scholarly journals Halloysite Nanotubes with Immobilized Plasmonic Nanoparticles for Biophotonic Applications

2021 ◽  
Vol 11 (10) ◽  
pp. 4565
Author(s):  
Anastasiia V. Kornilova ◽  
Sergey M. Novikov ◽  
Galiya A. Kuralbayeva ◽  
Subhra Jana ◽  
Ivan V. Lysenko ◽  
...  
Keyword(s):  
Electric Fields ◽  
Halloysite Nanotubes ◽  
Plasmonic Nanoparticles ◽  
Ag Nps ◽  
Optical Extinction ◽  
Transmission Electron ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Halloysite nanotubes (HNTs) with immobilized gold (Au) and silver (Ag) nanoparticles (NPs) belong to a class of nanocomposite materials whose physical properties and applications depend on the geometry of arrangements of the plasmonic nanoparticles on HNT’ surfaces. We explore HNTs:(Au, Ag)-NPs as potential nano-templates for surface-enhanced Raman scattering (SERS). The structure and plasmonic properties of nanocomposites based on HNTs and Au- and Ag-NPs are studied by means of the transmission electron microscopy and optical spectroscopy. The optical extinction spectra of aqueous suspensions of HNTs:(Au, Ag)-NPs and spatial distributions of the electric fields are simulated, and the simulation results demonstrate the corresponding localized plasmonic resonances and numerous “hot spots” of the electric field nearby those NPs. In vitro experiments reveal an enhancement of the protein SERS in fibroblast cells with added HNTs:Ag-NPs. The observed optical properties and SERS activity of the nanocomposites based on HNTs and plasmonic NPs are promising for their applications in biosensorics and biophotonics.

Local Electric Field Enhancement of Neighboring Ag Nanoparticles in Surface Enhanced Raman Scattering

2013 ◽  
Vol 760-762 ◽  
pp. 801-805 ◽  
Author(s):  
Chao Yue Deng ◽  
Gu Ling Zhang ◽  
Bin Zou ◽  
Hong Long Shi ◽  
Yu Jie Liang ◽  
...  
Keyword(s):  
Electric Field ◽  
Raman Scattering ◽  
Electric Fields ◽  
Ag Nanoparticles ◽  
Surface Enhanced Raman Scattering ◽  
Ag Nps ◽  
Sers Enhancement ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

We used a simple low-temperature hydrothermal approach to synthesize Ag nanoparticles (NPs) and demonstrated their efficiency as organic molecule detectors in surface enhanced Raman Scattering (SERS). Using finite difference time domain simulation, we described an investigation on the distribution of electric fields amplitude of the neighboring Ag NPs. The enhanced electric field is confined at the interparticle gaps and the enhancement factor can be further increased with reducing the spacing between the NPs. The theoretical simulation demonstrated good consistency with the experimental measurement results, which predicts an electric fields amplitude enhancement of 115 at the center of NPs gap and an electromagnetic SERS enhancement of 108. The evidence of clear correlations between SERS enhancement and morphology distribution offer a route to develop more effective SERS substrates.

scholarly journals Electric-Field Enhanced Molecule Detection in Suspension on Assembled Plasmonic Arrays by Raman Spectroscopy

2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Chao Liu ◽  
Xiaobin Xu ◽  
D. L. Fan
Keyword(s):  
Electric Fields ◽  
Nile Blue ◽  
Ag Nps ◽  
Dual Roles ◽  
Reaction Conditions ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
New Type ◽  
Enhanced Raman Scattering ◽  
Sers Sensing

One of the greatest challenges in surface enhanced Raman scattering (SERS) sensing is to detect biochemicals directly from suspension with ultrasensitivity. In this work, we employed strategically designed longitudinal nanocapsule structures with uniformly surface distributed Ag nanoparticles (Ag NPs) to dually focus and enhance SERS sensitivity of biochemicals in suspension assisted with electric fields. By tuning the reaction conditions, Ag NPs were synthesized and uniformly grown with optimized sizes and junctions on the surface of nanocapsules for well reproducible detection. The Ag NPs can further concentrate molecules from suspension due to induced electrokinetic effects in electric fields. As a result, the signals of Nile blue molecules can be enhanced by 34.4±3.1% at optimal alternating current (AC) frequencies and voltages compared to that without electric fields. This work demonstrates the dual roles of a new type of plasmonic NPs for molecule concentration and detection, which could inspire new Raman sensing devices for applications in microfluidics.

