Improved Label-Free Identification of Individual Exosome-like Vesicles with Au@Ag Nanoparticles as SERS Substrate

2019 ◽  
Vol 11 (43) ◽  
pp. 39424-39435 ◽  
Author(s):  
Juan C. Fraire ◽  
Stephan Stremersch ◽  
Davinia Bouckaert ◽  
Tinne Monteyne ◽  
Thomas De Beer ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Sers Substrate ◽  
Label Free

scholarly journals Label-free highly sensitive probe detection with novel hierarchical SERS substrates fabricated by nanoindentation and chemical reaction methods

2019 ◽  
Vol 10 ◽  
pp. 2483-2496
Author(s):  
Jingran Zhang ◽  
Tianqi Jia ◽  
Yongda Yan ◽  
Li Wang ◽  
Peng Miao ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Enhancement Factor ◽  
Low Cost ◽  
Hierarchical Structures ◽  
Production Method ◽  
Copper Surface ◽  
Sers Substrate ◽  
Label Free ◽  
Sers Substrates ◽  
Highly Sensitive

Nanostructures have been widely employed in surface-enhanced Raman scattering (SERS) substrates. Recently, in order to obtain a higher enhancement factor at a lower detection limit, hierarchical structures, including nanostructures and nanoparticles, appear to be viable SERS substrate candidates. Here we describe a novel method integrating the nanoindentation process and chemical redox reaction to machine a hierarchical SERS substrate. The micro/nanostructures are first formed on a Cu(110) plane and then Ag nanoparticles are generated on the structured copper surface. The effect of the indentation process parameters and the corrosion time in the AgNO3 solution on the Raman intensities of the SERS substrate with hierarchical structures are experimentally studied. The intensity and distribution of the electric field of single and multiple Ag nanoparticles on the surface of a plane and with multiple micro/nanostructures are studied with COMSOL software. The feasibility of the hierarchical SERS substrate is verified using R6G molecules. Finally, the enhancement factor using malachite green molecules was found to reach 5.089 × 109, which demonstrates that the production method is a simple, reproducible and low-cost method for machining a highly sensitive, hierarchical SERS substrate.

Flexible porous aerogels decorated with Ag nanoparticles as an effective SERS substrate for label-free trace explosives detection

2020 ◽  
Vol 12 (33) ◽  
pp. 4123-4129
Author(s):  
Wei Liu ◽  
Zihao Song ◽  
Yifan Zhao ◽  
Yu Liu ◽  
Xuan He ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Porous Silica ◽  
Silica Aerogels ◽  
Explosives Detection ◽  
Sers Substrate ◽  
Label Free ◽  
Ag Nanoparticle ◽  
Label Free Detection ◽  
Trace Explosives

Ag nanoparticle decorated porous silica aerogels as a flexible SERS substrate for sensitive, stable and label-free detection of explosive NTO was reported. And this substrate has a certain application prospect in the field of explosives sensing.

scholarly journals Design of Inverted Nano-Cone Arrayed SERS Substrate for Rapid Detection of Pathogens

2021 ◽  
Vol 11 (17) ◽  
pp. 8067
Author(s):  
Zixun Jia ◽  
Sarah Asiri ◽  
Asma Elsharif ◽  
Widyan Alamoudi ◽  
Ebtesam Al-Suhaimi ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Rapid Detection ◽  
Close Contact ◽  
Surface Enhanced Raman Spectroscopy ◽  
Sers Substrate ◽  
Label Free ◽  
Surface Enhanced Raman ◽  
Order Of Magnitude ◽  
The Right ◽  
Pathogen Diagnosis

Rapid detection of bacteria is a very critical and important part of infectious disease treatment. Sepsis kills more than 25 percent of its victims, resulting in as many as half of all deaths in hospitals before identifying the pathogen for patients to get the right treatment. Raman spectroscopy is a promising candidate in pathogen diagnosis given its fast and label-free nature, only if the concentration of the pathogen is high enough to provide reasonable sensitivity. This work reports a new design of surface-enhanced Raman spectroscopy (SERS) substrate which will provide high enough sensitivity and fast and close contact of the target structure to the optical hot spots for immunomagnetic capturing-based bacteria-concentrating technique. The substrate uses inverted nanocone structure arrays made of transparent PDMS (Polydimethylsiloxane) to funnel the light from the bottom to the top of the cones where plasmonic gold nanorods are located. A high reflective and low loss layer is deposited on the outer surface of the cone. Given the geometry of cones, photons are multi-reflected by the outer layer and thus the number density of photons at hotspots increases by an order of magnitude, which could be high enough to detect immunomagnetically densified bacteria.

scholarly journals Development of Effectual Substrates for SERS by Nanostructures-on flexible surfaces

