Sensitive Sensor Research Articles

Wave type fiber SPR sensor for rapid and highly sensitivity detection of hyperoside

The fiber surface plasmon resonance (SPR) sensor used for the detection of active ingredients in traditional Chinese medicine has the problems of low sensitivity and difficult specific recognition. This paper proposed a wave type fiber SPR sensor, which reduced the mode of transmitted light through a periodic wave structure and caused concentrated and total reflection of the transmitted beam at the interface between the bent peak cladding and the air. A 50 nm gold film was coated on the surface of the cladding in the wave structure area to form the SPR sensing area. By controlling the width and height of the wave structure to control the total reflection angle of the transmitted light, i.e., the SPR incidence angle, the sensitivity of the fiber SPR sensor was effectively improved to 4972 nm/RIU. Furthermore, HSP90AA protein was modified on the gold film of the sensor to achieve specific detection of hyperoside. The longest single detection time was only 3 minutes, and the detection sensitivity was 0.53 nm/(µg/ml), with a detection limit as low as 0.68µg/ml, which is comparable to liquid chromatography. The proposed wave type fiber SPR sensor is fast in production and has high structural mechanical strength, providing a new approach for the rapid, highly sensitive, and specific detection of active ingredients in traditional Chinese medicine.

Water adsorption kinetics on graphene controlled by surface modification of supporting substrates

Abstract Sensing layers with an increased affinity for water molecules are essential for the development of highly sensitive humidity sensors. Graphene possesses superior electrical properties that make it suitable for the fabrication of low-noise miniaturized sensors. However, the enhancement of water affinity by introducing surface defects such as covalently attached hydrophilic groups reduces the electrical conductivity of graphene. In this study, we exploit the wetting transparency of graphene to increase its water affinity without introducing defects. Kinetic measurements using a Kelvin probe with a large-diameter tip showed that the rate constant of water adsorption was higher for graphene deposited on a hydrophilic substrate. These findings suggest that the wetting transparency of graphene can be exploited to reduce defect introduction into the graphene sensing layer, and has potential applications in sensor technologies.

Half bridge configurated magneto-resistive sensors with flux guide structure for enhancing sensitivity

We demonstrate the enhancement in sensitivity of half Wheatstone bridge configurated magneto-resistive sensors with a design of the magnetic flux guide. The efficacy of our flux guide design, in comparison to the conventional micro-magnetic flux concentrator for improving the flux gain, is studied using finite element method and verified with the experimental result. We observed a sensitivity of 260%/mT for our half Wheatstone bridge sensor with a very small coercivity of 0.01 mT at room temperature. Our work will contribute to paving a road map for mass production of sensitive magneto-resistive sensors with small footprints (2.5 mm2 in this study).

Selective and sensitive MIP-Based electrochemical Sensor for the analytical determination of Lanreotide

Lanreotide (LAN) is an analog of somatostatin used to treat acromegaly and neuroendocrine tumors. Considering drug toxicity and the lack of sensitive techniques in drug analysis, the development of sensitive analytical methods is of great importance. During this research, a molecular imprinted polymer (MIP) based film [P(HEMA-MAGA)@MIP/GCE] was prepared by photopolymerization technique for electrochemical determination of LAN for the first time. N-methacryloyl-L-glutamic acid (MAGA) and hydroxyethyl methacrylate (HEMA) were used as functional and basic monomers, respectively. The surface alterations were investigated using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) and the chemical composition of the MIP-based sensor. Theelectrochemical characterization of the modifiedelectrodes was assessed using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Using differential pulse voltammetry (DPV) in standard solution and spiked serum sample of LAN, the linear response range for LAN was obtained as 1.0x10 − 14 M – 1.0x10 − 13 M. The limit of detection (LOD) values were 1.76x10 − 15 M and 1.82x10 − 15 M in water and commercial human serum, respectively. The limit of quantitation(LOQ) values for these were 5.85x10 − 15 M and 6.07x10 − 15 M, respectively. The P(HEMA-MAGA)@MIP/GCE sensor also showed excellent recovery in pharmaceutical preparation and commercial human serum form with of 99.37 % and 99.27 %, respectively, with a good RSD value (0.51–0.73), confirming the accuracy and precision of the sensor. As a control, the non-imprinted polymer (NIP) was also prepared to serve in the same way but without the template. The selectivity experiments were conducted using somatostatin (SOM) and octreotide (OC) as potential competitors to demonstrate the selectivity of the proposed sensor against LAN molecules.

