Search

Precisely detecting organophosphorus pesticides (OPs) is paramount in upholding human safety and environmental preservation, especially in food safety. Herein, an electrochemical acetylcholinesterase (AChE) sensing platform entrapped in chitosan (Chit) on the glassy carbon electrodes (GCEs) decorated with Pt/MoS 2 /Ti 3 C 2 MXene (Pt/MoS 2 /TM) was constructed for the detection of chlorpyrifos. It is worth noting that Pt/MoS 2 /TM possesses good biocompatibility, remarkable electrical conductivity, environmental stability and large specific surface area. Besides, the heterostructure formed by the composite of TM and MoS 2 improves the conductivity and maintains the original structure, which is conducive to improving the electrochemical property. The coordination effect between the individual components enables the even distribution of functional components and enhances the electrochemical performance of the biosensor (AChE-Chit/Pt/MoS 2 /TM). Under optimal efficiency and sensitivity, the AChE-Chit/Pt/MoS 2 /TM/GCE sensing platform exerts comparable analytical performance and a wide concentration range of chlorpyrifos from 10 -12 to 10 -6  M as well as a low limit of detection (4.71 × 10 -13  M). Furthermore, the biosensor is utilized to detect OPs concerning three kinds of fruits and vegetables with good feasibility and recoveries (94.81% to 104.0%). This work would provide a new scheme to develop high-sensitivity sensors based on the two-dimensional nanosheet/laminar hybrid structure for practical applications in environmental monitoring and agricultural product detection., Competing Interests: Declaration of competing interest There is no conflict of interest in this manuscript, and the work described is original research., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In this study, a hydrothermal process was utilized to grow mixed-valence CuFe 2 O 4 /Cu 0 nanosheets on carbon fiber paper, forming a three-dimensional hierarchical electrode (CuFe 2 O 4 /Cu 0 @CFP). The ordered array structure, coupled with the porous bowl-like structure, enhances the exposure of more electrode active sites and facilitates analyte penetration, thus enhancing the electrode sensing performance. As a binder-free sensor, the CuFe 2 O 4 /Cu 0 @CFP sensor exhibited remarkable sensitivity in detecting Malachite Green (MG), Sunset Yellow (SY) and Tartrazine (TA) over wide concentration ranges: 0.1-300 μM for MG (R 2  = 0.994), 0.005-200 μM for SY (R 2  = 0.996), and 0.005-300 μM for TA (R 2  = 0.995) with low detection limits of 0.033 μM for MG, 0.0016 μM for SY, and 0.0016 μM for TA (S/N = 3), respectively. Additionally, the 3D CuFe 2 O 4 /Cu 0 @CFP sensor detected MG, SY, and TA in a mixed solution with satisfactory results. It also performs well in beverage, fruit juice powder, and jelly samples, with results matching those from HPLC., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

It is highly desirable to develop a low-cost and rapid detection method for trace levels of carbendazim fungicide residues, which would be beneficial for improving human health and mitigating environmental issues. Herein, isolated single tungsten atoms were implanted onto well-organized metal-organic framework (MOF)-derived N-doped carbons to form W-N-C single-site heterojunctions with ultrahigh electrocatalytic activity. The coupling of W-N-C with Cu 3 (HHTP) 2 , an electronically conductive MOF with a large surface area and porous structure, exhibited enhanced electrocatalytic performance for the oxidation of carbendazim (CBZ) when they were used for decorating graphene nanoplatelet flexible electrode arrays fabricated via template-assisted scalable filtration. A wide linear range (3.0 nM-50 μM) with an ultra-low detection limit of 0.97 nM and fast response was achieved for CBZ analysis. Moreover, the sensing platform has been utilised to monitor CBZ levels in vegetable samples with satisfactory recovery rates of 97.2-102% and a low relative standard deviation of 1.9%., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Bisphenols threaten human health and sensitive detection is crucial. The present study aims to develop ternary composites of copper metal-organic framework (Cu-MOF) with AuAg microstructures. The composite structure was formed by a galvanic displacement reaction and confirmed using SEM. A binder-free catalyst was used to study the electrochemical redox reaction of bisphenol A (BPA) and bisphenol S (BPS); an irreversible cyclic voltammetric signal at +0.70 V and + 0.91 V (vs. Ag/AgCl), in the dynamic range of 20 nM to 2.0 mM, and 10 nM to 1.0 mM, with limits of detection of 2.9 nM, and 3.2 nM (S/N = 3) was obtained. Practical analysis was applied to frozen tomatoes, tuna fish, milk powder, PET bottles, raw milk, and urine samples with a recovery rate of 94.00-100.80% (n = 3). Voltammetric results were validated using HPLC detection with high precision. The sensor is a promising alternative platform for measuring BPA in food samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Background: In the process of food production, ciprofloxacin (CIP), a highly prescribed fluoroquinolone antibiotic, is often excessively used to reduce the risk of bacterial infection. However, this overuse can cause severe harm to human health, including allergic responses, gastrointestinal complications, and potential renal dysfunction. The development of a robust and precise detection method for CIP is crucial, given the interconnection between food security and human health. Compared to the single-mode detection methods currently in use, dual-mode detection provides enhanced accuracy in detecting results due to its inherent self-validation and self-correction capabilities., Results: Herein, a photoelectrochemical and photoelectrochromic self-validated dual-mode sensing platform was developed to detect CIP in milk by laser etching method, signal generation (SG) region, signal output (SO) region and conductive channel was integrated on the same fluoide-doped tin oxide electrode and Ti 3 C 2 /ZnO composite was modified in the electron SG region, and Prussian blue (PB) was electrodeposited in the SO region. By irradiating the SG region, photogenerated electrons are generated and injected into the SO region through the conductive pathway, resulting in the reduction of the PB to Prussian white (PW). Because the binding of CIP to its specifically recognized aptamers hinders electron transfer, a "Signal-Off" response mechanism can be used for simultaneous quantitative detection of CIP using photocurrent or color changes, which presents a great advantage in the detection process., Significance: By integrating different detection mechanisms within a single linear range, the constructed dual-mode sensor has a wide detection range and low detection limit in milk samples. Additionally, it shows good selectivity in anti-interference experiments, providing a new idea for the development of visual analysis and detection platforms for food safety., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Carcinoembryonic Antigen (CEA) and 4-nitroquinoline-N-oxide (4-NQO) are cancer markers that play a crucial role in tumor risk assessment and early cancer diagnosis. Therefore, it is in demand to develop a fast, accurate, simple, and cost-effective method to detect these cancer markers for quick and early stage-cancer diagnosis and treatment., Results: Herein, we report a dual signaling approach for direct and indirect signal transduction of cancer biomarker binding on molecularly imprinted-electrodes integrated on an ePAD, enabling sensitive and selective quantitative analysis of 4-NQO and CEA. Multiple test zones on a single device based on artificial recognition sites using core-shell Cu-MOF@MIP were developed to create a selective "Dual-signal-ePAD". An effective and facile imprinting method on a Cu-MOF surface based on the synthesized of 4-VPBA/MAA/TRIM polymer. It resulted in a novel MIP useable as a high-performance sensing tool for the ultrasensitive and specific quantification of the target cancer biomarkers. Multiple tests consisted of voltammetric analysis of 4-NQO via oxidation of the analyte on a WE 1 , and impedance analysis of CEA via the molecular interaction with the imprinted WE 2 ., Significance: The proposed device provides enhanced electrochemical signal amplification due to its high conductivity, electrocatalytic activity, and the target-specific recognition sites for accurate determination of 4-NQO and CEA targets. The Dual-signal-ePAD exhibits good voltammetric and EIS response, oxidation currents of 4-NQO at -0.06 V and R CT of CEA, resulting in high selectivity and sensitivity with a linear response range covering the concentration range of clinical interest for both analytes. Dual-signal ePAD is a good candidate for clinical screening and POCT., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Wearable patch biosensors for noninvasive and continuous diabetes management through sweat glucose analysis present a promising prospect. However, how to obtain sweat samples safely and effectively remains a huge challenge, especially in a resting state. In this work, we propose an innovative wearable patch biosensor through a heat-stimulated approach for sweat collection. A silver nanowire-loaded electrothermal film was designed as the heat source to stimulate sweat glands for sweat secretion. Subsequently, the secreted sweat sample was transported and enriched through microfluidic channels, which was continuously and sensitively analyzed by a Prussian blue and glucose oxidase comodified glucose electrochemical biosensor. Under optimal conditions, its sensitivity could achieve 14 μM sweat glucose within 15 min, which was 17 min shorter than that without heating. The specificity, reproducibility, and accuracy were also adequate. To achieve on-body perspiration monitoring of human subjects, the wearable patch biosensor was integrated with a portable electrochemical workstation, a temperature controller, and a power source. The glucose concentration was presented on a smartphone. Results showed that the glucose concentration in sweat detected by the wearable biosensor presented a highly consistent trend with the blood glucose measured by a blood glucose meter throughout the day with normal meals. Compared with other conventional sweat stimulation strategies, the simple device and safe principle made it more suitable for individuals who were sedentary or at rest. This work provides a new approach to realizing wearable patch biosensors for personalized health monitoring.

