Sensor Microsystem Research Articles

Continuous In Vivo Monitoring of Indole-3-Acetic Acid and Salicylic Acid in Tomato Leaf Veins Based on an Electrochemical Microsensor.

Indole-3-acetic acid (IAA) and salicylic acid (SA), as critical plant hormones, are involved in multiple physiological regulatory processes of plants. Simultaneous and continuous in vivo detection of IAA and SA will help clarify the mechanisms of their regulation and crosstalk. First, this study reports the development and application of an electrochemical microsensor for simultaneous and continuous in vivo detection of IAA and SA. This electrochemical microsensor system consisted of a tip (length, 2 mm) of platinum wire (diameter, 0.1 mm) modified with carbon cement and multi-walled carbon nanotubes, an untreated tip (length, 2 mm) of platinum wire (diameter, 0.1 mm), as well as a tip (length, 2 mm) of Ag/AgCl wire (diameter, 0.1 mm). It was capable of detecting IAA in the level ranging from 0.1 to 30 µM and SA ranging from 0.1 to 50 µM based on the differential pulse voltammetry or amperometric i-t., respectively. The dynamics of IAA and SA levels in tomato leaf veins under high salinity stress were continuously detected in vivo, and very little damage occurred. Compared to conventional detection methods, the constructed microsensor is not only suitable for continuously detecting IAA and SA in microscopic plant tissue in vivo, it also reduces the damage done to plants during the detection. More importantly, the continuous and dynamic changes in IAA and SA data obtained in stiu through this system not only can help clarify the interaction mechanisms of IAA and SA in plants, it also helps to evaluate the health status of plants, which will promote the development of basic research in botany and precision agriculture.

Modeling of integrated signal converters for biomedical sensor microsystems

The paper presents the results of computer modeling of the proposed functional-electrical circuit of integrated signal converters (ISC) from photosensitive elements based on CMOS operational amplifiers, which is intended for the construction of an element base of hybrid sensor microsystems for biomedical applications. A feature of this ISC is the regulation and filtering of the amplitude of the constant component in the amplified signal from the diode photosensitive element in the wave range of 400 - 1040 nm.
 Computer simulation of the functioning of the device was carried out, the constituent components were determined and their parametric optimization was carried out. The results of experimental studies and computer modeling agree well, which confirms the correct functioning of the proposed signal converter from photosensitive elements. The developed ISC is suitable for creating real devices, both on the basis of discrete components and in an integrated design, as an element of sensor microsystems-on-a-chip or intelligent sensors.

The Development and Progress of Multi-Physics Simulation Design for TSV-Based 3D Integrated System

In order to meet the requirements of high performance, miniaturization, low cost, low power consumption and multi-function, three-dimensional (3D) integrated technology has gradually become a core technology. With the development of 3D integrated technology, it has been used in imaging sensors, optical integrated microsystems, inertial sensor microsystems, radio-frequency microsystems, biological microsystems and logic microsystems, etc. Through silicon via (TSV) is the core technology of a 3D integrated system, which can achieve vertical interconnection between stacked chips. In this paper, the development and progress of multi-physics simulation design for TSV-based 3D integrated systems are reviewed. Firstly, the electrical simulation design of TSV in a 3D integrated system is presented, including the lumped parameters model-based design and numerical computation model-based design. Secondly, the thermal simulation design of TSV in a 3D integrated system is presented based on the analytical model or numerical computation model. Thirdly, the multi-physics co-simulation design of TSV in a 3D integrated system is presented, including the thermal stress and electron thermal coupling simulation design. Finally, this paper is concluded, and the future perspectives of 3D integrated systems are presented, including the advanced integrated microsystems, the crossed and reconfigurable architecture design technology and the standardized and intelligent design technology.

