High-sensitivity Applications Research Articles

Ultra-high sensitivity D-type photonic crystal fiber sensor deposited with MoO2 nanofilm

Fiber optic sensing technology has extensive applications in many fields and demands high sensitivity and cost-effectiveness for sensors. In this study, we propose an ultra-high sensitivity D-type photonic crystal fiber sensor based on MoO2 nano-film coating to meet this requirement. Firstly, MoO2 is selected as the plasmonic excitation material. Compared to expensive metals such as Au and Ag, MoO2 has the characteristics of low cost and charge carrier density, which is suitable for use in optical fiber sensing modules. The sensitivity of the sensor to the external environment can be increased by coating the surface of the optical fiber with MoO2 nano-film. Then, we use the finite element method to evaluate the performance of the sensor. Numerical simulation results show that the average wavelength sensitivity of the sensor in the x-polarization direction is as high as 24000 nm/RIU when analyzing substances with refractive indices ranging from 1.38 to 1.43. This means that the sensor has a very sensitive response to refractive index changes and can be widely applied to sensing needs in different fields. Overall, the D-type photonic crystal fiber sensor based on MoO2 nanofilm coating has enormous potential for applications. This sensor can achieve high-sensitivity detection within a specified range of refractive indices, providing new ideas and methods for research and applications in the field of fiber sensing.

Bimetallic Au and Pd Nanoparticles Modified WO3 Nanosheets for Enhancing the Sensitivity and Selectivity of Formaldehyde Assessment in Aquatic Products.

Formaldehyde, a common illegal additive in aquatic products, poses a threat to people's health and lives. In this study, a novel metal oxide semiconductor gas sensor based on AuPd-modified WO3 nanosheets (NSs) had been developed for the highly efficient detection of formaldehyde. WO3 NS modified with 2.0% AuPd nanoparticles showed a higher response (Ra/Rg = 94.2) to 50 ppm of formaldehyde at 210 °C, which was 36 times more than the pristine WO3 NS. In addition, the AuPd/WO3 gas sensor had a relatively short response/recovery time of 10 s/9 s for 50 ppm of formaldehyde at 210 °C, with good immunity to other interfering gases and good stability for formaldehyde. The excellent gas-sensitive performance was attributed to the chemical sensitization of Au, the electronic sensitization of Pd, and the synergistic effect of bimetallic AuPd, which facilitated the recognition and response of formaldehyde molecules. Additionally, the high sensitivity and broad application prospect of the 2.0% AuPd/WO3 NS composite-based sensor in real sample detection were also confirmed by using the above sensor for the detection of formaldehyde in aquatic products such as squid and shrimp.

High selective, sensitive, reversible and imaging application sensor for Aluminium detection

Aluminium plays an important role in many areas, which has been shown to be associated with some serious diseases. According to the coordination of aluminium with N and O, we conducted probe Sal-cn for the detection of Al3+, the structure of Sal-cn was determined by HR-MS, NMR and IR. Sal-cn showed a good selective and sensitive response towards Al3+ via a fluorescence turn-on output. The detection limit was 0.21 μM. The mechanism was carried out by Job's plot, HR-MS and DFT and related to the coordination of aluminium. What's more, the reversibility showed that Sal-cn could be used for 3 times. Besides, Sal-cn was used for imaging of Al3+ in HEK293T cells.

Design and Optimization of Silver Nanostructured Arrays in Plasmonic Metamaterials for Sensitive Imaging Applications

This paper delves into the strategic design and optimization of silver (Ag) nanostructured arrays within plasmonic metamaterials, targeting the enhancement of imaging sensitivity. Leveraging Finite-Difference Time-Domain (FDTD) simulations, our research rigorously compares various Ag nanostructured geometries, including nanospheres, nanocones, nanodisks, and nanocubes. The aim is to pinpoint configurations that significantly enhance electric field localization on the surfaces of nanostructures, a pivotal factor. The nanocube array exhibits superior field enhancement, particularly in narrow nanogaps, suggesting its suitability for high-sensitivity applications. Further exploration into nanocube arrays reveals the crucial role of nanogap size and spacer layer thickness in tuning the optical properties through the manipulation of Fabry–Pérot and mirror image modes in metal–insulator–metal (MIM) structures. By presenting a thorough analysis of these nanostructured arrays, the study not only contributes to our understanding of the fundamental principles governing plasmonic metamaterials but also provides a solid foundation for future innovation in highly sensitive imaging applications. It underscores the importance of nanostructure design and optimization in achieving significant improvements in the performance of plasmonic devices, marking a pivotal step forward in the field of nanophotonics and its application to sensitive imaging technologies.

