scholarly journals SERS Effect on Spin-Coated Seeding of Tilted Au-ZnO Nanorods for Low-Cost Diagnosis

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5321
Author(s):  
Miyeon Jue ◽  
Chan-Gi Pack ◽  
Seakhee Oh ◽  
Bjorn Paulson ◽  
Kwanhee Lee ◽  
...  

Uniformly parallel Au-coated ZnO nanorods have previously been shown to amplify local Raman signals, providing increased sensitivity to disease markers in the detection of inflammation and cancer. However, practical and cost-effective fabrication methods of substrates for surface-enhanced Raman spectroscopy (SERS) fail to produce highly uniform surfaces. Here, the feasibility of Raman enhancement on less-uniform substrates is assessed. ZnO nanorod structures were fabricated by hydrothermal synthesis, starting from spin-coated seed substrates. Following analysis, the nanostructures were coated with Au to create stochastically variant substrates. The non-uniformity of the fabricated Au-coated ZnO nanorod structures is confirmed morphologically by FE-SEM and structurally by X-ray diffraction, and characterized by the angular distributions of the nanorods. Monte Carlo finite element method simulations matching the measured angular distributions and separations predicted only moderate increases in the overall Raman enhancement with increasing uniformity. Highly variant substrates exhibited approximately 76% of the Raman enhancement of more uniform substrates in simulations and experiments. The findings suggest that, although highly inhomogeneous Au-coated ZnO nanorod substrates may not attain the same Raman enhancement as more uniform substrates, the relaxation of fabrication tolerances may be economically viable.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Angela Capaccio ◽  
Antonio Sasso ◽  
Giulia Rusciano

AbstractThe fabrication of plasmonic nanostructures with a reliable, low cost and easy approach has become a crucial and urgent challenge in many fields, including surface-enhanced Raman spectroscopy (SERS) based applications. In this frame, nanoporous metal films are quite attractive, due to their intrinsic large surface area and high density of metal nanogaps, acting as hot-spots for Raman signal enhancement. In this paper, we report a detailed study on the fabrication of nanoporous silver-based SERS substrates, obtained by the application of two successive treatments with an Inductively Coupled Plasma (ICP) system, using synthetic air and Ar as feeding gases. The obtained substrates exhibit a quite broad plasmonic response, covering the Vis–NIR range, and an enhancement factor reaching 6.5 $$\times\, 10^7$$ × 10 7 , estimated by using 4-mercaptobenzoic acid (4-MBA) as probe molecule at 532 nm. Moreover, the substrates exhibit a quite good spatial reproducibility on a centimeter scale, which assures a good signal stability for analytical measurements. Globally, the developed protocol is easy and cost effective, potentially usable also for mass production thanks to the remarkable inter-batches reproducibility. As such, it holds promise for its use in SERS-based sensing platforms for sensitive detection of targets molecules.


Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3184
Author(s):  
Gitchka G. Tsutsumanova ◽  
Neno D. Todorov ◽  
Stoyan C. Russev ◽  
Miroslav V. Abrashev ◽  
Victor G. Ivanov ◽  
...  

Micro- and nanoflowers are a class of materials composed of particles with high surface-to-volume ratio. They have been extensively studied in the last decade due to simple preparation protocols and promising applications in biosensing, as drug delivery agents, for water purification, and so on. Flowerlike objects, due to their highly irregular surface, may act also as plasmonic materials, providing resonant coupling between optical waves and surface plasmon excitations. This fact allows us to infer the possibility to use micro- and nanoflowers as effective surface-enhanced Raman scattering (SERS) substrate materials. Here, we report on the design and Raman enhancement properties of silver flowerlike structures, deposited on aluminum surface. A simple and cost-effective fabrication method is described, which leads to SERS substrates of high developed surface area. The morphology of the silver flowers on a nanoscale is characterized by self-organized quasiperiodic stacks of nanosheets, which act as plasmonic cavity resonators. The substrates were tested against rhodamine-6G (R6G) water solutions of concentration varying between 10−3 M and 10−7 M. Optimal SERS enhancement factors of up to 105 were established at R6G concentrations in the 10−6–10−7 M range.


Author(s):  
Victor Genchev Ivanov ◽  
Gitchka Tsutsumanova ◽  
Neno Todorov ◽  
Stoyan Russev ◽  
Miroslav Abrashev ◽  
...  

Micro- and nanoflowers are a class of materials composed of particles with high surface-to-volume ratio. They are being extensively studied in the last decade due to simple preparation protocols and promising applications in biosensing, as drug delivery agents, for water purification and so on. Flowerlike objects, due to their highly irregular surface, may act also as plasmonic materials, providing resonant coupling between optical waves and surface plasmon excitations. This fact infers for the possibility to use micro- and nanoflowers as effective surface-enhanced Raman scattering (SERS) substrate materials. Here, we report on the design and Raman enhancement properties of silver flowerlike structures, deposited on aluminum surface. A simple and cost-effective fabrication method is described, which leads to SERS substrates of high developed surface area. The morphology of the silver flowers on a nanoscale is characterized by self-organized quasiperiodic stacks of nanosheets, which act as plasmonic cavity-resonators. The substrates were tested against rhodamine-6G (R6G) water solutions of concentration varying between 10–3 M and 10–7 M. Optimal SERS enhancement factors of up to 105 were established at R6G concentrations in the range 10–6 – 10–7 M.


Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 886
Author(s):  
Massimo Rippa ◽  
Riccardo Castagna ◽  
Domenico Sagnelli ◽  
Ambra Vestri ◽  
Giorgia Borriello ◽  
...  