scholarly journals Large-Scale Fabrication of Ultrasensitive and Uniform Surface-Enhanced Raman Scattering Substrates for the Trace Detection of Pesticides

Nanomaterials ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 520 ◽  
Author(s):  
Jia Zhu ◽  
Guanzhou Lin ◽  
Meizhang Wu ◽  
Zhuojie Chen ◽  
Peimin Lu ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Large Scale ◽  
Capillary Flow ◽  
Surface Enhanced Raman Scattering ◽  
Ag Nps ◽  
Uniform Size ◽  
Sers Substrates ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Technology transfer from laboratory into practical application needs to meet the demands of economic viability and operational simplicity. This paper reports a simple and convenient strategy to fabricate large-scale and ultrasensitive surface-enhanced Raman scattering (SERS) substrates. In this strategy, no toxic chemicals or sophisticated instruments are required to fabricate the SERS substrates. On one hand, Ag nanoparticles (NPs) with relatively uniform size were synthesized using the modified Tollens method, which employs an ultra-low concentration of Ag+ and excessive amounts of glucose as a reducing agent. On the other hand, when a drop of the colloidal Ag NPs dries on a horizontal solid surface, the droplet becomes ropy, turns into a layered structure under gravity, and hardens. During evaporation, capillary flow was burdened by viscidity resistance from the ropy glucose solution. Thus, the coffee-ring effect is eliminated, leading to a uniform deposition of Ag NPs. With this method, flat Ag NPs-based SERS active films were formed in array-well plates defined by hole-shaped polydimethylsiloxane (PDMS) structures bonded on glass substrates, which were made for convenient detection. The strong SERS activity of these substrates allowed us to reach detection limits down to 10−14 M of Rhodamine 6 G and 10−10 M of thiram (pesticide).

scholarly journals Multiplexed Liquid Biopsy and Tumor Imaging Using Surface-Enhanced Raman Scattering

Biosensors ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 449
Author(s):  
Francesco Dell’Olio
Keyword(s):  
Raman Scattering ◽  
Single Molecule ◽  
Liquid Biopsy ◽  
Tumor Imaging ◽  
Surface Enhanced Raman Scattering ◽  
Detection Sensitivity ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

The recent improvements in diagnosis enabled by advances in liquid biopsy and oncological imaging significantly better cancer care. Both these complementary approaches, which are used for early tumor detection, characterization, and monitoring, can benefit from applying techniques based on surface-enhanced Raman scattering (SERS). With a detection sensitivity at the single-molecule level, SERS spectroscopy is widely used in cell and molecular biology, and its capability for the in vitro detection of several types of cancer biomarkers is well established. In the last few years, several intriguing SERS applications have emerged, including in vivo imaging for tumor targeting and the monitoring of drug release. In this paper, selected recent developments and trends in SERS applications in the field of liquid biopsy and tumor imaging are critically reviewed, with a special emphasis on results that demonstrate the clinical utility of SERS.

scholarly journals Nanoporous Ag-Au Bimetallic Triangular Nanoprisms Synthesized by Galvanic Replacement for Plasmonic Applications

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Hongmei Qian ◽  
Shoaib Anwer ◽  
G. Bharath ◽  
Shahid Iqbal ◽  
Lijuan Chen
Keyword(s):  
Metallic Nanoparticles ◽  
Galvanic Replacement ◽  
Transmission Electron ◽  
Surface Plasmon Coupling ◽  
Surface Enhanced ◽  
Particle Aggregates ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Good Biocompatibility ◽  
Elementary Mapping

Galvanic replacement is a versatile method of converting simple noble metallic nanoparticles into structurally more complex porous multimetallic nanostructures. In this work, roughened nanoporous Ag-Au bimetallic triangular nanoprisms (TNPs) are synthesized by galvanic replacement between smooth Ag triangular plates and AuCl4− ions. Transmission electron microscope and the elementary mapping measurements show that numerous protrusions and pores are formed on the {111} facets, and Ag and Au atoms are homogeneously distributed on the triangular plates. Due to the additional “hot spots” generated by the surface plasmon coupling of the newly formed protrusions and pores, the roughened nanoporous Ag-Au TNP aggregates demonstrate a higher surface-enhanced Raman scattering enhancement factor (seven times larger) and better reproducibility than that of smooth Ag triangular particle aggregates. These synthesized roughened nanoporous Ag-Au bimetallic TNPs are a promising candidate for the applications in analytical chemistry, biological diagnostics, and photothermal therapy due to their excellent plasmonic performances and good biocompatibility.