Intelligent sensing technology inspired by cell electrophoresis: Dielectric polarization sensor for monitoring the electrical equipment status of IoT nodes

The rapid development of the Internet of Things (IoT) era has led to the emergence of various types of information sensing devices. The operation and maintenance of IoT devices require a large-scale use of sensors at the expense of high energy consumption. In this work, we develop a self-powered voltage monitoring sensor (VSM-S) based on the principle of dielectric polarization, which is inspired by the cell electrophoresis phenomenon. This sensor imitates the structure of biological cells and takes advantage of the easier polarization characteristics of liquid medium with high dielectric constant in an external electric field. It collects electric field energy to achieve self-powering function and can monitor the position and status of the electric field source in real-time through output signals. Experiments show that the designed VSM-S has the characteristics of fast response (10−9-10−15 s), high sensitivity (0.3 nA/V), and wide application range. Furthermore, its integration with monitoring systems enables applications in smart industries, smart homes, and smart grids. This work has considerable development prospects in the fields of wearable sensors and the IoTs.

High enrichment and sensitive measurement of oxytetracycline in tea drinks by thermosensitive magnetic molecular imprinting based magnetic solid phase extraction coupled with boron doped carbon dots

As a typical kind of new pollutants, there are still some challenges in the rapid detection of antibiotics. In this work, a sensitive fluorescent probe based on boron-doped carbon dots (B-CDs) in combination with thermo-responsive magnetic molecularly imprinted polymers (T-MMIPs) was constructed for the detection of oxytetracycline (OTC) in tea drinks. T-MMIPs were designed, fabricated and employed to enrich OTC at trace level from tea drinks, and B-CDs were utilized as the fluorescent probe to detect the concentration of OTC. The proposed method exhibited good linear relationship with OTC concentration from 0.2 to 60 μg L−1 and the limit of detection was 0.1 μg L−1. The established method has been successfully validated with tea beverages. Present work was the first attempt application of T-MMIPs in combination with CDs in detection of OTC, and demonstrated that the proposed method endowed the detection of OTC with high selectivity, sensitivity, reliability and wide application prospect, meanwhile offered a new strategy for the method establishment of rapid and sensitive detection of trace antibiotics in food and other matrices.

Dry Lamp: A Point of Care Diagnostics for Diagnosis of Bovine Tropical Theileriosis

ABSTRACT Background & objectives: Theileriosis is an important tick-borne hemoprotozoan disease of cattle which causes severe economic loss due to morbidity and mortality. A diagnostic test having high sensitivity, specificity and easy application at the field level is the need of the hour. In this regard Loop mediated isothermal amplification (LAMP) is proven to be a sensitive, easy and time efficient method. One of the major obstacles for the application of LAMP is the difficulty in maintaining the cold chain to preserve reagents. Thus, the challenge is to develop a LAMP kit in a ready-to-use format with dried reagents useful for quick and simple application in field conditions. Methods: The optimized reaction of wet LAMP was followed for the standardization of dry LAMP with certain modifications which are needful. The major modification is vitrification technology of enzyme using trehalose. Results: LAMP assay (dry and wet LAMP) was found to be more sensitive (100%) when compared to microscopy (69.5%) and PCR (86.9%). It was observed that the dry LAMP reaction tubes at room temperature as well as refrigeration temperature provided successful amplification till 7 weeks. Interpretation & conclusion: The drying conditions of LAMP reagents were optimized, and finally managed to dry them in a single reaction tube without reducing the sensitivity. This technology enables us to transport LAMP kits to areas where the cold chain is not easily available.

An electrochemical sensor based on the composite UiO-66-NH2/rGO for trace detection of Pb(II) and Cu(II)

Pb(II) and Cu(II) can cause serious harm to human health. Therefore, it is of great significance to develop highly sensitive detection methods. Herein, the composite UiO-66-NH2/rGO was prepared by in-situ growth method. The UiO-66-NH2/rGO showed high sensitivity with Pb(II) of 6.27 μA/μM and Cu(II) of 6.83 μA/μM. Additionally, the UiO-66-NH2/rGO exhibits excellent repeatability, reproducibility, anti-interference properties and practical application potential. These results indicate that UiO-66-NH2/rGO is an excellent electrode modification material. The composite has the advantages of high sensitivity and good practical application effect. This work provides a strategy for the application of UiO-66-NH2 in the field of electrochemical sensing.

