Download or read book Optimisation of Surface Enhanced Raman Scattering from Gold and Silver Nanoparticle Solutions written by Johan Lundahl and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The efficiency of Surface enhanced resonance Raman spectroscopy (SERS or SERRS) as a technique is entirely dependent on controlling the parameters responsible for the enhancement effects. In this thesis, some of the critical parameters have been investigated. It is concluded that it is possible to predict and to some degree manipulate the maximum enhancement of the Raman scattering in an experimental setup. By applying the findings presented in this thesis it is possible to optimise an experimental setup according to a desired purpose where silver or gold nanoparticle solutions are used as the source of surface enhancement. Many of the findings herein are also expected to be applicable to other SER(R)S-systems, and also to be of interest in related techniques, such as metal enhanced fluorescence and surface plasmon resonance. Methods for the controlled synthesis of silver and gold nanoparticles, are presented and techniques for the characterisation of their physical properties are evaluated. Further, a technique enabling the separation of the relative contribution of absorption and scattering to the extinction profile is presented. Further, the effect of the nanoparticles physical properties on their suitability as SERS substrates is investigated. In particular, the effect of nanoparticle size and nanoparticle solution state of aggregation is investigated in order to optimise the SERS intensity at the detector. The results show that the SERS intensity is critically dependent on these properties, and that it is possible to predict the optimal combination of nanoparticle size, wavelength of the excitation source and aggregation state of the nanoparticle solution. Finally, the effect of a molecular resonance on the SERRS intensity is demonstrated and confirmed as a significant effect.

Download or read book Synthesis and Application of Colloidal Substrates for In solution Surface Enhanced Raman Scattering written by Casey John Rusin and published by . This book was released on 2020 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface-enhanced Raman scattering (SERS) has evolved into a powerful analytical measurement technique with the potential for single molecule detection. The technological advancement of handheld Raman instrumentation is powering the development of SERS applications in a variety of industries. Moreover, it is driving the movement from laboratory-based analyses to on-site/remote analyses. As a result, a main research component from this movement is to develop compatible SERS substrates. While the market is dominated by solid-based substrates, solution-based substrates do offer some benefits. These could include low production costs, high scalability, competitive reproducibility and shorter analysis times. The primary focus of the work in this thesis is to develop solution-based SERS substrates and explore their usage for in-solution measurements. This work highlights the development of three different types of solution-based substrates. The first substrate involves the synthesis and optimization of gold nanostars as a colloidal SERS substrate. The SERS performance is investigated and optimized using different Good's buffers, examining the buffer to gold salt concentration ratio and the use of an aggregating agent. In short, the results indicated that gold nanostars with smaller branches provided larger enhancement than those with larger branches, and this has been attributed to the Raman probe surface coverage on the nanostars rather than an electromagnetic effect. A SERS assay is also developed to quantitate methimazole in urine using a handheld Raman spectrometer. The second and third solution-based substrates are metal decorated cellulose nanofibers, also known as plasmonic cellulose nanofibers. These chapters focus on the growth of silver and gold nanoparticles onto oxidized cellulose nanofibers, and are used as a water dispersible substrate. In the development of plasmonic cellulose nanofibers, the cellulose nanofibers have two important roles: (1) to act as a dispersant in water and (2) act as a support for metallic nanoparticles. For both substrates, centrifugation played a key role in producing significant signal enhancement. Cellulose nanofibers decorated with silver nanoparticles were used for in-solution measurements of malachite green, while cellulose nanofibers decorated with gold nanoparticles were used for in-solution measurements of methimazole. Moreover, an assay is developed to quantitate methimazole in synthetic urine with cellulose nanofibers decorated with gold nanoparticles. Measurements using plasmonic cellulose nanofibers are taken with a Raman microscope, however, examples are shown to highlight the capability of remote analysis by coupling the substrates with a handheld Raman spectrometer. This work concludes with a comparative study between solid- and solution-based substrates. Using cellulose nanofibers decorated with gold nanoparticles, membrane- and glass- based SERS substrate are developed. This work discusses the benefits and challenges of solid- and solution-based substrates in terms of substrate development, measurement versatility and reproducibility. The primary contribution of this work is the development of multiple solution-based SERS substrates for in-solution measurements.

