Nanomaterials-based electrochemical sensors and biosensors for the detection of non-steroidal anti-inflammatory drugs

Benzoquinone-modified vertically aligned mesoporous silica for ratiometric electrochemical detection of diclofenac

A ratiometric electrochemical sensor featuring a benzoquinone-modified vertically aligned mesoporous silica film (BQ/VMSF) has been developed for the accurate detection of diclofenac (DCF), a widely utilized non-steroidal anti-inflammatory drug. The design process employed the Electrochemical assisted self-assembly (EASA) technique to grow a thiol-functionalized mesoporous silica film on a carbon screen-printed electrode, which was further modified with benzoquinone via click chemistry. Characterization using Transmission Electron Microscopy (TEM), Fourier-Transform Infrared Spectroscopy (FTIR), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS) confirmed the successful synthesis and optimal functionality of the mesoporous structure. In this configuration, benzoquinone serves as an internal redox reference, generating one redox signal, while the electrochemical oxidation of diclofenac produces a second redox signal. The sensor's output is derived from the ratio of these two signals, IDCF/IBQ, enhancing its sensitivity and selectivity for diclofenac detection. The sensor, tested through Differential Pulse Voltammetry (DPV), exhibited a linear response range from 1 to 10 μM for diclofenac and a remarkably low limit of detection (LOD) of 0.73 μM. Application of the sensor for diclofenac analysis in pharmaceutical formulations demonstrated recovery rates ranging from 97.68 % to 101.79 % and relative errors below 2.32 %, affirming its practical utility.

Machine Learning-Assisted Chemical Tongues Based on Dual-channel Inclusion Complexes for Rapid Identification of Nonsteroidal Anti-inflammatory Drugs in Food

The improper application of nonsteroidal anti-inflammatory drugs (NSAIDs) presents significant health hazards via vector food contamination. A critical limitation of these traditional existing approaches is their inability to concurrently discern and distinguish among diverse NSAIDs, presenting a notable gap in the analytical capabilities within this domain. Herein, a creative dual-channel fluorescence sensor array was developed for the rapid discrimination and determination of NSAIDs, utilizing complexes of cucurbit[8]uril (CB[8]) with three distinct modified poly(ethylenimines) (PEIs) to address this challenge. The array successfully differentiated and identified 19 NSAIDs with 97% accuracy at a concentration of 1 mM. In addition, it also achieved analyses of individual NSAIDs across a range of concentrations, NSAID mixtures, and impurities of aspirin using statistical analysis methods. More importantly, the approach effectively detected NSAIDs in complex matrices, such as milk and urine, demonstrating its potential for real-world applications.

Nanomaterial-Based Biosensors for the Detection of COVID-19

The COVID-19 outbreak began in December 2019 and has affected people worldwide. It was declared a pandemic in 2020 by the World Health Organization. Developing rapid and reliable diagnostic techniques is crucial for identifying COVID-19 early and preventing the disease from becoming severe. In addition to conventional diagnostic techniques such as RT-PCR, computed tomography, serological assays, and sequencing methods, biosensors have become widely accepted for identifying and screening COVID-19 infection with high accuracy and sensitivity. Their low cost, high sensitivity, specificity, and portability make them ideal for diagnostics. The use of nanomaterials improves the performance of biosensors by increasing their sensitivities and limiting detection by several orders of magnitude. This manuscript briefly reviews the COVID-19 outbreak and its pathogenesis. Furthermore, it comprehensively discusses the currently available biosensors for SARS-CoV-2 detection, with a special emphasis on nanomaterials-based biosensors developed to detect this emerging virus and its variants efficiently.

