Sensitive and selective electrochemical determination of uric acid in urine based on ultrasmall iron oxide nanoparticles decorated urchin-like nitrogen-doped carbon

Recent advances in the detection of microplastics in the aqueous environment by electrochemical sensors: A review

Microplastics (MPs), as an emerging contaminant, have become a serious threat to marine ecosystems due to their small size, widespread distribution and easy ingestion by organisms. Therefore, it is necessary to develop various analytical techniques to detect MPs in real water environment. Among these detection techniques, the advantages of electrochemical sensors, such as easy operation, high sensitivity and low cost, provide the possibility of online real-time detection of MPs in real water environment. The aim of this article is to analyze and compare the advantages and disadvantages of different MPs detection techniques. Compilation of various electrochemical sensors, we compiled various electrochemical sensors, evaluated the recent advances in carbon materials, metals and their oxides, biomass materials, composite materials, and microfluidic chips in electrochemical sensors for detecting MPs, and in-depth investigated their detection mechanisms and sensing performances, proposed hotspot nanomaterials for electrochemical sensors that could be used to detecting MPs and gave an outlook on the last years of electrochemical sensors in the area of microplastic detection. Finally, the challenges of electrochemical sensors for the detection of MPs are discussed and perspectives for this area are presented.

Electrochemical Determination of Dipyrone Using a Cold-Plasma-Treated Graphite Sheet Electrode

The development of fast, reliable, and cost-effective techniques for pharmaceutical compound analysis is an issue of paramount importance to the pharmaceutical industry, environmental sciences, and many other applications. In this work, a low-cost graphite sheet electrode (GSE) was used as a disposable working electrode. To this purpose, the GSE surface was subjected to a cold plasma discharge using a mixture of argon and O2. The sensor was applied to dipyrone (DIP) quantification. Initially, the influence of pH on the electrochemical response of DIP on the pyrolytic graphite sheet (PGS) electrodes was evaluated using a 0.12 mol L-1 Britton-Robinson buffer solution at pH values ranging from 2.0 to 12.0. The solution adjusted to pH 4.0 was selected as the supporting electrolyte for the experiments since a larger current intensity was obtained at this medium. The mass transport of DIP toward the PGS surface was investigated by cyclic voltammetry, evidencing a diffusion-controlled process. DIP was initially quantified by square wave voltammetry (SWV) with a linear range of about 2.5-200 μmol L-1 and a calculated limit of detection of about 0.31 μmol L-1. Finally, SWV was used to enable DIP detection in synthetic urine solutions, demonstrating its applicability as a sensor tool in real analysis.

Iron-based electrode material composites for electrochemical sensor application in the environment: A review

This review explores the expanding role of electrochemical sensors across diverse domains such as environmental monitoring, medical diagnostics, and food quality assurance. In recent years, iron-based electrocatalysts have emerged as promising candidates for enhancing sensor performance. Notable for their non-toxicity, abundance, catalytic activity, and cost-effectiveness, these materials offer significant advantages. However, further investigation is needed to fully understand how iron-based materials' physical, chemical, and electrical properties influence their catalytic performance in sensor applications. It explores the overview of electrochemical sensor technology, examines the impact of iron-based materials and their characteristics on catalytic activity, and investigates various iron-based materials, their advantages, functionalization, and modification techniques. Additionally, the review investigates the application of iron-based electrode material composites in electrochemical sensors for real sample detections. Ultimately, continued research and development in this area promise to unlock new avenues for using iron-based electrode materials in sensor applications.

Cost-effective quantification of uric acid using niobium oxide and graphene oxide-modified pencil-drawn electrodes on PVC substrates

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.

The concentration of pesticides in onion samples from Iran: a non-carcinogenic health risk assessment

Pesticide residues were extracted using the QuEChERS method, followed by detection by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The non-carcinogenic health risk in adult and child consumers was calculated by target hazard quotient (THQ) and total target hazard quotient (TTHQ) in the Monte Carlo Simulation (MCS) method. The rank order of pesticides detected by UHPLC-MS/MS based on median concentration in onion was tebuconazole (0.004551 mg/kg) > imidacloprid (0.00233 mg/kg) > boscalid (0.00211 mg/kg) > diazinon (0.00079 mg/kg) > thiabendazole (0.00075 mg/kg) > acetamiprid (0.00052 mg/kg) > thiophanate-methyl (0.00052 mg/kg) > dichlorvos (0.000349 mg/kg) > fenitrothion (0.000132 mg/kg) > penconazole (0.00005 mg/kg). The median of TTHQ in adults and children's consumers were 4.00E-3 and 2.00E-2, respectively. TTHQ in adults and children's consumers was lower than 1 value. Hence, consumers were in the acceptable range (TTHQ <1). Consequently, onion consumption cannot endanger consumers' health status due to the pesticide residues.

Highly Specific Non-Enzymatic Electrochemical Sensor for the Detection of Uric Acid Using Carboxylated Multiwalled Carbon Nanotubes Intertwined with GdS-Gd2O3 Nanoplates in Human Urine and Serum

Herein, the electrochemical sensing efficacy of carboxylic acid functionalized multiwalled carbon nanotubes (C-MWCNT) intertwined with coexisting phases of gadolinium monosulfide (GdS) and gadolinium oxide (Gd2O3) nanosheets is explored for the first time. The nanocomposite demonstrated splendid specificity for nonenzymatic electrochemical detection of uric acid (UA) in biological samples. It was synthesized using the coprecipitation method and thoroughly characterized. The presence of functional groups and disorder in the as-synthesized nanocomposite are confirmed using Fourier transform infrared spectroscopy and Raman spectroscopy. Furthermore, field emission scanning electron microscopy, high-resolution transmission electron microscope, X-ray powder diffraction, and X-ray photoelectron spectroscopy provides a clear understanding of the morphology, coexisting phases, and elemental composition of the as-synthesized nanocomposites. The differential pulse voltammetry technique was utilized to elaborate the electrochemical sensing of UA using a GdS-Gd2O3/C-MWCNT modified glassy carbon electrode (GCE), The sensor showed an enhanced current response by more than 2-fold compared to bare GCE. Also, the sensor's performance was further improved by dispersing the nanocomposite in an ionic liquid with the exceptional reproducibility (SD = 0.0025, n = 3). The fabricated UA sensor GdS-Gd2O3/C-MWCNT/IL/GCE demonstrated a wide linear detection range from 0.5-30 μM and 30-2000 μM, effectively covering the entire physiological range of UA in biological fluids with a limit of detection (LOD) of 0.380 μM (+3SD of blank) and a sensitivity of 356.125 μA mM-1 cm-2. Moreover, the electrodes exhibited storage stability for 2 weeks with decrease in zero-day current by only 4.5%. The sensor was validated by quantifying UA in 12 unprocessed clinical human urine and serum samples, and its comparison with the gold standard test yielded remarkable results (p < 0.05). Hence, the proposed nonenzymatic electrochemical UA sensor is selective, sensitive, reproducible, and stable, making it reliable for point-of-care diagnostics.