Boron nitride nanosheet modified amperometric biosensor for uric acid determination

In this study, enzyme-modified boron nitride nanosheets as a catalytic two-dimension material for the sensor application developed for the first time. In this developed system, uricase interacted with B-N groups by the two-dimensional structure of the boron nitride layer. In this way, a unique catalytic structure was created by binding uricase to B-N groups, and this structure was protected by NafionTM. The developed enzyme-based biosensor exhibited a wide linear detection range (5–3000 µM), and a low limit of detection and quantitation values (0.14 µM and 0.46 µM, respectively) for uric acid. Also, the developed system performed good reproducibility, reusability, high selectivity, sensitivity, low Km value, and excellent shelf-life properties. Furthermore, this enzyme-based biosensor has successfully identified uric acid in commercial human serum with a high recovery rate. It has promised rapid, high sensitivity and real serum applications to determine the level of uric acid.

Retarder design for long open-hole well cementing through the interfacial adsorption

In the long open-hole section well-cementing, cementing fluids frequently lose their effectiveness because of high temperature and slow development of the strength of the top cement slurry. In the present study, this problem has been addressed with the high temperature polymer retarder (HTX-1) based on interfacial adsorption because the cement slurries can be characterized as colloidal suspensions. The HTX-1 was characterized through Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and thermogravimetric analysis (TGA). Then, the performance of the HTX-1in the cement slurry was evaluated in our laboratory. It was found that the molecular structure of the designed HTX-1 by FTIR and MNR spectroscopy contain the characteristic functional groups of the four monomers. The HTX-1 has only 4.5% mass loss when the temperature is less than 332 ℃. The concentration sensitivity coefficient of the HTX-1 is in the range of 0.48～1.73, and the maximum temperature sensitivity coefficient of the HTX-1 is 6.2%. The 24 h compressive strength of the top cement column at temperatures between 60 ℃ and 100 ℃ is at least 10.6 MPa. This experimental investigation shows that the new retarder has high temperature resistance, low sensitivity and wide application range of temperature. The thickening time of cement slurry can be adjusted while meeting the required strength of top section in deeper wells through changing addition amount of the HTX-1.

Ultralow flow liquid chromatography and related approaches: A focus on recent bioanalytical applications.

Ultralow flow LC employs ultra-narrow bore columns and mid-range pL/min to low nL/min flow rates (i.e., ≤20 nL/min). The separation columns that are used under these conditions are typically 2-30μm in inner diameter. Ultralow flow LC systems allow for exceptionally high sensitivity and frequently high resolution. There has been an increasing interest in the analysis of scarce biological samples, for example, circulating tumor cells, extracellular vesicles, organelles, and single cells, and ultralow flow LC was efficiently applied to such samples. Hence, advances towards dedicated ultralow flow LC instrumentation, technical approaches, and higher throughput (e.g., tens-to-hundreds of single cells analyzed per day) were recently made. Here, we review the types of ultralow flow LC technology, followed by a discussion of selected representative ultralow flow LC applications, focusing on the progress made in bioanalysis of amount-limited samples during the last 10 years. We also discuss several recently reported high-sensitivity applications utilizing flow rates up to 100 nL/min, which are below commonly used nanoLC flow rates. Finally, we discuss the path forward for future developments of ultralow flow LC.

Dual core photonic crystal fiber based plasmonic refractive index sensor with ultra-wide detection range.

In this study, an ultra-wide range plasmonic refractive index sensor based on dual core photonic crystal fiber is suggested and analyzed numerically. The proposed design achieves fabrication feasibility by employing external sensing mechanism in which silver is deposited onto the flat outer surface of the fiber as plasmonic material. A thin layer of titanium oxide (TiO2) is considered on top of the silver layer for preventing its oxidation problem. The sensor attains identification of a vast array of analytes consisting a wide range of refractive indices of 1.10 - 1.45. It achieves a maximum spectral sensitivity of 24300 nm/RIU along with its corresponding resolution of 4.12 × 10-6 RIU. The maximum figure of merit of the sensor is 120 RIU-1. The sensor also supports amplitude interrogation approach and exhibits a maximum amplitude sensitivity of 172 RIU-1. The impact of the design parameters such as radius of air holes, polishing distance, thickness of silver and titanium oxide layers are investigated thoroughly. An ultra-wide detection range with high sensitivity, fabrication feasibility, and easy application make the sensor a potential candidate for detection of a wide array of bio-originated materials, chemicals, and other analytes.