Cardiovascular diseases (CVDs) are recognized as a significant threat to global health. The rapid, sensitive, and precise measurement of relevant biomarkers is essential for the timely diagnosis of CVDs. Molecularly imprinted polymers (MIPs), which act as artificial receptor recognition materials, have been extensively utilized in the detection of CVD biomarkers. Their widespread application is due to their cost-effectiveness, physical and chemical stability, straightforward preparation processes, and excellent compatibility with various sensor types. This review introduces the principles of MIP sensors in combination with electrochemical, optical, thermal transfer, and acoustic detection techniques for detecting CVD-related biomarkers. It then discusses methods developed over the past decade for detecting biomarkers of three major CVDs-coronary artery disease (CAD), acute myocardial infarction (AMI), and heart failure (HF)-using MIP sensors. Finally, the review summarizes the potential of MIP sensors in CVD biomarker detection and provides an outlook on future research directions.

Recognizing the need for a hand-held device capable of quantitatively measuring the concentration of bacteria in water, this paper describes a label-free method for rapid detection of Escherichia coli ( E. coli ) in water via H 2 O 2 decomposition using screen-printed electrodes (SPE) modified with nanostructured metal oxide layers. The study encompasses sensor preparation, bacteria culture, synthesis and characterization of nanostructures, and development of a readout circuitry for lab prototyping. During sensing measurements, the bacteria are first made to interact with H 2 O 2 and subsequently, the H 2 O 2 solution is exposed on the sensing surface. The electrochemical sensors are fabricated by modifying the working electrode of SPE with nanostructured metal oxide layers of MnO 2 and TiO 2 as these play a crucial role in the detection of E. coli in water. The sensing experiments of MnO 2 -modified SPE show a significant response to bacteria with a sensitivity of 0.82 mV.mL/log CFU and a limit of detection (LOD) of 1.8 CFU/mL, while the TiO 2 -modified SPE exhibits a linear response over a wide range of bacterial concentrations with a sensitivity of 1.12 mV·mL/log CFU and a limit of detection of 2.23 CFU/mL. Both sensors demonstrate a rapid response, stability, repeatability, and a recovery time of 70 ms. Additionally, selectivity with respect to other bacteria, wastewater components such as glucose, ammonium sulfate, and sodium carbonate, and testing with RO, DI, and tap water samples are conducted to evaluate the sensors' performance. A detailed sensing mechanism has been developed to comprehend the results, including chemical and biological reactions, metal oxide interfaces, morphology, and other surface studies of the sensing surface. A prototype comprising a sensor chip, an Arduino board, and other necessary circuit components is tested with various bacterial solutions. This enables its use for on-field rapid detection of bacteria in water using smaller volumes and a portable system.

Dependable and sensitive glucose (Glu) testing in foodstuff and blood serum is highly desirable to prevent and treat diabetes. Electrochemical quantification of Glu has attracted great interests due to the advantages, including simple operation, higher sensitivity, easy miniaturization, ease of on-site and wearable detection as well as fast response. High costs and environmental dependence of enzymes pose a challenge to the electrochemical enzymatic biosensors. Nonenzymatic electrochemical Glu sensors are urgently needed to aid the Glu detection in human serum and food samples. To fabricate flexible Glu electrochemical sensors, designing suitable electrode substrate and efficient electrocatalyst is of paramount significance. Herein, the porous patterned laser-induced graphene (LIG) was fabricated on polyimide substrates through an efficient laser-inducing technology, and then used directly as the electrode substrate. Electrochemical deposition of NiCo layered double hydroxide (LDH) nanoflakes on the LIG surface was then conducted to achieve NiCo-LDH/LIG electrode as a Glu sensor. Under optimal conditions, this sensor displays a low detection limit of 0.05 μM. Two sets of broad detection linear ranges were found to be from 0.5 to 270 μM and from 0.27 to 3.6 mM, with high sensitivities of 9.750 μA μM -1  cm -2 and 3.760 μA μM -1  cm -2 , respectively. The enhanced performance was ascribed to the cooperative action of NiCo-LDH and LIG, in which porous LIG provides extraordinary electroconductibility and a high surface area, while NiCo-LDH offers numerous exposed active sites and outstanding electrocatalytic performance. Practical application was further verified during the Glu detection in human serum and food samples. This research confirms that the NiCo-LDH/LIG composite is a prospective electrode for high-performance Glu sensor and provides a way of developing nonenzymatic electrochemical sensors to analyze the Glu in human serum and food samples, opening new avenues in electrochemical sensing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or relevant relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Lead ions (Pb 2+ ) are heavy metal environmental pollutants that can significantly impact biological health. In this study, the synthesis of a ternary nanocomposite, ErVO 4 /P@g-C 3 N 4 /SnS 2 , was achieved using a combination of hydrothermal synthesis and mechanical grinding. The as-fabricated photoelectrochemical (PEC) sensor was found to be an ideal substrate for Pb 2+ detection with high sensitivity and reliability. The ErVO 4 /P@g-C 3 N 4 /SnS 2 /FTO was selected as the substrate because of its remarkable and reliable photocurrent response. The Pb 2+ sensor exhibited a low detection limit of 0.1 pM and a broad linear range of 0.002-0.2 nM. Moreover, the sensor exhibited outstanding stability, selectivity, and reproducibility. In real-time applications, it exhibited stable recovery and a low relative standard deviation, ensuring reliable and accurate measurements. The as-prepared PEC sensor was highly stable for the detection of Pb 2+ in different water samples. This promising characteristic highlights its significant potential for use in the detection of environmental pollutants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Wearable electrochemical sweat sensors are potentially promising for health monitoring in a continuous and non-invasive mode with high sensitivity. However, due to the complexity of sweat composition and the growth of skin bacteria, the wearable sweat sensors may gradually lose their sensitivity or even fail over time. To deal with this issue, herein, we proposed a new strategy to construct wearable sweat sensors with antifouling and antimicrobial capabilities. Amyloid albumin hydrogels (ABSAG) were doped with two-dimensional (2D) nanomaterial MXene and CeO 2 nanorods to obtain the antifouling and antimicrobial amyloid albumin composite hydrogels (ABSACG, CeO 2 /MXene/ABSAG), and the wearable sensors were prepared by modifying flexible screen-printed electrodes with the ABSACG. Within this sensing system, the hydrophilic ABSAG possesses strong hydration capability, and it can form a hydration layer on the electrode surface to resist biofouling in sweat. The 2D nanomaterial MXene dispersed in the hydrogel endows the hydrogel with good conductivity and electrocatalytic capability, while the doping of CeO 2 nanorods further improves the electrocatalytic performance of the hydrogel and also provides excellent antimicrobial capability. The designed wearable electrochemical sensors based on the ABSACG demonstrated satisfying antifouling and antimicrobial abilities, and they were capable of detecting dopamine accurately in human sweat. It is expected that wearable sensors utilizing the antifouling and antimicrobial ABSACG may find practical applications in human body fluids analysis and health monitoring., Competing Interests: Declaration of competing interest We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Herein, a signal stable molecularly imprinted photoelectrochemical (MIP-PEC) sensing platform was designed to sensitively detect Escherichia coli by incorporating polythiophene film with Cu: ZIF-8/KZ3TTz heterojunction. Attributed to the formation of a staggered type II heterostructure between KZ3TTz and Cu: ZIF-8 semiconductors, the Cu: ZIF-8/KZ3TTz heterojunction exhibited stable and significant cathode PEC response. Impressively, selective MIP film was grown on the surface of Cu: ZIF-8/KZ3TTz/GCE by electro-polymerization of 2,2-Dimethyl-5-(3-thienyl)-1,3-dioxane-4,6-dione (DTDD) in the presence of E. coli. After removing E. coli, more electrons were transferred to the electrolyte solution through the imprinting cavity on the MIP film, which was eliminated by O 2 in the electrolyte, causing further enhancement of the cathode PEC response. On the contrary, when the imprinted cavity was filled with E. coli, the cathodic PEC response gradually decreased due to steric hindrance effect. The sensor showed excellent linearity in the range of 10 1 to 10 8  CFU/mL with a detection limit of 4.09 CFU/mL (S/N = 3). This strategy offered a novel approach for pathogenic bacteria detection in food safety and environmental monitoring., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