Characterization of a Food‐Safe Colorimetric Indicator Based on Black Rice Anthocyanin/PET Films for Visual Analysis of Fish Spoilage

ABSTRACTThe safety of food products is of prime importance for consumers and manufacturers. Many means can be used to validate a food product's safety before it is consumed. This study is about the preparation, characterization and evaluation of a generally recognized as safe (GRAS) sensitive colorimetric sensor that detects volatile gases (TVB‐N) resulting from fish spoilage, thus indicating the pH variation of packaged fish products. This is performed by coating a thin layer of ink sensors on the surface of the supporting matrix (corona‐treated PET). Various visual pH indicators were prepared based on black rice anthocyanin as an FDA‐approved dye. Black rice, which contains more than 80% cyanidin‐3‐glucoside, is the most prevalent anthocyanin component. Because of its low toxicity and high concentration, it can be utilized as a natural food colourant. pH indicators based on black rice can show distinct colours in various pH: from red (low pH) to violet (4–6) and deep purple/blue (6–7), blue (7–9) to yellowish/light brown (9–13) throughout the acid–base reaction by the analyte. The ink formulation was prepared by incorporating a binder system (PVOH‐PEG) for higher surface wettability, a crosslinking agent (citric acid) for higher adhesion, an antifoaming agent (natural vanillin) and acetic acid as a pH fixing agent. Corona treatments affected substrate surface chemistry in this study. The samples with thermal treatment passed the ASTM D3330 tape test, the 8000 passages for dry sponge and the 25 passages for wet sponge through the abrasion method. Anthocyanin concentration in formulated ink based on calculation by UV–vis spectra is 0.240 mg/100 g. Sensitivity tests towards TVB‐N gases were carried out at a temperature of 4°C to evaluate the performance of colorimetric films with formulated ink along with thermal treatment (temperature: 165°C, time: 5 min) using the volatile gases emitted by the fish sample inside the package.

A “2-in-1” Bioanalytical System Based on Nanocomposite Conductive Polymers for Early Detection of Surface Water Pollution

This work proposes an approach to the formation of receptor elements for the rapid diagnosis of the state of surface waters according to two indicators: the biochemical oxygen demand (BOD) index and toxicity. Associations among microorganisms based on the bacteria P. yeei and yeast S. cerevisiae, as well as associations of the yeasts O. polymorpha and B. adeninivorans, were formed to evaluate these indicators, respectively. The use of nanocomposite electrically conductive materials based on carbon nanotubes, biocompatible natural polymers—chitosan and bovine serum albumin cross-linked with ferrocenecarboxaldehyde, neutral red, safranin, and phenosafranin—has made it possible to expand the analytical capabilities of receptor systems. Redox polymers were studied by IR spectroscopy and Raman spectroscopy, the contents of electroactive components were determined by atomic absorption spectroscopy, and electrochemical properties were studied by electrochemical impedance and cyclic voltammetry methods. Based on the proposed kinetic approach to modeling individual stages of bioelectrochemical processes, the chitosan–neutral red/CNT composite was chosen to immobilize the yeast association between O. polymorpha (ks = 370 ± 20 L/g × s) and B. adeninivorans (320 ± 30 L/g × s), and a bovine serum albumin (BSA)–neutral composite was chosen to immobilize the association between the yeast S. cerevisiae (ks = 130 ± 10 L/g × s) and the bacteria P. yeei red/CNT (170 ± 30 L/g × s). After optimizing the composition of the receptor systems, it was shown that the use of nanocomposite materials together with associations among microorganisms makes it possible to determine BOD with high sensitivity (with a lower limit of 0.6 mg/dm3) and detect the presence of a wide range of toxicants of both organic and inorganic origin. Both receptor elements were tested on water samples, showing a high correlation between the results of biosensor analysis of BOD and toxicity and the results of standard analytical methods. The results obtained show broad prospects for creating sensitive and portable bioelectrochemical sensors for the early warning of environmentally hazardous situations based on associations among microorganisms and nanocomposite materials.

