created on an ITO substrate by electrodeposition, their morphological and optical properties were analyzed with scanning electron microscopy and UV–Vis spectroscopy. Hb was immobilized on 3-mercaptopropionic acid-coated AgNFs through carbodiimide cross-linking to form an Hb/AgNF/ITO biosensor. Electrochemical measurement and analysis demonstrated that Hb retained its direct electron transfer and electrocatalytic properties and acted as a H2O2 sensor with a detection limit of 0.12 µM and a linear detection range of 0.2 to 3.4 mM in phosphate-buffered saline (PBS). The sensitivity, detection limit, and detection range of the Hb/AgNF/ITO biosensor toward detection H2O2 in human serum was also found to be 0.730 mA mM−1 cm−2, 90 µM, and 0.2 to 2.6 mM, indicating the clinical application for the H2O2 detection of the Hb/AgNF/ITO biosensor. Moreover, interference experiments revealed that the Hb/AgNF/ITO sensor displayed excellent selectivity for H2O2.

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Gold nanostars as SERS-active substrates for FT-Raman spectroscopy

Abstract: Surfactant-free and CTAB-stabilized gold nanostars were synthesized. Their FT-SERS activity was tested. A nanomolar limit of detection and a Raman enhancement factor of more than 105 were found.

Cited by 11 publications

References 55 publications

Ag nanoparticles obtained by pulsed laser ablation in water: surface properties and SERS activity

Ag nanoparticles obtained by pulsed laser ablation in water: surface properties and SERS activity

Ultrabroadband Metasurface for Efficient Light Trapping and Localization: A Universal Surface‐Enhanced Raman Spectroscopy Substrate for “All” Excitation Wavelengths

Bioelectrocatalysis of Hemoglobin on Electrodeposited Ag Nanoflowers toward H2O2 Detection

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