Trends and Hotspots in Nanomedicine Applications for Pain: A Bibliometric Analysis from 1999 to 2024

Background: Pain, especially chronic pain, is a leading cause of individuals seeking medical attention and presents a significant public health challenge due to its widespread prevalence and associated healthcare costs. Nanomedicine has shown considerable potential in pain management research. However, there is a lack of comprehensive bibliometric and trend analyses that explore the current status, research hotspots, and future directions of nanomedicine applications in pain. Methods: To fill this gap, we analyzed English language publications related to nanomedicine and pain from the Web of Science Core Collection, spanning the period from January 1, 1999, to May 24, 2024. The analysis focused on publication trends, contributions by countries/regions, institutions, journals, research categories, prominent authors, key references, and keywords. Results: A total of 2370 papers were included. China leads in the number of published papers (785, 33.12%) and hosts numerous high-output institutions and funding agencies, followed by the USA. The International Journal of Pharmaceutics emerged as the leading journal in terms of publication volume. A clear interdisciplinary platform has been established between nanomedicine and the field of pain. "Nanoparticles" and "drug delivery" were identified as high-frequency keywords. The drug delivery systems for pain treatment were considered the main research hotspots, particularly for chronic pain. The keyword citation bursts indicate that the pain of biomarker monitoring is a future trend. Conclusions: The application of nanomedicine in pain has advanced rapidly. Increased funding and international collaboration are necessary with future potential to expand from pain treatment to monitoring and diagnosis.

Electrochemical sensor based on molecularly imprinted polypyrrole-MWCNTs-OH/covalent organic framework for the detection of ofloxacin in water

A platform was developed to accurately detect the content of ofloxacin (OFX) based on molecularly imprinted polypyrrole-MWCNTs-OH/1,3,5-Tris(4-aminophenyl) benzene (TAPB)-2,5-dimethoxybenzene-1,4-dicarboxaldehyde (DMTP)-covalent organic framework (MIP-MWCNTs-OH/COF)-modified glassy carbon electrode (GCE) sensor (MIP-MWCNTs-OH/COF/GCE). The complex of MWCNTs-OH and COF synergistically enhanced the active area and electrochemical signal, based on which a molecularly imprinted membrane was polymerized on its surface to further improve the selectivity. Under optimized conditions, the prepared MIP-MWCNTs-OH/COF/GCE sensor exhibited strong detection performance to OFX in a linear range 1.969 × 10-11-9.619 × 10-9 M with the limit of detection (LOD, 3S/N) of 4.989 × 10-12 M, excellent selectivity, stability, and reproducibility. Furthermore, the MIP-MWCNTs-OH/COF/GCE sensor can be successfully applied to the detection of OFX in lake water and eye drops with a relative standard deviation (RSD) of less than 4.95%, indicating its high potential in practical applications.

Ruthenium(II) N-heterocyclic carbene polymer based sensors for detection of predatory drugs like ketamine and scopolamine

The current demand in the field of abusive drug research is to have a highly sensitive and rapid method for detecting ketamine and scopolamine, which are frequently used in drug-facilitated sexual assaults administered via beverages and food. We report here the first electrochemical sensors of N-heterocyclic carbene (NHC) coordinated ruthenium organometallic 1-dimensional polymers and their multi-walled carbon nano tube (MWCNT)-based composite for detecting ketamine and scopolamine. The preparation of ruthenium NHC organometallics and the MWCNT composite as sensors offers significant advantages for electrochemical applications, with enhanced sensitivities of 121.979 and 3.273 μA μM-1 cm-2 for ketamine and scopolamine, respectively, and selectivity in sensing applications. The complex-carbon composite sensor has a low limit of detection i.e., 0.194 and 3.18 nM for ketamine and scopolamine identification, respectively. Alongside, the selectivity of the composite sensor was evaluated in the presence of other blood constituents, and the study evidenced remarkable discernment towards the title drugs. Furthermore, real-time analyses using the composite sensor demonstrated quantitative identification of ketamine and scopolamine. Therefore, this innovation has the potential to provide valuable tools for forensic investigations and address the urgent need for real-time detection of date rape drugs. This contribution demonstrates a robust proof-of-concept that emphasizes the importance of creating non-enzymatic, environmentally friendly, and cost-effective sensors for on-site sensing applications as point-of-care devices.

