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Handbook of Graphene || Quantitative Real‐Time Evaluation of C/O Ratios and Stepwise Control of Deoxidization of Graphene Oxide Using Plasmonic‐Based Electrochemical Spectroscopy
摘要： Graphene oxide (GO) is composed of carbon and oxygen functional groups. It has been the subject of extensive research because these oxygen functional groups can be readily processed for various applications. A novel technique to deoxidize GO to reduced graphene oxide (rGO) sheets to enable the stepwise control of surface oxygen content and maximize the quality of carbon-based composites at low cost is needed. This chapter introduces new technology using the electrochemical (EC) technique of cyclic voltammetry to reduce GO, and shows that surface plasmon resonance (SPR) technology can be used to detect refractive index variations of dielectric materials near the metal surface while simultaneously using surface plasmon waves (SPWs) to detect the reduction of GO. It is important to understand the mechanisms of the atomic construction of GO surface oxygen-containing functional groups so that they can be developed in bulk for biosensor and optoelectronic applications. Directions for future research in the field of rGO film-based composites include increasing the stability of the electrodes, improving charge carrier mobility, tuning the dielectric layer and its optical band-gap properties, enhancing the binding interaction to improve the sensitivity of biosensors using the film, and modulating the SP resonance energy.
关键词： cyclic voltammetry (CV),reduced graphene oxide (rGO),Graphene oxide (GO),electrochemical surface plasmon resonance (EC-SPR)
更新于2025-09-11 14:15:04
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Surface Plasmon Resonance Sensing of Biological Warfare Agent Botulinum Neurotoxin A
摘要： A label free real time method was developed for the detection as well as quantification of botulinum neurotoxin A (BoNT/A) using surface plasmon resonance (SPR). In the present work, antibody against rBoNT/A-HCC fragment and synaptic vesicles (SV) were immobilized on carboxymethyldextran modified gold chip. The immobilization of BoNT/A antibody and interaction of BoNT/A with immobilized antibody were in-situ characterized by SPR and electrochemical impedance spectroscopy. A sample solution containing BoNT/A antigen in the concentration ranging from 0.225 fM to 4.5 fM and 0.045 fM to 5.62 fM was interacted with immobilized antibody and immobilized SV, respectively. By using kinetic evaluation software, KD (equilibrium constant) and Bmax (maximum binding capacity of analyte) values were calculated and found to be 0.53 fM and 38.23 mo for immobilized antibody and 0.22 fM and 116.0 mo for immobilized SV, respectively. Moreover, thermodynamic parameters such as change in Gibb’s free energy (?G), change in enthalpy (?H) and change in entropy (?S) were determined and the values revealed that the interaction between BoNT/A antigen and BoNT/A antibody as spontaneous, endothermic and entropy driven one. In order to optimize the detection method, temperature and pH variation studies were also performed.
关键词： SPR,Impedance,Biological warfare agent,BoNT/A
更新于2025-09-10 09:29:36
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Fabrication of thin films of phosphonated calix[4]arene bearing crown ether and their gas sensing properties
摘要： Calix[4]arenes bearing phosphate and crown ether groups are shown to hold considerable promise as the active layer in volatile organic compound (VOC) vapor sensor. Its chemical sensing selectivity and sensitivity can be altered by different alkyl side chains. These organic architectures were successfully deposited by spin coating method on gold-coated glass surfaces. Surface Plasmon Resonance (SPR) technique was used for VOCs detection to evaluate the chemical-sensing properties of these calix[4]arene derivatives. Spun thin films of calix[4]arene derivatives were exposed to a variety of VOC vapors, and the resonance angles changes of these films were recorded for the specific analyte vapors such as chloroform, carbon tetrachloride, dichloromethane, ethanol, benzene, and toluene. Measurements were made at room temperature, and the responses were found to be fast and appeared to be completely reversible. The sensing results showed similar response patterns, and our data strongly indicate that response of used thin films of calix[4]arene derivatives to chloroform is much higher than those of any other VOCs used with the values of 0.47×10-3, 1.042×10-3 and 1.952×10-3 (% / ppm) for the compounds 1, 2 and 3 respectively. Furthermore, gas sensing interaction mechanisms of the thin films were evaluated in terms of the molar volumes, dipole moments and refractive indexes of the analyzed gas molecules.