Sulfonated-polypyrene aniline/polyaniline composite fortified with Cu-GQD@ZIF8 as an electrochemical enzymatic urea biosensor

The determination of urea concentration is essential for human health owing to its crucial role in the ability to metabolize nitrogen-containing substances. This study developed new electrochemical enzymatic detection systems via the synergistic effect of the superior features of novel electropolymerizable pyranine-aniline (PA, 4), polyaniline (PANI) compounds, graphene quantum dots (GQDs) and zeolitic imidazolate framework-8 (ZIF8). The novel compound 4 was characterized via1H-NMR, 13C-NMR, FTIR, and MALDI-TOF mass spectroscopies. Furthermore, Cu-GQD@ZIF8 hybrid materials containing GQD and integrated electroactive Cu metal were prepared in this study. The surface morphology of the prepared Cu-GQD@ZIF8 hybrid material was investigated through microscopic methods such as SEM and TEM, and chemical characterizations were performed using FTIR, XPS, XRD, and TGA analyses. After the characterization of the novel materials, the urease (Urs) enzyme was bound to the new modified electrode surface. Next, the enzymatic biosensor properties of the Urs/Cu-GQD@ZIF8/PANI/PA/GCE sensor electrode for urea detection via reduction of PANI were investigated by DPV and CV techniques. The LOD and LOQ values of the presented sensor were calculated to be 0.77 μM and 2.31 μM, respectively, in the linear range of 1.0-80.0 μM, based on DPV measurements. The presented biosensor system determined the amount of urea in an artificial serum sample, and its accuracy was confirmed via the recovery test and GC-MS analysis.

Human and ecological risk assessments of potentially toxic elements in sediments around a pharmaceutical industry

Potentially toxic elements (PTEs) in sediment can be highly hazardous to the environment and public health. This study aimed to assess the human and ecological risks of PTEs in sediments around a pharmaceutical industry in Ilorin, Nigeria. Physicochemical parameters and the concentrations of lead (Pb), chromium (Cr), cadmium (Cd), cobalt (Co), arsenic (As), and nickel (Ni) were analyzed in sediment samples collected from seven locations in the wet and dry seasons. Standard two-dimensional principal component analysis (PCA) and risk assessments were also conducted. The concentrations of Pb, Co, Ni, Cr, Cd, and As in the sediments ranged from 0.001 to 0.031 mg/kg, 0-0.005 mg/kg, 0.005-0.012 mg/kg, 0.001-0.014 mg/kg, 0.005-0.024 mg/kg, and 0.001-0.012 mg/kg, respectively. The mean concentrations of the total PTEs content were found in decreasing order of concentration: Pb > Cd > Ni > Cr > As > Co. PCA showed that some of the PTEs were highly concentrated in samples obtained at other locations as well as at the discharge point. The Hazard Index was mostly <1 across locations, indicating little to no probable non-cancerous effect. However, the incremental lifetime cancer risk for arsenic and nickel was high and required attention. The ecological risk assessment showed that lead and arsenic were the major PTEs pollutants in all locations. The study identifies PTEs profiles in sediments and emphasises the necessity of continual monitoring and action to stop long-term negative impacts on the local environment and public health.

Development of a Diethylcarbamazine Citrate‐Based Electrochemical Sensor for Quick and Affordable Detection of Sulfadiazine and Uric Acid in Environmental Monitoring

The widespread use of antibiotics like sulfadiazine (SDZ) in various industries has raised environmental and health concerns due to their potential for bioaccumulation and the subsequent effects on human health and the environment. Diethylcarbamazine citrate (DCZ), a well‐established antifilarial drug, has yet to be explored as a sensing agent despite its extensive use. This study proposes a cost‐effective and efficient method for detecting SDZ and Uric acid (UA) using a DCZ‐modified carbon paste electrode (poly‐DCZ/MCPE). The poly‐DCZ film is synthesized via cyclic voltammetry (CV) on the carbon paste electrode surface, demonstrating excellent electrocatalytic activity for SDZ and UA detection at pH 7.4. The diffusion‐controlled electrode process is observed with a lower limit of detection (LOD) and limit of quantification (LOQ) for SDZ as 3.8×10−9 M and 12.94×10−9 M respectively. For UA, LOD and LOQ were found to be 6.291×10−9 M and 20.97×10−9 M respectively at the poly‐DCZ/MCPE. Notably, the sensor exhibits simultaneous detection capabilities for SDZ and UA by CV and differential pulse voltammetry (DPV) methods, addressing the need to monitor antibiotic residues in aquatic ecosystems and animal‐derived products.

A Novel Electrochemical Sensor Based on Pd Confined Mesoporous Carbon Hollow Nanospheres for the Sensitive Detection of Ascorbic Acid, Dopamine, and Uric Acid

In this study, we designed a novel electrochemical sensor by modifying a glass carbon electrode (GCE) with Pd confined mesoporous carbon hollow nanospheres (Pd/MCHS) for the simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The structure and morphological characteristics of the Pd/MCHS nanocomposite and the Pd/MCHS/GCE sensor are comprehensively examined using SEM, TEM, XRD and EDX. The electrochemical properties of the prepared sensor are investigated through CV and DPV, which reveal three resolved oxidation peaks for AA, DA, and UA, thereby verifying the simultaneous detection of the three analytes. Benefiting from its tailorable properties, the Pd/MCHS nanocomposite provides a large surface area, rapid electron transfer ability, good catalytic activity, and high conductivity with good electrochemical behavior for the determination of AA, DA, and UA. Under optimized conditions, the Pd/MCHS/GCE sensor exhibited a linear response in the concentration ranges of 300-9000, 2-50, and 20-500 µM for AA, DA, and UA, respectively. The corresponding limit of detection (LOD) values were determined to be 51.03, 0.14, and 4.96 µM, respectively. Moreover, the Pd/MCHS/GCE sensor demonstrated outstanding selectivity, reproducibility, and stability. The recovery percentages of AA, DA, and UA in real samples, including a vitamin C tablet, DA injection, and human urine, range from 99.8-110.9%, 99.04-100.45%, and 98.80-100.49%, respectively. Overall, the proposed sensor can serve as a useful reference for the construction of a high-performance electrochemical sensing platform.