Base mismatching-fueled highly efficient catalytic hairpin assembly to regulate Ag nanoclusters brightness for amplifiable fluorescence biosensor

Exploring base mismatching-fueled catalytic hairpin assembly (mfCHA) is intriguing to regulate the fluorescence of DNA-scaffolded red Ag nanoclusters (rAgNC) for rapid and amplifiable biosensing of miRNA-155 (miR-155). Herein, we report the first design of a miR-155-responsive mfCHA route with rapid reaction kinetics and high conversion efficiency to light-up the fluorescence of rAgNC. The mfCHA was operated by a signaling hairpin (SH) programmed with the rAgNC template sequence and miR-155-discernible segment, and a G-rich (G12) enhancing hairpin (EH*). To implement faster and more efficient mfCHA amplification as a big challenge in traditional CHA, the locked stem of SH and the loop of EH* were encoded with single mismatched base in different sites, endowing mfCHA with more negative reaction standard free energy as driving force. Note that the originally synthesized rAgNC in SH was non-emissive. However, the presence of miR-155 initiated hairpin assembly between SH and EH* , leading to the displacement of miR-155 for repeated recycling and progressive mfCHA. Rationally, the red fluorescence of rAgNC was remarkably lighted-up due to the proximity to G12 enhancer in the shared dsDNA duplex products. Thus, this mfCHA-based assay platform displayed good simplicity, cost-effectiveness, rapidness, high sensitivity, and potential application for cell imaging.

Simulation and Fabrication of Higher‐Mode Lamb Wave Acoustic Devices for Sensing Applications

Recently Lamb wave devices have originated as an alternate acoustic device for high‐frequency wireless sensing applications. Their potential for sensing devices, including biomedical diagnostics and environmental monitoring as a wireless and passive device, calls for further analysis of the device with higher sensitivity. ZnO‐based sensor has always been of research interest due to its biocompatibility, sensing abilities, and yet cost‐effectivity. A Lamb wave device based on ZnO/SiO2/Si membrane has been theoretically simulated using finite element analysis method (FEM) to study the higher modes, as higher working frequency leads to higher sensitivity of the device toward sensing applications. Optimized properties are identified and utilized for the fabrication of Lamb wave devices. It is observed that for optimized parameters of ZnO/SiO2/Si Lamb device, higher antisymmetric modes are not only advantageous for high sensitivity applications but also more stable within the given operating conditions. Experimentally obtained results indicate close matching with theoretical results.

A theoretical investigation of magnetic susceptibility measurement of diamagnetic liquids using a Mach–Zehnder interferometer

In this study, we present a novel method for measuring the magnetic susceptibility of liquids using a Mach–Zehnder interferometer. The proposed technique employs a ring magnet to deform the liquid, while a laser beam passes through the liquid to measure the resulting interference pattern. The deformation of the liquid, caused by the known magnetic field of the ring magnet, is used to calculate the magnetic susceptibility. We provide a comprehensive theoretical framework, including the relevant equations and models, for analyzing the data obtained using this method. We compare the Mach–Zehnder interferometer method with other established techniques, highlighting its advantages and disadvantages. Our findings indicate that the Mach–Zehnder interferometer technique offers high accuracy, sensitivity, and potential applications in characterizing the magnetic properties of various liquid systems.

Linear dynamic range of a Rydberg-atom microwave superheterodyne receiver

In recent years, electric field measurement techniques based on Rydberg atoms have shown unique advantages in high sensitivity and wideband applications and miniaturization. The Rydberg atom receiver senses the electromagnetic signal using the quantum coherence effect, which overcomes the inherent defects of traditional electronic receivers in terms of thermal noise, insertion loss of microwave devices, and the use of wavelength-dependent antennas, thus providing the Rydberg atomic receivers the potential to become the next generation of microwave receivers. For some particular application scenarios such as radar and communication, superheterodyne reception is a critical technical approach, and the linear dynamic range is an essential factor in evaluating the performance of the superheterodyne receivers. It is challenging to promote the Rydberg atomic receiver without figuring out the influence of system parameters on the linear dynamic range. This paper starts with the response mechanism of the Rydberg atomic superheterodyne receiver, and a theoretical model is established to simulate the atom-microwave responses. Then the harmonics' generation mechanism is discussed, and the atomic linear dynamic range under different probe light Rabi frequencies is studied further. Furthermore, a method to evaluate the antiblocking performance of the system is proposed. This work is expected to provide theoretical guidance for the design and performance optimization of the Rydberg atomic superheterodyne receiver.