关键词： Calixarene,SPR,thin film,gas sensing
更新于2025-09-10 09:29:36
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[IEEE 2018 17th International Conference on Ground Penetrating Radar (GPR) - Rapperswil, Switzerland (2018.6.18-2018.6.21)] 2018 17th International Conference on Ground Penetrating Radar (GPR) - Initial Laboratory Field Tests of the Rover-mounted GPR for China's First Mission to Mars
摘要： China’s first Mars probe including an orbiter and a landing rover will be launched by 2020. A subsurface penetrating radar instrument has been selected to be a part of payload on the rover. The main scientific objective of the SPR is to characterize the thickness and sub-layer distribution of the Martian soil. The SPR consists of two channels. The low frequency channel of the SPR will provide a penetrating depth of 10 to 100 meters with a resolution of a few meters within the Martian soil. The higher frequency channel will penetrate to a depth of 3 to 10 meters with a resolution of a few centimeters within the Martian soil. The engineering model of the SPR was designed and manufactured. In order to illustrate and validate the equipment’s performance, some laboratory field tests have been performed. The objectives of these tests were to evaluate the interaction between the radar and the rover and detect the internal objects buried in the pool filled with artificial volcanic ash.
关键词： SPR,Rover,Mars,China’s Mars 2020,LFM
更新于2025-09-10 09:29:36
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A Method for Estimating the Filling Rate of the Mold Cavity in Nanoimprint Lithography
摘要： When the dimensions of a microelectronic structure decrease, high manufacturing costs are inevitable. A low cost and high throughput manufacturing technique for nanostructures is desired. Nanoimprint lithography involves patterning the resist through physical deformation by using a mold at nanoscale and has the potential to meet these expectations. Therefore, nanoimprint lithography has been extensively studied in recent years. Many real time measurements have been proposed for enhancing the yield of nanoimprint lithography. Among these measurements, the application of surface plasmon resonance has the advantage of quick, highly accurate analysis. In surface plasmon resonance application, the mold contains a gold ?lm for exciting surface plasmon resonance and an adhesion layer is applied to both sides of the gold ?lm to increase the lifespan of the mold. However, the effect of the geometric characteristics of the adhesive layer on the surface plasmon resonance spectrum and the mechanical strength of the mold has not been extensively studied. To improve the detection accuracy and reliability of the measurement, this study investigated the aforementioned effect. Analytical and experimental investigations con?rmed that the shape of the spectrum is in?uenced by the surface roughness and thickness of the titanium adhesion layer. To maintain the sharpness of the resonance dip, we suggest reducing the thickness of the titanium adhesion layer to below 6 nm and maintaining the surface roughness below 3 nm. Moreover, the proposed mold structure conforms to these requirements and is applied to estimate the ?lling rate. The measurement results demonstrate that the surface plasmon resonance spectrum is clearly affected by the mold ?lling. Speci?cally, the change in the surface plasmon resonance spectrum curve and resonance angle can indicate the quality of the imprinted pattern. This study demonstrates the effectiveness and high sensitivity of the proposed technique for estimating the ?lling rate of the mold cavity in nanoimprint lithography.
关键词： Nanoimprint Lithography (NIL),Surface Roughness,Filling Rate,Surface Plasmon Resonance (SPR),Non-Destructive Measurement
更新于2025-09-10 09:29:36
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Analysis of interaction between sulfated polysaccharides and HIV oligopeptides by surface plasmon resonance
摘要： This study aims to quantitatively investigate the interaction between sulfated polysaccharides with potent anti-HIV activity, dextran and curdlan sulfates with negatively charged sulfate groups, and poly-L-lysine as a model protein and oligopeptides from a HIV surface glycoprotein gp120 with positively charged amino acids using surface plasmon resonance (SPR) and dynamic light scattering (DLS) to elucidate the anti-HIV mechanism of sulfated polysaccharides. The apparent association- (ka) and dissociation rate (kd) constants of dextran and curdlan sulfates against poly-L-lysine were ka=6.92×104?2.17×106 1/Ms and kd=4.29×10-5? 2.22×10-4 1/s; these kinetic constants were dependent on the molecular weights and degree of sulfation of sulfated polysaccharides. For interaction, the three oligopeptides from the HIV gp120 were peptide A 297TRPNNNTRKRIRIQRGPGRA316 with several lysine (K) and arginine (R) in the V3 loop region, peptide B 493PLGVAPTKAKRRVVQREKR511 with several K and R in the C-terminus region, and oligopeptide C 362KQSSGGDPEIVTHSFNCGG380 with little basic amino acids in the CD4 binding domain. Sulfated polysaccharides exhibited strong interaction against oligopeptides A and B, (ka=5.48×104?2.96×106 1/Ms and kd=1.74×10-4?6.24×10-3 1/s), no interaction was noted against oligopeptide C. Moreover, the particle size and zeta potential by DLS indicated the interaction between sulfated polysaccharides and oligopeptides A and B, suggesting the anti-HIV mechanism of sulfated polysaccharides to be the electrostatic interaction of negatively charged sulfated polysaccharides and HIV at the positively charged amino acid regions.