2021 ◽  
Vol 2114 (1) ◽  
pp. 012084
Author(s):  
Hammad R. Humud ◽  
Fatimah Jumaah Moaen
Keyword(s):  
Raman Scattering ◽  
Ag Nanoparticles ◽  
Surface Enhanced Raman Scattering ◽  
Wave Number ◽  
Plasmonic Nanostructures ◽  
Sers Substrate ◽  
Two Dimensional ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Abstract The current study examines recent advancements in surface-enhanced Raman scattering (SERS), a technique that employs flexible surfaces as an active substrate, this surfaces consist from two-dimensional thermo-plasmonic grating. With 53 nm Au layer (was deposited on the 2D grating structure of the PDMS by the PVD method). The explosive wire technique was used to preparing Ag nanoparticles that were used for the purpose of SERS. The effect of the plasmonic nanostructures on the absorption spectra and Surface - Enhanced Raman Scattering (SERS) activities was examined. Rhodamine 6G dye was used as a probe molecule. X-Ray diffraction (XRD) was used to examine the structural characteristics of the nanoparticles. The morphology was assessed using Field Emission Scanning Electron Microscopy(FESEM). A twin beam UV-Vis Spectrophotometer was used to measure the absorption of the combined Rh6G dye (concentration 1×10“–6M) with the nanostructures. a Sunshine Raman microscope system and a 50mm objective lens, used for investigating the Raman spectra of the Rh6G combined with nanostructures. The results showed that the enhancement factor (EF) for SERS of R6G (1×M) reached to (2.2×10 3) When using Ag nanoparticles and (0.08 × 103) when R6G deposited directly on the flexible substrates without nanostructures at the wave number (1650 cm−1), we produced a recyclable, homogeneous, and highly sensitive SERS substrate with dependable reproducibility. For the SERS substrate, a surface made up of two-dimensional (2D) flexible grating substrates was chosen to provide multiple modalities in electrical and medicinal applications.

scholarly journals Organic Molecule Detection Based on SERS in Microfluidics

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xin Zhang ◽  
Haiyan Zhang ◽  
Sheng Yan ◽  
Zugang Zeng ◽  
Anshou Huang ◽  
...  
Keyword(s):  
Environmental Monitoring ◽  
Ag Nanoparticles ◽  
Organic Molecule ◽  
Organic Molecules ◽  
Chemical Reduction ◽  
Fdtd Method ◽  
Great Influence ◽  
High Sensitivity ◽  
Surface Enhanced Raman Spectroscopy ◽  
Sers Substrate

AbstractSensitive in situ detection of organic molecules is highly demanded in environmental monitoring. In this work, the surface enhanced Raman spectroscopy (SERS) is adopted in microfluidics to detect the organic molecules with high accuracy and high sensitivity. Here the SERS substrate in microchannel consists of Ag nanoparticles synthesized by chemical reduction. The data indicates the fabrication conditions have great influence on the sizes and distributions of Ag nanoparticles, which play an important role on the SERS enhancement. This result is further confirmed by the simulation of electromagnetic field distributions based on finite difference time domain (FDTD) method. Furthermore, the SERS spectra of organic molecule (methylene blue) obtained in this plasmonic microfluidic system exhibit good reproducibility with high sensitivity. By a combination of SERS and microfluidics, our work not only explores the research field of plasmonics but also has broad application prospects in environmental monitoring.

scholarly journals Application of Aluminum Hydroxide for Improvement of Label-Free SERS Detection of Some Cephalosporin Antibiotics in Urine

Biosensors ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 91 ◽  
Author(s):  
Natalia E. Markina ◽  
Alexey V. Markin
Keyword(s):  
Aluminum Hydroxide ◽  
Surface Enhanced Raman Spectroscopy ◽  
Negative Influence ◽  
Quantitative Detection ◽  
Therapeutic Drug ◽  
Excitation Wavelength ◽  
Sers Substrate ◽  
Label Free ◽  
Surface Enhanced Raman ◽  
Sers Detection

This report is dedicated to development of surface-enhanced Raman spectroscopy (SERS) based analysis protocol for detection of antibiotics in urine. The key step of the protocol is the pretreatment of urine before the detection to minimize background signal. The pretreatment includes extraction of intrinsic urine components using aluminum hydroxide gel (AHG) and further pH adjusting of the purified sample. The protocol was tested by detection of a single antibiotic in artificially spiked samples of real urine. Five antibiotics of cephalosporin class (cefazolin, cefoperazone, cefotaxime, ceftriaxone, and cefuroxime) were used for testing. SERS measurements were performed using a portable Raman spectrometer with 638 nm excitation wavelength and silver nanoparticles as SERS substrate. The calibration curves of four antibiotics (cefuroxime is the exception) cover the concentrations required for detection in patient’s urine during therapy (25/100‒500 μg/mL). Random error of the analysis (RSD < 20%) and limits of quantification (20‒90 μg/mL) for these antibiotics demonstrate the applicability of the protocol for reliable quantitative detection during therapeutic drug monitoring. The detection of cefuroxime using the protocol is not sensitive enough, allowing only for qualitative detection. Additionally, time stability and batch-to-batch reproducibility of AHG were studied and negative influence of the pretreatment protocol and its limitations were estimated and discussed.

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