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Investigation of a D-Shaped Optical Fiber Sensor with Graphene Overlay
摘要： A surface plasmon resonance sensor based on a D-shaped plastic optical fiber using graphene layers coated over a thin silver film is numerically analyzed. The performance of the sensing structure is studied as a function of the number of graphene layers, sensing area length, and polishing depth. Sensor’s quality parameters, such as signal-to-noise ratio, the figure of merit, and sensitivity, are also calculated. The graphene overlay increases the sensitivity reaching a peak of 5,161 nm/RIU for 16 graphene layers. The sensor’s quality parameters increases as the sensing area length decrease. On the other hand, the polishing depth is directly proportional to the sensor’s quality parameters.
关键词： surface plasmon resonance,D-shaped sensor,plastic optical fiber,Biosensor
更新于2025-09-12 10:27:22
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Terahertz multi-band unidirectional reflectionless phenomenon in a MIM plasmonic waveguide system based on near-field coupling
摘要： Existing oil leakage detection approaches on the ocean or on the land have suffered from shortcomings like low-sensitivity, environment-vulnerability and high cost and energy consumption. A unique simple-structured upward open-channel microbial fuel cell (UOC-MFC) was developed to solve these challenges, in which the open-channel rolled cathode vertically floated on the electrolyte solution surface and simultaneously contacted with both air and water. Oil presence covered the cathode surface, blocked the oxygen diffusion on the cathode and thus caused the prompt drop of the potential readings of the UOC-MFC sensors. The oil shock tests using engine oil (EO) showed that the potential decrease and the response time exhibited excellent linear relationships (R2 > 0.99) with the EO amount, indicating a good sensitivity. Due to the separation of the anode and the invading oil, the UOC-MFC sensor recovered its external potential within 2.3 h after the EO shock tests, indicating a good reusability. The power density of the UOC-MFC was 450 mW/m3 under normal condition and dropped to 207 mW/m3 after EO shock due to the internal resistance increasing from 1.29 to 3.80 kΩ. The UOC-MFC integrated with a power management system (PMS) theoretically supported a voltage meter and data transmitter. This study well demonstrated the great potential of the UOC-MFC for in-situ detecting oil presence in a real-time self-sustained mode.
关键词： Biosensor,Upward open-channel (UOC),Self-sustainability,Oxygen diffusion on cathode,Microbial fuel cell,Oil presence monitoring
更新于2025-09-12 10:27:22
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Giant plasmonically induced circular conversion dichroism in an anisotropic golden slit grating filled by a chiral medium
摘要： We report the giant plasmonically induced (PI) circular conversion dichroism in transmission (CCDT ) and PI-unconverted CD effect (unCCDR ) in re?ection from the golden slit grating ?lled by chiral medium (GSGCM). The CCDT and unCCDR are the differences between the off-diagonal elements in transmission matrix and diagonal elements in re?ection matrix, respectively, and originate from both the chirality and anisotropy. Our research indicates that the PI ? CCDT and PI-unCCDR in the plasmonic resonance wave band come from the coupling between the inherent chiroptical resonance of chiral medium and the plasmonic resonance of the golden slit grating, where the real part of chiral parameter ξ from chiral medium plays a main role in the coupling process. The isotropic chiral medium slab, the anisotropic chiral medium grating, the golden slit grating, and the GSGCM have been rigorously investigated in this work. Our research clearly reveals the difference of PI-chiroptical effect between the anisotropic and isotropic system, and will ?nd potential applications in biosensor and nanophotonic devices.
关键词： golden slit grating,biosensor,plasmonically induced circular conversion dichroism,nanophotonic devices,anisotropy,chiral medium
更新于2025-09-12 10:27:22
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[IEEE 2019 7th International Conference on Information, Communication and Networks (ICICN) - Macao, Macao (2019.4.24-2019.4.26)] 2019 7th International Conference on Information, Communication and Networks (ICICN) - High-Sensitivity Plasmonics Biosensor Based on Graphene Ribbon Arrays
摘要： A finite-difference-time-domain (FDTD) approach was undertaken to investigate the extraordinary optical transmission (EOT) phenomenon of graphene ribbon arrays deposited on a silica substrate for refractive index (RI) sensing. The numerical investigation shows that the choice of chemical potentials and its layer’s number of graphene will affect the sensitivity enhancement. The critical parameters of graphene ribbon arrays including the duty ratio, as well as its period, which affect the EOT and RI sensitivity for the sensor, are discussed and optimized. It is demonstrated that a high average sensitivity of 2900 nm per refractive index unit (RIU) is achieved for the dip wavelength interrogation. The averaged figure of merit (FOM) of the proposed sensor is calculated to be 10 RIU-1. Our findings hold potential applications in designing a high-performance plasmonic biosensor.