Comments on “A CMOS Front-End Hall Sensor Microsystem for Linear Magnetic Field Measurement With Best Tradeoff Between Sensitivity and SNR”

In the paper ”Xu, Y., Wang, B., Hu, X., & Jiang, L. (2022). A CMOS Front-End Hall Sensor Microsystem for Linear Magnetic Field Measurement With Best Tradeoff Between Sensitivity and SNR. IEEE Transactions on Instrumentation and Measurement, 71, 1-8.” it is claimed that the sensitivity of the output signal of a Hall-plate with respect to applied magnetic field is doubled when the Hall-plate is operated in current mode instead of traditional voltage mode. The proof was based on a Wheatstone bridge model where two resistors increase with magnetic field while the other two resistors decrease. However, a resistor network with magnetic field dependent resistors can only describe the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">magneto-resistance effect</i> of a Hall-plate, yet it cannot describe the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Hall-effect</i> of a Hall-plate. A correct representation of a Hall-plate is given by a resistor network <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">and</i> controlled voltage or current sources, or gyrators. The application of this correct network shows that neither the sensitivity of the output signal nor the SNR differ in current and voltage modes. It also shows that the proposed spinning current scheme does not perfectly eliminate offset errors of the Hall-plate.

All-in-one portable microsystem for on-site electrochemical determination of phosphate in turbid coastal waters

The direct detection of phosphate in turbid coastal waters is important but difficult to achieve. Herein, we propose an effective and portable all-in-one microsystem for the electrochemical determination of phosphate in turbid coastal waters without adding additional reagents and requiring a pump filter device. The all-in-one portable microsystem is composed of a simple 3D-printed manufactured electrochemical sensor microsystem, a commercial micropipette, and a disposable molybdate-functionalized tip. It integrates the complexation step, in which non-electroactive phosphate is converted to a phosphomolybdate complex by a molybdate functionalized tip, and the detection step, in which a phosphomolybdate complex is reduced in an electrochemical sensor microsystem. The microsystem showed a low detection limit of 0.04 μM under optimized experimental conditions; one entire test cycle could be accomplished within 3 min. The proposed all-in-one portable microsystem was successfully used in a variety of real coastal water samples with high turbidity and high salinity. It represents a competitive alternative analytical tool and a novel approach for the assessment of turbid costal water quality.

Use of a Distributed Micro-sensor System for Monitoring the Indoor Particulate Matter Concentration in the Atmosphere of Ferroalloy Production Plants

Airborne particulate matter (PM) is a concern for both occupational health and the environment, and, in the ferroalloy industry, the level of such particles in the air can be considerable. Small, low-cost sensors for measuring PM have generated interest in recent years, providing widespread monitoring of PM levels in the environment. However, such sensors have not yet been sufficiently tested under conditions relevant for the indoor environment of the metallurgical industry. This study aims to bridge this gap by benchmarking the commercial, low-cost Nova PM SDS011 particle sensor in two different ferroalloy plants. Benchmarking was performed against the Fidas 200S, which has been suitability-tested and certified according to the latest EU requirements (EN 15267, EN 16450). Twelve Nova sensors were tested over 3 months at a silicomanganese alloy (SiMn) plant, and 35 sensors were tested during 1 month at a silicon (Si) plant. The results showed that the low-cost Nova sensors exhibited all the same trends and peaks in terms of PM concentration, but measured lower dust concentrations than the Fidas 200S. The difference was larger at the silicon plant, which is in line with expectations, due to the size and mass fractions of particles in Si dust compared to SiMn dust, and to the larger measurement range of the Fidas, measuring down to 180 nm compared to the Nova which measures down to 300 nm. Despite the difference in absolute values, the Nova sensors were found to provide data for comparing dust levels over time for different processes, at different locations, and under different operational conditions.

Sensor-Based Nerve Compression Measurement: A Scoping Review of Current Concepts and a Preclinical Evaluation of Commercial Microsensors.

Background: Chronic nerve compression is the most common indication for nerve surgery. However, the clinical diagnosis still relies on surrogate parameters since devices for direct nerve compression pressure measurement (DNCPM) are clinically unavailable yet. Objectives: To review previous approaches to DNCPM and evaluate presently available microsensor systems for their feasibility and reliability in preclinical nerve compression models. Methods: A scoping literature review was conducted in accordance with the PRISMA-ScR guidelines. A subsequent market research aimed at identifying commercially available sensor systems potentially suitable for DNCPM. Sensors were evaluated for feasibility and safety of perineural sensor positioning, tissue compatibility and measurement reliability in a synthetic nerve compression model and an ex-vivo chicken leg model. Results: A scoping literature review identified 197 potentially eligible studies of which 65 were included in the analysis. Previous approaches to DNCPM predominantly used pressure sensing catheters designed for fluid- or intra-compartmental pressure measurement. A market research identified two piezoresistive sensor systems (IntraSense, SMi, United States; Mikro-Cath, Millar, United States) as potentially suitable for intraoperative DNCPM. In both preclinical models, the detected compression pressure differed significantly between sensors and systems showed substantial measurement variability with a median percent coefficient of variation between 15.5% and 32%. Sensor position was accountable for up to 99.1% of the variance. Conclusion: Measurement variability caused by unreliable sensor positioning is a key limitation of presently available sensors when applied for nerve compression measurements. Redesigned systems with small, flat-shaped and longitudinally oriented sensors and dedicated introducers would facilitate sensor positioning and therefore may allow for reliable measurements.

A CMOS Front-End Hall Sensor Microsystem for Linear Magnetic Field Measurement With Best Tradeoff Between Sensitivity and SNR

A monolithic integrated front-end CMOS Hall sensor microsystem working at the current mode is presented for linear magnetic field measurement. The geometry of the cross-shaped Hall plates is optimized to enable the best tradeoff between current sensitivity and signal-to-noise ratio (SNR) by theoretical modeling. Furthermore, a novel current-mode four-phase spinning current method combined with the correlated double sampling demodulation technique is proposed to amplify the weak Hall current signals and to cancel the high offset and noise. Fabricated using a standard 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> low-voltage CMOS technology, it is experimentally demonstrated that a maximum current sensitivity of 6.86%/T and an optimal SNR are achieved when the cross length-to-width ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$L/W)$ </tex-math></inline-formula> ratio of the Hall plate is about 0.4. At a supply voltage of 3.3 V, the linearity of the Hall sensor microsystem is up to 99.9% in the magnetic field range within ±200 mT. The magnetic field resolution is as low as 100 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{T}$ </tex-math></inline-formula> , the residual offset is less than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$52~\mu \text{T}$ </tex-math></inline-formula> , and the power consumption is about 15.4 mW.

Localized sensing of bulk properties of oils

A convenient method for measuring the isothermal bulk modulus and the isobaric heat expansion coefficient is shown using a vibrating microsensor system that measures fluid density versus applied pressure and temperature. In contrast to the conventional volume-change method, the fluid properties are measured locally in the vicinity of the sensor, such that inflation of vessels due to high hydraulic pressures, or the influence of entrained air on the measured bulk modulus are reduced.

Digital Evaluation Algorithm for Upper Limb Motor Function Rehabilitation Based on Micro Sensor

The electroencephalogram (EEG) of the cerebral cortex reflects the upper limb motion control information of the human body. The electro myographic signal (EMG) of the body muscle tissue reflects the response of the upper limb muscle to the brain control. The intersection of two physiological electrical signals has become a new hot field in artificial intelligence, medical rehabilitation and neuroscience. Firstly, starting with the analysis of the power consumption characteristics of the micro-sensor system, by studying the working principle and design scheme of the energy self-capture technology, various energy supply methods of the combined vibration energy harvesting system, the thermoelectric energy harvesting system and the RF energy harvesting system are proposed. Combined upper limb exercise rehabilitation energy is self-capture program. Secondly, the upper limb motor EEG and EMG signal acquisition experiments were designed to preprocess the acquired signals. Based on the wavelet threshold denoising method, an improved threshold algorithm is proposed to remove the noise in the EEG signal and improve the signal-to-noise ratio of the EEG signal. On the basis of the wavelet analysis method, the stratified threshold denoising method is applied to the collected EMG signals for denoising processing and digital evaluation of upper limb motor function rehabilitation. Finally, a digital evaluation method for upper limb motor function rehabilitation combined with wavelet low-frequency coefficients and significant information is proposed. The algorithm combines wavelet transform, motion estimation, and significant information to design a video quality evaluation algorithm. It can be seen from the experimental results that the performance of this algorithm is superior and maintains high consistency with the human motion system.

Research on the Self-powered Wireless Sensor Micro-system Based on the Hybrid Vibration Energy Harvester

Research on the Self-powered Wireless Sensor Micro-system Based on the Hybrid Vibration Energy Harvester

Protocol development for real-time ship fuel sulfur content determination using drone based plume sniffing microsensor system

Pollutants from navigation sector are key contributors to emission inventories of most coastal cities with heavy port activities. The use of high fuel sulfur content (FSC) bunker oil by ocean going vessels (OGVs) has been identified as a major source of sulfur dioxide (SO2). Government authorities all over the world, including Hong Kong government, have implemented air pollution control regulations to cap FSC of fuel used by OGVs to 0.5%, from the existing 3.5%, to reduce SO2 emissions. However, the lack of efficient screening tools to identify non-compliant OGVs has prevented effective enforcement. This study developed and evaluated an unmanned aerial vehicle (UAV)-borne lightweight (750 g) microsensor system (MSS), which is capable of measuring ship plume SO2, NO2, NO, CO2, CO, and particulate matter in real-time. Extensive experiments were conducted on the sensor system to evaluate its performance during laboratory and field operations. The effects of cross-sensitivity and meteorological conditions were studied and incorporated to account for the measurement conditions in dispersed ship plumes. The SO2 to CO2 concentration ratio-based FSC expression was formulated as per the 2016 European Union Directive and Regulations. Furthermore, the impact of plume dilution on the accuracy of FSC measurement was investigated at different stages using the MSS, with and without the UAV in both simulated conditions and real-world scenarios, maintaining a safe distance from the OGV exhaust stacks. The study demonstrates the robustness of using UAV-borne sensor system for ship emission sniffing and FSC determination. The results will assist in development of a technological framework for effective enforcement of ship emission control regulations.

Free-standing ZnO nanorod arrays modified with single-walled carbon nanotubes for betavoltaics and photovoltaics

A full-duplex radiant energy converter based on both betavoltaic and photovoltaic effects in an easy-to-implement way is an attractive alternative for the autonomous wireless sensor microsystem. Here, we report a novel beta/photovoltaic cell based on free-standing ZnO nanorod arrays (ZNRAs) modified with metallic single-walled carbon nanotubes (m-SWCNTs), using radioisotope 63Ni as beta-emitting source. The ZNRAs were grown on Al-doped ZnO (AZO) conductive glass using hydrothermal method. The optimum length and diameter of ZnO nanorods were determined by Monte Carlo simulation for beta energy deposition in ZNRAs. The m-SWCNTs were anchored into the ZNRAs to form a three-dimensional (3-D) Schottky junction structure for effectively separating the beta/photo-excited electron-hole pairs. Experimentally, the betavoltaic and photovoltaic effects were confirmed through the I–V measurements of beta/photovoltaic cells under beta/UV/Vis irradiations, respectively. It is suggested that the m-SWCNTs play key role for the enhancement of beta/photovoltaic performance through the formation of extensive 3-D Schottky junction, the conductive network for hole transport, and the surface plasmon resonance exciton absorption for visible light.

Phase-Regulated Sensing Mechanism of MoS2 Based Nanohybrids toward Point-of-Care Prostate Cancer Diagnosis.

Alpha-methylacyl-CoA racemase (AMACR) has been proven to be consistently overexpressed in prostate cancer epitheliums, and is expected to act as a positive biomarker for the diagnosis of prostate carcinoma in clinical practice. Here, a strategy for specific determination of AMACR in real human serum by using an electrochemical microsensor system is presented. In order to implement the protocol, a self-organized nanohybrid consisting of metal nanopillars in a 2D MoS2 matrix is developed as material for the sensing interface. The testing signal outputs are strongly enhanced with the presence of the nanohybrids owing to that the metal pillars provide an efficient mass difussion and electron transfer path to the MoS2 film surface. Furthermore, the phase-regulated sensing mechanism over MoS2 is noticed and demonstrated by density functional theory calculation and experiments. The explored MoS2 based nanohybrids are employed for the fabrication of an electrochemical microsensor, presenting good linear relationship in both ng µL-1 and pg µL-1 ranges for AMACR quantification. The sampling analysis of human serum indicates that this microsensor has good diagnostic specificity and sensitivity toward AMACR. The proposed electrochemical microsensor system also demonstrates the advantages of convenience, cost-effectiveness, and disposability, resulting in a potential integrated microsystem for point-of-care prostate cancer diagnosis.

Hydrogel Fluorescence Microsensor with Fluorescence Recovery for Prolonged Stable Temperature Measurements

This work describes a hydrogel fluorescence microsensor for prolonged stable temperature measurements. Temperature measurement using microsensors has the potential to provide information about cells, tissues, and the culture environment, with optical measurement using a fluorescent dye being a promising microsensing approach. However, it is challenging to achieve stable measurements over prolonged periods with conventional measurement methods based on the fluorescence intensity of fluorescent dye because the excited fluorescent dye molecules are bleached by the exposure to light. The decrease in fluorescence intensity induced by photobleaching causes measurement errors. In this work, a photobleaching compensation method based on the diffusion of fluorescent dye inside a hydrogel microsensor is proposed. The factors that influence compensation in the hydrogel microsensor system are the interval time between measurements, material, concentration of photo initiator, and the composition of the fluorescence microsensor. These factors were evaluated by comparing a polystyrene fluorescence microsensor and a hydrogel fluorescence microsensor, both with diameters of 20 µm. The hydrogel fluorescence microsensor made from 9% poly (ethylene glycol) diacrylate (PEGDA) 575 and 2% photo initiator showed excellent fluorescence intensity stability after exposure (standard deviation of difference from initial fluorescence after 100 measurement repetitions: within 1%). The effect of microsensor size on the stability of the fluorescence intensity was also evaluated. The hydrogel fluorescence microsensors, with sizes greater than the measurement area determined by the axial resolution of the confocal microscope, showed a small decrease in fluorescence intensity, within 3%, after 900 measurement repetitions. The temperature of deionized water in a microchamber was measured for 5400 s using both a thermopile and the hydrogel fluorescence microsensor. The results showed that the maximum error and standard deviation of error between these two sensors were 0.5 °C and 0.3 °C, respectively, confirming the effectiveness of the proposed method.

Metabolic consequences of lactate dehydrogenase inhibition by oxamate in hyperglycemic proximal tubular cells

Diabetic kidney disease (DKD) is associated with altered metabolic patterns, leading to increased lactate production even in the presence of sufficient oxygen supply. Studies have shown hyperglycemia to be an important factor in determining development of DKD.Here we explore the metabolic consequences of lactate dehydrogenase (LDH) inhibition exerted by the LDH inhibitor, oxamate, in the isolated rat renal proximal tubular cells (NRK-52E) under hyperglycemic conditions.Cells treated with oxamate (100 mM) for 24 h, with or without high D-glucose (25 mM) load, were investigated with hyperpolarized [1-13C]pyruvate in a 1T NMR system. Respiratory measurements using an oxygen microsensor system was conducted.Oxamate treatment of cells with or without the presences of high D-glucose, reduced the lactate production/accumulation with 36.5% or 22.5% respectively. Reduced proliferation, hypertrophic effects, as well as elevated vascular endothelial growth factor (VEGF) expression in the NRK-52E cells were found. The increased glycolytic flux in high D-glucose cultured NRK-52E cells resulted in an upregulation of the cellular oxygen consumption rate upon treatment with oxamate.Our findings suggested that in vitro cultured NRK-52E cells exposed to hyperglycemic conditions, could redirect the glycolytic flux towards oxidative phosphorylation by LDH inhibition. This link between aerobic and anaerobic metabolism may be determined by the redox balance (NAD+/NADH ratio). In conclusion, hyperglycemic conditions and oxamate treatment alters the metabolic phenotype of NRK-52E cells towards increased oxygen utilization mediated by a decreased NAD+/NADH ratio, which in turn decreases cell proliferation/survival.

Feasibility of using basalt fiber as biofilm Carrier to construct bio-nest for wastewater treatment

Generally, biofilms developed for wastewater treatment readily detach from carrier medium once available thickness exceeds about 2 mm. Carrier media made of basalt fibers (BFs) could form ball-like aggregates (more than 10 cm in size, and called bio-nest). To demonstrate its feasibility for wastewater treatment, both reactors with and without BF carriers (RBF and RCO) were evaluated in terms of nutrient removal, oxygen mass transport and biological viabilities as well as biofilm adsorption characteristics. Therefore, oxygen microprofiles and confocal images for bio-nest as well as functional groups for biofilm-attached BF were performed on microsensor systems, confocal laser scanning microscopy (CLSM) and Fourier transform infrared (FTIR). Despite COD:N ratio, both reactors removed about 90% of COD, while only RBF reactor achieved high denitrification capabilities, with nitrogen removal efficiencies varying between 60.10 ± 0.45% and 82.07 ± 0.64%. Microprofile and confocal images showed that dissolved oxygen could reach the core with depth up to 50 mm, at which viable bacteria were detected. Characteristic peaks on FT-IR spectrum demonstrated that various functional groups of polysaccharide and proteins in EPS played a key role in aggregating biofilm-attached BFs into a bio-nest. Thus, BF provides a promising alternative to conventional carrier medium for wastewater treatment.

CMOS Monolithic Electrochemical Gas Sensor Microsystem Using Room Temperature Ionic Liquid.

The growing demand for personal healthcare monitoring requires a challenging combination of performance, size, power, and cost that is difficult to achieve with existing gas sensor technologies. This paper presents a new CMOS monolithic gas sensor microsystem that meets these requirements through a unique combination of electrochemical readout circuits, post-CMOS planar electrodes, and room temperature ionic liquid (RTIL) sensing materials. The architecture and design of the CMOS-RTIL-based monolithic gas sensor are described. The monolithic device occupies less than 0.5mm2 per sensing channel and incorporates electrochemical biasing and readout functions with only 1.4mW of power consumption. Oxygen was tested as an example gas, and results show that the microsystem demonstrates a highly linear response (R2 = 0.995) over a 0 - 21% oxygen concentration range, with a limit of detection of 0.06% and a 1 second response time. Monolithic integration reduces manufacturing cost and is demonstrated to improve limits of detection by a factor of five compared to a hybrid implementation. The combined characteristics of this device offer an ideal platform for portable/wearable gas sensing in applications such as air pollutant monitoring.

Electrochemical multisensor system for monitoring hydrogen peroxide, hydrogen and oxygen in direct synthesis microreactors

We present an electrochemical microsensor system for the monitoring of hydrogen peroxide, dissolved hydrogen and dissolved oxygen inside a direct synthesis microreactor. The setup allows the online, in situ measurement of high reactant concentrations by amperometric detection of all three reactants in aqueous solution using chronoamperometric protocols. Hydrogen peroxide is a key chemical for industrial oxidation applications, and its catalyzed direct synthesis is an attractive process route. For the first time, we integrated an electrochemical cell into a high pressure stainless steel microreactor environment (pressures up to 100 bar, pH of 3–4 and presence of bromide) by fabricating sensor plugs with 300 μm platinum microelectrodes encapsulated into a robust epoxy housing. The first microfabricated silver/silver bromide pseudo-reference electrode, integrated by electrodeposition, allowed to obtain a stable measurement potential directly from the electrolyte containing bromide. The investigation of platinum electrochemistry in the presence of bromide by cyclic voltammetry led to the development of chronoamperometric protocols for the stable, precise and reproducible measurement in this environment. Hydrogen peroxide was detected under reaction conditions showing linear behaviour up to 20 mM with high sensitivity of 55 μA cm−2 mM−1 and excellent stability by application of a diffusion limiting hydrogel layer to the electrode surface. This linear range surpasses most micro- and nanostructured platinum approaches. Oxygen and hydrogen were both measured at elevated pressures up to 70 bar and high dissolved concentrations up to 52 mM and 40 mM with measured sensitivities of 26 μA cm−2 mM−1 and 356 μA cm−2 mM−1, respectively. We have successfully shown the application of electrochemical sensors for online, in situ monitoring of analyte concentrations under conditions found in direct synthesis microreactors.

In-situ 3D micro-sensor model using embedded plasmonic island for biosensors

The design of the microsensor system for biosensors using the plasmonic island is proposed. The sensor head is formed by the stacked layers of silicon-graphene-gold materials. The dual-mode operations of the sensor can be performed using the relationship of the changes between the electron mobility and optical phase, where the exciting environment can be light intensity (phase), electrical transient, heat, pressure, flavour and smoke, The change in light phase (intensity) in silicon and conductivity (mobility) in gold layers cause change in the output measurands. The design and simulation interpretation of the sensor is presented. The sensor manipulation using the MCM arrangement is simulated and interpreted for biosensor applications 3D imaging can also be applied to the MCM function, where the 3D in situ sensor function is possible. The sensor sensitivity of 2.0 × 10−21 cm2 V−1 s−1 (mW)−1 via simulation is obtained.