An effective electrochemical sensor was developed to detect and determine of the As(III) by modifying the carbon paste electrode (CPE) with graphitic carbon nitride decorated with iron-based metal-organic frameworks (Fe-MOF/g-C 3 N 5 ). The differential pulse anodic stripping voltammetry (DPASV) method was used to analyze As(III) ions in a phosphate buffer solution (0.10 M, pH = 5). Fe-MOF/g-C 3 N 5 /CPE showed high sensitivity (4.24 μA μg -1  L), satisfactory linear range (0.50 μg L -1 -5.00 μg L -1 and 5.00 μg L -1 -30.00 μg L -1 ), and low detection limit (LOD, 0.013 μg L -1 ). The prepared sensor was showed an excellent repeatability and selectivity, and successfully used for determination of the As(III) ion in ambient waters and apple juice samples., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Mostafa najafi reports was provided by Imam Hossein University. Mostafa Najafi reports a relationship with Imam Hossein university that includes: board membership. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Real-time, high-frequency measurements of pharmaceuticals, metabolites, exogenous antigens, and other biomolecules in biological samples can provide critical information for health management and clinical diagnosis. Electrochemical aptamer-based (EAB) sensor is a promising analytical technique capable of achieving these goals. However, the issues of insufficient sensitivity, frequent calibration and lack of adapted portable electrochemical device limit its practical application in immediate detection. In response we have fabricated an on-chip-integrated, cold-hot Janus EAB (J-EAB) sensor based on the thermoelectric coolers (TECs). Attributed to the Peltier effect, the enhanced/suppressed current response can be generated simultaneously on cold/hot sides of the J-EAB sensor. The ratio of the current responses on the cold and hot sides was used as the detection signal, enabling rapid on-site, calibration-free determination of small molecules (procaine) as well as macromolecules (SARS-CoV-2 spike protein) in single step, with detection limits of 1 μM and 10 nM, respectively. We have further demonstrated that the J-EAB sensor is effective in improving the ease and usability of the actual detection process, and is expected to provide a universal, low-cost, fast and easy potential analytical tool for other clinically important biomarkers, drugs or pharmaceutical small molecules., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

L-tyrosine is a recognized biomarker of albinism, whose endogenous level in human bodies is directly linked to melanin synthesis while no attention has been paid to its specific diagnosis. To this end, we have developed an electrochemical point-of-care testing device based on a molecularly imprinted gel prepared by a universal paradigm shift design to achieve the enhanced specific recognition of the L-tyrosine. Interestingly, this theoretically optimized molecularly imprinted gel validates the recognition pattern of L-tyrosine and optimizes the structure of the polymer itself with the aid of computational chemistry. Besides, modified extended-layer MXene and Au nanoclusters have significantly improved the sensing activity. As a result, the linear diagnostic range of this electrochemical point-of-care testing device for L-tyrosine is 0.1-100 μM in actual human fluids, which fully covers the L-tyrosine levels of healthy individuals and people with albinism. The diagnosis is completed in 90 s and then the results are transmitted by Bluetooth low energy to the smart mobile terminal. Therefore, we are convinced that this electrochemical point-of-care testing device is a promising tool in the future smart medical system., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Heavy metals are one of the most important pollutants in the environment due to their toxic properties, accumulation, and indestructibility. So that when the metals enter the body of plants from natural and artificial sources, they accumulate in the organs and tissues. Therefore, in the present study, a sensitive and selective strategy is reported for the detection of cadmium(II) ions. To achieve this purpose, first sodium aluminate nanostructures were synthesized using a sol-gel method and green route. Then, using the nanostructures, a modified nanostructured sensor was designed. The characterization of the nanostructures was performed using various techniques. Next, the electrochemical behavior of the modified nanostructured electrode was investigated. The studies show the environment-friendly sensor has an enhanced voltammetric response than the unmodified sensor for cadmium(II) ions. After confirming the performance of the modified sensor, the analysis of cadmium(II) ions at the surface of the nanostructured modified electrode was investigated. Then, by differential pulse voltammetry (DPV) technique, the detection limit of cadmium(II) ions in optimal conditions was obtained at 1.10 nM with a broad dynamic linear range of 0.02-20.00 μM and 20.00-900.00 μM. Finally, the performance of the modified nanostructure sensor was investigated in food, biological and environmental samples, and acceptable results were obtained using the proposed method., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Enzyme-inhibited electrochemical sensor is a promising strategy for detecting organophosphorus pesticides (OPs). However, the poor stability of enzymes and the high oxidation potential of thiocholine signal probe limit their potential applications. To address this issue, an indirect strategy was proposed for highly sensitive and reliable detection of chlorpyrifos by integrating homogeneous reaction and heterogeneous catalysis. In the homogeneous reaction, Hg 2+ with low oxidation potential was employed as signal probe for chlorpyrifos detection since its electroactivity can be inhibited by thiocholine, which was the hydrolysate of acetylthiocholine catalyzed by acetylcholinesterase. Additionally, Co,N-doped hollow porous carbon nanocage@carbon nanotubes (Co,N-HPNC@CNT) derived from ZIF-8@ZIF-67 was utilized as high-performance electrode material to amplify the stripping voltammetry signal of Hg 2+ . Thanks to their synergistic effect, the sensor exhibited outstanding sensing performance, excellent stability and good anti-interference ability. This strategy paves the way for the development of high-performance OP sensors and their application in food safety., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

In response to the growing need for sustainable analytical methods, this study explores the repurposing of screen-printed electrodes (SPEs) that would otherwise be discarded. This involves recoating the working electrode surface with a graphite (Gr) and chitosan (CTS) dispersion, creating a reusable SPE (SPE-Gr/CTS). Demonstrating its utility, SPE-Gr/CTS was employed for the detection of 4-bromo-2,5-dimethoxyphenethylamine (2C-B), a phenylethylamine commonly used for recreational proposes. Identifying 2C-B in fluid oral and seized samples is of great interest for forensic and toxicological applications. The 2C-B detection using SPE-Gr/CTS was optimized in Britton-Robinson buffer solution (0.1 mol L -1 ) at pH 2.0, employing square-wave adsorptive stripping voltammetry. The electrochemical behavior of 2C-B on SPE-Gr/CTS exhibited one irreversible oxidation and a reversible redox process. The proposed method presented a dynamic linear range for 2C-B determination (0.05 to 7.5 μmol L -1 ) with a low LOD (0.015 μmol L -1 ). Moreover, the stability of 2C-B electrochemical responses on SPE-Gr/CTS was confirmed using the same or different electrodes ( N = 3), with a relative standard deviation of less than 5.0%. Interference studies with seventeen other illicit drugs and adulterants demonstrated that the proposed method is selective for 2C-B detection even in the presence of these substances. Real seized and oral fluid samples containing 2C-B were analyzed using this method, and the results were confirmed by LC-MS. The proposed device demonstrates to be an environmentally friendly and selective sensor for 2C-B detection in forensic analysis, offering a rapid and straightforward screening method for seized and biological samples. In addition, a portable and sensitive determination of 2C-B in forensic samples is presented with minimal sample consumption (50 μL).

