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Sensing of Furfural by Molecularly Imprinted Polymers on Plasmonic and Electrochemical Platforms
摘要： The goal of this work is to test the possibility of selective detection of furfural (2-FAL) in aqueous solutions, with a molecularly imprinted polymer (MIP) receptor exploiting two different transduction methods, for food safety applications. In particular, sensors with electrochemical and surface plasmon resonance (SPR) transduction are considered. Two concentration ranges could be investigated by the different sensing approaches since the detectable concentration level depends on the sensitivity of the detection technique employed. The determination of 2-FAL at different concentration levels in the aqueous medium of interest, as for example beverages, is becoming a very crucial task not only for the relevance of furanic compounds in affecting the flavor but also for their possible toxic and carcinogenic effects on the human beings. For these reasons, their determination by a fast, easy and low-cost method is of interest. The sensor methods here proposed appears to be particularly suitable, since, although together and not individually, they allow the determination in a wide concentration range.
关键词： furfural (2-FAL),electrochemical sensors,molecularly imprinted polymers (MIPs),optical-chemical sensors,plastic optical fibers (POFs),surface plasmon resonance (SPR)
更新于2025-09-23 15:19:57
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Theoretical analysis on SPR based optical fiber refractive index sensor with resonance wavelength covering communication C+L band
摘要： Surface plasmon resonance (SPR) based optical fiber refractive index sensor with resonance wavelength covering communication C+L band with high sensitivity. When the thicknesses of MgO, TeO2 and TiO2 are set at 80nm, 45nm and 40nm respectively, the sensitivity are all larger than 9000nm/RIU, meanwhile the resonance wavelength covers communication C+L band(1530nm-1625nm).
关键词： Oxide,Optical fiber sensor,Sensitivity,Surface plasmon resonance (SPR),Communication C+L band
更新于2025-09-23 15:19:57
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Enhanced solar- photocatalytic activity for the simultaneous degradation and detoxification of multiple chlorophenols by embedding plasmonic Pt into TiO2/H3PW12O40 nanopore
摘要： A novel Pt-TiO2/H3PW12O40 film was fabricated, which showed a considerable nonselective degradation and detoxification efficiency towards multiple chlorophenols (CPs), owing to the enhanced yield and separation efficiency of photogenerated electrons and holes. Based on the Mott-Schottky analysis, the carrier density of as-prepared Pt-TiO2/H3PW12O40 film reached 9.72 × 1022 cm?1, which was higher than that of Pt-TiO2, TiO2/H3PW12O40, and TiO2. The outstanding properties were attributed to the SPR effect and the formation of electrons traps from Pt0 (which was well protected by the nanopores that were formed by Ti-O-W and Ti-O-P); and H3PW12O40 that can efficiently transport electrons via its self-generated redox cycle. Meanwhile, the Pt-TiO2/H3PW12O40 film considerably lowers ecological risks of multiple CPs because O2?, as the primary radicals, can largely avoid the generation of products with a quinoid structure. The degradation pathways of multiple CPs were similar to those of single CP because the same hydroxyl substitution intermediate products were detected during the degradation, all of which followed the first-order reaction kinetics. Moreover, the excellent recycling performance of the Pt-TiO2/H3PW12O40 film guaranteed the reduction in economic cost and risks of secondary pollution. Therefore, the Pt-TiO2/H3PW12O40 film showed a considerable application potential in the removal of organic contaminants in aqueous environments.
关键词： Acute toxicity,Schottky junction,SPR effect,Multiple CPs,Degradation pathway
更新于2025-09-23 15:19:57
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Fe3O4@PDA immune probe-based signal amplification in surface plasmon resonance (SPR) biosensing of human cardiac troponin I
摘要： This work reports immunomagnetic separation technology-assisted surface plasmon resonance (SPR) biosensing for human cardiac troponin-I (cTnI), a well-known diagnostic marker for myocardial damage. Au film modified by Au nanoparticles (AuNPs) and polydopamine (PDA) was employed as the platforms for immobilizing capture antibody (cAb) and SPR sensing. Magnetic immune probe was prepared by attaching detection antibody (dAb) on the surface of Fe3O4 nanoparticles (Fe3O4 NPs) coated by PDA for precise capture, magnetic separation and enrichment of target analyte (cTnI) from samples. This extraction process greatly improves the sensitivity and effectively reduces the nonspecific interference from complex matrixes. The analyte cTnI collected via Fe3O4@PDA-dAb immune probe can be specially recognized by cAb immobilized on the sensing platform. By introducing secondary antibody (Ab2) conjugated with multi-walled carbon nanotube-PDA-AgNPs (MWCNTs-PDA-AgNPs/Ab2) to the sensing system, the residual binding sites of cTnI were occupied, and the SPR response signals were further amplified. The obtained detection limit for cTnI is 3.75 ng mL-1, which is 320-folds lower than that achieved by PDA-based sensing strategy. The present method was applied to the examination of serum samples spiked with cTnI, and the good recoveries demonstrate its future applicability in clinical diagnosis.