scholarly journals Fabrication and Characterization of a Highly-Sensitive Surface-Enhanced Raman Scattering Nanosensor for Detecting Glucose in Urine

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 629 ◽  
Author(s):  
Yudong Lu ◽  
Ting Zhou ◽  
Ruiyun You ◽  
Yang Wu ◽  
Huiying Shen ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Internal Standard ◽  
Surface Enhanced Raman Scattering ◽  
Quantitative Detection ◽  
Core Shell ◽  
Ag Nps ◽  
Vis Spectroscopy ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Herein we utilized coordination interactions to prepare a novel core-shell plasmonic nanosensor for the detection of glucose. Specifically, Au nanoparticles (NPs) were strongly linked with Ag+ ions to form a sacrificial Ag shell by using 4-aminothiophenol (4-PATP) as a mediator, which served as an internal standard to decrease the influence of the surrounding on the detection. The resultant Au-PATP-Ag core-shell systems were characterized by UV-vis spectroscopy, transmission electron microscopy, and surface-enhanced Raman scattering (SERS) techniques. Experiments performed with R6G (rhodamine 6G) and CV (crystal violet) as Raman reporters demonstrated that the Au@Ag nanostructure amplified SERS signals obviously. Subsequently, the Au@Ag NPs were decorated with 4-mercaptophenylboronic acid (4-MPBA) to specifically recognize glucose by esterification, and a detection limit as low as 10−4 M was achieved. Notably, an enhanced linearity for the quantitative detection of glucose (R2 = 0.995) was obtained after the normalization of the spectral peaks using 4-PATP as the internal standard. Finally, the practical applicability of the developed sensing platform was demonstrated by the detection of glucose in urine with acceptable specificity.

Au-on-Ag nanostructure for in-situ SERS monitoring of catalytic reactions

2022 ◽  
Author(s):  
Shuyue He ◽  
Di Wu ◽  
Siwei Chen ◽  
Kai Liu ◽  
Eui-Hyeok Yang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Thermal Evaporation ◽  
Reduction Process ◽  
Ag Nps ◽  
Au Nps ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Raman Probe

Abstract Dual-functionality Au-on-Ag nanostructures (AOA) were fabricated on a silicon substrate by first immobilizing citrate-reduced Ag nanoparticles (Ag NPs, ~43 nm in diameter), followed by depositing ~7 nm Au nanofilms (Au NFs) via thermal evaporation. Au NFs were introduced for their catalytic activity in concave-convex nano-configuration. Ag NPs underneath were used for their significant enhancement factor (EF) in surface-enhanced Raman scattering (SERS)-based measurements of analytes of interest. Rhodamine 6G (R6G) was utilized as the Raman-probe to evaluate the SERS sensitivity of AOA. The SERS EF of AOA is ~37 times than that of Au NPs. Using reduction of 4-nitrothiophenol (4-NTP) by sodium borohydride (NaBH4) as a model reaction, we demonstrated the robust catalytic activity of AOA as well as its capacity to continuously monitor via SERS the disappearance of reactant 4-NTP, emergence and disappearance of intermediate 4, 4’-DMAB, and the appearance of product 4-ATP throughout the reduction process in real-time and in situ.

scholarly journals Optical Diagnostic Based on Functionalized Gold Nanoparticles

2019 ◽  
Vol 20 (18) ◽  
pp. 4346 ◽  
Author(s):  
Jiemei Ou ◽  
Zidan Zhou ◽  
Zhong Chen ◽  
Huijun Tan
Keyword(s):  
Optical Properties ◽  
Future Perspective ◽  
Au Nps ◽  
Optical Diagnostic ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Diagnostic Applications

Au nanoparticles (NPs) possess unique physicochemical and optical properties, showing great potential in biomedical applications. Diagnostic spectroscopy utilizing varied Au NPs has become a precision tool of in vitro and in vivo diagnostic for cancer and other specific diseases. In this review, we tried to comprehensively introduce the remarkable optical properties of Au NPs, including localized surfaces plasmon resonance (LSPR), surface-enhanced Raman scattering (SERS), and metal-enhanced fluorescence (MEF). Then, we highlighted the excellent works using Au NPs for optical diagnostic applications. Ultimately, the challenges and future perspective of using Au NPs for optical diagnostic were discussed.

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