Download or read book Developing Surface enhanced Raman Spectroscopy Substrates with Cell Membrane Patches for Material Identification written by 林牧謙 and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Novel Approaches to Prepare and Utilize Surface enhanced Raman Spectroscopy SERS Substrates written by and published by . This book was released on 2008 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past few decades, surface enhanced Raman spectroscopy (SERS) has garnered respect as an analytical technique with significant chemical and biological applications. SERS is important for the life sciences because it can provide trace level detection and a high level of molecular structure information. The development of quantitative, highly sensitive substrates requires control over size, shape, and position of metal nanoparticles which function as the SERS active medium. Thus, creating and successfully implementing a sensitive, reproducible, and robust SERS active substrate continues to be a challenging task. Its future development depends critically on techniques for lithography and nanofabrication. Herein, we report a novel method for SERS that is based upon using colloidal silver nanoparticles in a multiplexed microfluidics (MMFs) platform. The MMF is created in polydimethylsiloxane (PDMS) polymer material and used to perform parallel, high throughput, and sensitive detection/identification of single or various analytes under easily manipulated conditions. A facile passive pumping method is used to deliver samples into the channels under flowing conditions that are highly conducive for SERS measurments. Also an unconventional nanofabrication approach is modified to produce efficient SERS substrates. Metallic nanopatterns of silver discs are transferred from a stamp onto PDMS to create nanocomposite substrates with regular periodic morphologies. The stamp with periodic arrays of square, triangular, and elliptical pillars is created via Electron Beam Lithography of ma-N 2403 resist. A modified cyclodextrin is thermally evaporated on the stamp to overcome the adhesive nature of the ebeam resist and to function as a releasing layer. Subsequently, the stamp is over coated with Ag by physical vapor deposition at a controlled rate and thickness and used directly for nanotransfer printing (nTP). Stamps, substrates, and the efficiency of the nTP process were explored by SEM. Ag nano-disc-PDMS substrates are studied by SERS using Rhodamine 6G as the probe analyte. The SERS response of metallic nano-discs of various shapes/sizes on the original stamp is compared to the corresponding nTP substrates. We demonstrate that physical manipulation of the PDMS post nTP can be used to alter morphology. Additionally, stamps are shown to be reusable after the nTP process.

Download or read book Surface Enhanced Raman Spectroscopy for Biophysical Applications written by Claudia Fasolato and published by Springer. This book was released on 2018-12-05 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book explores the phenomenon of surface-enhanced Raman scattering (SERS), the huge amplification of Raman signal from molecules in the proximity of a metallic nanostructured surface, allowing readers to gain an in-depth understanding of the mechanisms affecting the spectroscopic response of SERS-active systems for effective applications. SERS spectroscopy is an ultrasensitive analytical technique with great potential for applications in the field of biophysics and nanomedicine. As examples, the author presents the design of nanocolloid-based SERS-active substrates for molecular sensing and of a folate-based SERS-active nanosensor capable of selectively interacting with cancer cells, enabling cancer diagnostics and therapy at the single-cell level. The author also suggests novel paths for the systematization of the SERS nanosystem design and experimental protocols to maximize sensitivity and reproducibility, which is essential when real-world biomedical applications are the goal of the study. With a combined approach, both fundamental and applied, and a detailed analysis of the state of the art, this book provides a valuable overview both for students new to SERS spectroscopy and for experts in the field.