Download or read book Optical Properties of Nanoparticle Systems written by Michael Quinten and published by John Wiley & Sons. This book was released on 2010-11-29 with total page 507 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filling the gap for a description of the optical properties of small particles with sizes less than 1000 nm and to provide a comprehensive overview on the spectral behavior of nanoparticulate matter, this is the most up-to-date reference on the optical physics of nanoparticle systems. The author, an expert in the field with both academic and industrial experience, concentrates on the linear optical properties, elastic light scattering and absorption of single nanoparticles and on reflectance and transmittance of nanoparticle matter.

Download or read book Optimization Modification and Application of Gold Nanoparticles as the Substrates of Surface Enhanced Raman Spectroscopy written by Seongmin Hong and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Gold and Silver Nanoparticles written by Suban K. Sahoo and published by Elsevier. This book was released on 2023-01-20 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gold and Silver Nanoparticles: Synthesis and Applications provides detailed information on the preparation and utilization of Au- and Ag-based nanoparticles in a range of novel areas. Gold and silver nanoparticles offer a range of interesting properties, including unique size-dependent optoelectronic properties, chemical stability and biocompatibility, ease of synthesis and surface modification, excellent resistance to corrosion, and catalytic properties, hence paving the way to a wide range of cutting-edge applications with continual advances and innovations. Sections introduce gold and silver nanoparticles, fundamental theory, synthesis, and characterization techniques before focusing on requirements and preparation methods. Specific applications areas, such as surface-enhanced Raman spectroscopy (SERS), sensing and biosensing, imaging, drug and gene delivery, disease diagnosis, catalysis, and optoelectronic device fabrication are covered. Finally, synthesis and applications of platinum- and palladium-based nanoparticles are discussed. This is a valuable resource for researchers and advanced students across nanoscience and nanotechnology, chemistry, and materials science, as well as scientists, engineers, and R&D professionals with an interest in noble metal nanomaterials for a range of industrial applications. Explains theory, synthesis, characterization, and properties of Au- and Ag- based nanoparticles Explores a range of novel applications across biomedicine, optoelectronics, and other areas Analyzes the latest developments in the field and considers noble metal nanoparticles beyond gold and silver

Download or read book Surface Enhanced Raman Scattering New Theoretical Approaches Materials and Strategies written by Ivano Alessandri and published by Frontiers Media SA. This book was released on 2020-03-25 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization and Optimization of Novel Nanostructured Metallic Substrates for Surface Enhanced Raman Spectroscopy written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface enhanced Raman spectroscopy (SERS) is a highly sensitive technique for quantifying trace amounts of analyte adsorbed at a roughened metal surface. We have shown that novel gold nanostructured films, simply fabricated using gold nanoparticles and latex microspheres, can be used as highly sensitive SERS substrates. The films are templated by layers of colloidal crystals and display long ranged ordered regions, and porosity on two length scales that results in high surface area. By integrating these substrates into a flow chamber we have obtained consistent reproducible data and demonstrated the quantitative detection of sodium cyanide in the concentration range from 5 to 500 ppb, with detection significantly enhanced by lowering the pH after cyanide adsorption. We have found that the optimum size of the latex microspheres is approximately equal to the wavelength of the laser. Finally, the SERS activity of the gold substrates coated with silver nanoparticles was investigated using methyl phosphonic acid (MPA). Detection of MPA was dependent on the time between substrate coating and the SERS measurement. These studies show that novel materials formed by simple wet chemistry techniques can be used efficiently in practical devices for the detection of chemical agents.