关键词： surface plasmon resonance,finite-difference time-domain,periodic ribbon arrays,plasmonics biosensor,graphene
更新于2025-09-12 10:27:22
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Non-Invasive Plasmonic Based Real Time Characterization of Cardiac Drugs on Cardiomyocytes Functional Behavior
摘要： In fabrication of cardiac tissue, an important factor is continuous measurement of its contraction features. A module that allows for a dynamic system capable of non-invasive and label-free monitoring of contraction profile under administering chemicals and drugs, is highly valuable for understanding accurate tissue mechanobiology. In this research, we have successfully demonstrated the use of Surface Plasmon Resonance (SPR) technology for the first time to characterize the contractility of cardiac cells in response to Blebbistatin and ATP as drug exposure in real-time. An optimal flow rate of 10 μlit/min was selected for continuous flow of warm media and 10 μM drug administration effect was detected with high spatiotemporal sensitivity on contracting cardiomyocytes. Our drug screening has identified the source of SPR periodic signal to be directly cell contraction rather than action potentials or calcium signaling. Per our results, SPR has high potential in applications in least interference real-time and label-free tissue characterizations and cellular properties analysis from a functional and structural point of view.
关键词： drug development,cardiomyocyte contraction,surface plasmon resonance,in-vitro,label-free,biosensor,imaging
更新于2025-09-12 10:27:22
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Laser-Scribed Graphene Electrodes Derived from Lignin for Biochemical Sensing
摘要： Laser scribing of porous graphene electrodes on flexible substrates is of great interest for developing disposable electrochemical biosensors. In this work, we present a new patterning process for highly conductive nitrogen-doped graphene derived from a lignin-based precursor. A CO2 laser scribing process was performed under ambient conditions to produce the porous graphene electrodes from lignin. The obtained nitrogen-doped laser-scribed graphene (N-LSG) is binder-free, hierarchical, and conductive. The interconnected carbon network displayed enhanced electrochemical activity with improved heterogeneous electron transfer rate. These features can be attributed to the high-conductivity of porous N-LSG (down to 2.8 ? per square) and its enriched active edge plane sites. Furthermore, the N-LSG electrodes were decorated with MXene/Prussian Blue (Ti3C2Tx/PB) composite via a simple spray coating process, designed for sensitive detection of analytes. The Ti3C2Tx/PB modified N-LSG electrodes were functionalized with catalytic enzymes for detecting glucose, lactate, and alcohol. The enzyme/Ti3C2Tx/PB/N-LSG electrodes exhibited remarkably enhanced electrochemical activity toward the detection of these biomarkers, making them highly competitive with previously reported on-chip carbon-based biosensors. Therefore, our sensors demonstrate excellent potential for applications in personalized healthcare.
关键词： laser-scribed graphene,MXene,alcohol,lactate,glucose,lignosulfonate,biosensor,high conductivity
更新于2025-09-12 10:27:22
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Size effect of metal nanodome arrays on performance of plasmonic biosensor
摘要： Size effect of metal nanodome arrays on performance characteristics of a plasmonic biosensor is investigated using reflection spectroscopy. Ag and Au nanodome arrays are created by a bottom-up nanofabrication process by which the dome diameter and metal thickness can be controlled. Reflectivity measurements of metal nanodome arrays showed that the wavelengths and width of resonance dip were changed by the dome diameter and metal thickness, respectively. Bulk refractive index (RI) sensing and detection of DNA hybridization were performed to characterize the sensing performance of metal nanodome arrays. Bulk RI sensitivity were significantly improved as the dome diameter enlarged from 100 to 500 nm. In contrast, metal nanodome arrays with smaller diameter exhibited higher sensor signals against the immobilization of DNA modified gold nanoparticles used for signal amplification indicating strong plasmonic coupling effects. With respect to the dome diameter, the effect of metal thickness was moderate for the presented sensing scheme.