Highly sensitive acetone gas sensor based on gold nanoparticles modified W18O49 porous polymeric spheres

Highly sensitive acetone gas sensor based on gold nanoparticles modified W18O49 porous polymeric spheres

Optimization Design of CMUT Sensors with Broadband and High Sensitivity Characteristics Based on the Genetic Algorithm

In this study, we propose a method for optimizing the design of CMUT sensors using genetic algorithms. Existing CMUT sensors face frequency response and sensitivity limitations, necessitating optimization to enhance their sensing performance. Traditional optimization methods are often intricate and time-consuming and may fail to yield the optimal solution. Genetic algorithms, which simulate the biological evolution process, offer advantages in global optimization and efficiency, making them widely utilized in the optimization design of Microelectromechanical Systems (MEMS) devices. Based on the theoretical framework and finite element model of CMUT sensors, we propose a CMUT array element optimization design method based on genetic algorithms. The optimization and validation results demonstrate that we have successfully designed a broadband CMUT array element consisting of four microelements with a 1–2 MHz frequency range. Compared with a randomly arranged array element, the optimized array shows a 63.9% increase in bandwidth and a 7.5% increase in average sensitivity within the passband. Moreover, the sensitivity variance within the passband is reduced by 50.2%. Our proposed method effectively optimizes the design of high sensitivity CMUT sensors with the desired bandwidth, thereby offering significant reference value for the optimization design of CMUT sensors.

A Highly Sensitive and Selective Fluorescent Sensor for Folic Acid Detection Based on D-penicillamine Stabilized Ag/Cu Alloy Nanoclusters.

In this work, a highly sensitive and selective method for detecting folic acid (FA) was developed using D-penicillamine (DPA) stabilized Ag/Cu alloy nanoclusters (DPA@Ag/Cu NCs). The yellow emission of DPA@Ag/Cu NCs was found to be quenched upon the addition of FA to the system. The fluorescence intensity quenching value demonstrated a linear relationship with FA concentrations ranging from 0.01 to 1200 μM,with a limit of detection(LOD) of 5.3 nM. Furthermore, the detection mechanism was investigated through various characterization analyses, including high resolution transmission electron microscopy, fluorescence spectra, ultraviolet-visible absorption spectra, and fluorescence lifetime. The results indicated that the fluorescence quenching induced by FA was a result of electron transfer from FA to the ligands of DPA@Ag/Cu NCs.The selectivity of the FA sensor was also evaluated, showing that common amino acids and inorganic ions had minimal impact on the detection of FA. Moreover, the standard addition method was successfully applied to detect FA in human serum, chewable tablets and FA tablets with promising results. The use of DPA@Ag/Cu NCs demonstrates significant potential for detecting FA in complex biological samples.

Highly sensitive rhodamine B dye-based electrochemical sensor for lactose detection

Lactose (LAC) is the main disaccharide sugar found in milk and dairy products, making it easily accessible as a food source. In addition to its importance for human and animal health, LAC concentrations serve as a biomarker of milk quality. In this study, we reported the detection of LAC using a highly sensitive electrochemical sensor based on rhodamine B (RhB) dye. The prepared RhB-based sensor exhibited excellent characteristics, including a straightforward manufacturing technique, cost-effectiveness, and exceptional sensitivity. We conducted a comparative analysis of the electrochemical response of the novel RhB-based sensor, evaluating its electrochemical performance across varying LAC concentrations and when different analyte materials (glucose, fructose, and maltose) were employed. The proposed analytical method was utilized to determine LAC using an electrochemical RhB-based sensor under optimal experimental conditions. As a result, it was experimentally observed that high sensor sensitivity of RhB based sensor against LAC was inversely proportional to the impedance value and directly proportional to conductance which corolated with the transport mechanism of RhB.