Brucella is a foodborne pathogen globally affecting both the economy and healthcare. Surface Enhanced Raman Spectroscopy (SERS) nano-biosensing can be a promising strategy for its detection. We combined high-performance quasi-crystal patterned nanocavities for Raman enhancement with the use of covalently immobilized Tbilisi bacteriophages as high-performing bio-receptors. We coupled our efficient SERS nano-biosensor to a Raman system to develop an on-field phage-based bio-sensing platform capable of monitoring the target bacteria. The developed biosensor allowed us to identify Brucella abortus in milk by our portable SERS device. Upon bacterial capture from samples (104 cells), a signal related to the pathogen recognition was observed, proving the concrete applicability of our system for on-site and in-food detection.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1197
Author(s):  
Xiaoyu Zhao ◽  
Aonan Zhu ◽  
Yaxin Wang ◽  
Yongjun Zhang ◽  
Xiaolong Zhang

In the present study, a sunflower-like nanostructure array composed of a series of synaptic nanoparticles and nanospheres was manufactured through an efficient and low-cost colloidal lithography technique. The primary electromagnetic field contribution generated by the synaptic nanoparticles of the surface array structures was also determined by a finite-difference time-domain software to simulate the hotspots. This structure exhibited high repeatability and excellent sensitivity; hence, it was used as a surface-enhanced Raman spectroscopy (SERS) active substrate to achieve a rapid detection of ultra-low concentrations of Alpha-fetoprotein (AFP). This study demonstrates the design of a plasmonic structure with strong electromagnetic coupling, which can be used for the rapid detection of AFP concentration in clinical medicine.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 518
Author(s):  
Margherita Longoni ◽  
Maria Sole Zalaffi ◽  
Lavinia de Ferri ◽  
Angela Maria Stortini ◽  
Giulio Pojana ◽  
...  

The electrochemical preparation of arrays of copper ultramicrowires (CuUWs) by using porous membranes as templates is critically revisited, with the goal of obtaining cheap but efficient substrates for surface enhanced Raman spectroscopy (SERS). The role of the materials used for the electrodeposition is examined, comparing membranes of anodized aluminum oxide (AAO) vs. track-etched polycarbonate (PC) as well as copper vs. glassy carbon (GC) as electrode material. A voltammetric study performed on bare electrodes and potentiostatic tests on membrane coated electrodes allowed the optimization of the deposition parameters. The final arrays of CuUWs were obtained by chemical etching of the template, with NaOH for AAO and CH2Cl2 for PC. After total etching of the template, SERS spectra were recorded on CuUWs using benzenethiol as SERS probe with known spectral features. The CuUW substrates displayed good SERS properties, providing enhancement factor in the 103–104 range. Finally, it was demonstrated that higher Raman enhancement can be achieved when CuUWs are decorated with silver nanostars, supporting the formation of SERS active hot-spots at the bimetallic interface.


Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 688 ◽  
Author(s):  
Asli Yilmaz ◽  
Mehmet Yilmaz

Despite numerous attempts to fabricate the core–shell nanoparticles, novel, simple, and low-cost approaches are still required to produce these efficient nanosystems. In this study, we propose the synthesis of bimetallic core–shell nanoparticles of gold (AuNP) and silver (AgNP) nanostructures via a bioinspired polydopamine (PDOP) layer and their employment as a surface-enhanced Raman spectroscopy (SERS) platform. Herein, the PDOP layer was used as an interface between nanostructures as well as stabilizing and reducing agents for the deposition of silver ions onto the AuNPs. UV-vis absorption spectra and electron microscope images confirmed the deposition of the silver ions and the formation of core–shell nanoparticles. SERS activity tests indicated that both the PDOP thickness and silver deposition time are the dominant parameters that determine the SERS performances of the proposed core–shell system. In comparison to bare AuNPs, more than three times higher SERS signal intensity was obtained with an enhancement factor of 3.5 × 105.


2006 ◽  
Vol 951 ◽  
Author(s):  
Motofumi Suzuki ◽  
Kaoru Nakajima ◽  
Kenji Kimura ◽  
Takao Fukuoka ◽  
Yasushige Mori

ABSTRACTWe have demonstrated surface-enhanced Raman spectroscopy on arrays of Au nanorods aligned in line by a dynamic oblique deposition technique. For the light polarized along the major axis of the nanorods, the plasma resonance of the Au nanorods has been tuned to a wavelength suitable for Raman spectroscopy. The Raman scattering on the discrete nanorods is enhanced significantly compared with that on semi continuous Au films. Since the preparation process is physically bottom-up, it is robust in its selection of the materials and is useful in providing the SERS sensors at low cost.


2021 ◽  
Author(s):  
revathy m s ◽  
D Murugesan ◽  
Naidu Dhanpal Jayram

Abstract Thin films and Surface Enhanced Raman spectroscopy have a strong bonding towards development of Sensors. From last 4 decades SERS has been used as effective tool for detection of toxic dyes, in food industry and agriculture world. To minimize the cost and fabrication over large surface is the most challenging task in substrate fabrication. In the present work an attempt has been made towards dual coatings, which could act as an effective SERS Substrates. An effective and facile approach of low cost bi-metallic Nanostructured film has been fabricated using thermal evaporation. Using the standard characterization techniques such as FE-SEM and XRD, the obtained films were Rhodamine 6G was used as an analyte for the SERS studies. The detection of R6G was up to 10− 10mol l− 1solution.The present bi-metallic coating can be serves as an excellent SERS active surface and provides a versatile pathway to fabricate anisotropic nanostructure on a glass film.


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