A home-made screen printed electrode (SPE) was designed with a magnetic multi-walled carbon nanotube composite (MWCNT-Fe 3 O 4 ) and a molecularly imprinted polymer (MIP) for sensitive and selective electrochemical analysis of famotidine (FAM). The SPE was fabricated using non-commercial conductive inks such as carbon and silver inks. The electrodes were printed by a painting technique on polyvinyl chloride (PVC) sheets as a substrate. To optimize the composition of the carbon ink, a mixture design methodology was employed. A computational approach was used to select the functional monomer. The imprinted layer was synthesized by electropolymerization of FAM (template) and pyrrole (PY) (monomer) using cyclic voltammetry (CV) on the working electrode surface modified with the MWCNT-Fe 3 O 4 nanocomposite. Differential pulse voltammetry (DPV) was applied to characterize the template removal and rebinding processes. The Plackett-Burman design (PBD) and central composite design (CCD) investigated the effect of parameters on the MIP/MWCNT-Fe 3 O 4 /SPE performance. The sensor exhibited a linear dynamic range of 1-1000 μM ( R 2 = 0.9919) with a limit of detection (LOD) of 0.027 μM (3 s b , n = 3). It demonstrated good repeatability and reproducibility, with relative standard deviations (RSD) of 3.6 and 4.2, respectively. This disposable and cost-effective sensor successfully detected FAM in simulated real samples and correlated well with high-performance liquid chromatography (HPLC) results.

Towards the nicotine addiction challenge in the smoking of hookah pipe products, we hereby present the development of an electrochemical sensor for nicotine detection. A nitrogen-doped carbon nanosheet (N-CNS)/poly(amidoamine) dendrimer (PAMAM) nanocomposite-modified electrode was prepared as a sensor for the detection of nicotine in analytical and real samples. The N-CNSs were prepared by a hydrothermal method and dropcast on a glassy carbon electrode followed by electro-deposition of the PAMAM dendrimer to form the sensor (GCE/N-CNSs/PAMAM). The N-CNSs were characterized with electron microscopy, Raman spectroscopy and FTIR. The sensor was characterized with voltammetry and electrochemical impedance spectroscopy. The N-CNS/PAMAM enhanced the electrochemical performance of the electrode towards the oxidation of nicotine. The sensor achieved a detection limit of 0.05 μM in a linear concentration range of 1.93-61.64 μM nicotine standard samples. The sensor showed good reproducibility, repeatability, and selectivity. The sensor was successful in selectively detecting nicotine in two local brands of hookah pipe tobacco with a 113-121 percent recovery. Nicotine, up to a concentration of 0.35-0.39 mg g -1 , was found in the sampled hookah pipe tobacco products suggesting possible harm to human health.

For the first time an electrochemical sensor based on nanomaterial-supported molecularly imprinted polymers (MIPs) is applied to the sensitive and specific determination of chloroquine phosphate (CHL). The sensor was produced using an electropolymerization (EP) approach, and it was formed on a glassy carbon electrode (GCE) using CHL as a template and 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) and aniline (ANI) as functional monomers. Incorporating Prussian blue polyethyleneglycol-amine nanoparticles (PB@PEG-NH 2 ) in the MIP-based electrochemical sensor increased the active surface area and porosity. The developed CHL/AMPS-PANI/PB@PEG-NH 2 /MIP-GCE sensor was characterized morphologically and electrochemically using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and scanning electron microscopy (SEM). The indirect measurement of CHL was accomplished in 5.0 mmol L -1 [Fe(CN) 6 ] -3/-4 solution using differential pulse voltammetry, displaying linear response between 1.75 × 10 -12 and 2.50 × 10 -13  M, and limits of detection (LOD) and quantitation (LOQ) of 6.68 × 10 -14  M and 2.23 × 10 -13  M, respectively, in standard solutions. CHL recoveries in spiked serum and tablet form ranged from 99.13 to 101.51%, while the relative standard deviations (RSD%) were below 2.41% in both types of samples. In addition, the sensor's excellent selectivity was successfully demonstrated in the presence of components with a chemical structure similar to CHL., Competing Interests: Declarations Ethics approval No approval of research ethics committees was required to accomplish the goals of this study. Conflict of interest The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

We demonstrate an organic electrochemical transistor (OECT) biosensor for the detection of interleukin 6 (IL6), an important biomarker associated with various pathological processes, including chronic inflammation, inflammaging, cancer, and severe COVID-19 infection. The biosensor is functionalized with oligonucleotide aptamers engineered to bind specifically IL6. We developed an easy functionalization strategy based on gold nanoparticles deposited onto a poly(3,4-ethylenedioxythiophene) doped with polystyrenesulfonate (PEDOT:PSS) gate electrode for the subsequent electrodeposition of thiolated aptamers. During this functionalization step, the reduction of sulfide bonds allows for simultaneous deposition of a blocking agent. A detection range from picomolar to nanomolar concentrations for IL6 was achieved, and the selectivity of the device was assessed against Tumor Necrosis Factor (TNF), another cytokine involved in the inflammatory processes.

This work demonstrates sensitive and low-cost piezoelectric sensors on skin-friendly, ultrathin, and conformable substrates combined with organic electrochemical transistors (OECTs) for the detection and amplification of alternating low-voltage input signals. The fully screen-printed (SP) piezoelectric sensors were manufactured on commercially available tattoo paper substrates, while the all-printed OECTs, relying on an extended gate electrode architecture, were manufactured either by solely using SP or by combining SP and aerosol jet printing (AJP) on PET substrates. Applying a low-voltage signal (±25 mV) to the gate electrode of the SP+AJP OECT results in approximately five times higher current modulation as compared to the fully SP reference OECT. The tattoo paper-based substrate enables transfer of the SP piezoelectric sensor to the skin, which in turn allows for radial pulse monitoring when combined with the SP+AJP OECT; this is possible due to the ability of the conformable sensor to convert mechanical vibrations into voltage signals along with the highly sensitive current modulation ability of the transistor device to further amplify the output signal. The results reported herein pave the way toward all-printed fully conformable wearable devices with high sensitivity to be further utilized for the real-time monitoring of electrophysiological signals.

