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An automatic multi-thread image segmentation embedded system for surface plasmon resonance sensor
摘要： In order to reduce the uncertainties associated with manual selection of regions of interest (ROIs) commonly used in Surface Plasmon Resonance (SPR) imaging system, we proposed and implemented an automatic image segmentation method in an embedded system to facilitate the potential real-time applications. Intuitive marker-controlled watershed algorithm is developed to segment ROIs (reaction, blank, and background regions) from images acquired from an experimental image SPR system. The marker assignment algorithms and pre-processing algorithms are executed in parallel by multi-threading programming on the multi-core embedded system to both real-time and good quality of segmentation. This method exhibited a good robustness in a series of ROIs segmentation test. Furthermore, the intensity response from triplicate detection of glucose standard solutions indicated a good reproducibility of data. The linear range was from 2.5 mg/mL to 20.4 mg/mL, with a correlation coefficient (R2) of 0.999 and sensitivity of 2.69 a.u./mg/mL. In conclusion, the proposed automatic image segmentation method effectively makes the measurement more precise and simplified.
关键词： Optical sensor,Surface plasmon resonance (SPR),Biosensor,Watershed algorithm,Image segmentation
更新于2025-09-23 15:23:52
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Reusable surface plasmon resonance sensor for rapid detection of Cu2+ based on modified-chitosan thin film as an active layer
摘要： In this article, a reusable surface plasmon resonance (SPR) sensor for rapid detection of copper ions (Cu2+), based on optimized silver/gold (Ag/Au) composite film modified by modified-chitosan (MCS) thin film as an active layer, was achieved. We employed a four-layer Kretchmann semi-cylindrical prism configuration and induced a reference beam into the experimental system to improve the sensitivity and stability, and investigated the cross-linking technique of CS solution, the spin coating process of MCS film, the stability of active layer, the rebirth power of SPR sensor, and the detection for trace Cu2+. The rate of swelling or dissolution of MCS film after flushing sensor chip for four times is less than 9×10?4/min, and the decline of signal value is less than 1.5% after MCS film adsorbing Cu2+ and multiple flushing. The elution and capacity rates are above 96% after five times of elution for the sensor by EDTA solution with 0.5mmol/L. Within 1-5ppm, the SPR sensor was found to possess sensitivity of 0.7271ppm?1. The LOD is 18ppb for the trace Cu2+. The present SPR sensor not only could be used in trace monitoring of Cu2+ but also could be extended to other potential applications.
关键词： Copper ions,Reutilization,Composite film,Modified-chitosan,Surface plasmon resonance
更新于2025-09-23 15:23:52
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Ultrasensitive U-shaped fiber optic LSPR cytosensing for label-free and in situ evaluation of cell surface N-glycan expression
摘要： Label-free and in situ detection of N-glycan expression on surface of cells is vital for understanding the progression of cancer. Herein, cytosensing based on U-shaped fiber optic local surface plasmon resonance (LSPR) was developed for cancer cell detection and N-glycan evaluation on cell surface. The U-shaped fiber optic LSPR has high refractive index sensitivity (RIS). Therefore, U-shaped fiber optic LSPR cytosensing afforded ultrasensitivity for cancer cell detection with the limit of detection (LOD) of 30 cells/mL and good linearity in a wide range of 1×102-1×106 cells/mL under the optimal conditions of modified AuNPs size and Con A concentration. The U-shaped fiber optic LSPR cytosensing shows more than 29 times lower limit of detection than the straight ones. More importantly, the prepared U-shaped cytosensing was applied to evaluate the N-glycan expression level on the surface of cancer cells under different concentration external stimuli of inhibitor tunicamycin (TM). Noticeably, U-shaped fiber optic LSPR cytosensing showed an acceptable reproducibility, satisfactory anti-interference and good selectivity, and was also applied in the assessment of N-glycan expression on surface of six kinds of cell lines. Therefore, the U-shaped fiber optic LSPR offers a feasible tool in biophysical research and clinical diagnosis for cancer.