Download or read book Development of Surface Enhanced Raman Scattering Substrate for Sensitive Detection of Aqueous Contaminants written by Md. Shah Alam and published by . This book was released on 2018 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Towards the development of flexible substrate materials for label free Surface Enhanced Raman Spectroscopy written by Zahra Khan and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Towards the Development of Flexible Substrate Materials for Label free Surface Enhanced Raman Spectroscopy SERS and Photo induced Enhanced Raman Spectroscopy PIERS written by Zahra Khan and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of the Surface enhanced Infrared Spectroscopic Approach and Surface enhanced Raman Spectroscopy Coupled with Electrochemistry to Study Reaction Mechanism of Membrane Proteins written by Natalia Grytsyk and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis concerns the development of surface-enhanced infrared and Raman spectroscopic approaches: surface-enhanced infrared absorption spectroscopy (SEIRAS) combined with perfusion cell and surface-enhanced Raman spectroscopy (SERS) combined with electrochemistry. Within the first project different proteins were studied: Lactose Permease (LacY), complex I and IM30.The pKa of Glu325 in LacY WT and in different mutants carrying mutations in the proton translocation active center was determined. WT complex I was oxidized with different oxidizing agents and reduced with NADH. Corresponding redox-induced conformational changes were studied. The evidence was given that Mg2+ ions induce conformational changes in the protein IM30.Within the second project the spectroelectrochemical cell containing gold grid electrode was adopted for the studies of redox active proteins. This gold grid serves both as working electrode and as SERS active substrate. First Cyt c, Hb and Mb were used to validate the setup and then the approach was extended to study a membrane protein.

Download or read book Dry and Wet Surface Enhanced Raman Scattering Substrates written by Ahmed Mahmoud and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past few decades, surface enhanced Raman scattering (SERS) has been evolving as a powerful analytical technique for the detection of a wide of chemical and biological molecules. The technique can reach a sensitivity of single molecule detection, which triggered plenty of ongoing research. In addition, technological advancements in photonics and nanoscience have resulted in the advent of portable and handheld Raman systems. These devices help SERS analysis move from expensive heavy-equipped research labs to low cost field deployable-research. The development of efficient SERS substrates that can provide signal enhancement by many orders of magnitude is a core component for SERS. The SERS substrates market and research are generally dominated by rigid solid substrates that are fabricated mostly by micro/nanofabrication techniques. Although these methods can provide reproducible substrates, they suffer from usability constraints because of their high cost of fabrication. The work presented in this thesis explored cost-effective approaches to develop and optimize SERS substrates. The substrates investigated are divided into two main categories, membrane-based SERS substrates and in-solution SERS substrates. The membrane-based SERS substrates were fabricated by equipment-free methods. In these deviceless methods, gold and silver nanostructures were incorporated in-situ within the micropores of polyvinylidene fluoride (PVDF) membranes by seed mediated and seedless protocols, respectively. The SERS performance of these substrates was investigated and optimized by controlling the loading of plasmonic nanostructures. These flexible inexpensive substrates have the advantages of being easy to fabricate and to use. In addition, the variation in the SERS performance of these substrate was less than 20% within the same substrate and from substrate-to-substrate, which reflects acceptable reproducibility. Analytical applications of these substrates were demonstrated using a Raman microscope as well as a handheld Raman spectrometer. The second category of the SERS substrates studied was based on the optimization of gold nanostars and graphene-silver nanocomposites for water dispersible SERS measurements. In-solution SERS platforms are not used as commonly as solid-based substrates; however, these wet platforms can provide some advantages over the dried-based ones in terms of cost, reproducibility, and analysis time. The SERS performance of gold nanostars with different branch lengths was optimized based on the type of Good's buffer, the ratio of buffer to gold concentration, and their aggregation. Our results were counterintuitive in that the gold nanostars with the shorter branches provided the largest in-solution SERS intensity. These findings can be attributed to higher surface coverage of the Raman probe rather than enhanced electromagnetic effects. Graphene-silver nanocomposites were investigated also as in-solution SERS substrates with a large 2D surface area. The SERS behavior of these nanocomposites were studied using graphene, a thiolated Raman probe, and a dye labelled ssDNA to simulate different possible interactions. The SERS and plasmonic performance of these nanocomposites can be tuned by the size of silver nanoparticles on these substrates. The nanocomposites were more stable and showed superior SERS performance when compared to commercial silver nanoparticles. The contributions of this work can pave the way for flexible membrane-based and in-solution SERS substrates to be accompanied with a handheld Raman device for field-deployable SERS measurements.