The inability of surgical biopsy to monitor the dynamic evolution of cancer cells hampers its capacity to reflect real-time tumor heterogeneity. Circulating tumor cells (CTCs), as a crucial target in liquid biopsy, offer a novel approach for accurate monitoring of tumors. However, the rarity and complex phenotype resulting from epithelial-mesenchymal transition pose challenges for conventional methods such as CellSearch and immunohistochemistry, which have insufficient ability for simultaneous phenotyping and enumeration of CTCs. The enumeration of a single phenotype CTCs is insufficient for accurately assessing disease progression. Herein, we propose a strategy to address this issue by fabricating an electrochemiluminescence cytosensor via the integration of dual-target enrichment and nanozymes-catalyzed cascade signal amplification. The graphene oxide@hollow mesoporous Prussian blue/Pt (GO@HMPB/Pt) complex, possessing a large specific surface area and exceptional catalytic activity, is employed for loading a substantial amount of luminol as the signal probe. Dual-target magnetic PPy@Fe 3 O 4 /Au-antibody/aptamer is utilized for the magnetic capture of both epithelial and interstitial CTCs. Glutathione (GSH) can disrupt the Au-S bond on aptamer by a thiol exchange reaction and selectively releases a specific subset of phenotypic CTCs, thereby facilitating the efficient capture, accurate classification, and ultrasensitive detection of CTCs in peripheral blood. Using the epithelial MCF-7 and mesenchymal Hela cells as models, the ECL cytosensor demonstrates excellent performance in identifying cells spiked into whole blood. This study presents a novel approach for early detection of metastasis, tracking tumor recurrence, and monitoring therapeutic efficacy., Competing Interests: Declarations Ethical approval No approval of research ethics committees was required to accomplish the goals of this study because experimental work did not involve human or animal samples. Competing interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Wearable, noninvasive sweat sensors enable real-time monitoring of metabolites in human health management. However, the commercial enzyme-based and currently nonenzymatic glucose sensor represents sluggish glucose oxidation kinetics and a narrow sensing range. Rational design of sensitive materials is significant yet faces a huge challenge. Herein, we construct a single-atom Pt supported on NiCo-LDH/Ti 3 C 2 T x heterostructures (Pt 1 -NiCo-LDH/Ti 3 C 2 T x ) as the nonenzymatic electrochemical glucose sensor sensitive materials for selective detection of glucose level in human sweat. The obtained Pt 1 -NiCo-LDH/Ti 3 C 2 T x with improved structural stability and enhanced charge transfer efficiency shows a low oxidation peak potential of 0.49 V, high sensitivity of 506.6 μA mM -1 cm -2 , a low detection limit of 0.035 μM, and long-term stability toward the glucose detection. The wearable sensor, coupled with a wireless transmission module and a signal processing chip, is used for real-time perspiration glucose monitoring during outdoor exercise. The result is comparable to that of high-performance liquid chromatography (HPLC). This research provides a new paradigm for designing a wearable nonenzymatic electrochemical glucose sensor, enabling noninvasive real-time monitoring of glucose concentrations in human sweat.

Disposable biosensors provide high portability and advantageous response time, which are crucial in the next generation of analytical platforms. Herein, we report on zeolites embedding silver clusters as an electroactive material that enhances the electrode-analyte interaction in disposable electrochemical strips made of plastic or paper. The resulting analytical platform effectively immobilizes analytes and facilitates electron exchange transfer. Two detection mechanisms were explored in the electrodes decorated with zeolites embedding silver clusters. The oxidative-reductive character of zeolites embedding silver clusters was applied for chloride ion detection, which is suitable for environmental analysis. Additionally, the electrocatalytic activity of the composite was applied in glucose sensing in the presence of glucose oxidase, demonstrating the versatility of the composites for detecting molecules of a different nature (clinically or environmentally relevant) without further modification. Our approach contributes to the development of simple and low-cost modification procedures for integrating electroactive materials into miniaturized electrochemical sensors for portable platforms and point-of-care devices.

Nitrite is a common nitrogen-containing compound that possesses high biological toxicity, thereby posing a serious threat to aquatic organisms. Therefore, it is imperative to develop a rapid and quantitative determination approach for nitrite. In this study, the aim was to prepare a novel electrochemical sensor to determine nitrite. This was achieved by synthesizing Au/Zn dendritic complexes on a carbon cloth self-supported electrode after plasma treated by a stepwise strategy of electrodeposition and in-situ corrosion. In accordance with the optimal experimental conditions, the electrode exhibited remarkable catalytic activity for the electrooxidation of nitrite ions (pH = 8.0), accompanied by a considerable enhancement in peak anodic current in comparison to the unmodified electrode. The sensor exhibited a wide linear range (1-833 μM, 833-8330 μM), high sensitivity (3506 μA mM -1  cm -2 , 538 μA mM -1  cm -2 ), a low detection limit (0.43 μM), and excellent selectivity, reproducibility, and stability for the determination of nitrite. Furthermore, the prepared sensor was successfully applied to the detection of nitrite in tap water, fish holding pond water and duck pond water, demonstrating good recovery and no significant difference from the spectrophotometric results. The results suggest that the electrochemical sensor developed in this study represents a straightforward yet efficacious approach to the development of advanced portable sensors for aquaculture applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study introduces a cost-effective approach for quantifying uric acid (UA), the main antioxidant species in human physiology and implicated in inflammatory regulation. Using a PVC substrate and pencil drawing technique, electrodes were fabricated and modified with niobium oxide and graphene oxide via a straightforward "drop casting" method. The nanostructures of the substrate, electrode, and modified electrode were evaluated using SEM images. The synergistic effect between these materials significantly facilitated the uric acid oxidation process with a 400 mV peak potential shift and 45% current increase. The evaluation of the electrode's response to common blood and urine components showed minimal deviation. Among the components tested-ascorbic acid, glucose, nitrate, nitrite, cysteine, urea, creatinine, and ammonium ion-only the ammonium ion exhibited a 10% interference at concentrations commonly found in urine. The sensors showed a good detection limit of 8.7 μmol L -1 , with a wide linear range from 8.7 to 2000 μmol L -1 with a correlation factor of 0.9993 for five different sensors. The reproducibility and repeatability of the produced sensors were estimated by the RSD at 4% and 1%, respectively. Synthetic urine samples spiked exhibited reliable analysis, with recovery values within a 5% error margin. This work presents a practical, simple, and affordable sensor platform for rapid and accurate UA quantification.

Dual-mode-based sensors have drawn a lot of interest due to their high accuracy and sensitivity compared to single-response systems. A simple electrochemical and colorimetric dual-mode sensor based on enzyme-linked immunosorbent assay (ELISA), without complex electrode surface modification, was developed for accurate and sensitive detection of carcinoembryonic antigen (CEA). The target CEA is recognized by an antibody coupled to horseradish peroxidase (HRP), which then oxidizes the substrate 3,3',5,5'-tetramethylbenzidine (TMB) to generate both a colorimetric and an electrochemical signal. A paper-based analysis device (μPAD) with dual-mode homogeneous sensing microfluidic was created; three paper-based detection areas for colorimetric testing, and a two-electrode embedded detection area for electrochemical testing. When applying colorimetric analysis technology, the linear range of CEA detection is 0.6-40 ng mL -1 , and the limit of detection (LOD) is 0.2 ng mL -1 . The linear range is 0.1-40 ng mL -1 and the LOD is 0.03 ng mL -1 by applying electrochemical analysis. The visibility and intuitiveness of colorimetry provide a reference for higher sensitivity and quick response of the electrochemical method. A smartphone application (APP) was also developed to realize the dual extraction of colorimetric signals. The colorimetric detection system based on ELISA can provide a new path for the development of electrochemical sensing and makes it have inherent self-verification and self-correction functions and is expected to provide more reliable and accurate detection results.

In a world that is becoming increasingly concerned with health, safety, and the sustainability of food supply chains, the control and assurance of food quality have become of utmost importance. This review examines the application and potential of electrochemical sensors in the dynamic field of food science to meet these expanding demands. The article introduces electrochemical sensors and describes their operational mechanics and the components contributing to their function. A summary of the most prevalent electrochemical methods outlines the diverse food analysis techniques available. The review shifts to discussing the food science applications of these sensors, highlighting their crucial role in detecting compounds in food samples like meat, fish, juice, and milk for contemporary quality control. This paper showcases electrochemical sensors' utility in food analysis, underscoring their significance as powerful, efficient tools for maintaining food safety and how they could transform our approach to global food quality control and assurance.