Electrochemical sensors modified with iron oxide nanoparticles/nanocomposites for voltammetric detection of Pb (II) in water: A review

Permissible limits of Pb2+ in drinking water are being reduced from 10 μgL-1 to 5 μgL-1, which calls for rapid, and highly reliable detection techniques. Electrochemical sensors have garnered attention in detection of heavy metal ions in environmental samples due to their ease of operation, low cost, and rapid detection responses. Selectivity, sensitivity and detection capabilities of these sensors, can be enhanced by modifying their working electrodes (WEs) with iron oxide nanoparticles (IONPs) and/or their composites. Therefore, this review is an in-depth analysis of the deployment of IONPs/nanocomposites in modification of electrochemical sensors for detection of Pb2+ in drinking water over the past decade. From the analyzed studies (n = 23), the optimal solution pH, deposition potential, and deposition time ranged between 3 and 5.6, -0.7 to -1.4 V vs Ag/AgCl, and 100-400 s, respectively. Majority of the studies employed square wave anodic stripping voltammetry (n = 16), in 0.1 M acetate buffer solution (n = 19) for detection of Pb2+. Limits of detection obtained (2.5 x 10-9 - 4.5 μg/L) were below the permissible levels which indicated good sensitivities of the modified electrodes. Despite the great performance of these modified electrodes, the primary source of IONPs has always been commercial iron-based salts in addition to the use of so many materials as modifying agents of these IONPs. This may limit reproducibility and sustainability of the WEs due to lengthy and costly preparation protocols. Steel and/or iron industrial wastes can be alternatively employed in generation of IONPs for modification of electrochemical sensors. Additionally, biomass-based activated carbons enriched with surface functional groups are also used in modification of bare IONPs, and subsequently bare electrodes. However, these two areas still need to be fully explored.

Sensing potential of C6N8 for ammonia (NH3) and nitrogen triflouride (NF3): A DFT study

The detection of toxic gases (NH3 and NF3) in regulating and monitoring air quality in the atmosphere has drawn a lot of attention. Herein, we explored a novel material (C6N8) for the detection of the important but toxic gases (NH3 and NF3). We investigated the interactions of the NH3 and NF3 with C6N8 through DFT at B3LYP, ωB97XD, and non-DFT M06-2X. Counterpoise interaction energy values (Eint. cp.) of NH3@C6N8 and NF3@C6N8 are -0.45 eV and -3.51 eV (for B3LYP), -0.42 eV and 2.11 eV (for ωB97XD) and -0.44 eV and -3.41eV (for M06-2X), respectively. Complexes having the most stable configurations were then subjected to further analyses including frontier molecular orbitals, H-L gap, and conductivity of complexes. An increase in the H-L gap in complexes (NH3@C6N8 and NF3@C6N8) is observed. The conductivity of NH3@C6N8 and NF3@C6N8 decreases as compared to C6N8. A considerable change in dipole moment was seen in C6N8 before and after complex formation. This is because of the shifting of charge between C6N8 and gases (NH3 and NF3). CHELPG and NBO charge analysis were used to evaluate the amount of charge transfer between C6N8 and gases. These analyses demonstrate that NH3 and NF3 withdraw electron density from C6N8. It was found that NH3 tends to be physically adsorbed on C6N8 while NF3 adsorbs chemically on C6N8. NCI and QTAIM analyses were performed to investigate the kind of interactions between the surface (C6N8) and gases (NH3 and NF3). Furthermore, the recovery time of NH3@C6N8 and NF3@C6N8 shows that C6N8 can be a better choice for sensing NH3 and NF3 gases.

Flow-Through Amperometric Biosensor System Based on Functionalized Aryl Derivative of Phenothiazine and PAMAM-Calix-Dendrimers for the Determination of Uric Acid

A flow-through biosensor system for the determination of uric acid was developed on the platform of flow-through electrochemical cell manufactured by 3D printing from poly(lactic acid) and equipped with a modified screen-printed graphite electrode (SPE). Uricase was immobilized to the inner surface of a replaceable reactor chamber. Its working volume was reduced to 10 μL against a previously reported similar cell. SPE was modified independently of the enzyme reactor with carbon black, pillar[5]arene, poly(amidoamine) dendrimers based on the p-tert-butylthiacalix[4]arene (PAMAM-calix-dendrimers) platform and electropolymerized 3,7-bis(4-aminophenylamino) phenothiazin-5-ium chloride. Introduction of the PAMAM-calix-dendrimers into the electrode coating led to a fivefold increase in the redox currents of the electroactive polymer. It was found that higher generations of the PAMAM-calix-dendrimers led to a greater increase in the currents measured. Coatings consisted of products of the electropolymerization of the phenothiazine with implemented pillar[5]arene and PAMAM-calix-dendrimers showing high efficiency in the electrochemical reduction of hydrogen peroxide that was formed in the enzymatic oxidation of uric acid. The presence of PAMAM-calix-dendrimer G2 in the coating increased the redox signal related to the uric acid assay by more than 1.5 times. The biosensor system was successfully applied for the enzymatic determination of uric acid in chronoamperometric mode. The following optimal parameters for the chronoamperometric determination of uric acid in flow-through conditions were established: pH 8.0, flow rate 0.2 mL·min-1, 5 U of uricase per reactor. Under these conditions, the biosensor system made it possible to determine from 10 nM to 20 μM of uric acid with the limit of detection (LOD) of 4 nM. Glucose (up to 1 mM), dopamine (up to 0.5 mM), and ascorbic acid (up to 50 μM) did not affect the signal of the biosensor toward uric acid. The biosensor was tested on spiked artificial urine samples, and showed 101% recovery for tenfold diluted samples. The ease of assembly of the flow cell and the low cost of the replacement parts make for a promising future application of the biosensor system in routine clinical analyses.

