Thermally Stable Plasmonic Nanocermets Grown on Microengineered Surfaces as Versatile Surface Enhanced Raman Spectroscopy Sensors for Multianalyte Detection (original) (raw)
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ACS Nano, 2011
Efforts to create reproducible surface-enhanced Raman scattering (SERS)-based chemical and biological sensors has been hindered by difficulties in fabricating large-area SERSactive substrates with a uniform, reproducible SERS response that still provides sufficient enhancement for easy detection. Here we report on periodic arrays of Au-capped, vertically aligned silicon nanopillars that are embedded in a Au plane upon a Si substrate. We illustrate that these arrays are ideal for use as SERS sensor templates, in that they provide large, uniform and reproducible average enhancement factors up to ∼1.2 Â 10 8 over the structure surface area. We discuss the impact of the overall geometry of the structures upon the SERS response at 532, 633, and 785 nm incident laser wavelengths. Calculations of the electromagnetic field distributions and intensities within such structures were performed and both the wavelength dependence of the predicted SERS response and the field distribution within the nanopillar structure are discussed and support the experimental results we report.
Nanostructured plasmonic substrates for use as SERS sensors
Nano convergence, 2016
Plasmonic nanostructures strongly localize electric fields on their surfaces via the collective oscillations of conducting electrons under stimulation by incident light at a certain wavelength. Molecules adsorbed onto the surfaces of plasmonic structures experience a strongly enhanced electric field due to the localized surface plasmon resonance (LSPR), which amplifies the Raman scattering signal obtained from these adsorbed molecules. This phenomenon is referred to as surface-enhanced Raman scattering (SERS). Because Raman spectra serve as molecular fingerprints, SERS has been intensively studied for its ability to facilely detect molecules and provide a chemical analysis of a solution. Further enhancements in the Raman intensity and therefore higher sensitivity in SERS-based molecular analysis have been achieved by designing plasmonic nanostructures with a controlled size, shape, composition, and arrangement. This review paper focuses on the current state of the art in the fabrica...
RSC Advances, 2019
This report describes the systematic combination of structurally diverse plasmonic metal nanoparticles (AgNPs, AuNPs, Ag core-Au shell NPs, and anisotropic AuNPs) on flexible paper-based materials to induce signal-enhancing environments for surface enhanced Raman spectroscopy (SERS) applications. The anisotropic AuNP-modified paper exhibits the highest SERS response due to the surface area and the nature of the broad surface plasmon resonance (SPR) neighboring the Raman excitation wavelength. The subsequent addition of a second layer with these four NPs (e.g., sandwich arrangement) leads to the notable increase of the SERS signals by inducing a high probability of electromagnetic field environments associated with the interparticle SPR coupling and hot spots. After examining sixteen total combinations, the highest SERS response is obtained from the second layer with AgNPs on the anisotropic AuNP paper substrate, which allows for a higher calibration sensitivity and wider dynamic range than those of typical AuNP-AuNP arrangement. The variation of the SERS signals is also found to be below 20% based on multiple measurements (both intra-sample and inter-sample). Furthermore, the degree of SERS signal reductions for the sandwiched analytes is notably slow, indicating their increased long-term stability. The optimized combination is then employed in the detection of let-7f microRNA to demonstrate their practicability as SERS substrates. Precisely introducing interparticle coupling and hot spots with readily available plasmonic NPs still allows for the design of inexpensive and practical signal enhancing substrates that are capable of increasing the calibration sensitivity, extending the dynamic range, and lowering the detection limit of various organic and biological molecules.
2018
The growing need for noninvasive diagnostics and nondestructive structural analysis led to great progress in SERS medical applications. By using SERS one can improve the detection limit of biomarkers that allow the detection of some diseases. This work has as final objective the production of plasmonic substrates that can be used in biomedical applications. This study has 2 goals: 1) Analyze and adaptation of different techniques to deposit silver nanostars in glass and paper to form reproducible and homogeneous substrates; 2) Using SERS to analyze the redox state of the thiols measuring DTNB/TNB proportion in the samples. Two different deposition methods were testes, direct drop deposition and centrifuge sedimentation method. In the first method an enhancement of 10 2 was achieved and for the second one the enhancement was of 10 4 order. Furthermore, a commercial substrate, with an enhancement of 10 4 , was functionalized with DTNB and analyzed by SERS to serve as comparison. On the second part of this work the SERS results of the DTNB and TNB are promising, because of the differences shown in both spectra. Nevertheless, more studies are still need before the process could be applied to clinical samples.
Plasmonic Materials for Surface-Enhanced Sensing and Spectroscopy
MRS Bulletin, 2005
Localized surface plasmon resonance (LSPR) excitation in silver and gold nanoparticles produces strong extinction and scattering spectra that in recent years have been used for important sensing and spectroscopy applications. This article describes the fabrication, characterization, and computational electrodynamics of plasmonic materials that take advantage of this concept. Two applications of these plasmonic materials are presented: (1) the development of an ultrasensitive nanoscale optical biosensor based on LSPR wavelength-shift spectroscopy and (2) the use of plasmon-sampled and wavelength-scanned surface-enhanced Raman excitation spectroscopy (SERES) to provide new insight into the electromagnetic-field enhancement mechanism.