An electrochemical sensor was developed for the sensitive and selective detection of sulfadiazine (SDZ), based on a molecularly imprinted polymer (MIP) film formed on an indium tin oxide (ITO) electrode through a self-assembly process. The SDZ-imprinted ITO electrode (SDZ-MIP/APTES-ITO) was prepared through in situ polymerization using sulfadiazine, methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA), and 2,2'-azobisisobutyronitrile (AIBN) as the template, functional monomer, cross-linker, and initiator respectively. Before polymerization, the ITO electrode was functionalized with 3-aminopropyltriethoxysilane (APTES) to promote covalent attachment of the polymer to the electrode. After polymerization, the template molecule SDZ was removed to create selective recognition sites, forming the molecularly imprinted polymer electrode (MIP/APTES-ITO), which facilitates sulfadiazine detection. The sensor's performance was evaluated using cyclic and differential pulse voltammetry, demonstrating a linear response in the sulfadiazine concentration range 0.1 to 300 μM, with a detection limit of 0.11 μM. The MIP-based sensor exhibited good reproducibility, repeatability, selectivity, and stability in sulfadiazine detection. Its practical applicability was confirmed by the successful quantification of sulfadiazine in spiked milk samples., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Additive abuse in fishery, such as tricaine methanesulfonate (MS222), ciprofloxacin (CPFX), and malachite green (MG), threatens public human health and interferes with the ecological equilibrium of water resources. However, the majority of the present detection methods suffer from high costs, complex operations, and poor portability. Therefore, real-time and rapid detection of the above additive by mobile devices is becoming increasingly important. Here we report the fabrication and performance of an entirely electrochemical system with USB-stick size for simultaneous detection of MS222, CPFX, and MG, as well as pH and permittivity. The limits of detections are 0.17, 0.67, and 0.28 µg/mL, while the resolution ratios are 10 %, 10 %, and 5 % for MS222, MG, and CPFX, respectively. For both pH and permittivity, they have linear regressions measured by brightness and capacitance of the sample respectively, at the range of 1.5-9 (pH) and 10-20 (permittivity). The interference experiments, using target analytes (40 μg/mL) and 15 interfering analytes (80 μg/mL), demonstrated the anti-interference performance of the sensor patches. The field studies on carps, catfishes, and chubs indicated that the developed integrated portable system could be used for real sample analysis with high performance., Competing Interests: Declaration of Competing Interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, and there is no professional or other personal interest of any nature or kind in any product, service, and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled, “Fully integrated sensor array for additives, permittivity, and pH monitoring for fishery”., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The growing concern over micropollutants in aquatic ecosystems motivates the development of electrochemical membrane reactors (EMRs) as a sustainable water treatment solution. Nevertheless, the intricate interplay among adsorption/desorption, electrochemical reactions, and byproduct formation within EMR complicates the understanding of their mechanisms. Herein, the degradation of micropollutants using an EMR equipped with carbon nanotube membrane are investigated, employing isotope-labeled steroid hormone micropollutant. The integration of high-performance liquid chromatography with a flow scintillator analyzer and liquid scintillation counting techniques allows to differentiate hormone removal by concurrent adsorption and degradation. Pre-adsorption of hormone is found not to limit its subsequent degradation, attributed to the rapid adsorption kinetics and effective mass transfer of EMR. This analytical approach facilitates determining the limiting factors affecting the hormone degradation under variable conditions. Increasing the voltage from 0.6 to 1.2 V causes the degradation dynamics to transition from being controlled by electron transfer rates to an adsorption-rate-limited regime. These findings unravels some underlying mechanisms of EMR, providing valuable insights for designing electrochemical strategies for micropollutant control., (© 2024. The Author(s).)

An electroanalytical method based on disposable screen-printed carbon electrodes modified with non-toxic carbonaceous nanodots is proposed as a reliable and effective device for codeine determination in biological fluids and soft drinks. Graphene quantum dots (GQDs), carbon quantum dots (CQDs) and carbon nanodots (CNDs) were evaluated as electrode modifiers for the determination of the drug. The electroactive areas of the modified electrodes were assessed by cyclic voltammetry using potassium ferricyanide. Results demonstrated that GQDs provided the best analytical response for codeine, displaying an intense and well-defined anodic wave approximately 0.9 V vs reference electrode. The method exhibits an acceptable linear dynamic range, low limits of detection and quantification (0.21 and 0.73 µM, respectively), and satisfactory precision (below 3.9% expressed as relative standard deviation (RSD)) in saliva. Only the analysis of biofluids requires a simple extraction protocol. The feasibility and applicability of this novel approach were assessed by determining codeine in different matrices, with recoveries ranging from 69 to 112%. This cost-effective, simple, easily miniaturised and portable method was applied not only to biofluids but also for the direct detection of codeine in soft drinks combined with a codeine-enriched syrup, a medication that is being used to adulterate beverages, particularly at specific events (drinking and nightclub parties). There is no need for any sample treatment, demonstrating its versatility in analysing beverages for potential adulteration as well., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

The increasing demand in healthcare for accessible and cost-effective analytical tools is driving the development of reliable platforms to the customization of therapy according to individual patient drug serum levels, e.g. of anti-psychotics in schizophrenia. A modifier-free microfluidic paper-based electroanalytical device (μPED) holds promise as a portable, sensitive, and affordable solution. While many studies focus on the working electrode catalysts, improvements by engineering aspects e.g. of the electrode arrangement are less reported. In our study, we demonstrate the enhanced capabilities of the 3D electrode layout of μPED compared to 2D μPED arrangements. We especially show that screen printing can be employed to prepare 3D μPEDs. We conducted a comparison of different 2D and 3D electrode arrangements utilizing cyclic voltammetry in [Fe(CN) 6 ] 3-/4- , along with square-wave voltammetry for clozapine (CLZ) sensing. Our findings reveal that the utilization of the 3D μPED leads to an increase in both the electrochemically active surface area and the electron transfer rate. Consequently, this enhancement contributes to improve sensitivity in the CLZ sensing. The 3D μPED clearly outperforms the 2D μPED arrangement in terms of signal strength. With the 3D μPED under the optimized conditions, a linear dose-response for a concentration range from 7.0 to 100 μM was achieved. The limit of detection and sensitivity was determined to be 1.47 μM and 1.69 μA μM -1 cm -2 , respectively. This evaluation is conducted in the context of detection and determination of CLZ in a human blood serum sample. These findings underscore the potential of the 3D μPED for future applications in pharmacokinetic analyses and clinical tests to personalize the management of schizophrenia.

The study of research proposes a systematic pattern for optimization and fabrication of a sustainable-cost effective electrochemical sensor made by Bi-CdFe 2 O 4 (BCDF) nanoparticle and graphite powder. The structural examinations of synthesized BCDF materials were analyzed by specific spectral techniques viz.; P-XRD, SEM-EDX, TEM, XPS, FT-IR and DRS techniques. The modified sensor electrode offer a significant electrochemical properties that can improve the material selectivity and sensitivity actions measured by Cyclic Voltammetric (CV) and Electrochemical Impedance Spectral (EIS) plots. We demonstrated a developed highly-purity BCDF-graphite paste electrode for sensing actions on Paracetamol and Lead (Pb 2+ ) ions under 0.1 M KCl. The excellent sensing activity towards Lead ions and Paracetamol confirmed by its redox potential peaks at scan rate of 1-5 V/s with maximum sensitivity of -0.61 V and 0.69 V respectively. The excellent photo-dye-degradation action of BCDF (98.2%) than those of host CDF (81.6%) on Rose Bengal (RB) dye was demonstrated. Its kinetic study reveals that this process follows first order kinetics and rate constants of the host (18.1 × 10 -3 min -1 ) and BCDF (39.2 × 10 -3 min -1 ) were measured. Thus, the synthesized BCDF electrode provides a new perception for developing specific nano-sensor towards detection of toxic metals., (© 2024. The Author(s).)