A Novel Dielectric Modulated Gate-Stack Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistor-Based Sensor for Detecting Biomolecules

In this article, the performance of n-type junctionless (JL) double-gate (DG) MOSFET-based biosensors with and without gate stack (GS) has been studied. Here, the dielectric modulation (DM) method is applied to detect biomolecules in the cavity. The sensitivity of n-type JL-DM-DG-MOSFET and n-type JL-DM-GSDG-MOSFET-based biosensors have also been evaluated. The sensitivity (ΔVth) improved in JL-DM-GSDG MOSFET/JL-DM-DG-MOSFET-based biosensors for neutral/charged biomolecules is 116.66%/66.66% and 1165.78%/978.94%, respectively, compared with the previously reported results. The electrical detection of biomolecules is validated using the ATLAS device simulator. The noise and analog/RF parameters are compared between both biosensors. A lower threshold voltage is observed in the GSDG-MOSFET-based biosensor. The Ion/Ioff ratio is higher for DG-MOSFET-based biosensors. The proposed GSDG-MOSFET-based biosensor demonstrates higher sensitivity than the DG-MOSFET-based biosensor. The GSDG-MOSFET-based biosensor is suitable for low-power, high-speed, and high sensitivity applications.

ITDetect: a method to detect internal tandem duplication of FMS-like tyrosine kinase (FLT3) from next-generation sequencing data with high sensitivity and clinical application

Internal tandem duplication (ITD) of the FMS-like tyrosine kinase (FLT3) gene is associated with poor clinical outcomes in patients with acute myeloid leukemia. Although recent methods for detecting FLT3-ITD from next-generation sequencing (NGS) data have replaced traditional ITD detection approaches such as conventional PCR or fragment analysis, their use in the clinical field is still limited and requires further information. Here, we introduce ITDetect, an efficient FLT3-ITD detection approach that uses NGS data. Our proposed method allows for more precise detection and provides more detailed information than existing in silico methods. Further, it enables FLT3-ITD detection from exome sequencing or targeted panel sequencing data, thereby improving its clinical application. We validated the performance of ITDetect using NGS-based and experimental ITD detection methods and successfully demonstrated that ITDetect provides the highest concordance with the experimental methods. The program and data underlying this study are available in a public repository.

ZnO-CNT/Nano-Au modified electrodes for the detection of trace Hg(II) in coastal seawater

Mercury (Hg) in seawater enters the body through the food chain, causing damage to organs and the nervous system. Thus, there is an urgent need to explore a rapid and convenient sensor for the detection and monitoring of Hg(II) in seawater. Herein, a ZnO-CNTs/Nano-Au modified glassy carbon electrode was prepared by the dropping method. The structure of the composite membrane is mainly observed by scanning electron microscopy (SEM), and the results show that the composite has a larger specific surface area. Moreover, the composite can increase the ion adsorption of the surface electrode and enhance the conductivity. Differential pulse voltammetry (DPV) was applied to determine trace amounts of Hg(II) in seawater. The optimized conditions were as follows: accumulation potential, accumulation time, pH value, film thickness and concentration. Under the optimal experimental conditions, the linear relationship between the values of the oxidation peak current and concentration was kept in the range of 1.49 ∼ 5.97 μM, with a linear correlation coefficient R2 = 0.991 and a detection limit of Hg(II) of 0.0118 μM. The proposed method was applied to the analysis of coastal water of the Maowei Sea, giving values of recovery in the range of 94.2%∼98.4%. The ZnO-CNTs/Nano-Au-modified electrode has high sensitivity, convenient operation and good practical application value.

Highly Sensitive Wearable Pressure Sensor Over a Wide Sensing Range Enabled by the Skin Surface‐Like 3D Patterned Interwoven Structure

AbstractFlexible electronic equipment is an emerging field in recent years, which attaches more attention to be researched and applied in health monitoring and human–machine interface. However, for the existing pressure sensors, even a very slight pressure will greatly reduce their sensitivity, so it is an urgent problem to be solved for achieving high sensitivity and wide application range simultaneously. Hence, a high‐performance piezoresistive pressure sensor based on PAN nanofiber films (PAN NFs) and MXene (Ti3C2Tx) is proposed. The realization of high sensitivity and wide sensing range is based on the microstructure of accordion‐like MXene and the macrostructure of fluffy porous blowing spinning PAN nanofibers, which exhibits a high sensitivity of 81.89 kPa−1 over a wide sensing range of 0.83–38.13 kPa and the dynamic responses to external pressures can reach 98.73 kPa. The pressure sensors based on skin surface‐like 3D patterned interwoven structure are used for health monitoring and tiny pressure detecting. Moreover, the application in human–machine interface is demonstrated. Additionally, to meet the requirement of long‐term wearing, the structure of the sensor is optimized and endowed with excellent breathability and conformal properties, which promotes the further development of flexible electronic equipment.