Download or read book Frontiers of Surface Enhanced Raman Scattering written by Yukihiro Ozaki and published by John Wiley & Sons. This book was released on 2014-02-19 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive presentation of Surface-Enhanced Raman Scattering (SERS) theory, substrate fabrication, applications of SERS to biosystems, chemical analysis, sensing and fundamental innovation through experimentation. Written by internationally recognized editors and contributors. Relevant to all those within the scientific community dealing with Raman Spectroscopy, i.e. physicists, chemists, biologists, material scientists, physicians and biomedical scientists. SERS applications are widely expanding and the technology is now used in the field of nanotechnologies, applications to biosystems, nonosensors, nanoimaging and nanoscience.

Download or read book Postharvest Disinfection of Fruits and Vegetables written by Mohammed Wasim Siddiqui and published by Academic Press. This book was released on 2018-08-13 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Postharvest Disinfection of Fruits and Vegetables describes available technologies to reduce microbial infection for maintaining postharvest quality and safety. The book analyzes alternative and traditional methodologies and points out the significant advantages and limitations of each technique, thus facilitating both cost and time savings. This reference is for anyone in the fresh produce industry who is involved in postharvest handling and management. It discusses, in detail, the latest disinfection approaches, low-cost treatment strategies, management and protocols to control fresh produce qualities, diseases and insect infestation. Includes methods to reduce microbial contamination using chlorination, ozone, pulsed light, irradiation and plasma technology Provides practical applications of recently developed, natural anti-microbial agents for eco-friendly and sustainable solutions Explores various disinfection technologies for quality assurance and for the development of potential new technologies

Download or read book Surface Enhanced Vibrational Spectroscopy written by Ricardo Aroca and published by John Wiley & Sons. This book was released on 2006-05-01 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface Enhanced Vibrational Spectroscopy (SEVS) has reached maturity as an analytical technique, but until now there has been no single work that describes the theory and experiments of SEVS. This book combines the two important techniques of surface-enhanced Raman scattering (SERS) and surface-enhanced infrared (SEIR) into one text that serves as the definitive resource on SEVS. Discusses both the theory and the applications of SEVS and provides an up-to-date study of the state of the art Offers interpretations of SEVS spectra for practicing analysts Discusses interpretation of SEVS spectra, which can often be very different to the non-enhanced spectrum - aids the practicing analyst

Download or read book Modification and Application of Gold Nanorods in Surface Enhanced Raman Scattering Based Assays written by Shereen Abdelhakeim Tawfik Elbayomy and published by . This book was released on 2015 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface enhanced Raman scattering (SERS) is an ultrasensitive vibrational spectroscopic technique to detect molecules on or near the surface of plasmonic nanoparticles. More recently, this technique has been used to design novel nanoprobes named "SERS labels" that combine metallic nanoparticles and specific organic Raman reporter molecules. Such SERS labels can be conjugated to capture probes of biological molecules to be used to indirectly sense the target biological molecules by using laser Raman spectroscopy. Various metal nanoparticles act as a Raman signal amplifier for engineering of nanoprobes. In general, their size, geometry, chemical composition, and surface chemistry can influence the Raman enhancement ability. Recently, interest in gold nanorods (GNRs) has increased, as they possess unique optical and electronic properties. Many of the targeted applications for GNRs require their surface modification, but it can often be a challenge due to their cetyltrimethylammonium bromide (CTAB) coating, which is a stabilizing agent used during GNR synthesis. The work presented in Chapter 2 of this thesis explored spectroscopic and electronic microscopy characterization of GNRs after CTAB replacement with a mixed thiolate layer of a Raman reporter such as 4-nitrobenzenethiol (tNB) and 2-(2-{2-[2-(2-[2-(11-mercapto-undecyloxy)-ethoxy]-ethoxy)-ethoxy]-ethoxy}-ethoxy)-ethoxy-acetic acid (HSC11(EO)6~COOH). This HSC11(EO)6~COOH linker provides; steric stability through hydrophobic alkyl chain; water solubility due to presence of an ethoxy moiety that improves ligand exchange in aqueous solution; and anchor points such as carboxylic acid or amino groups for further conjugation with biological molecules. Chapter 3 presents the SERS response of the -SC11(EO)6~COO-/tNB modified GNRs of four different aspect ratios and 30 nm diameter spherical gold nanoparticles, the characteristic Raman spectrum of 4-nitrobenzenethiol was measured for five gold nanoparticle solutions. The capability of using the -SC11(EO)6~COO-/tNB modified GNRs of aspect ratio 2.4, which were covalently linked to immunoglobulin G (IgG) through terminal-carboxylic acid group of thiolate linker were explored with a chip-based SERS immunoassay in Chapter 4. The sensitivity of SERS based sandwich immunoassay utilizing gold nanorods of aspect ratio 2.4 for goat IgG detection was translated to a limit of detection (LOD) of 15 fM. The detection and quantification of small metabolite molecules is being targeted as a promising diagnostic method in disease assessment. Chapter 5 in this thesis presents an indirect competitive SERS based assay for the analysis of the thyroid hormone thyroxine in its free form (fT4). In this assay, we used fT4 conjugated SERS labels of GNRs to compete with fT4 standard solutions for monoclonal antibody binding sites. Lower levelss of free thyroxine than threshold, that accompanies hypothyroidism disease, can be detected and the results were correlated well with the results from a commercial enzyme-linked immunosorbent assay (ELISA) kit.