Download or read book Surface enhanced Raman Scattering written by Deepak Bhandari and published by . This book was released on 2011 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: To advance the capabilities of surface-enhanced Raman scattering (SERS), we developed a silver modied polypropylene filter (AgPPF) substrate which acts as a pseudo stationary phase in harvesting SERS signatures of so called "phytochemical estrogens" and other environmentally significant chemicals. To augment electron beam lithography (EBL) in SERS research, we also introduced an interesting nanotransfer printing (nTP) technique which could circumvent the low throughput and extremely high resolution (

Download or read book Advanced Substrate Design for Label free Detection of Trace Organic and Biological Molecules written by Zachary Allen Combs and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To truly realize and exploit the extremely powerful information given from surface-enhanced Raman scattering (SERS) spectroscopy, it is critical to develop an understanding of how to design highly sensitive and selective substrates, produce specific and label-free spectra of target analytes, and fabricate long-lasting and in-the-field ready platforms for trace detection applications. The study presented in this dissertation investigated the application of two- and three-dimensional substrates composed of highly-ordered metal nanostructures. These systems were designed to specifically detect target analytes that would enable the trace, label-free, and real-time detection of chemicals and biomolecules. Specifically, this work provides new insight into the required properties for maximizing electromagnetic and chemical Raman enhancement in three-dimensional porous alumina substrates by designing metal nanostructure shape, density, aggregated state, and most importantly aligning the substrate pore size with the excitation wavelength used for plasmonic enhancement leading to the ppb detection of vapor phase hazardous chemicals. A new micropatterned silver nanoparticle substrate fabricated via soft lithography with specific functionalization was developed, which allows the simultaneous analyte and background detection for trace concentrations of the target biomolecule, immunoglobulin G. Also, a novel functionalized SERS hot spot fabrication technique, which utilizes highly specific aptamers as both the mediator for electrostatic assembly of gold nanoframe dimers as well as the biorecognition element for the target, riboflavin, to properly locate the tethered biomolecule within the enhanced region for trace detection, was demonstrated. We suggest that the understanding of SERS phenomena that occur at the interface of nanostructures and target molecules combined with the active functionalization and organization of metal nanostructures and trace detection of analytes discussed in this study can provide important insight for addressing some of the challenges facing the field of SERS sensor design such as high sensitivity and selectivity, reliable and repeatable label-free identification of spectral peaks, and the well-controlled assembly of functional metal nanostructures. This research will have a direct impact on the future application of SERS sensors for the trace detection of target species in chemical, environmental, and biomedical fields through the development of specific design criteria and fabrication processes.

Download or read book Improving Analytical Utility of Surface Enhanced Raman Spectroscopy Through Unique Lithographic Substrate Development written by Sabrina Marie Wells and published by . This book was released on 2012 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface enhanced Raman spectroscopy (SERS) has the potential to be a useful analytical technique due to large signal enhancements. Unfortunately, SERS has several drawbacks, including a lack of reproducibility, which inhibits it from being a practical option. These large signals often arise from "hot spots" of extremely high enhancement on nanofeatured metallic substrates, the most common being comprised of aggregated silver colloid. It is difficult to reproducibly create these hot spots due to the randomness of the colloid substrates. However, through controlled substrate fabrication, many problems associated with SERS analysis can be overcome. Electron beam lithography (EBL) combined with reactive-ion etching (RIE) was used to fabricate a wide variety of aggregate-like structures that allow for methodically surveying the system to determine if areas of high enhancement are present. Any well performing areas were then recreated consistently to produce areas of similar enhancement. While the aforementioned "combinatorial" approach has its advantages, simple structures are often easier to fabricate and theoretically model. As such, a single structure consisting of a metal disc on a silicon pillar was created. A variety of tests were performed on these structures to determine the overall utility of the simple pillar system. The system was found to possess extremely high enhancement, making it an ideal system to both theoretically model and test experimentally. The system also has strong enough overall signal to allow for potential analytical implications. Studies were also conducted to determine the feasibility of using a strong enhancing silicon nanopillar system to make analytical measurements without a metal surface present. A special fabrication process using EBL and RIE was used to created tall, high aspect ratio pillars of known diameters. These nanopillars were then observed to exhibit special optical properties not seen in bulk silicon. Aside from modest Raman enhancement, these structures also demonstrated the ability to enhance the signal of specific analytes similar to SERS. Surface enhanced fluorescence (SEF) was also observed for different analytes, allowing for a variety of potential analytical areas.