关键词： plasmonic biosensor,metal nanodome arrays,bulk refractive index sensitivity,DNA hybridization,reflection spectroscopy
更新于2025-09-11 14:15:04
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Bioelectrochemical Interface Engineering || Quantum Dots for Bioelectrochemical Applications
摘要： In this chapter, the structure, characteristics, and synthesis processes of QDs were summarized. The most common electrochemical methods for QDs were also represented by reviewing their potential applications in biosensor technology. Many specific applications have been realized by utilizing the unique characteristics of QDs. However, their limited commercial availability; requirements of demanding synthesis procedures, analysis of multicomponent complex samples, and in situ analysis; and lack of validation with real samples are other disadvantage of QDs. The design of QD-based biosensors is also complicated due to limitedly defined redox behavior of nanocrystals resulting in difficulty with probing their redox levels. Therefore, extensive investigations are needed on the redox properties of QDs, despite having a large amount of literature on their synthesis, properties, and applications. The interactions between the system parameters can be clarified by using the mathematical models. To solve the model equations analytically, it is introduced to equivalent systems having identical spectra and wave functions, and these forms have to satisfy the solvability conditions. 3D QDs can be modeled by an ODE accurately, when the dimension of the cross section is very small and the energy levels are low. To obtain high accuracy of the effective mass approximation model, sizes of the QDs should be 10–20 nm. Optimum design problems for QD systems generally have discrete search spaces and involve highly nonlinear terms. Therefore, the selection of any traditional optimization methods to solve optimization problems is not appropriate. In these circumstances, it is useful to perform modern optimization algorithms such as the GA, DE, and SA methods. By incorporating mathematical models and optimization approximations to QD-based bioloelectrochemical systems, their performances will excel far beyond the current state in the near future.
关键词： Optimization Algorithms,Mathematical Models,Bioelectrochemical Applications,Electrochemical Methods,Biosensor Technology,Quantum Dots
更新于2025-09-11 14:15:04
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Immobilization of ssDNA on the surface of silver nanoparticles-graphene quantum dots modified by gold nanoparticles towards biosensing of microorganism
摘要： Rapid screening of pathogenic microorganisms are widely demand in the last decade. According to fastidious and hard to grow nature, Legionella penumophila is important pathogen for bioassay and biomedical analysis. In this work a novel paper-based genoassay was developed for monitoring of L. penumophila. For the first time, silver-graphene quantum dots (Ag/GQDs) ink was synthesized and used for construction of new substrate for bioassay of L. penumophila. The prepared interface was modified by gold nanoparticles grafted by Cysteamine A (CysA/AuNPs) which is necessary for ssDNA immobilization and hybridization by cDNA. All of the genoassay fabrication steps were characterized by field emission scanning electron microscope (FE-SEM), Energy-dispersive X-ray spectroscopy (EDS), Atomic force microscopic (AFM) and also TEM (transmission electron microscopy). Using chronoamperometry technique, the measurement of target cDNA was performed successfully. Also, cDNA was determined in the linear rang of 1μM to 1ZM which low limit of quantification was 1ZM. The results show that the designed bio-platform despite a simple structure with high sensitivity and specificity for the DNA based bioassay of L. penumophila genome.
关键词： nanotechnology,hybridization,biosensor,nucleic acid,advanced nanomaterial,bioanalysis
更新于2025-09-11 14:15:04
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Application of quantum dot‐based biosensor to the conjunctiva in Wistar albino rats
摘要： This study was conducted to get an idea about the distribution of the lymphatic fluid in conjunctiva throughout the body parts. For this purpose, Qdot655 (QD), fluorescence nanoparticles, spread onto the conjunctiva were used on Wistar albino rats. Drainage of QD particles from conjunctiva was followed up via fluorescence images at different hours on body parts such as eye, ears, forearms, hind legs and tails. The first fluorescence signals within the 30th minutes following administration of QD were observed in the nasal region and the anterior extremities. Whereas within 60th minutes following QD spread, fluorescent signals were obtained from the ears, forearms, hind legs and tail of the female and male rats.
关键词： rat,conjunctiva,quantum dot,biosensor,in vivo imaging,eyelid lymphatics
更新于2025-09-11 14:15:04