关键词： Polydopamine,Human cardiac troponin-I (cTnI),Immune probe,Surface plasmon resonance (SPR),Magnetic separation
更新于2025-09-19 17:15:36
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Silicon nanostructuring by Ag ions implantation through nanosphere lithography mask
摘要： Nanosphere lithography is an effective technique for high throughput fabrication of well-ordered patterns on large areas. This study reports on nanostructuring of silicon samples by means of Ag ions implantation through self-organized polystyrene (PS) masks. The PS nanospheres with a diameter of ～150 nm were self-assembled in a hexagonal array on top of Si(100) wafers, and then used as a mask for subsequent 60 keV silver ion implantation. Different fluences were applied up to 2 × 10^16 ions/cm^2 in order to create a distribution of different sizes and densities of buried metal nanoparticles. The surface morphology and the subsurface structures were studied by scanning electron microscopy and cross-sectional transmission electron microscopy, as a function of the mask deformation upon irradiation and the implantation parameters itself. We demonstrate that Ag is implanted into Si only through the mask openings, thus forming a regular array of amorphized regions over the wide area of silicon substrate. These fragments are of similar dimensions of the spheres with widths of about 190 nm and distributed over 60 nm in depth due to the given ion range. At the subsurface region of the implanted fragments, the synthesis of small sized and optically active Ag nanoparticles is clearly observed. The samples show a strong absorption peak in the long-wavelength region from 689 to 745 nm characteristic for surface plasmon resonance excitations, which could be fitted well using the Maxwell-Garnett`s theory.
关键词： Nanostructuring,Ag nanoparticles,SPR peak,Silicon,Polystyrene nanomask,Ion beam implantation
更新于2025-09-19 17:15:36
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High sensitivity hollow core circular shaped PCF surface plasmonic biosensor employing silver coat: A numerical design and analysis with external sensing approach
摘要： This article numerically o?ers and analyses a hollow core circular shaped photonic crystal ?ber-based surface plasmon resonance (CH-PCF-SPR) biosensor. The biosensor sensitivity is analyzed with applying a mode solver built ?nite element method (FEM) incorporating multi-physics software “COMSOL”. A nano ?lm of silver is coated as sensing layer on the external surface for easy sensing and more practical realization. The biosensor unveils the highest wavelength sensitivity valued 21000 nm/RIU and amplitude sensitivity valued 2456 RIU?1, and corresponding wavelength resolution of 4.76 × 10?6 RIU, respectively, using wavelength interrogation technique (WIT) and technique of amplitude interrogation (AIT), in detecting e?ective refractive index range 1.33 RIU and 1.42 RIU. Besides, the consequence of changing structural parameters like – pitch, diameter of air hole, various plasmonic metals and silver (Ag) layer thickness are also resulted in results section. The sensitivity of the o?ered sensor is analyzed to examine the means of spectral loss depth, resolution and amplitude sensitivity. In arrears to the modest scheme, highly sensitive and resolution nature, the o?ered design can be precisely applied in detection of bio molecular analytes.
关键词： SPR,Sensitivity,Resolution,Hollow core
更新于2025-09-19 17:13:59
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Detection and Quantification of HspX Antigen in Sputum Samples Using Plasmonic Biosensing: Toward a Real Point-of-Care (POC) for Tuberculosis Diagnosis
摘要： Advances occurred during the last years in the diagnosis of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis infection, have prompted increased survival rates of patients. However, limitations related to the inefficiency of an early detection still remain: some techniques and laboratory methods do not have enough specificity, most instruments are expensive, and require handling by trained staff. In order to contribute to a prompt and effective diagnosis of tuberculosis, we report the development of a portable, user-friendly and low-cost biosensor device for its early detection. By using a label-free Surface Plasmon Resonance (SPR) biosensor, we have established a direct immunoassay for the direct detection and quantification of the Heat shock protein X (HspX) of Mtb, a well-established biomarker of this pathogen, directly in pre-treated sputum samples. The method relies on highly specific monoclonal antibodies which are previously immobilized on the plasmonic sensor surface. This technology allows the direct detection of the biomarker without amplification steps, showing a Limit of Detection (LOD) of 0.63 ng mL-1 and a Limit of Quantification (LOQ) of 2.12 ng mL-1. The direct analysis in pre-treated sputum shows significant differences in the HspX concentration in patients with tuberculosis (with concentration levels in the order of 116-175 ng mL-1) compared with non-tuberculosis infected patients (values below the LOQ of the assay).