Chemical Society Reviews, 2012
In recent years, Surface-Enhanced Raman Spectroscopy (SERS) has experienced a tremendous increase of attention in the scientific community, expanding to a continuously wider range of diverse applications in nanoscience, which can mostly be attributed to significant improvements in nanofabrication techniques that paved the way for the controlled design of reliable and effective SERS nanostructures. In particular, the plasmon coupling properties of interacting nanoparticles are extremely intriguing due to the concentration of enormous electromagnetic enhancements at the interparticle gaps. Recently, great efforts have been devoted to develop new nanoparticle assembly strategies in suspension with improved control over hot-spot architecture and cluster structure, laying the foundation for the full exploitation of their exceptional potential as SERS materials in a wealth of chemical and biological sensing. In this review we summarize in an exhaustive and systematic way the state-of-art of plasmonic nanoparticle assembly in suspension specifically developed for SERS applications in the last 5 years, focusing in particular on those strategies which exploited molecular linkers to engineer interparticle gaps in a controlled manner. Importantly, the novel advances in this rather new field of nanoscience are organized into a coherent overview aimed to rationally describe the different strategies and improvements in the exploitation of colloidal nanoparticle assembly for SERS application to real problems.
Design of a Plasmonic Platform to Improve the SERS Sensitivity for Molecular Detection
Photonic Sensors, 2019
We suggested a plasmonic platform based on a cubic pattern of gold spheres for surface enhanced Raman spectroscopy (SERS). In the case of linear polarization along the symmetry axes, the SERS enhancement per area is identical to hexagonally patterned surfaces. The validity of this model was tested using the simulation package of COMSOL Multiphysics® Modeling Software. We found an improved sensitivity in the near infrared and visible region of the electromagnetic spectrum. This method considered tolerance towards stacking faults and suggested a plasmonic platform for ultra-sensing applications. The design can be extended towards the molecular detection if the proposed plasmonic platform is used with SERS.
Nanostructure-based plasmon-enhanced Raman spectroscopy for surface analysis of materials
Since 2000, there has been an explosion of activity in the field of plasmon-enhanced Raman spectroscopy (PERS), including surface-enhanced Raman spectroscopy (SERS), tip-enhanced Raman spectroscopy (TERS) and shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). In this Review, we explore the mechanism of PERS and discuss PERS hotspots — nanoscale regions with a strongly enhanced local electromagnetic field — that allow trace-molecule detection, biomolecule analysis and surface characterization of various materials. In particular, we discuss a new generation of hotspots that are generated from hybrid structures combining PERS-active nanostructures and probe materials, which feature a strong local electromagnetic field on the surface of the probe material. Enhancement of surface Raman signals up to five orders of magnitude can be obtained from materials that are weakly SERS active or SERS inactive. We provide a detailed overview of future research directions in the field of PERS, focusing on new PERS-active nanomaterials and nanostructures and the broad application prospect for materials science and technology.
2017
Plasmonic nanostructures have attracted considerable interest in biomarker sensing with the goal of rapid diagnostics and personalized nanomedicine. Surface‐enhanced Raman scattering (SERS) is a versatile technique for the characterization of the plasmonic effect of the metallic nanostructures as well as a sensitive read‐out approach for biomarkers detection. In this contribution, we will give a review on the key optical properties of plasmonic nanostructures as SERS substrate for protein biomarkers detection. As a con‐ sequence, two approaches, label‐free and SERS labels will be discussed in details for pro‐ tein biomarkers sensing by using the plasmonic nanostructures as the substrate.
SERS is a thirty years old physical phenomenon that has become one of the most exciting analytical techniques with a wide range of applications in physics, chemistry and biology, and the corresponding applied sciences. This ultrasensitive analytical tool covers the complete scale of sensitive analysis and diagnostics down to the limit of single molecule detection (SMD). There are now thousands of SERS publications in a wide range of scientifi c journals (for instance, SERS papers can be found in all the journals published by the ACS). The applications are relevant to trace analysis, environmental monitoring, nanobioscience among many others. The fi eld is intrinsically connected with the optical properties of nanostructures and SERS techniques are also used for nanostructure characterization, since it can be discussed in terms of surface plasmon resonance of nanoparticles, nanoshells or voids, leading to nanophotonics, plasmonics and single-molecule detection. Therefore, nowadays, no attempt or claim can be made to review the fi eld exhaustively in its entirety nor to cover all applications. Some of the above invited speakers contributed to the present issue. The speakers and the audience were able to exchange their views and newly acquired results in lively and sometimes heated discussions. The poster session was also quite active and successful. A total of 49 posters were displayed during the symposium. The following presentations received the Poster Awards. H. K. Park et al. "Silver-Particle-Based Surface-Enhanced Raman Scattering Spectroscopy for Biomolecular Sensing and Recognition" M. Meyer et al. "Can the Orientation of Molecules be Measured with SERS?" A. Maio et al. "SERRS measurement and Structural Characterization of J-and H-Aggregates in Langmuir-Blodgett (LB) Films Containing Merocyanine Dye"