关键词： Cancer cell,N-Glycan expression,Cytosensing,U-shaped fiber optic probe,Local surface plasmon resonance
更新于2025-09-23 15:23:52
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The Effect of Physical and Geometric Parameters on the Surface Plasmon Resonance Response of a Fiber Optic Biosensor: Sensitivity Analysis and Numerical Optimization
摘要： The study of the influence of optical and geometric parameters on the spectral response of the biosensor is an important step towards the optimization of these parameters. In this study, an improved SPR biosensor with a high resolution is proposed. The present SPR biosensor is based on an optical fiber that takes the place of the prism, compared with the conventional configuration, in order to simplify the detection process, overcome the stresses caused by the massive prism and obtain a reliable and efficient miniature device. The modeling procedure is based on a matrix formalism developed for the optical studies of multilayer media. We have discussed the effect of physical and optical parameters on the resonance curves, from the theoretical analysis of the transmitted power. The obtained results show that the response of the biosensor is highly dependent on these parameters. The optimum values of the length of the sensitive area, the core diameter of the optical fiber, the thickness of the metal layer and the refractive index of external environment have been determined.
关键词： Optical Fiber,Biosensors,Numerical Optimization,Surface Plasmon Resonance SPR,Sensitivity
更新于2025-09-23 15:23:52
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Design of titanium nitride coated PCF-SPR sensor for liquid sensing applications
摘要： In this paper, a titanium nitride (TiN) coated highly sensitive PCF-SPR sensor design is proposed and numerically analyzed. Titanium shows the excellent plasmonic properties in the visible and infrared regions and it has low loss and corrosion resistive nature. In this theoretical analysis, we introduce the dependencies of the confinement loss, wavelength sensitivity and amplitude sensitivity to the operating wavelength, thickness of TiN, channel width and refractive index of the measured liquid. For the proposed PCF-SPR sensor design, the high wavelength sensitivity and the refractive index resolution of ～10,000 nm/RIU and ～2.0 × 10?5 has been achieved in the refractive index (RI) range of 1.385–1.40, respectively. Even the proposed design has low amplitude sensitivity, but this proposed sensor will be used in detection of RI of chemicals, biochemical analyte with low concentrations, and highly demand in lab-on-a-chip PCF-SPR sensing probe devices.
关键词： Sensitivity,PCF,Surface plasmon resonance
更新于2025-09-23 15:23:52
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Bumpy Hollow Gold Nanospheres for Theranostic Application: Effect of Surface Morphology on Photothermal Conversion Efficiency
摘要： The combination of hollow core and rugose surface morphology is highly attractive for photoactive near-infrared (NIR) nanomaterials. Here, we present a facile pH modification to hollow gold nanosphere (HGN) synthesis to enable controlled tuning of the surface morphology from smooth to very bumpy. Unlike other methods, the synthetic protocol does not require harsh surfactants, secondary reducing agents, or organic solvents. The resultant bumpy HGNs (bHGNs) are highly monodisperse with little variation in protrusion length from particle to particle. Mechanistic studies suggest that surface rugosity is mainly controlled by the presence of free OH- ions in solution. We also present the first systematic investigation into the effect of surface morphology on the photothermal conversion efficiency (PCE) of bumpy as well as smooth HGNs, with a maximum PCE reaching 99%. Although expected to have a higher scattering component, the bHGNs retain the excellent PCE of their smooth counterparts, which may be due to efficient reabsorption of scattered light.
关键词： surface plasmon resonance,photothermal conversion efficiency,heat generation,surface morphology,hollow gold nanospheres
更新于2025-09-23 15:23:52
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DNA Engineered Noble Metal Nanoparticles (Fundamentals and State-of-the-art-of Nanobiotechnology) || Photochemical and Photophysical Events
摘要： DNA Engineered Noble Metal Nanoparticles: Fundamentals and State-of-the-art of Nanobiotechnology. This chapter covers photochemical and photophysical events involving noble metal nanoparticles, DNA nucleobases, DNA/PNA interactions, DNA-dye conjugates, DNA-AuNP-dye conjugates, DNA-gold nanoparticle conjugates, DNA-AgNPs, and hot gold nanoparticles, discussing their applications in bioanalysis, spectroscopy, photothermal therapy, imaging, and sensing.