关键词： Model peptide,Interaction,SPR,Sulfated polysaccharide,HIV surface oligopeptide
更新于2025-09-10 09:29:36
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Aspects of the a-TiO <sub/>x</sub> memristor active medium technology
摘要： New physical approaches make fast-response non-volatile resistive memory (ReRAM) very attractive for digital, neuromorphic, and other data processing systems considered in many previous publications. Even though the effect of resistance and memory switching in metal-dielectric-metal structures is well known, the physical mechanisms underlying these phenomena are still vague. Considerable instability and insufficient reproducibility of electrical characteristics are the major factors that hold back the practical use of memristors. This problem can be solved by combining the theory of filaments and physics of amorphous wide-bandgap semiconductors which make up the majority of active memristor media currently being investigated. The properties of amorphous and crystalline nanostructures are radically different. Being rather specific, the characteristics of amorphous nanostructures are much dependent on the manufacturing technique. The methods of controlling the amorphous state and its stability are the subject of this paper. The conventional technique of electron-beam induced deposition is used to make the samples. Well-studied TiO2 is taken as a base material for active memristor media. The amorphous state of resultant coats is modified by varying the deposition temperature at an unvaried deposition rate, a residual vacuum-chamber pressure, and coat thicknesses. Sensitive surface plasmon resonance method, spectral technique, and total-external-reflection X-ray diffractometry are the tools to control the stability of the coats. In the experiment, we have observed the long and distinct relaxation of the optical parameters of amorphous layers and the manifestation of the development of an inhomogeneous amorphous layer.
关键词： ReRAM,amorphous,memristor,SPR,TiO2,HRXRD
更新于2025-09-10 09:29:36
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Reflectance spectra characteristics from an SPR grating fabricated by nano-imprint lithography technique for biochemical nanosensor applications
摘要： In this paper, we report our research work on developing a Surface Plasmon Resonance (SPR) element with sub-micron (hundreds of nanometers) periodicity grating structure. This grating structure was fabricated by using a simple nano-imprint lithography technique from an organically siloxane polymers, which was then covered by nanometer thin gold layer. The formed grating structure was a very well defined square-shaped periodic structure. The measured reflectance spectra indicate the SPR wave excitation on this grating structure. For comparison, the simulations of reflectance spectra have been also carried out by using Rigorous Coupled-Wave Analysis (RCWA) method. The experimental results are in very good agreement with the simulation results.
关键词： biochemical nanosensor,SPR,grating,nano-imprint lithography,reflectance spectra
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Kiev (2018.4.24-2018.4.26)] 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Efficient Geometry of Surface Plasmon Resonance Based Fiber Optic Sensor
摘要： The efficient structure for optical fiber based surface Plasmon resonance sensor has been investigated. The sensor structure is based on removing the cladding of a multimode optical fiber and replacing it with thin film of gold. The incident light inside the fiber will excite surface plasmons which will be resulted in the absorption in specific wavelengths. The absorption behavior is dependent on the dielectric constants at the vicinity of the metallic thin film. Based on the amount of removed cladding and deposition regions on the core structure of the fiber, different configurations can be considered. Based on the computational analysis, we have studied performance of sensor for three different configurations. Our method of study is based on solving wave equation in different sensor geometry and calculating absorption for different available modes using Finite Element Method in COMSOL environment. The results of our study show that, the optimum configuration of sensor considering wavelength sensitivity is for a fiber which half of core and cladding has been removed and the gold thin film is deposited on its surface.
关键词： Refractive Index Sensor,Surface Plasmon Resonance,SPR Fiber,Fiber Based Sensor,Finite Element Method,COMSOL
更新于2025-09-10 09:29:36
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Novel Four Layer Metal Sensing in Portable SPR Sensor Platform for Viral Particles Quantification
摘要： Label-free, direct, rapid and real-time quantification method for human enterovirus 71 (EV71) using surface plasmon resonance (SPR) sensor is presented in this study. The performance of the four layer sensor chip was compared with the conventional Au monolayer sensor chip. Four layer sensor chip gave optimum resonance wavelength around 610 nm, which was same with the OLED light source peak wavelength and gave better quality factor (Q = DIP/FWHM). The result showed that the structure with 3 nm Al, 10 nm Au, 20 nm Ag, 10 nm Au layer sensor chip gave better limit of detection than the 3 nm Cr, and 47 nm Au layer sensor chip. The detection limit of direct quantification of EV71 particles is improved to 43 vp/mL of EV71 in DMEM medium. The results proved that the SPR biosensor with four layer sensor chip structure demonstrated great performance in the quantification of EV71 virus species.
关键词： OLED,quantification,SPR sensor,EV71 virus,four layer sensor chip
更新于2025-09-09 09:28:46