Ultra-high sensitive dual-parameter sensor based on double-hole fiber for simultaneous detection of magnetic field and temperature

An ultra-high sensitive dual-parameter sensor based on double-hole fiber (DHF) is proposed for simultaneous detection of magnetic fields and temperatures. The sensor utilizes the DHF containing a Ge-doped core with two large air holes symmetrically arranged at its two sides. To enhance the sensitivity to both a magnetic field and temperature, Al wires with different diameters are embedded on the inner walls of the air holes in the DHF, creating a magnetic field sensing channel filled with magnetic fluid and a temperature sensing channel filled with thermo-sensitive liquid. Structural parameters and metal materials of the sensor are optimized by using the finite element method. Numerical results demonstrate that this DHF-based dual-parameter sensor can detect magnetic fields ranging from 40 Oe to 130 Oe and temperatures ranging from 24.3 °C to 49.3 °C simultaneously. The maximum magnetic field sensitivity reaches up to 64000 pm/mT, while the maximum temperature sensitivity is approximately 44.6 nm/°C, both exceeding current reports by more than one order of magnitude for simultaneous detection of magnetic field and temperature. With its high sensitivity, low fabrication difficulty, and simple structure, this DHF-based dual-parameter sensor has potential applications in the fields of material characterization analysis, geological environmental monitoring, and aeronautical engineering.

Rapid and Sensitive Detection by Combining Electric Field Effects and Surface Plasmon Resonance: A Theoretical Study

Surface plasmon resonance (SPR) has been extensively employed in biological sensing, environmental detection, as well as chemical industry. Nevertheless, the performance possessed by conventional surface plasmon resonance (SPR) biosensors can be further limited by the transport of analyte molecules to the sensing surface, noteworthily when small molecules or low levels of substances are being detected. In this study, a rapid and highly sensitive SPR biosensor is introduced to enhance the ability of the target analytes’ collection by integrating AC electroosmosis (ACEO) and dielectrophoresis (DEP). Both the above-mentioned phenomena principally arise from the generation of the AC electric fields. This generation can be tailored by shaping the interdigitated electrodes (IDEs) that also serve as the SPR biomarker sensing area. The effects exerted by different parameters (e.g., the frequency and voltage of the AC electric field as well as microelectrode structures) are considered in the iSPR (interdigitated SPR) biosensor operation, and the iSPR biosensors are optimized with the sensitivity. The results of this study confirm that the iSPR can efficiently concentrate small molecules into the SPR sensing area, such that SPR reactions achieve an order of magnitude increase, and the detection time is shortened. The rapid and sensitive sensor takes on critical significance in the development of on-site diagnostics in a wide variety of human and animal health applications.

The Impact of GIMMF Pitch on Sensitivity of Curvature Sensor Based on Anti-Resonance

The Impact of GIMMF Pitch on Sensitivity of Curvature Sensor Based on Anti-Resonance

Highly Sensitive Magnetic Field Sensor Based on Few-Mode Fiber Interferometry

Highly Sensitive Magnetic Field Sensor Based on Few-Mode Fiber Interferometry

A sensitive methane gas sensor based on sagnac interferometer with a cryptophane-A film-coated birefringent photonic crystal fiber : design and FEM simulation

Abstract As being sensitive to methane gas, cryptophane-A is widely used in fiber optic methane gas sensors. In order to further improve the sensitivity, a Sagnac interference (SI) was constructed with a cryptophane-A film coated birefringent photonic crystal fiber (PCF) to realize the methane gas sensing. Cryptophane-A film absorbs the methane gas and as a result its refractive index decreases linearly with the increasing of methane gas concentration. Simulation results utilizing the finite element method demonstrate that sensitivity reaches 124.4 nm/% when the methane concentration ranges from 0% to 3.5%. The high sensitivity performance ensures a candidate of the designed sensor in early warning of methane gas leakage.

A Novel Highly Sensitive Angular Rate Sensor Employing Anti-Parity-Time Symmetry

A Novel Highly Sensitive Angular Rate Sensor Employing Anti-Parity-Time Symmetry

Tuning sensitivity of surface plasmon resonance gas sensor based on multilayer black phosphorous