Hydrogen and renewable fuels were generated using cost-effective and efficient electrocatalysts for water splitting. In this work, a CuO-based photocathode is used for the water splitting to generate hydrogen energy by PVD technique. The XRD analysis reveals the deposition of CuO thin film on ITO substrates, which is monoclinic. The XRD and LSV analysis of CuO confirmed the type of semiconductor and observed to be P-type semiconductor. SEM study of CuO confirmed the shape, morphology to be a circular and regular shape. The grain size of deposited CuO thin film was found to be 18 nm. The absorption and transmission of CuO thin film were observed through UV spectroscopy analysis and were found to be better photocatalyst in visible range 415-425 nm. The transmittance of the prepared thin film was noted to be maximum 7.6% in the UV range (280-300 nm). The band gap was also measured employing the Tauc plot and found to be 2.98 eV, which is most favorable for water splitting application. FTIR study showed the stretching, vibration, and the functional group of the deposited CuO thin film; the broad band of stretching of Cu-O in monoclinic CuO was observed at the range of 500-700 cm -1 , and further peaks were also noted at the range of 1500-1600 cm -1 . The linear sweep voltammetry (LSV) of CuO thin film was calculated in the absence of solar spectra and the presence of solar spectra and observed to be enhanced in current under solar spectra. The solar light to hydrogen emission percentage (STH %) of CuO through LSV was observed to be 2.04% under solar spectra. The low Nyquist curve of blank ITO and CuO-coated ITO substrate via electrochemical impedance spectroscopy (EIS) analysis was observed, which confirmed the enhancement of EIS of CuO-coated ITO. The hydrogen generation rate was also calculated by electrochemical cell and observed to be 5325.21 mol g -1 for 6 h., (© 2024 John Wiley & Sons, Ltd.)

Antibiotic residues have become a significant challenge in food safety, threatening both ecosystem integrity and human health. To combat this problem, we developed an innovative photo-powered, self-powered aptasensor that employs a novel carbon-doped three-dimensional graphitic carbon nitride (3D-CN) combined with a metal-organic framework composed of N-doped copper(I) oxide-carbon (Cu 2 O@C) skeletons. The 3D-CN serves as the photoanode, offering stable photocurrent production due to its three-dimensional open framework structure. The N-doped Cu 2 O@C acts as the photocathode, providing oxidation protection for the metal core and enhancing light absorption due to its metal-organic framework structure. A key feature of our work is exploiting the Fermi level difference between the n-type photoanode and p-type photocathode, which facilitates faster migration of photogenerated electrons toward the photocathode, thereby enhancing the sensor's self-powered effect. Experimental results reveal that upon aptamer loading, the sensor can linearly detect tetracycline (TC) within a range of 0.5 pmol/L to 300 nmol/L, with a detection limit as low as 0.13 pmol/L. It also demonstrates excellent selectivity, stability, and reproducibility, making it applicable to real samples such as milk and river water. Consequently, our research provides a highly efficient and sensitive method for monitoring TC in food, with significant practical implications and profound impacts on food safety., (© 2024 Institute of Food Technologists.)

Upadacitinib (UPA) is a selective and reversible oral Janus kinase (JAK) 1 inhibitor and is of great importance in treating inflammatory bowel disease (Zheng et al., Int Immunopharmacol 126:111229, 2024; Foy et al., JAAD Case Rep 42:20-22, 2023). Although there are limitations to the effectiveness of UPA, it has received positive responses in clinical trials and is approved for the treatment of atopy dermatitis (AD) (Li et al., Int Immunopharmacol 125:111193, 2023). In this study, a nanoparticle-doped molecularly imprinted polymer (MIP)-based electrochemical sensor was developed for sensitive and selective detection of UPA. The developed sensor was designed as a thin film layer using the photopolymerization method on the surface of the prepared nanoparticle-doped polymerization solution glassy carbon electrode (GCE). Various nanoparticles, such as multi-walled carbon nanotube, titanium dioxide, oxide, and zinc oxide (ZnO) nanoparticles, were the most suitable for UPA. Surface characterization of the developed sensor was done by scanning electron microscopy (SEM), and electrochemical characterization was done by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The quantitative analysis of UPA was performed in 5.0 mM [Fe (CN) 6 ] 3-/4- solution using the differential pulse voltammetry (DPV) technique. Under optimum conditions, the calibration range was between 0.1 and 1 pM. The limit of detection (LOD) and limit of quantification (LOQ) were calculated as 0.005 pM and 0.017 pM, respectively. The sensor's accuracy was proven by performing a recovery study in serum. The sensor's selectivity was also evaluated using common interfering substances such as KNO 3 , CaCl 2 , Na 2 SO 4 , uric acid, ascorbic acid, dopamine, and paracetamol. According to the results obtained, the performance of the designed sensor was found to be quite sensitive and selective in determining UPA. The developed UPA-ZnO/3-APBA@MIP-GCE sensor showed high sensitivity and selectivity towards UPA. In addition, the selectivity, the most important feature of the MIP-based sensor, was confirmed by imprinting factor (IF) calculations using tofacitinib (TOF) and ruxolitinib (RUX). The sensor's unique selectivity is demonstrated by its successful performance even in the presence of UPA impurities., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

In this study, multiple particle binding-liposomes (MPB-Lips), encapsulating the luminophore tris(2',2-bipyridyl)ruthenium (II) complex ([Ru(bpy) 3 ] 2+ ), were developed as an electrochemiluminescence (ECL) signal amplifier and were applied to detect the model analyte streptavidin (SA) using the indirect competitive ECL method. The MPB-Lips were prepared by mixing various ratios of two different liposomes-one containing a phospholipid with a primary amine group and a biotinyl group (BIO/NH 2 -Lip) and one containing a phospholipid with an N-hydroxysuccinimide group (NHS-Lip) to allow binding between particles via amide bonds. Quartz crystal microbalance analysis using SA-modified gold-coated quartz crystals showed that the frequency shift values of MPB-Lips gradually decreased in the order BIO/NH 2 -Lip:NHS-Lip = 1:0 < 1:1 < 1:3 < 1:5. This indicated that MPB-Lips were successfully formed. The indirect competitive ECL method using SA-modified gold electrodes showed that the 1:5-Lip system had greater sensitivity than the 1:0-Lip system-the limit of detection and quantification values for the systems were 1.84 and 6.30 μg mL -1 for 1:0-Lip, and 1.20 and 1.74 μg mL -1 for 1:5-Lip. Finally, the recovery of SA spiked in fetal bovine serum samples using the 1:5-Lip system showed good accuracy and precision with a recovery rate of 83-106% and relative standard deviation of 4-14%. Our study demonstrated that the MPB-Lips system was an effective and useful ECL amplifier and the ECL method using MPB-Lips could be applied to detect an analyte in a real sample., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Current methods for therapeutic drug monitoring (TDM) have a long turnaround time as they involve collecting patients' blood samples followed by transferring the samples to medical laboratories where sample processing and analysis are performed. To enable real-time and minimally invasive TDM, a microneedle (MN) biosensor to monitor the levels of two important antibiotics, vancomycin (VAN) and gentamicin (GEN) is developed. The MN biosensor is composed of a hydrogel MN (HMN), and an aptamer-functionalized flexible (Flex) electrode, named HMN-Flex. The HMN extracts dermal interstitial fluid (ISF) and transfers it to the Flex electrode where sensing of the target antibiotics happens. The HMN-Flex performance is validated ex vivo using skin models as well as in vivo in live rat animal models. Data is leveraged from the HMN-Flex system to construct pharmacokinetic profiles for VAN and GEN and compare these profiles with conventional blood-based measurements. Additionally, to track pH and monitor patient's response during antibiotic treatment, an HMN is developed that employs a colorimetric method to detect changes in the pH, named HMN-pH assay, whose performance has been validated both in vitro and in vivo. Further, multiplexed antibiotic and pH detection is achieved by simultaneously employing the HMN-pH and HMN-Flex on live animals., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Animal diseases are a major concern to animal welfare, human health and the global economy. Early detection, prevention and control of these animal diseases are crucial to ensure sustainability of livestock sector, to reduce farm losses and protecting public health. Points of care (POC) devices are small, portable instruments that provide rapid results thus reduce the risk of disease transmission and enable early intervention. CRISPR based diagnostics offer more accurate and efficient solution for monitoring animal health due to their quick response, can detect very low level of pathogenic organism or disease markers and specificity. These diagnostics are particularly useful in the in area with limited resources or access to common diagnostic methods, especially in developing countries. The ability of electrochemical sensors to detect accurately very low analyte concentration makes them suitable for POC diagnostics and field application. CRISPR base electrochemical biosensors show great potential in revolutionizing disease detection and diagnosis including animal health. However, challenges, such as achieving selectivity and sensitivity, need to be addressed to enhance the competitiveness of these biosensors. Currently, most CRISPR based bioassay research focuses on nucleic acid target detection, but researchers exploring to monitor small organic/inorganic non-nucleic acid molecules like toxins and proteins. Emerging diagnostics would be centered on CRISPR-Cas system will offer great potential as an accurate, specific and effective means to identify microorganism, virus, toxins, small molecules, peptides and nucleic acid related to various animal health disorders particularly when integrated into electrochemical biosensing platform., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Reusable point-of-care biosensors offer a cost-effective solution for serial biomarker monitoring, addressing the critical demand for tumour treatments and recurrence diagnosis. However, their realization has been limited by the contradictory requirements of robust reusability and high sensing capability to multiple interactions among transducer surface, sensing probes and target analytes. Here we propose a drug-mediated organic electrochemical transistor as a robust, reusable epidermal growth factor receptor sensor with striking sensitivity and selectivity. By electrostatically adsorbing protonated gefitinib onto poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and leveraging its strong binding to the epidermal growth factor receptor target, the device operates with a unique refresh-in-sensing mechanism. It not only yields an ultralow limit-of-detection concentration down to 5.74 fg ml -1 for epidermal growth factor receptor but, more importantly, also produces an unprecedented regeneration cycle exceeding 200. We further validate the potential of our devices for easy-to-use biomedical applications by creating an 8 × 12 diagnostic drug-mediated organic electrochemical transistor array with excellent uniformity to clinical blood samples., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Real-time detection of renal biomarkers is crucial for immediate and continuous monitoring of kidney function, facilitating early diagnosis and intervention in kidney-related disorders. This proactive approach enables timely adjustments in treatment plans, particularly in critical situations, and enhances overall patient care. Wearable devices emerge as a promising solution, enabling non-invasive and real-time data collection. This comprehensive review investigates numerous types of wearable sensors designed to detect kidney biomarkers in body fluids such as sweat. It critically evaluates the precision, dependability, and user-friendliness of these devices, contemplating their seamless integration into daily life for continuous health tracking. The review highlights the potential influence of wearable technology on individualized renal healthcare and its role in preventative medicine while also addressing challenges and future directions. The review's goal is to provide guidance to academics, healthcare professionals, and technologists working on wearable solutions for renal biomarker detection by compiling the body of current knowledge and advancements., (© 2024. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