Spatial distribution and seasonal variation of trace hazardous elements contamination in the coastal environment

Groundwater is the second largest water source for daily consumption, only next to surface water resources. Groundwater has been extensively investigated for its pollution level in urban areas. The groundwater quality assessments in industrial areas associated with every urban landscape are still lacking. In order to examine the spatial distribution characteristics, pollution levels, and sources of trace metals in the densely populated Chennai coastal region of Tamilnadu, India, physicochemical parameters and trace element concentrations have been determined in groundwater. 55 groundwater samples from Tamil Nadu's coastal region were collected and analyzed for physicochemical parameters such as pH, (EC), (TDS), and (TH) during the pre-monsoon (June 2015) and post-monsoon (January 2016) seasons. We used trace elements and analyzed them in this study (Mg, Zn, Pb, Ni, Co, Cu, Cr, and Fe). Furthermore, anthropogenic input from industries and power plants exacerbates the pollution of Ni, Mg, Fe, and Mn. Due to evaporites and anthropogenic input, samples with excessive salinity, total hardness, and water quality are considered unsuitable for irrigation or drinking. The results demonstrated that seasonal, geogenic, and anthropogenic influences all have a significant impact on the heterogeneous chemistry of groundwater.

Hydrolytic degradation and biodegradation of polylactic acid electrospun fibers

Increased use of bioplastics, such as polylactic acid (PLA), helps in reducing greenhouse gas emissions, decreases energy consumption and lowers pollution, but its degradation efficiency has much room for improvement. The degradation rate of electrospun PLA fibers of varying diameters ranging from 0.15 to 1.33 μm is measured during hydrolytic degradation under different pH from 5.5 to 10, and during aerobic biodegradation in seawater supplemented with activated sewage sludge. In hydrolytic conditions, varying PLA fiber diameter had significant influence over percentage weight loss (W%L), where faster degradation was achieved for PLA fibers with smaller diameter. W%L was greatest for PLA-5 > PLA-12 > PLA-16 > PLA-20, with average W%L at 30.7%, 27.8%, 17.2% and 14.3% respectively. While different pH environment does not have a significant influence on PLA degradation, with W%L only slightly higher for basic environments. Similarly biodegradation displayed faster degradation for small diameter fibers with PLA-5 attaining the highest degree of biodegradation at 22.8% after 90 days. Hydrolytic degradation resulted in no significant structural change, while biodegradation resulted in significant hydroxyl end capping products on the PLA surface. Scanning electron microscopy (SEM) imaging of degraded PLA fibers showed a deteriorated morphology of PLA-5 and PLA-12 fibers with increased adhesion structures and irregularly shaped fibers, while a largely unmodified morphology for PLA-16 and PLA-20.

A probabilistic health risk assessment of potentially toxic elements in edible vegetable oils consumed in Hamadan, Iran

In this study, potential toxic element (PTEs) including lead (Pb), arsenic (As), cadmium(Cd), iron (Fe) and zinc (Zn) in traditional and industrial edible vegetable oils (peanut, sunflower, olive and sesame) collected from Hamadan, west of Iran were determined using Inductivity Coupled Plasma Optical Emission Spectrometry (ICP-OES). Besides, probabilistic health risk assessment (non-carcinogenic and carcinogenic risks) was identified via total target hazard quotient (TTHQ) and cancer risk (CR) by the Monte Carlo Simulation (MCS) model. The ranking of concentration PTEs in traditional and industrial edible vegetable oils was Fe > Zn > As > Pb > Cd. The in all samples, content of PTEs in industrial oils were upper than traditional oils (p < 0.001). The level of PTEs in most of vegetable oils was lower than permissible concentration regulated by Codex and national standard. In term of non-carcinogenic, consumers were at acceptable range (TTHQ < 1) due to ingestion both traditional and industrial vegetable oils content of PTEs. In term of carcinogenic, CR the both adults and children was higher than acceptable range (CR < 1E-6), Hence consumer are at unacceptable risk due to ingestion industrial vegetable oils content of inorganic As. Therefore, it is recommended to implement control plans for PTEs in vegetable oils consumed in Hamadan, Iran.

Construction and characterization of a magnetic nanoparticle-supported Cu complex: a stable and active nanocatalyst for synthesis of heteroaryl-aryl and di-heteroaryl sulfides

Diaryl and di-heteroaryl sulfides exist in the structure of many drugs and important biological compounds, also these compounds are well-known in medicinal chemistry due to important biological and pharmaceutical activities. Therefore, the development of novel, ecofriendly and efficient catalytic systems for the preparation of diaryl and di-heteroaryl sulfides is a very attractive and important challenge in organic synthesis. In this attractive methodology, we wish to introduce Fe3O4-supported 3-amino-4-mercaptobenzoic acid copper complex (Fe3O4@AMBA-CuI) nanomaterials as a novel and efficient magnetically recoverable catalyst for the preparation of heteroaryl-aryl and di-heteroaryl sulfides with high yields through reaction of heteroaryl halides with aryl or heteroaryl boronic acids and S8 as the sulfur source under ecofriendly conditions. This catalytic system was very efficient and practical for a diverse range of heteroaryl substrates including benzothiazole, benzoxazole, benzimidazole, oxadiazole, benzofuran, and imidazo[1,2-a]pyridine, because the desired diaryl and di-heteroaryl sulfides were prepared with high yields. The reusability-experiments revealed that the Fe3O4@AMBA-CuI nanocatalyst can be magnetically separated and reused at least six times without a significant decrease in its catalytic activity. VSM and ICP-OES analyses confirmed that despite using the Fe3O4@AMBA-CuI nanocatalyst 6 times, the magnetic properties and stability of the catalyst were still maintained. Although all the obtained heteroaryl-aryl and di-heteroaryl sulfide products are known and previously reported, the synthesis of this number of heteroaryl-aryl and di-heteroaryl sulfides has never been reported by any previouse methods.