We investigated a gas sensor that makes use of the surface plasmon resonance (SPR) effect in a thick layer of gold (Au), copper (Cu), ZnO, and multilayer black phosphorous (BP). The suitability of the proposed gas sensor was investigated for a range of analyte gases recognized for their toxicity, greenhouse effect, or flammability. The proposed gas sensor obtains a maximum sensitivity of 258.77°/RIU with a remarkable full width at half maximum (FWHM) of 7.12°, detection accuracy (DA) of 0.14/°, and Figure of merit (FoM) of 36.22. The result of our enhanced numerical analysis indicates that the performance of a multilayer BP is enhanced when compared to a conventional gas sensor. As a result, using a SiO2 prism to sense different gases at a wavelength of 633[Formula: see text]nm, the suggested gas sensor may be more advantageous. Moreover, the maximum sensitivity of 374.31/RIU is obtained with a remarkable DA of 0.11° and FoM of 37.63/RIU to detect NO2 gas sensing to maintain the [Formula: see text]value. The gas sensor performance is high at different refractive indices for gas analyte (1–1.07). The performance of the proposed gas sensor is superior to that of the existing gas sensors.

A Novel MXene@MOF@Pt NPs-Based Enzyme-Free Electrochemical Sensor for highly Sensitive Detection of Hydrogen Peroxide Released from Living Cells

Abstract Rapid and accurate detection of hydrogen peroxide (H2O2), an important reactive oxygen species (ROS) released from living cells, is of great significance for early diagnosis of tumors. Here, a high sensitive enzyme-free electrochemical sensor for the detection of H2O2 released from living cells was constructed based on MXene@ZIF-8@Pt NPs nanocomposites. Through the characterization of physical and chemical properties, it was observed that Pt NPs with excellent catalytic activity were uniformly supported on MXene@ZIF-8, which exhibited excellent conductivity and large specific surface area. Thanks to the significantly enhanced catalytic activity derived from the successful integration of MXene, ZIF-8 and Pt NPs, under the optimal conditions, the sensing platform based on MXene@ZIF-8@Pt NPs exhibited a wide linear range from 355.4 nM to 21.75 mM, with a limit of detection as low as 120.9 nM, while showing satisfactory reproducibility and selectivity. Furthermore, the developed electrochemical sensor enables real-time monitoring of H2O2 released from living Hela cells under N-formylmethionyl-leucyl-phenylalanine stimulation. Overall, the MXene@ZIF-8@Pt NPs developed in this article will become a promising candidate in monitoring physiological processes.

A Simple Photosensitive Circuit Based on a Mutator for Emulating Memristor, Memcapacitor, and Meminductor: Light Illumination Effects on Dynamical Behaviors

This contribution investigates a photosensitive circuit based on a mutator for emulating memristor, memcapacitor, and meminductor. The circuit contains a phototube, a mutator, and several basic electronic components. The phototube is employed within the circuit to capture the external illumination for energy injection in order to obtain a continuous signal source. By varying the light intensity on the phototube, chaotic dynamics such as attractors, bifurcation diagrams, and Lyapunov exponents spectrum are analyzed, while the mutator is switched to different mem-elements without changing the structure of the circuit. Especially, the special phenomenon of the coexistence of attractors is discovered. Ultimately, the circuit is realized using DSP. This circuit holds promise in offering potential insights into the dynamics of neural networks, and it could find applications in the development of highly sensitive sensors.

Surface phonon resonance: A new mechanism for enhancing photonic spin Hall effect and refractive index sensor

Abstract Metal-based surface plasmon resonance (SPR) plays an important role in enhancing the photonic spin Hall effect (SHE) and developing sensitive optical sensors. However, the very large negative permittivities of metals limit their applications beyond the near-infrared regime. In this work, we theoretically present a new mechanism to enhance the photonic SHE by taking advantage of SiC-supported surface phonon resonance (SPhR) in the mid-infrared regime. The transverse displacement of photonic SHE is very sensitive to the wavelength of incident light and the thickness of SiC layer. Under the optimal parameter setup, the calculated largest transverse displacement of SiC-based SPhR structure reaches up to 163.8 μm, which is much larger than the condition of SPR. Moreover, a NO2 gas sensor based on the SPhR-enhanced photonic SHE is theoretically proposed with the superior sensing performance. Both the intensity and angle sensitivity of this sensor can be effectively manipulated by varying the damping rate of SiC. The results may provide a promising paradigm to enhance the photonic SHE in the mid-infrared region and open up new opportunity of highly sensitive refractive index sensors.