Surface Enhanced Raman Scattering Investigation of the Halide Anion Effect on the Adsorption of 1,2,3Triazole on Silver and Gold Colloidal Nanoparticles (original) (raw)
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Colloidal Metal Surfaces as Biosensors of Biological Samples
Journal of Casting & Materials Engineering, 2017
Colloidal solutions of silver (AgNPs), gold (AuNPs), and platinum nanoparticles (PtNps) obtained under controlled conditions in an aqueous media by chemical methods were used as effective biosensors of biological compounds such as bombesins (BN). The BN adsorption at the metal/aqueous interface was investigated by surface-enhanced Raman scattering (SERS). Briefly, the spectral pattern of BN in the silver, gold, and platinum sols is strongly influenced by the indole ring vibrations of L-tryptophan at position 8 of the amino acid sequence (Trp 8). In addition, L-methionine (Met) at the C-terminus determines the BN adsorption, mainly onto the AuNPs and AgNPs surfaces.
2016
Introduction Material and Methods Results and Discussion Conclusion References by 91 107 111 needed. i'2Fortunately, it was found that Raman scattering can be highly enhanced at nano-roughed metal surface, which is called surface-enhanced Raman scattering (SERS). 3-6 Due to its great enhancement of Raman signal, SERS has been used to detect a variety of biomolecules including lipids, carbohydrates, DNA, peptides and proteins with a low detection of 1imit. 3'ii A number of SERS spectra of proteins have been published.iO'22 However, quantitative study of proteins by use of SERS is lack of reporting, except for one work in our group.i5 Moreover, experimental parameters for sample preparation are poorly reported in previous studies. And also the adsorption mechanism ofprotein on Ag surface has not been well investigated by use ofsERs. iO'22 Chapter 1 describes a novel method developed for protein detection used through the studies of this thesis. A heat-induced SERS-sensing method was used to selectively enhance the peak at 1049 cm'i originating from N03-for detection of proteins. A bell shape variation in the concentration dependent study was found, which can be used for semi-quarttitative detection of proteins. The detection limit for lysozyme and insulin is 1Ony9M and 1O-8M, respectively. Chapter 2 describes effects of experimental parameters on SERS intensities ofN03' and proteins by use ofthe SERS method established in Chapter 1. The results have shown that strong SERS signal can be In the present study, we have developed a novel heat-induced SERS-sensing method that can selectively enhance the peak at 1049 cm'i originating from N03' for detection of proteins without any additional resonant effect. A bell shape variation in the concentration dependent study was found, which can be used as a semi-quantitative method for protein detection. The detection limit for lysozyme and insulin is 10-9M and 10-8M, respectively. This method is simple, rapid, reproducible and label-free. The laser power is low (6 mW) and the exposure time is short (20 s), which meets the need for routine analyses. The intensity and the sharpness of the N03-peak suggest its potential in more extended applications. The bell shape indicates the potential of this method in exploring adsorption phenomenon of a protein on a colloidal interface.
Journal of Applied Physics, 2011
In this paper, we study the relationship between nanoparticles' structure/composition and the chemical nature of the molecules to be identified in surface enhanced Raman scattering (SERS) spectroscopy. Three types of nanoparticles (NPs) were synthesized, including Ag, Au, and silver coated by gold (Ag@Au), in order to study the resulting enhancement effects. When a rhodamine 6G dye molecule was used to assemble the NPs, it was found that Ag NPs exhibited the highest enhancement activity. However, when a thiol containing 3-amino-1,2,4-triazole-5-thiol molecule was used to assemble the NPs, it was found that the Ag@Au NPs exhibited high Raman activity as well as the Ag NPs. The results give insight into how the chemical properties of the molecules to be analyzed play an important role in the SERS detection. An additional parameter of the analysis reveals the relative stability of the three types of NP probes synthesized with regard to oxidation in the presence of different mediating molecules and varying salt concentrations. The results are of interest in designing and employing NP probes to detect biological molecules using colorimetric and SERS based approaches.
Applied Spectroscopy, 2008
Keywords: Nano-Au PAMAM Self-assembly SERS In this paper we report the surface-enhanced Raman scattering (SERS) spectroscopy, which is used to detect the probe in chemical and biological analysis based on the colloidal gold (Au) plasmonic resonance spectroscopy. The Au nano-particles (NP) synthesized by the hydroxylamine seed mediated growing method with controllable sizes of 30 nm, 50 nm to 90 nm, respectively, are employed to study the assembled nano-Au thickness effect. For the purpose of high sensitivity of SERS the dendrimer polyamido amine (PAMAM) is also used. The results reveal that SERS efficiency depended on the Au NPs size and the generation of dendrimer PAMAM. The highest intensity in the spectroscopy is achieved in 50 nm Au NPs assembled Si substrates, which increases significantly along with the generations of PAMAM.