A wide-range UAC sensor for the classification of hyperuricemia in spot samples

Hyperuricemia (HUA) has received wide attention as an independent risk factor for various chronic diseases. HUA is usually asymptomatic, and the related damage can be reduced by effective classification and treatment according to uric acid clearance (UAC). UAC is a calculated ratio based on the uric acid level in blood and urine. This important method is not universally used due to the inconvenience of collecting 24-h urine samples in the clinic, and most sensors are limited by the need for wide ranges and for two testing samples. In this study, a pH-sensitive urate oxidase-modified electrochemical sensor with filter membrane was proposed to calculate UAC by detecting uric acid in blood and urine. The results demonstrated that the sensor had high selectivity for uric acid with a detection limit of 0.25 μM in 5 μL spot sample, the wide linear range was 2.5-7000 μM, and the impact of the sample pH was calibrated. The linear correlation of the measurement results between the UAC sensor and clinical instrument was higher than 0.980 for 87 patients. The change in UAC in spot urine may reflect alteration in body-transport mechanisms. Thus, the UAC sensor may open a new window for the management of HUA and broaden its application in point-of-care testing.

A graphene oxide/polyaniline nanocomposite biosensor: synthesis, characterization, and electrochemical detection of bilirubin

The level of free bilirubin is a considerable index for the characterization of jaundice-related diseases. Herein, a biosensor was fabricated via the immobilization of bilirubin oxidase (BOx) on graphene oxide (GO) and polyaniline (PANI) that were electrochemically co-precipitated on indium tin oxide (ITO) conductive glass. The structural enzyme electrode was characterized by FTIR, XRD, and Raman spectroscopy, while the spectral and thermal properties were investigated by UV-vis and thermogravimetric analysis (TGA). Owing to the activity of the fabricated BOx/GO@PANI/ITO biosensor, it could detect free bilirubin with good selectivity and sensitivity in a low response time. The electrochemical response was studied using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). At polarization potential 0.2 V vs. Ag/AgCl, the fabricated sensor illustrated a response in only 2 s at 30 °C and pH 7.5. The LOD and LOQ for the BOx/GO@PANI/ITO biosensor were calculated and found to be 0.15 nM and 2.8 nM, respectively. The electrochemical signal showed a linear response in the concentration range 0.01-250 μM. At 5 °C, the biosensor demonstrated a half-time of 120 days, through which it could be utilized 100 times at this temperature conditions. By using a common colorimetric method, the data on bilirubin levels in serum showed a determination coefficient (R2) of 0.97.

Predicting water quality through daily concentration of dissolved oxygen using improved artificial intelligence

As an important hydrological parameter, dissolved oxygen (DO) concentration is a well-accepted indicator of water quality. This study deals with introducing and evaluating four novel integrative methods for the prediction of DO. To this end, teaching-learning-based optimization (TLBO), sine cosine algorithm, water cycle algorithm (WCA), and electromagnetic field optimization (EFO) are appointed to train a commonly-used predictive system, namely multi-layer perceptron neural network (MLPNN). The records of a USGS station called Klamath River (Klamath County, Oregon) are used. First, the networks are fed by the data between October 01, 2014, and September 30, 2018. Later, their competency is assessed using the data belonging to the subsequent year (i.e., from October 01, 2018 to September 30, 2019). The reliability of all four models, as well as the superiority of the WCA-MLPNN, was revealed by mean absolute errors (MAEs of 0.9800, 1.1113, 0.9624, and 0.9783) in the training phase. The calculated Pearson correlation coefficients (RPs of 0.8785, 0.8587, 0.8762, and 0.8815) plus root mean square errors (RMSEs of 1.2980, 1.4493, 1.3096, and 1.2903) showed that the EFO-MLPNN and TLBO-MLPNN perform slightly better than WCA-MLPNN in the testing phase. Besides, analyzing the complexity and the optimization time pointed out the EFO-MLPNN as the most efficient tool for predicting the DO. In the end, a comparison with relevant previous literature indicated that the suggested models of this study provide accuracy improvement in machine learning-based DO modeling.

Influence of brassinosteroid and silicon on growth, antioxidant enzymes, and metal uptake of leafy vegetables under wastewater irrigation

Vegetable cultivation under sewage irrigation is a common practice mostly in developing countries due to a lack of freshwater. Long-term usage provokes heavy metals accumulation in soil and ultimately hinders the growth and physiology of crop plants and deteriorates the quality of food. A study was performed to investigate the role of brassinosteroid (BRs) and silicon (Si) on lettuce, spinach, and cabbage under lead (Pb) and cadmium (Cd) contaminated sewage water. The experiment comprises three treatments (control, BRs, and Si) applied under a completely randomized design (CRD) in a growth chamber. BRs and Si application resulted in the highest increase of growth, physiology, and antioxidant enzyme activities when applied under canal water followed by distilled water and sewage water. However, BRs and Si increased the above-determined attributes under the sewage water by reducing the Pb and Cd uptake as compared to the control. It's concluded that sewerage water adversely affected the growth and development of vegetables by increasing Pb and Cd, and foliar spray of Si and BRs could have great potential to mitigate the adverse effects of heavy metals and improve the growth. The long-term alleviating effect of BRs and Si will be evaluated in the field conditions at different ecological zones.

CO2 reduction reaction on Sc-doped nanocages as catalysts

CONTEXT

The catalytic ability of Sc-doped C46 and Sc-doped Al23P23 as catalysts of CO2-RR to create the CH4 and CH3OH is investigated. The mechanisms of CO2-RR are examined by theoretical methods and ΔGreaction of reaction steps of CO2-RR mechanisms are calculated. The overpotential of CH4 and CH3OH production on Sc-doped C46 and Sc-doped Al23P23 is calculated. The Sc atoms of Sc-doped C46 and Sc-doped Al23P23 can adsorb the CO2 molecule as the first step of CO2-RR. The CH4 is produced from hydrogenation of *CH3O and the *CO → *CHO reaction step is the rate limiting step for CH4 production. The CH3OH can be formed on Sc-doped C46 and Sc-doped Al23P23 by *CO → *CHO → *CH2O → *CH3O → CH3OH mechanism and HCOOH → *CHO → *CH2O → *CH3O → CH3OH mechanism. The Sc-C46 and Sc-Al23P23 can catalyze the CO2-RR to produce the CH4 and CH3OH by acceptable mechanisms.