Download or read book Surface Enhanced Raman Scattering written by Zhong-Qun Tian and published by John Wiley & Sons Incorporated. This book was released on 2010-06-14 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface-Enhanced Raman Spectroscopy: Principles, Experiments, and Applications is a comprehensive, up to date, and balanced treatment of the theoretical and practical aspects of Surface-Enhanced Raman Scattering (SERS), a useful branch of spectroscopy for several areas of science. This book describes the basic principles of SERS, including SERS mechanisms, performing SERS measurements, and interpreting data. Also emphasized are applications in electrochemistry; catalysis; surface processing and corrosion; Self-Assemble-Layer and L-B Films; polymer science; biology; medicine and drug analysis; sensors; fuel cells; forensics; and archaeology. It is an essential guide for student and professional analytical chemists.

Download or read book Using Correlated Super resolution Optical and Structural Studies to Investigate Surface enhanced Raman Scattering on Silver Gold Nanoparticles written by Maggie Leona Weber and published by . This book was released on 2015 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface-enhanced Raman scattering (SERS) from organic molecules is used to study how geometry affects plasmonic enhancement in noble metal nanoparticles using super-resolution analysis techniques coupled with scanning electron microscope (SEM) imaging. We demonstrate that super-resolution analysis can track emission from Raman-active molecules on nanoaggregate surfaces with resolution typically better than 5 nm, a significant improvement over the diffraction limit. This optical analysis technique is used to identify active junction regions, known as hot spots, in correlated SEM structural images of aggregated particles based on shape, size, and angular position of SERS emission. This correlated analysis is further extended to study the mechanism of silver nanoparticle luminescence and its positional relationship to SERS emission. These studies support the hypothesis that silver luminescence is enhanced via a different mechanism than SERS. Discrete dipole approximation calculations agree with experimental results, indicating that SERS emission is a product of local plasmonic enhancement in specific junction regions between nanoparticles whereas silver luminescence is dependent upon nanoaggregate geometry and the collective plasmon modes within a structure. These theoretical calculations of luminescence centroid location can assist with SERS-active junction region assignment in higher order aggregates (e.g. trimers, tetramers, etc.) Finally, correlated optical and structural studies are used to develop understanding of site-specific electrochemical potentials on silver and gold nanoparticle aggregates using a redox active Raman reporter molecule. We demonstrate that there is a weak correlation between emission centroid location and bulk sample potential. Silver colloid studies demonstrate variability in modulation behavior and are highly unpredictable, whereas gold colloids with the redox molecule covalently tethered to their surface via a gold-thiol bond show more reproducible modulation. Furthermore, these tethered studies demonstrate geometrical agreement between site-specific emission at negative potentials and junction regions in nanoaggregate SEM images indicating that plasmonic enhancement may affect local nanoparticle surface potentials.