The Analyst, 2013
The ability to easily prepare Surface Enhanced Raman Scattering (SERS) substrates by the assembly of chemically synthesized gold nano-colloids is of great interest for the advancement of SERS-based optical detection and identification of molecular species of biological or chemical interest, pollutants or warfare agents. In this work we employ three very simple strategies, which can be implemented in any laboratory without the need of specialized equipment, to prepare assemblies of citrate-stabilized spherical gold 10 colloids: (i) drop-coating, which induces the assembly of colloids in so-called coffee rings; (ii) a simplified variant of convective self-assembly (CSA), based on water evaporation in a constrained geometry, which yields highly uniform strips of nanoparticles (NP); (iii) assembly onto chemically functionalized glass surfaces which yields randomly assembled colloids and colloidal clusters. The SERS properties of the resulting colloidal assemblies are comparatively evaluated under multiple excitation 15 lines with p-aminothiophenol (pATP) as a model Raman scatterer. The NP strips obtained by CSA prove to be SERS-active both in the visible and NIR and posses a highly uniform SERS response as demonstrated by spectra at individually selected sites and by confocal SERS mapping. Further it is shown that these NP strips are effective for the detection of cytosine, a DNA component, and for multi-analyte SERS detection. These results, showing how an efficient SERS substrate can be obtained by a very 20 simple assembly method from easy-to-synthesize colloidal gold nanoparticles, can have an impact on the development of analytical SERS applications. 65 In this work we address the following question: what types of Au NP assemblies can be prepared by very simple methods, without using special equipment, to make SERS substrates of decent quality for SERS-based detection and analytical applications? Accordingly we propose three different assembly strategies, 70 65
Gold nanoparticles as a substrate in bio-analytical near-infrared surface-enhanced Raman scattering
The Analyst, 2015
As biospectroscopy techniques continue to be developed for screening or diagnosis within a point-of-care setting, an important development for this field will be high-throughput optimization. For many of these techniques, it is therefore necessary to adapt and develop parameters to generate a robust yet simple approach delivering high-quality spectra from biological samples. Specifically, this is important for surface-enhanced Raman spectroscopy (SERS) wherein there are multiple variables that can be optimised to achieve an enhancement of the Raman signal from a sample. One hypothesis is that "large" diameter (>100 nm) gold nanoparticles provide a greater enhancement at near-infrared (NIR) and infrared (IR) wavelengths than those <100 nm in diameter. Herein, we examine this notion using examples in which SERS spectra were acquired from MCF-7 breast cancer cells incubated with 150 nm gold nanoparticles. It was found that 150 nm gold nanoparticles are an excellent material for NIR/IR SERS. Larger gold nanoparticles may better satisfy the theoretical restraints for SERS enhancement at NIR/IR wavelengths compared to smaller nanoparticles. Also, larger nanoparticles or their aggregates are more readily observed via optical microscopy (and especially electron microscopy) compared to smaller ones. This allows rapid and straightforward identification of target areas containing a high concentration of nanoparticles and facilitating SERS spectral acquisition. To some extent, these observations appear to extend to biofluids such as blood plasma or (especially) serum; SERS spectra of such biological samples often exhibit a low signal-to-noise ratio in the absence of nanoparticles. With protein-rich biofluids such as serum, a dramatic SERS effect can be observed; although this might facilitate improved spectral biomarker identification in the future, it may not always improve classification between control vs. cancer. Thus, use of "large" gold nanoparticles are a good starting point in order to derive informative NIR/IR SERS analysis of biological samples.
Journal of Molecular Structure, 2009
We investigate the direct interaction between bovine serum albumin (BSA) protein and the surface of gold nanoparticles (GNPs) of different shapes (nanospheres and nanorods) by using localized surface plasmon resonance (LSPR) spectroscopy, fluorescence spectroscopy and surface-enhanced Raman scattering (SERS). The spectral modifications observed in LSPR bands of GNPs after mixing with BSA are consistent with the formation of protein-GNPs bioconjugates. While the monitoring of fluorescence quenching of tryptophan residues from BSA in the presence of GNPs is exploited for determining the binding constant (K b ) and the numbers of binding sites (n), the SERS data allow us to reveal some specific molecular groups involved in conjugation.
Chemistry - A European Journal, 2010
The synthesis, characterization, and assembly of different types of nanoparticles, which was established as a necessary prerequisite for the application of nanotechnology, have dramatically advanced over the last 20 years. However, it has recently been realized that the incorporation of multiple functionalities within nanoscale systems would become much more useful for most of the foreseen applications. Thus, the fabrication of multifunctional nanoparticles has become a major challenge. Among these systems, the incorporation of active (optically, catalytically, magnetically…) nanoparticles within so-called "smart" thermosensitive microgels has received significant attention over the last few years. The incorporation of nanoparticles can be accomplished either by in situ formation, by post-synthesis assembly or by direct polymerization on the nanoparticles surface. We have recently reported the growth of thermosensitive poly(N-isopropylacrylamide) (pNIPAM) microgels on the surface of gold nanoparticles, involving several steps, including the formation of a first polystyrene thin layer, followed by pNIPAM polymerization after the required purification process. Although gold nanoparticle growth could be achieved within the microgel shell, this synthesis was restricted to spherical nanoparticle seeds, whereas, for example, nanorods (which display a much more interesting optical response) were not properly incorporated. Thus, there was a need to both simplify the coating process and make it more widely applicable.
Journal of the Chilean Chemical Society
The development of new biomaterials has gained increasing attention in the last decade. One of the most important aspects in the development of these new materials is to understand the chemical cues presents in the native niche. Among all the techniques currently available for measuring those interactions, Raman spectroscopy offers a unique and non-invasive tool for exploring the behavior of the components within a given biomaterial and their surrounding microenvironment. This technique exploits the unique molecular vibrational fingerprints for pinpointing those interactions. The vibrational response can be improved to the single molecule level, in the presence of metal nanoparticles (NPs) with plasmonic properties (silver, gold and copper) in the so-called Surface-Enhanced Raman Scattering (SERS), which can be used for in-situ measurements. Another technique recently developed is the Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy (SHINERS), which overcomes signal contamination from chemical interactions between biomolecules and the metal surface; it does this by coating the metal surface with an inert layer of alumina or silica. In the present contribution, the role and the applications of Raman, SERS and related spectroscopic techniques in the study of biomolecules in biomaterials are reviewed and discussed.