METHODS

Here, the structures are optimized by PW91PW91/6-311+G (2d, 2p) and M06-2X/cc-pVQZ methods in GAMESS software. The frequencies of nanocages and their complexes with species of CO2-RR are investigated by mentioned methods. The transition state of each reaction step of CO2-RR is searched by Berny method to find the CO2-RR intermediates. The ∆Eadsorption of intermediates of CO2-RR on surfaces of nanocages is calculated and the ∆Greaction of reaction steps of CO2-RR is calculated.

Palladium complex supported on the surface of magnetic Fe3O4 nanoparticles: an ecofriendly catalyst for carbonylative Suzuki-coupling reactions

Diaryl ketone derivatives include well-known compounds with important physiological and biological properties. In order to prepare diaryl ketone derivatives, we constructed a pallidum (0) complex immobilized on Fe3O4 nanoparticles modified with aminobenzoic acid and phenanthroline [Fe3O4@ABA/Phen-DCA-Pd(0)], and evaluated its catalytic performance for carbonylative Suzuki-coupling reactions of aryl iodides with aryl boronic acid in the presence of Mo(CO)6 as the CO source under mild conditions. FT-IR, SEM, TEM, EDX, VSM, TGA, XRD, ICP-OES and Elemental mapping techniques were employed to identify the structure of the Fe3O4@ABA/Phen-DCA-Pd(0) nanocatalyst. Different derivatives of aryl iodides and aryl boronic acids containing withdrawing and donating functional groups were studied for the preparation of diaryl ketones. Also, various derivatives of heteroaryl iodides and boronic acids were used and the desired products were prepared with high yields. The Fe3O4@ABA/Phen-DCA-Pd(0) nanocatalyst was separated magnetically and reused 7 consecutive times without reducing its catalytic activity. VSM, TEM and ICP-OES spectroscopic techniques confirmed that the synthesized Fe3O4@ABA/Phen-DCA-Pd(0) catalyst was still stable and maintained its structure despite repeated reuse.

Upcycling spent palladium-based catalysts into high value-added catalysts via electronic regulation of Escherichia coli to high-efficiently reduce hexavalent chromium

Upgrading and recycling Palladium (Pd) from spent catalysts may address Pd resource shortages and environmental problems. In this paper, Escherichia coli (E. coli) was used as an electron transfer intermediate to upcycle spent Pd-based catalysts into high-perform hexavalent chromium bio-catalysts. The results showed that Pd (0) nanoparticles (NPs) combined with the bacterial surface changed the electron transfer by enhancing the cell conductivity, thus promoting the removal rate of Pd(II). The recovery efficiency of Pd exceeded 98.6%. Notably, E. coli heightened the adsorption of H• and HCOO• via electron transfer of the Pd NPs electron-rich centre, resulting in a higher catalytic performance of the recycled spent catalysed the reduction of 20 ppm Cr(VI) under mild conditions within 18 min, in which maintained above 98% catalytic activity after recycling five times. This efficiency was found to be higher than that of the reported Pd-based catalysts. Hence, an electron transfer mechanism for E. coli recovery Pd-based catalyst under electron donor adjusting is proposed. These findings provide an important method for recovering Pd NPs from spent catalysts and are crucial to effectively reuse Pd resources.

Room-Temperature Synthesis of Biogenic δ-MnO2 NPs for the Dehydrogenative Coupling of Diamines with Alcohols for Benzimidazole and Quinoxaline Synthesis: An Efficient Catalyst for Electrochemical Applications

An efficient, unique, and eco-friendly biogenic synthesis of single-crystalline δ-phase manganese oxide nanoparticles (MnO2 NPs) using Gliricidia sepium leaves (GSL) extract at room temperature has been revealed for the first time. The active chemicals present in the GSL extract were found to serve as both reducing and stabilizing agents. The catalyst shows an excellent surface area of 301.13 m2 g-1, a mean pore diameter of 4.01 nm, and 39.97% w/w of active metal content. The reactivity of the synthesized catalyst was demonstrated by achieving a one-pot synthesis of benzimidazoles and quinoxalines via an acceptorless dehydrogenative coupling strategy utilizing biorenewable alcohols. The release of hydrogen gas was observed as the only side product and proven by its successful utilization for alkene reduction which supports the mechanistic elucidation. The release of hydrogen gas as a useful byproduct highlights the scientific importance of the present methodology. Additionally, gram-scale synthesis and catalyst recyclability studies are deliberated. Importantly, the δ-MnO2 NP catalyst exhibited superior catalytic activity and high durability toward hydrogen evolution reaction in alkaline media, highlighting the dual use of the catalyst. The δ-MnO2 NPs attain the current density of 10 mA/cm2 at an overpotential of 154 mV with a Tafel slope of 119 mV/dec.

Exploring the promising application of Be12O12 nanocage for the abatement of paracetamol using DFT simulations

The removal of paracetamol from water is of prime concern because of its toxic nature in aquatic environment. In the present research, a detailed DFT study is carried out to remove paracetamol drug from water with the help of Be12O12 to eliminate the related issues. Three different geometries (CMP-1, CMP-2, CMP-3,) are obtained with the highest adsorption energies value (Eads) of - 31.2316 kcal/mol for CMP-3 without any prominent structural change. It is observed from the study that O atom from the carbonyl group (C=O) and H atom from O-H group successfully interact with O and Be atoms of the nanocage respectively. Natural bonding orbitals analysis reveals charge transfer to paracetamol drug from Be12O12 nanocage with maximum charge transfer of - 0.159 e for CMP-3 with bond angle of 1.65 Å confirming the stability of the CMP-3 among the optimized complexes. The quantum theory of atoms in molecule concludes that the interaction between paracetamol drug molecule and Be12O12 is purely closed-shell weak electrostatic in nature in CMP-1 and CMP-3 and shared interaction in CMP-2. The thermodynamics analysis witnesses that the process is exothermic and spontaneous. The regeneration study reveals the reversible nature of the adsorbent. The overall study presents Be12O12 nanocage as a potential adsorbent and may be used in future for the purification of water from a number of emerging pollutants.

Surface modification of a screen-printed electrode with a flower-like nanostructure to fabricate a guanine DNA-based electrochemical biosensor to determine the anticancer drug pemigatinib

The present study developed a DNA biosensor to determine pemigatinib for the first time. Three-dimensional carnation flower-like Eu3+:β-MnO2 nanostructures (3D CF-L Eu3+:β-MnO2 NSs) and a screen-printed electrode (SPE) modified with polyaniline (PA) were employed. The double-stranded DNA was also immobilized completely on the PA/3D CF-L Eu3+:β-MnO2 NSs/SPE. Then, electrochemical techniques were used for characterizing the modified electrode. After that, the interaction between pemigatinib and DNA was shown by a reduction in the oxidation current of guanine using differential pulse voltammetry (DPV). According to the analysis, the dynamic range of pemigatinib was between 0.001 and 180.0 μM, indicating the new electrode has a low limit of detection (LOD = 0.23 nM) for pemigatinib. Afterwards, pemigatinib in real samples was measured using the PA/3D CF-L Eu3+:β-MnO2 NSs/SPE loaded with ds-DNA. The proposed DNA biosensor showed good selectivity toward pemigatinib in the presence of other interference analytes, such as other ions, structurally related pharmaceuticals, and plasma proteins. In addition, the interaction site of pemigatinib with DNA was predicted by molecular docking, which showed the interaction of pemigatinib with the guanine bases of DNA through a groove binding mode. Finally, we employed the t-test to verify the capability of the ds-DNA/PA/3D CF-L Eu3+:β-MnO2 NSs/SPE for analyzing pemigatinib in real samples.

Electrochemical detection of kynurenic acid in the presence of tryptophan with the carbon paste electrode modified with the flower-like nanostructures of zinc oxide doped with terbium

With the help of a hydrothermal approach in this study, we could provide flower-like nanostructures (NSs) of zinc oxide (ZnO) doped with Tb (FL-NS Tb3+/ZnO). Then, FL-NS Tb3+/ZnO morphology was investigated by energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and map analysis. The results revealed higher activity centers and porosity of this nanocomposite, which were followed by acceptable electrochemical function. Hence, it can be utilized for fabricating an electrochemical sensor with an appropriate response for the simultaneous determination of kynurenic acid (KYN) and tryptophan (TRP). However, as compared with the modified carbon paste electrode (FL-NS Tb3+/ZnO/CPE), the bare carbon paste electrode (BCPE) exhibited a weak response toward KYN and TRP but the modified electrode was followed by a high current response for KYN and TRP at a potential 0.35 and 0.809 V. Therefore, cyclic voltammetry (CV) was applied in optimal experimental conditions to study the electrochemical behaviors of KYN and TRP over the surface of the proposed modified electrode. Moreover, we used differential pulse voltammetry (DPV) for quantitative measurements. It was found that this new modified electrode linearly ranged from 0.001 to 700.0 μM, with detection limits of 0.34 nM and 0.22 nM for KYN and TRP, respectively. In addition, KYN and TRP in real samples can be analyzed by this sensor, with a recovery of 97.75%-103.6% for the spiked KYN and TRP in real samples.

Urine protein quantification in human urine on boron-doped diamond electrodes based on the electrochemical reaction of Coomassie brilliant blue

Urinalysis is attracting interest in personal healthcare management as part of a general move to improve quality of life. Urine contains various metabolites and the protein level in urine is an indicator of kidney function. In this study, a novel electrochemical sensing system based on boron-doped diamond (BDD) electrodes was developed for the detection of protein concentrations in human urine. BDD electrodes have the advantages of a wide electrochemical potential window and low non-specific adsorption, making them ideal for simple, rapid, and compact devices for home detection of bio-relevant substances. Coomassie brilliant blue (CBB), a dye that selectively and strongly binds to urine proteins, was found to be a redox-active indicator to show a decrease in its redox currents in relation to the concentration of protein in urine samples. Our detailed studies of BDD electrodes showed their limit of detection to be 2.57 μg mL-1 and that they have a linear response that ranges from 0 to 400 μg mL-1 in urine samples. We also investigated the detection of urine protein in different urine samples. Our results agreed with those obtained using conventional colorimetric analysis. We believe this to be the first study of electrochemical detection of urine protein in urine samples on BDD electrodes, which is of great significance to be able to obtain results with electrical signals rapidly compared to conventional colorimetric analysis. This CBB-BDD technique has the potential to assist healthcare management in the form of a rapid daily diagnostic test to judge whether a more detailed examination is needed.

The food and biomedical applications of curcumin-loaded electrospun nanofibers: A comprehensive review

Encapsulating curcumin (CUR) in nanocarriers such as liposomes, polymeric micelles, silica nanoparticles, protein-based nanocarriers, solid lipid nanoparticles, and nanocrystals could be efficient for a variety of industrial and biomedical applications. Nanofibers containing CUR represent a stable polymer-drug carrier with excellent surface-to-volume ratios for loading and cell interactions, tailored porosity for controlled CUR release, and diverse properties that fit the requirements for numerous applications. Despite the mentioned benefits, electrospinning is not capable of producing fibers from multiple polymers and biopolymers, and the product's effectiveness might be affected by various machine- and material-dependent parameters like the voltage and the flow rate of the electrospinning process. This review delves into the current and innovative recent research on nanofibers containing CUR and their various applications.

Selective Determination of Norfloxacin in Pharmaceutical Formulations and Human Urine Samples Using Poly(8-aminonaphthaline-2-sulfonic Acid)-Modified Glassy Carbon Electrodes

In this study, a glassy carbon electrode was modified potentiodynamically with poly(8-aminonaphthaline-2-sulfonic acid) [poly(ANSA)/GCE] for the detection of norfloxacin (NFN) in tablet formulations and human urine samples. Improvement of the effective surface area of the modified electrode and decreased charge-transfer resistance confirmed surface modification of the GCE by a conductive poly(ANSA) film. The appearance of an oxidative peak without a reductive peak in the reverse scan direction showed the irreversibility of the electrochemical oxidation of NFN in both the bare GCE and poly(ANSA)/GCE. A better coefficient of determination for the peak current on the square root of the scan rate (R² = 0.99514) than the scan rate (R² = 0.97109), indicating the oxidation of NFN at the poly(ANSA)/GCE, was predominantly diffusion mass transport-controlled. Under optimized pH and square wave parameters, the voltammetric current response of NFN at the poly(ANSA)/GCE showed linear dependence on the concentration, ranging from 1.0 × 10^-8 to 4.0 × 10^-4 M with a limit of detection of 4.1 × 10^-10. The NFN level in the studied tablet brands was in the range of 90.30-103.3% of their labeled values. Recovery results in tablet and urine samples ranged from 98.35 to 101.20% and 97.75 to 99.60%, respectively, and interference recovery results were less than 2.13% error in the presence of ampicillin, chloroquine phosphate, and cloxacillin. The present method had a better performance for the determination of NFN in tablet formulations and urine samples as compared with recently reported voltammetric methods due to its requirement of a simple electrode modification step, which provides the least limit of detection and a reasonably wider linear dynamic range.

Boron-cluster-based porous BCN material modified electrode for electrochemical determination of morphine in serum

Porous highly boron-doped BCN (p-BCN) was produced by using a boron cluster salt (closo-[B₁₂H₁₂]^2-) as the boron-based precursor and SiO₂ as a hard template. The synthesized p-BCN was used in an electrochemical sensor for the ultrasensitive and highly selective detection of morphine (MOP). The optimal conditions for MOP detection were determined by optimizing the experimental conditions. Under these optimal conditions, the p-BCN-based sensor exhibited excellent MOP detection performance (working potential of 0.2 V). Specifically, it showed a detection range of 0.05 to 200 μM and a detection limit of 17.8 nM. Notably, the p-BCN-based electrochemical sensor was successfully applied to the determination of MOP in human blood, and the results showed satisfactory recovery and accuracy. Therefore, this sensor can be used as an effective platform for the detection of MOP in human blood samples.

Electrochemical detection of uric acid in human serum based on ultrasmall Ta2O5 nanoparticle anchored Pt atom with ultrahigh uricase and catalase activities

The synthesis of ultrasmall Ta₂O₅ nanoparticle anchored Pt atom using aspartic acid-functionalized graphene quantum dot (Asp-GQD) is reported. The Asp-GQD was combined with tantalic acid and chloroplatinic acid to rapidly form water-soluble Ta-Asp-GQD and Pt-Asp-GQD complex. Followed by thermal annealing at 900 °C in N₂ to obtain Ta₂O₅-Asp-GQD-Pt. The study shows that the introduction of Asp-GQD as a chelating agent and p-type semiconductor achieves to the formation of ultrasmall Ta₂O₅ nanoparticle, PN junction at the interface and Pt single atom anchored on the surface of Ta₂O₅ nanocrystals. The unique structure realizes ultrahigh uricase activity and catalase activities of Ta₂O₅-Asp-GQD-Pt. The Ta₂O₅-Asp-GQD-Pt was used as the bifunctional sensing material for the construction of an electrochemical uric acid sensor. The differential pulse voltammetric current at 0.45 V linearly increases with the increase of uric acid concentration in the range 0.001-5.00 mM with the detection limit of 0.41 μM (S/N = 3). The sensor exhibits a much better sensitivity compared with the reported methods for the detection of uric acid. The proposed analytical method has been applied to the electrochemical detection of uric acid in human serum with a spiked recovery of 95-105%. The study also offers one way to design and synthesize multifunctional sensing materials with high catalytic activity.

Amino-Functionalized Hierarchical Porous Carbon Derived from Zeolitic Imidazolate Frameworks for Ultrasensitive Electrochemical Sensing of Heavy Metals in Water

Electrochemical sensing provides a feasible avenue to monitor heavy metal ions (HMIs) in water, whereas the construction of highly sensitive and selective sensors remains challenging. Herein, we fabricated a novel amino-functionalized hierarchical porous carbon by the template-engaged method using ZIF-8 as the precursor and polystyrene sphere as the template, followed by carbonization and controllable chemical grafting of amino groups for efficient electrochemical detection of HMIs in water. The amino-functionalized hierarchical porous carbon features an ultrathin carbon framework with a high graphitization degree, excellent conductivity, unique macro-, meso-, and microporous architecture, and rich amino groups. As a result, the sensor exhibits prominent electrochemical performance with significantly low limits of detection for individual HMIs (i.e., 0.93 nM for Pb²⁺, 2.9 nM for Cu²⁺, and 1.2 nM for Hg²⁺) and simultaneous detection of HMIs (i.e., 0.62 nM for Pb²⁺, 1.8 nM for Cu²⁺, and 0.85 nM for Hg²⁺), which are superior to most reported sensors in the literature. Moreover, the sensor displays excellent anti-interference ability, repeatability, and stability for HMI detection in actual water samples.

Hierarchical copper-based metal-organic frameworks nanosheet assemblies for electrochemical ascorbic acid sensing

Noninvasive human health monitoring requires the development of efficient electrochemical sensors for the quantitative analysis of infinitesimal biomolecules. In this work, we reported a novel hierarchical nanosheet assemblies (HSA) of copper-based metal-organic frameworks (MOFs) as an electrochemical sensor for ascorbic acid (AA) detection. Copper 1,4-benzenedicarboxylate (CuBDC) HSA was constructed by three steps of in situ growth on stone paper, including hydrolysis, anion exchange, and heteroepitaxy growth. The monodispersed two-dimensional MOFs nanosheet units were aligned in an orderly manner and arranged into three-dimensional hierarchical assemblies. The CuBDC HSA-based AA sensor displayed a high sensitivity of 396.8 μA mM^-1 cm^-2 and a low detection limit of 0.1 μM. Excellent selectivity, stability and reproducibility were also obtained. Benefiting from the advantages of ultrathin nanosheets and nature-inspired hierarchy, this unique architecture facilitated reactant dispersion and maximized the accessible active sites and charge-transport capability and thus had superior catalytic ability for the electro-oxidation of ascorbic acid compared to bulk MOFs. Moreover, the CuBDC HSA sensor performed AA level detection in juice samples with acceptable accuracy and verified the feasibility for sweat AA sensing. This novel MOFs architecture holds great potential as an electrochemical sensor to detect AA for noninvasive human health monitoring in the future.