Download or read book Surface Enhanced Raman Scattering Dependence on Chain length of 1 alkanethiols on Gold and Silver Nanoparticles written by Ndivhuwo Prince Shumbula and published by . This book was released on 2018 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Solution based Characterization of Surface enhanced Raman Response of Single Scattering Centers written by and published by . This book was released on 2008 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: We demonstrate the rapid optical characterization of large numbers of individual metal nanoparticles freely diffusing in colloidal solution by confocal laser spectroscopy. We find that hollow gold nanospheres and solid silver nanoparticles linked with a bifunctional ligand, both designed nanostructures, exhibit significantly higher monodispersity in their Rayleigh and Raman scattering response than randomly aggregated gold and silver nanoparticles. We show that measurements of rotational diffusion timescales allow sizing of particles significantly more reliably than can be obtained using translational diffusion timescales.

Download or read book A Chemical Free Approach for Increasing the Biochemical Surface enhanced Raman Spectroscopy SERS based Sensing Capabilities of Colloidal Silver Nanoparticles written by Kevin Michael Dorney and published by . This book was released on 2014 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unique optoelectronic properties of silver nanoparticles (AgNPs) have led to their explosive use in a multitude of both research and industrial settings in recent years. Localized surface plasmon resonance (LSPR) exhibited by AgNPs has been exploited extensively as a nano-scale probe in a variety of spectroscopic detection modalities, particularly in surface-enhanced Raman spectroscopy (SERS). The SERS effect is highly dependent upon the LSPR interaction with optical laser frequencies, thus optimization of LSPR via specific control of AgNP dimensionality and composition of the surrounding medium is vital for increasing the efficacy of SERS-based nano-sensing. This work aimed to augment LSPR of AgNPs by applying the chemical free technique of tangential flow filtration (TFF) to a Creighton colloid of spherical AgNPs and specifically tailoring their size-distribution, concentration, and purity. First, a large batch of Creighton AgNPs (1-100 nm in diameter) were size-selected (20 nm and 12 nm in average diameter), concentrated, and purified via a three-step TFF procedure and characterized for effectiveness as SERS substrates in pre-resonance, resonance, and single-molecule resonance conditions for a Raman reporter, rhodamine 6G. The 20 nm AgNPs were found to have the highest surface enhancement factors (SEFs) in pre-resonance and single molecule resonance (SEFS of 2.1 x 10^6 and 2.5 x 10^10), while the 12 nm AgNPs yielded the highest SEFs in resonant conditions (2.0 x 10^6). The TFF procedure was then introduced to a diverse class of undergraduate and graduate students in an Experimental Nanomaterials and Nanoscience course to demonstrate the versatility of the proposed method for both gold nanoparticles and AgNPs, as well as the ease of applicability for use in different research disciplines and settings. Lastly, the 20 nm TFF-obtained AgNPs were employed for the sub-nanomolar biochemical detection of a potent apoptotic metabolite, chelerythrine (CET), in human lens epithelial cell extracts. The TFF-fractionated AgNP colloid allowed for quantification of CET content within several cell compartments via a reproducible calibration curve extending over five orders of magnitude (10^-5 to 10^-10 M in CET concentration). The results of these aims offer strong evidence that TFF can be 1) utilized to yield SERS substrates capable of extending detection limits and increasing spectral signals, 2) easily adapted for a variety of nanoparticle colloids as well as research and industrial settings, and 3) employed to obtain AgNPs that facilitate trace biochemical SERS-based detection even in extensive biological matrices.

Download or read book Spark Ablation written by Andreas Schmidt-Ott and published by CRC Press. This book was released on 2019-12-19 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spark ablation has been used worldwide for decades. However, in many fields, the special properties of nanoparticles, which come into play especially for sizes