Download or read book Fabrication of Surface Enhanced Raman Scattering Substrates by Controlled Assembly and Morphology Tuning of Gold Nanoparticles written by Agampodi Swarnapali De Silva Indrasekara and published by . This book was released on 2014 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design and fabrication of nanoparticles (NPs) and NP assemblies to sustain intense electromagnetic field enhancement for surface enhanced Raman scattering (SERS)-based imaging and sensing have recently gained significant attention. In SERS, the intrinsic optical properties of plasmonic NPs are used to overcome the relatively low Raman cross-sections and thereby increase sensitivity. Sharp features in anisotropic NPs and interparticle gaps within NP assemblies have been identified as the locations where the highest SERS enhancements can be achieved, also known as "hot spots". Many attempts have been reported that deal with the bottom-up assembly of NPs to achieve highly reproducible, sensitive, and well characterized SERS substrates, but it still remains a challenge to attain monodisperse, highly reproducible "hot spots" and directional assembly. The focus of this dissertation is to develop synthetic protocols for controlled engineering of NPs with SERS "hot spots", and thereby to contribute to the advancement of SERS-based sensing and imaging applications. In this dissertation, the development of SERS substrates has evolved from dimers of spherical gold NPs (SP), to star-shaped gold NPs (ST), and finally to assembled superstructures of ST and SPs. The kinetically controlled assembly of SPs into dimers was achieved by using Raman active dithiolated linker molecules, with the highest yield reported for this method to the best of our knowledge, leading to SERS tags with a reproducible SERS enhancement on the order of 105. NP dimers, surface-functionalized to target U87 glioblastoma cancer cells, demonstrated a fast, reliable, and selective SERS-based detection of the diseased cells that outperforms fluorescence. The morphology of the STs was modified to possess longer and sharper spikes with a narrower tip curvature thereby increasing the electromagnetic field localization at the tips. SERS substrates were designed by periodically and reproducibly immobilizing STs on a planar substrate with high surface coverage and limited to no clustering, thus enabling femtomolar detection of organic analytes with an outstanding 109 SERS enhancement. Finally, the core-satellite assemblies of ST with SPs were achieved through conjugation linker chemistry. These assemblies demonstrated SERS enhancement of two orders of magnitudes greater than isolated STs thereby improving the sensitivity of potential SERS-based imaging and sensing applications.

Download or read book Determining the Electronic Properties of Surface Enhanced Raman Spectroscopy Substrates written by Liam David Whelan and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface Enhanced Raman Spectroscopy (SERS) is an ultra-sensitive technique for optical detection of target analytes. Our work focuses on detecting oil in water using SERS, with this thesis using phenanthrene as a model compound. SERS is a technique which takes advantage of the optical properties of metal substrates to greatly increase the intensities of adsorbed analytes' vibrational modes. The rapid development of novel materials as SERS active substrates requires an efficient screening method. SERS Enhancement Factor (EF) does correlate somewhat with surface morphology and UV-Vis absorption, however we present a technique which shows an even stronger correlation and is ultimately a better screening tool: Kelvin Probe Force Microscopy (KPFM). This technique maps the electronic properties of a substrate to its surface morphology. This thesis covers two classes of SERS substrates: annealed bimetallic systems and nanosphere patterned mono- and bimetallic systems. The ability to directly map the electronic properties of a substrate to its morphological properties is of critical importance in determining a key link between the macroscale SERS sensor response and the microscale substrate structure. Our major findings indicate that when Au/Cr nanostructured films' work function is near the calculated and experimental values for the HOMO-LUMO gap of the target analyte, phenanthrene, the observed SERS intensity reaches a maximum.

Download or read book Development and Application in Surface Enhanced Raman Scattering Substrate written by 王懷賢 and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Surface enhanced Raman and Resonance Raman Scattering written by Paul J. G. Goulet and published by . This book was released on 2006 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: