Development Of Sensors Research Articles

Development and Mechanistic Exploration of a Graphene Oxide-Based Fluorescent Sensor for Prostate-Specific Antigen Detection

Development and Mechanistic Exploration of a Graphene Oxide-Based Fluorescent Sensor for Prostate-Specific Antigen Detection

Investigating gold nanorod-mediated hydrolysis of acetylthiocholine: A way for electrochemical detection of organophosphate pesticides

Pesticides and their metabolites threaten the environment and human health even at low concentrations. Therefore, the development of sensors to track such substances is crucial. Nanoparticle-based sensors have been widely...

Synthesis and application of tungsten oxide nanostructure for ascorbic acid sensing

Engineered nanomaterials that exhibit enzyme-like activity are highly sought after for designing enzymeless sensors, which circumvent the need for costly enzymes. In this context, we synthesized tungsten oxide (WO3) nanostructures via the hydrothermal method and characterized them using various techniques. A slurry of the resulting WO3 nanostructure was prepared and drop-cast onto a screen-printed carbon electrode (SPCE) to construct an enzymeless sensor. The electrochemical characteristics of the WO3/SPCE sensor were evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). An optimized WO3/SPCE sensor was electrochemically evaluated for ascorbic acid (AA) detection at varying concentrations employing CV analysis. The CV response exhibited a significant oxidation peak for AA, which gradually intensified with an increment in the AA concentration. The sensor demonstrated a linear response up to 1000 μM, high sensitivity (5.62 μA/μMcm2), and a detection limit (DL) of 0.6 μM. Moreover, the engineered enzymeless WO3/SPCE sensor displayed excellent selectivity, stability (94.5 % over 6 weeks), and fabrication reproducibility (RSD of 9.2 % across 7 devices). Thus, this WO3 nanostructure proves to be a promising candidate for the large-scale, cost-effective sensor development for AA detection and holds potential for the fabrication of enzyme-based biosensors.

Spatio-Temporal Regularized Stochastic Configuration Network for Supervised and Semi-Supervised Soft Sensor Development

Spatio-Temporal Regularized Stochastic Configuration Network for Supervised and Semi-Supervised Soft Sensor Development

ColorNet: An AI-based framework for pork freshness detection using a colorimetric sensor array.

Pork freshness is crucial for flavour, nutrition and consumer health. The current colorimetric sensor array (CSA) detection systems face challenges related to high sensor development costs, low recognition accuracy and limitations in the platform use. Herein, we developed a CSA and ColorNet framework to detect pork freshness. The 53-point CSA was designed by selecting sensitised pH indicators and aldehyde/ketone indicators. To optimize the sensor, the Euclidean distance method was used to identify 24 array points with dyes that exhibited more sensitive responses. The ColorNet captured the color information of pork freshness, allowing real-time detection with a 99.5% accuracy. For practical deployment and mobile applications, a refined 12-point CSA was developed using gradient activation mapping, maintaining a 99% recognition rate, which is comparable with the 24-point CSA. The proposed CSA and model ensure consumer health and safety, providing strong technical support for quality monitoring and control in the pork industry.

The description of the development of the photoelectric sensors in detecting heart sound lesions

Cutting-edge developments in medicine require more precise medical equipment and more effective methods. In response to the current societal challenges of an ageing population and the prevalence of coronary heart disease, I propose a photoelectric stethoscope in this study to enhance the diagnostic capabilities of existing medical equipment and reduce the barrier to using traditional stethoscopes. This photoelectric stethoscope, firstly, by pressing its metallic inner chamber closely to the chest, detects heart vibrations and converts them into optical signals with a phase difference using a built-in LED. Secondly, it employs photoelectric conversion to transform the optical signals to electronic signals, which is then filtered and amplified to output the human heart sound signals. Finally, those signals will be collected in large quantities and used for training heart sound models, enabling the photoelectric stethoscope to have the capability to distinguish heart murmurs and pathological sounds among heart sound, which can effectively avoid the drawbacks of using traditional stethoscopes.

Enhanced Electrochemical Detection of Valganciclovir Using a Hierarchically Structured Lisianthus Flower-Inspired Bimetallic Ni-Ce Organic Framework.

This study reports the development of an innovative electrochemical sensor based on organometallic framework nanostructures for detecting valganciclovir (VLCV). VLCV is employed in the treatment of cytomegalovirus retinitis in AIDS patients. Rational design of nanoarchitectures for electroactive materials is a crucial approach for boosting their electrocatalytic performance. Herein, Lisianthus flower-inspired Ni-Ce-metal-organic framework (MOF), Ni-MOF, and rod-inspired Ce-MOF were synthesized by the solvothermal method. An electrochemical sensor for VLCV was developed by employing a multilayer approach using Lisianthus flower-inspired Ni-Ce metal-organic framework/multiwall carbon nanotubes (Ni-Ce-MOF/MWCNTs) modification on a glassy carbon electrode (GCE). Incorporating a bimetallic Ni-Ce-MOF into a conventional conductive material, such as MWCNTs, significantly increases the specific surface area and improves the conductivity and catalytic properties of the MWCNTs. Relative to the rod-inspired Ce-MOF and Ni-MOF, the electrocatalytic performance of the Lisianthus flower-inspired Ni-Ce-MOF coated on MWCNTs surpasses that of the rod-inspired Ce-MOF, showcasing enhanced performance in VLCV oxidation. This superiority arises from their enhanced electrical conductivity and enlarged surface area. The Lisianthus flower-inspired Ni-Ce-MOF/MWCNTs/GCE demonstrated extensive linear ranges (ranging from 4.0 to 3800.0 nM), a lower detection limit (1.4 nM), remarkable selectivity, and sustained stability over an extended period in the context of VLCV sensing. The real samples underwent analysis through using both electrochemical and UV-vis spectrophotometry methods, and the findings from both methods exhibited no substantial difference, validating the sensor's remarkable practical performance. These results suggest that Lisianthus flower-inspired Ni-Ce-MOF/MWCNTs/GCE electrocatalysts provide a promising sensing platform for analyzing biological samples.

Efficient and Visual Detention of Ammonia and TNP Vapors by a Sustainable Highly Luminescent 1D Zn(II) Coordination Polymer.

To realize the aim of easy and accurate detection of ammonia and picric acid (PA) in both aqueous and vapor phases based on function-oriented investigation principles, in the present study, we include a luminescent performance with recognition performance, taking into account the application conditions. Zn(II) ions with luminescence qualities and an amine-substituted imidazole moiety with selective recognition properties towards picric acid and ammonia are coupled to generate a novel 1D luminous Zn(II) coordination polymer, Zn-CP [{Zn(II)( 2-ABZ)2(2-BDC)}].MeOH]∞, where 2-ABZ and 2-BDC stand for terephthalic acid and protonated 2 aminobenzimidazole, respectively. Tests for luminescence recognition demonstrate that Zn-CP has potent selectivity, and strong sensitivity to ammonia and PA in both media. In both detection processes, the limit of detection (LOD) values are determined to be 40 nm. Spectroscopic and DFT studies reveal that the detection of Trinitrophenol (TNP) primarily involves a synergistic mechanism of Photoinduced Electron Transfer (PET), Fluorescence Resonance Energy Transfer (FRET), and Charge Transfer (CT). In contrast, the detection of ammonia (NH3) vapor is predominantly driven by hydrogen bonding (H-bonding) formation. The constructed 1D luminous Zn-CP is a new material that guides the development of novel luminous sensors in the future.

TiO2 Nanosphere/MoSe2 Nanosheet-Based Heterojunction Gas Sensor for High-Sensitivity Sulfur Dioxide Detection.

With the growing severity of air pollution, monitoring harmful gases that pose risks to both human health and the ecological environment has become a focal point of research. Titanium dioxide (TiO2) demonstrates significant potential for application in SO2 gas detection. However, the performance of pure TiO2 is limited. In this study, TiO2 nanospheres and MoSe2 nanosheets were synthesized using a hydrothermal method, and the gas-sensing properties of TiO2/MoSe2 nanostructures for SO2 detection were investigated. The TiO2/MoSe2 composites (with a TiO2-to-MoSe2 volume ratio of 2:1) were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The TiO2/MoSe2 sensor exhibited high sensitivity to SO2; the response to 100 ppm of SO2 reached as high as 59.3, with a significantly shorter response and recovery time (15 s/13 s), as well as excellent repeatability, selectivity, and long-term stability. The experimental results suggest that the enhanced SO2 adsorption capacity of the TiO2/MoSe2 composite can be attributed to the formation of an n-n heterojunction and the unique microstructural features of TiO2/MoSe2. Therefore, the TiO2/MoSe2 sensor represents a promising candidate for rapid SO2 detection, providing a theoretical foundation for the development and application of high-performance SO2 sensors.

High-Efficiency Fluorescent-Coupled Optical Fiber Passive Tactile Sensor with Integrated Microlens for Surface Texture and Roughness Detection.

Integrating ZnS:Cu@Al2O3/polydimethylsiloxane (PDMS) flexible matrices with optical fibers is crucial for the development of practical passive sensors. However, the fluorescence coupling efficiency is constrained by the small numerical aperture of the fiber, leading to a reduction in sensor sensitivity. To mitigate this limitation, a microsphere lens was fabricated at the end of the multimode fiber, which resulted in a 21.585% enhancement in the fluorescence coupling efficiency. A passive, flexible mechanoluminescent (ML) tactile sensor (MLTS) was developed by embedding a fiber microsphere probe within a ZnS:Cu@Al2O3/PDMS film featuring a pyramid surface structure. The MLTS demonstrated exceptional pressure sensing capabilities, exhibiting rapid response times of 250 ms for loading and 200 ms for unloading, along with strong durability, surviving over 2000 cycles. It effectively distinguished Braille patterns and sandpapers of varying roughness by detecting the ML signals generated by the sensor's surface microstructures. Notably, this sensor operates without the need for external light stimulation, making it a promising candidate for application in photonic skin and robotic tactile perception.

Unveiling with Density Functional Theory the Optical Property Variations of Three Kinds of Graphene for Acetaminophen Sensor Design.

Understanding the interactions between molecules and sensing elements is crucial to improving sensors. We present one step toward getting closer to the breach between theory and empirical sensor development. Through density functional theory (DFT) calculations, we explored the changes in some optical properties of pristine graphene (G), graphene oxide (GO), and reduced graphene oxide (rGO) interacting with one molecule of acetaminophen (APAP). The main goal is to unveil which graphene-G, GO, and rGO-works better as a substrate to detect APAP for sensor applications based on UV/vis and near-infrared absorption, refractive index changes, and plasmon resonances. For this effort, we used Quantum ESPRESSO software. We calculated each supercell's adsorption energy and recovery time containing the APAP and one graphene variant. Afterward, we calculated the optical absorption, refractive index, reflectivity, and electron energy loss spectroscopy (EELS), a technique to identify the material's plasmons. Then, we analyzed the changeovers in the optical properties mentioned for each graphene layer with and without APAP. We found that G works for UV/vis and plasmon sensors operating in blue and UV-C regions; GO has the highest performance range in UV/vis and plasmonic sensors operating in UV-C; rGO has the highest performance range in UV/vis sensors working on near-infrared and UV-C. Additionally, rGO plasmonic sensors present an "oscillation of percentage variations" from visible to UV. Our study offers a strategy for creating a map to select the best substrate to develop selective APAP optical sensors.

Development of biomimetic sensors to determine the functionality of in vitro cell models

Development of biomimetic sensors to determine the functionality of in vitro cell models

Evaluation of Corrosion Potential Stability of Stainless Steels in Dilute Electrolyte Solution for Application to a Quasi-Reference Electrode Used in Electrochemical Sensing System

To evaluate the long term corrosion potential stability of stainless steel (SS) in environmental water, the corrosion potential of SUS304, SUS316, SUS316L, and SUS430 was measured for 1 week in a solution of 0.9 mM NaHCO3 and 0.5 mM CaCl2, referred to as “sub-tap water.” The potential of the SSs upon initial immersion in sub-tap water was approximately 10 times less stable than the potentials of Fe and Cu. However, as immersion continued, the stability of the corrosion potential of the SS improved and became equivalent to those of Fe and Cu. The stability could be manipulated by pretreatment (pre-immersion) before samples were immersed in sub-tap water. The stability was increased by pre-immersion in an acidic solution but was reduced by a passivation treatment. The formation of iron oxides on the SS surface stabilized the potential, whereas surface enrichment with Cr led to instability. This behavior can also be inferred from a comparison of the polarization curves, where the passive current after the passivation treatment was the largest. This result is also speculatively attributed to the corrosion potential in sub-tap water decreasing over time after the passivation treatment. The charge transfer resistance likely contributes significantly to the potential stability, as indicated by an equivalent circuit analysis based on electrochemical impedance spectroscopy. The results showed that, when stabilizing the corrosion potential of SS, there is no need to reduce the charge transfer resistance as with existing reference electrodes. Stability is achieved when the surface thickness is such that the pseudo-capacitance in a dilute solution is less than 10 µF sα−1cm−2 and potential stability does not influence a few changes in the CPE1 value after potential stability is achieved. The results of this study show that SS can be used as a quasi-reference electrode material. We expect the findings presented herein to strongly affect the development of electrochemical sensors that can be easily used in long term continuous measurements and in situ applications.

Triboelectric Nanogenerator Based on CPDs-WO3/MXene Bilayer Film for Triethylamine Sensing and Fish Meat Spoilage Detection.

With the increasing demand for food safety monitoring, the development of efficient, convenient, and green gas sensors has become a current research hotspot. Triboelectric nanogenerator (TENG) as a triethylamine sensor is a cutting-edge strategy for detection without the need for an additional power source. In this study, synthesized WO3/MXene materials were prepared and bilayer thin films of carbon quantum dots (CPDs)-WO3/MXene TENG. WO3 provides more active sites for improved material charge transfer efficiency. TENG achieved a maximum open-circuit voltage (Voc) of 30 V. The CPDs-WO3/MXene-3 TENG can also be used as a self-powered gas sensor (SPGS). As a charge-trapping layer, CPDs exhibit excellent charge trapping. The SPGS has a 53% response to 200 ppm TEA, and low detection at ppb level (139 ppb). The presence of WO3 improves the gas-sensing performance. Additionally, CPDs possess excellent conductivity and moisture resistance. Finally, it was studied to see how it reacts to TEA in fish meat under different conditions of spoilage. It provides approach to solving the transportation and preservation problems of fish meat.

Putting piezoelectric sensors into Fano resonances

AbstractPiezoelectric resonance sensors are essential to many diverse applications associated with chemical and biological sensing. In general, they rely on continuously detecting the resonant frequency shift of piezoelectric resonators due to analytes accreting on their surfaces in vacuum, gas or fluid. Resolving the small analyte changes requires the resonators with a high quality factor. Here, we propose theoretically and demonstrate experimentally a scheme using a physics concept, i.e., a Fano resonance, to enhance the quality factor rather than optimizing the structure and material of the resonator itself though these are important. The Fano resonance arises due to the interference between a discrete mode and a continuum of modes, leading to the asymmetric and steep dispersion. In our scheme, the as-fabricated piezoelectric sensors are put into the Fano resonance by connecting an external shunt capacitor to them. As a verification case, one-port surface acoustic wave (SAW) resonators on LiNbO3 substrate, incorporating a composite of polymethyl methacrylate (PMMA) and graphene oxide (GO) for humidity sensing, have been fabricated and characterized. We enhance the quality factor by up to a factor of about 8, from 929 for the as-fabricated sensor to 7682 for that with the external shunt capacitor. Our results pave the way for the practical development of piezoelectric resonance sensors with high quality factor.

Clinically-Driven Rapidly Developed Nanoparticle Corona for Label-Free Cerebrospinal Fluid Leakage Detection.

Rapid diagnosis of cerebrospinal fluid (CSF) leaks is critical as endoscopic endonasal skull base surgery gains global prominence. Current clinical methods such as endoscopic examination with and without intrathecal injection of fluorescent dye are invasive and rely on subjective judgment by physicians, highlighting the clinical need for label-free point-of-care (POC). However, a viable solution remains undeveloped due to the molecular complexity of CSF rhinorrhea mixed with nasal discharge and the scarcity of specific biomarkers, delaying sensor development. In this study, we accelerated the development of a label-free CSF detection method for clinical use using a nanoparticle corona. We engineered corona nanointerfaces on near-infrared (nIR) fluorescent single-walled carbon nanotubes (SWCNTs) through noncovalent functionalization with 12 custom-designed poly(ethylene glycol) (PEG) lipids. By high-throughput screening of the corona library for the CSF biomarker β-trace protein (βTP), we selected the optimal corona, achieving a limit of detection (LOD) down to 1.46 mg/L, maintaining its selectivity even in human nasal discharge. Using molecular dynamics and docking simulations, we characterized the 3D morphology and βTP binding energy of the optimal corona in a quantified way. The corona nanosensor accurately diagnosed CSF leakages from eight patients having lumbar drainage and one patient with CSF leakage due to diverse diseases without any sample preparations. By integrating the nanosensor with custom-designed in vivo and in vitro form factors such as a camera and endoscope, we showed its potential for versatile and practical use in clinical settings. This accelerated sensor development platform can meet future urgent clinical demands for various diseases and conditions.

Research Progress of Magnetic Nanomaterials and Magnetic Field based Chemiresistive Gas Sensors

With the increasing demand for environmental protection and safety monitoring, the development of gas sensors with high sensitivity, fast response and selectivity is imperative. Magnetic field-assisted gas sensing is gradually becoming a research hotspot. This review aims to provide an overview of magnetic-related chemiresistive gas sensing from two segments, including magnetic sensing materials and magnetic field-assisted gas sensing. The type of sensors, the classification and parameters of magnetic materials, and the various materials employed in gas sensing are summarized. The review presents the currently commonly used methods for influencing magnetic structure and properties: chemical doping, defect engineering, and heterostructure construction et al., as well as the application of applied magnetic field in gas sensing. This paper provides the first overview of chemiresistive gas sensors from a magnetic point of view, which is crucial for the development of magnetically correlated gas sensing technology and the subsequent study of the intrinsic mechanisms.

Frontiers in medical physics: material classification and blood pressure measurement of wearable piezoelectric sensors

Wearable piezoelectric sensors, as an emerging tool for blood pressure measurement, have attracted much attention at the forefront of medical physics and have broad application prospects due to their portability, real-time monitoring and low interference with human activities. However, the development of piezoelectric materials is currently a key factor restricting the development of wearable piezoelectric sensors. In order to continuously improve the accuracy and speed of blood pressure measurements by wearable piezoelectric sensors, new measurement methods need to be designed in addition to the development of high-performance piezoelectric materials. We present the advantages and disadvantages of different types of piezoelectric materials for wearable piezoelectric sensors, illustrate their future development directions, and discuss the current new strategies and the latest applied research of piezoelectric sensors applied to blood pressure measurement. In addition, the challenges and future prospects of wearable piezoelectric sensors for blood pressure measurement are revealed, providing new ideas for future applications of high-performance wearable piezoelectric sensors for health monitoring.

Fiber optics-based surface enhanced Raman Spectroscopy sensors for rapid multiplex detection of foodborne pathogens in raw poultry

AbstractA new high-sensitivity, low-cost, Surface Enhanced Raman Spectroscopy (SERS) sensor allows for the rapid multiplex detection of foodborne pathogens in raw poultry. Self-assembled microspheres are used to pattern a hexagonal close-packed array of nanoantennas onto a side-polished multimode fiber core. Each microsphere focuses UV radiation to a photonic nanojet within a layer of photoresist on the fiber which allows the nanoantenna geometry to be controlled. Optimizing the geometry for the excitation layer generates electric field concentrations− referred to as a hotspot− within the analyte, thereby maximizing the Raman signal and improving the signal-to-noise ratio. The side polished configuration with a larger surface area has significantly better performance than the SERS sensor on the fiber tip. The use of additive manufacturing for the fiber polishing jigs as well as the sample testing compartment simplifies the sensor development and testing. Experimental results demonstrate a sensitivity range of 0.4–0.5 cells/ml achieved using raw chicken rinsates spiked with Salmonella typhimurium. Additionally, the sensor demonstrated its capability for multiplex and specific detection of Salmonella and E. coli O157:H7 with an optimal detection time of 10 min. The new sensor addresses a major global foodborne pathogen that poses significant public health concerns and can be readily adapted for the detection of other bacterial and viral pathogens such as E. coli O157:H7, Campylobacter, Listeria, and avian influenza and in other food products, e.g., dairy, beef, and produce, as well as clinical applications.

Additive Manufacturing of a Frost-Detection Resistive Sensor for Optimizing Demand Defrost in Refrigeration Systems.

This article presents the development of a resistive frost-detection sensor fabricated using Fused Filament Fabrication (FFF) with a conductive filament. This sensor was designed to enhance demand-defrost control in industrial refrigeration systems. Frost accumulation on evaporator surfaces blocks airflow and creates a thermal insulating barrier that reduces heat exchange efficiency, increasing energy consumption and operational costs. Traditional timed defrosting control methods can mitigate these effects but often lead to inefficiencies due to their inability to align with actual frost accumulation, which can vary according to system and environmental conditions. Frost-detection sensors aim to solve this problem by acting as a tool to support defrosting control. A series of tests were conducted to evaluate the sensor's performance in detecting frost under controlled conditions on a heat exchanger (HX). The sensor reliably detected frost in all cases, demonstrating its effectiveness in real-time frost detection. The sensor measurements were validated by comparison with results obtained through a computer vision method, confirming its reliability. It was also found that the sensor can detect temperature changes. This advancement in sensor technology highlights the potential of additive manufacturing to provide cost-effective, customizable, replicable, and compact sensor designs, contributing to improved system performance and energy efficiency in refrigeration systems.