关键词： biosensing,nanobiotechnology,localized surface plasmon resonance,noble metal nanoparticles,photophysical events,DNA,photochemical events,photothermal therapy,fluorescence
更新于2025-09-23 15:23:52
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Target-recycling-amplified colorimetric detection of pollen allergen using non-cross-linking aggregation of DNA-modified gold nanoparticles
摘要： Increasing prevalence of pollen allergies has raised concerns about human health. Development of a facile and precise method to detect pollen allergens would thus be of significance for environmental assessments and medical diagnoses. Here we report a sensitive colorimetric method to detect the Japanese cedar pollen allergen, Cry j 2. The method consists of two steps: a signal amplification based on the catalytic DNA hairpin self-assembly, followed by a signal transduction using the salt-induced non-cross-linking aggregation of gold nanoparticles densely modified with short DNA. The assay exhibits a detection limit of 0.2 ng/mL, which is 130-fold greater than that of the previously reported one. Moreover, the assay enables the detection of Cry j 2 spiked in soil solutions by avoiding any interference from the contaminants. The signal amplification system includes an anti-Cry j 2 DNA aptamer, which accounts for the absence of false responses to five non-target allergen proteins. The present method could be of general applicability to various proteins by using appropriate aptamers.
关键词： Surface plasmon resonance,Allergen,Aptamer,Gold nanoparticle,DNA,Cry j 2
更新于2025-09-23 15:23:52
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Real-time profiling Anti-EpCAM Based Immune capture, from Molecules to Cells using MP-SPR
摘要： Antibodies of epithelial cell-adhesion-molecule (anti-EpCAM)-based interfaces have proven to be highly efficient at capturing circulating tumor cells (CTCs). To achieve the bonding of anti-EpCAM to the interface, biotin and streptavidin are used to modify the surface. These processes are critical to subsequent cell-capture efficiencies. However, quantitative research on the interactions between biotin, streptavidin and biotinylated anti-EpCAM on the interface is lacking. In this work, the thermodynamics and kinetics of biomolecular interactions were determined by using surface plasmon resonance. The equilibrium binding affinities for biotinylated anti-EpCAM to streptavidin and streptavidin to biotin (illustrated by biotin-PEG400-thiol) were found to be 2.75×10^6 M^-1 and 8.82×10^6 M^-1, respectively. Each streptavidin can bind up to 2.30 biotinylated anti-EpCAM under thermodynamic equilibrium. The findings provide useful information to optimize the modification of anti-EpCAM and improve the capture efficiency of CTCs.
关键词： surface plasmon resonance,antibodies of epithelial cell-adhesion-molecule,cell capture,biotin–streptavidin interaction,thermodynamics,kinetics
更新于2025-09-23 15:23:52
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Enhancement of local electromagnetic fields by periodic optical resonators
摘要： The periodically profiled metasurfaces of silicon and of the same surfaces coated with a thin layer of silver are experimentally investigated to improve the signal-to-noise ratio in the observation of Raman light scattering from molecular compounds. The noise in this case is the unavoidable background molecular luminescence. Our experimental and computer simulation data demonstrate an anomalous optical response due to the excitation of metal-dielectric surface resonances. An enhanced Raman scattering signal is observed from 5,5'-dithiobis(2-nitrobenzoic) acid (DTNB) organic molecules deposited on the metasurface. The proposed metasurface provides a significant enhancement of the RS signal in comparison with the luminescence signal and is an efficient substrate for realising giant Raman scattering of light.
关键词： silicon,metasurface,dielectric resonators,nanostructures,plasmon resonance,giant Raman scattering of light
更新于2025-09-23 15:23:52