In this study, we developed a wearable nanozyme-enzyme electrochemical biosensor that enablies sweat lactate monitoring. The biosensor comprises a flexible electrode system prepared on a polyimide (PI) film and the Janus textile for unidirectional sweat transport. We obtained favorable electrochemical activities for hydrogen peroxide reduction by modifying the laser-scribed graphene (LSG) electrode with cerium dioxide (CeO 2 )-molybdenum disulphide (MoS 2 ) nanozyme and gold nanoparticles (AuNPs). By further immobilisation of lactate oxidase (LOx), the proposed biosensor achieves chronoamperometric lactate detection in artificial sweat within a range of 0.1-50.0 mM, a high sensitivity of 25.58 μA mM -1 cm -2 and a limit of detection (LoD) down to 0.135 mM, which fully meets the requirements of clinical diagnostics. We demonstrated accurate lactate measurements in spiked artificial sweat, which is consistent with standard ELISA results. To monitor the sweat produced by volunteers while exercising, we conducted on-body tests, showcasing the wearable biosensor's ability to provide clinical sweat lactate diagnosis for medical treatment and sports management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: Due to most likely use of Bacillus anthracis in biological terrorism agents, the rapid and sensitive detection of its spores is crucial in both taking prophylactic measures and proper treatment. This study aimed to develop an amperometric electrochemical immunosensor for the detection of B. anthracis spores., Methods: A new amperometric biosensor was designed using a combination of magnetic beads and multiplex screen-printed electrodes. This method measures changes in current intensity resulting from oxidation and reduction in the working electrode directly to spore concentrations., Results: A standard curve was formed to test the number of live spores between 2 × 102-2 × 104 spores/ml concentrations. LOD and LOQ values were found to be 92 and 272 spores/ml, respectively. No cross-reactions were seen for Bacillus subtilis, Bacillus cereus and Bacillus thuringiencis spores., Conclusions: It is shown that the designed Anthrax immunosensor has high sensitivity and selectivity with rapid detection results., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Chloramphenicol (CAP) poses a threat to human health due to its toxicity and bioaccumulation, and it is very important to measure it accurately and sensitively. This work explored a host-guest recognition strategy to mediate dual aggregation-induced electrochemiluminescence (AIECL) of 1,1,2,2-tetrakis(4-(pyridin-4-yl) phenyl)-ethene (TPPE) for ratio detection of CAP, in which, cucurbit[8]uril (CB[8]) served as host to assemble guest TPPE. The resulting supramolecular complex CB[8]-TPPE exhibited excellent dual-AIECL-emission with signal strength approximately four times that of TPPE aggregates and black hole quencher-1 (BHQ1) could efficiently quench dual-AIECL signal. CB[8]-TPPE coupled dual-function quencher BHQ1 and high-efficiency DNA reactor to achieve ultra-sensitive detection of CAP, exhibiting a linearity range of 10 fmol·L -1 -100 nmol·L -1 and limit of detection of 1.81 fmol·L -1 . CB[8]-TPPE provides a novel way to improve the dual-emission of TPE derivatives and sets up a promising platform for CAP detection, demonstrating a good practical application potential., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Despite the beneficial effects of antibiotics such as chloramphenicol (CAP), they exert some destructive impacts on human health. We designed an electrochemical sensor based on reduced graphene oxide (rGO)/Au/Co 2 CuS 4 nanohybrid for determination of CAP in food and biological samples. The Co 2 CuS 4 was synthesized from binuclear metal-organic framework (CoCu-BDC) through a two-step process. Nanohybrid was characterized by X-ray photoelectron spectroscopy and transmission electron microscopy. The rGO/Au/Co 2 CuS 4 provides more active sites and good electrical conductivity to reduce charge transfer resistance and improve the electrocatalytic activity for determination of CAP. The prepared sensor has a wide linear range from 7 to 141 nM with a limit of detection of 2.5 nM and a limit of quantification of 21.92 nM. It also provided high selectivity and repeatability with a relative standard deviation of 2.6%. Stability studies showed that the electrode has acceptable performance with efficiency of 95% after 33 days., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Endothelial cells are sensitive to mechanical force and can convert it into biochemical signals to trigger mechano-chemo-transduction. Although conventional techniques have been used to investigate the subsequent modifications of cellular expression after mechanical stimulation, the in situ and real-time acquiring the transient biochemical information during mechanotransduction process remains an enormous challenge. In this work, we develop a flexible and multi-functional three-dimensional conductive scaffold that integrates cell growth, mechanical stimulation, and electrochemical sensing by in situ growth of enokitake-like Au nanowires on a three-dimensional porous polydimethylsiloxane substrate. The conductive scaffold possesses stable and desirable electrochemical sensing performance toward nitric oxide under mechanical deformation. The prepared e-AuNWs/CC/PDMS scaffold exhibits a good electrocatalytic ability to NO with a linear range from 2.5 nM to 13.95 μM and a detection limit of 8 nM. Owing to the excellent cellular compatibility, endothelial cells can be cultured directly on the scaffold and the real-time inducing and recording of nitric oxide secretion under physiological and pathological conditions were achieved. This work renders a reliable sensing platform for real-time monitoring cytomechanical signaling during endothelial mechanotransduction and is expected to promote other related biological investigations based on three-dimensional cell culture., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)