关键词： SPR Immunosensor,Tuberculosis diagnosis,HspX recombinant protein,human sputum samples,Point-of-Care device
更新于2025-09-19 17:13:59
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AIP Conference Proceedings [AIP Publishing TECHNOLOGIES AND MATERIALS FOR RENEWABLE ENERGY, ENVIRONMENT AND SUSTAINABILITY: TMREES19Gr - Athens, Greece (4–6 September 2019)] TECHNOLOGIES AND MATERIALS FOR RENEWABLE ENERGY, ENVIRONMENT AND SUSTAINABILITY: TMREES19Gr - Time effect on the red shift of surface plasmonic resonance core-shell SiO2: Gold nanoparticles (AuNPs)
摘要： Spherical gold nanoparticles (AuNPs) chemically synthesized by Turkevich method, it coated with sodium silicate stock solution (Na2SiO3). Study different rate effect (SiO2 and ethanol) on position of surface plasmon resonance (SPR) of gold nanoparticles (AuNPs) after coated by using UV–Vis absorption spectroscopy. UV–vis spectrum showed that rate (SiO2 and ethanol) had effect in the coated gold nanoparticles (AuNPs), that Peak band gold nanoparticles (AuNPs) uncoated at (515nm) and this peak was shifted to longer wavelength (518nm) after coating. Coated after get a little shift in position of surface plasmon resonance (SPR) this means that coated method has an important role in maintain on gold nanoparticles (AuNPs) stability.
关键词： gold nanoparticles (AuNPs),Surface Plasmon Resonance (SPR),Sodium Silicate (Na2SiO3),Turkevich method
更新于2025-09-16 10:30:52
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Response Properties of Gold- and Aluminum-deposited SPR-based Glass Rod Sensors Using Light-emitting Diodes with Various Wavelengths; 各種波長の発光ダイオードを用いる金とアルミニウムを蒸着したガラス棒SPRセンサーの応答特性;
摘要： The response curves of gold (Au)- and aluminum (Al)-deposited surface plasmon resonance (SPR)-based glass rod sensors with various light-emitting diodes (LEDs) of visible and near-infrared emission as the light sources were measured. Au films with thicknesses of 30, 45, and 70 nm, and Al films with thicknesses of 15, 30, and 45 nm were deposited on half of the surfaces of glass rods of 2 mm in diameter with a deposition length of 100 mm. The LEDs of blue (464 nm), green (533 nm), yellow (591 nm), red (654 nm), and near-infrared (934 nm) emissions for Au films, and those of violet (402 nm), blue, green, yellow, red emissions for Al were used. The response curves of these sensors, calculated using a multi-layer Fresnel equation using various dielectric constants for the emission wavelengths reported in literatures, were compared with those obtained in the measurements. The important parameters for the calculations were the LED intensity distribution, the range of the angle of incidence of light into the sensor element, and the thickness distributions of the metal films deposited on the glass rods. Native oxide layers with a thickness of 3.0 nm were considered for Al films. The minimum positions of the experimental response curves agreed well with those of the theoretical response curves within the limits of the experimental uncertainties, though those of the experimental response curves using the LED of near-infrared emission shifted to higher refractivity values, mainly due to the wide wavelength distribution to longer wavelengths of the LED. The agreements between the experimental and theoretical response curves indicate both the potential and the usefulness of the sensor performance estimation process based on the multi-layer Fresnel equation. It was also found that the value of the ratio of the real and imaginary part of the dielectric constant is an easy and useful estimation for SPR.
关键词： multi-layer Fresnel equation,dielectric constant,Au,metal-deposited SPR-based glass rod sensor,Al
更新于2025-09-16 10:30:52
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Plasmonic Contrast Imaging Biosensor for the Detection of H3N2 Influenza Protein-Antibody and DNA-DNA Molecular Binding
摘要： We report a plasmonic contrast imaging biosensor. It measures the intensity difference between the p- and s-polarization images at plasmonic excitation. At plasmonic resonance, only the p- polarization light is excited, while s-polarization light remains the same. Image intensity subtraction between both polarizations can eliminate common system noise and enhance sensor resolution. In refractive index measurements, the sensor resolution was found to be 4.36 × 10-7 RIU. The plasmonic contrast imaging sensor has further been demonstrated for H3N2 influenza antibody detection and DNA-DNA molecular binding detections. The detection limit was found to be 8.6nM (320 ng mL-1) for H3N2 influenza antibodies. This value is 56% and 216% better than the detection limit reported for influenza antibody detection with commercial Biacore systems. A computer control device prototype has further been developed based on the optical design, which is ready for various bio-molecular binding detections.
关键词： Label free,DNA,SPR imaging,Plasmonic biosensor,Resonator,Influenza
更新于2025-09-16 10:30:52