Development of an Escherichia coli Cell-Based Biosensor for Aspirin Monitoring by Genetic Engineering of MarR

Multiple antibiotic resistance regulators (MarRs) control the transcription of genes in the mar operon of Escherichia coli in the presence of salicylic acid (SA). The interaction with SA induces conformational changes in the MarR released from the promoter of the mar operon, turning on transcription. We constructed an SA-specific E. coli cell-based biosensor by fusing the promoter of the mar operon (PmarO) and the gene that encodes an enhanced green fluorescent protein (egfp). Because SA and aspirin are structurally similar, a biosensor for monitoring aspirin can be obtained by genetically engineering MarR to be aspirin (ASP)-responsive. To shift the selectivity of MarR toward ASP, we changed the residues around the ligand-binding sites by site-directed mutagenesis. We examined the effects of genetic engineering on MarR by introducing MarRs with PmarO-egfp into E. coli. Among the tested mutants, MarR T72A improved the ASP responses by approximately 3 times compared to the wild-type MarR, while still showing an SA response. Although the MarR T72A biosensor exhibited mutual interference between SA and ASP, it accurately determined the ASP concentration in spiked water and medicine samples with over 90% accuracy. While the ASP biosensors still require improvement, our results provide valuable insights for developing E. coli cell-based biosensors for ASP and transcription factor-based biosensors in general.

Recent Advancements in MXene-Based Biosensors for Health and Environmental Applications-A Review

Owing to their unique physicochemical properties, MXenes have emerged as promising materials for biosensing applications. This review paper comprehensively explores the recent advancements in MXene-based biosensors for health and environmental applications. This review begins with an introduction to MXenes and biosensors, outlining various types of biosensors including electrochemical, enzymatic, optical, and fluorescent-based systems. The synthesis methods and characteristics of MXenes are thoroughly discussed, highlighting the importance of these processes in tailoring MXenes for specific biosensing applications. Particular attention is given to the development of electrochemical MXene-based biosensors, which have shown remarkable sensitivity and selectivity in detecting various analytes. This review then delves into enzymatic MXene-based biosensors, exploring how the integration of MXenes with enzymes enhances sensor performance and expands the range of detectable biomarkers. Optical biosensors based on MXenes are examined, focusing on their mechanisms and applications in both healthcare and environmental monitoring. The potential of fluorescent-based MXene biosensors is also investigated, showcasing their utility in imaging and sensing applications. In addition, MXene-based potential wearable biosensors have been discussed along with the role of MXenes in volatile organic compound (VOC) detection for environmental applications. Finally, this paper concludes with a critical analysis of the current state of MXene-based biosensors and provides insights into future perspectives and challenges in this rapidly evolving field.

Structural classification of Ag and Cu nanocrystals with machine learning

We use machine learning (ML) to classify the structures of mono-metallic Cu and Ag nanoparticles. Our datasets comprise a broad range of structures - both crystalline and amorphous - derived from parallel-tempering molecular dynamics simulations of nanoparticles in the 100-200 atom size range. We construct nanoparticle features using common neighbor analysis (CNA) signatures, and we utilize principal component analysis to reduce the dimensionality of the CNA feature set. To sort the nanoparticles into structural classes, we employed both K-means clustering and the Gaussian mixture model (GMM). We evaluated the performance of the clustering algorithms through the gap statistic and silhouette score, as well as by analysis of the CNA signatures. For Ag, we found five structural classes, with 14 detailed sub-classes, while for Cu, we found two broad classes (crystalline and amorphous), with the same five classes as for Ag, and 15 detailed sub-classes. Our results demonstrate that these ML methods are effective in identifying and categorizing nanoparticle structures to different levels of complexity, enabling us to classify nanoparticles into distinct and physically relevant structural classes with high accuracy. This capability is important for understanding nanoparticle properties and potential applications.

Platinum-Selenopeptide Interfaces in Support of High Fidelity Electrochemical Biomarker Quantification in Complex Biological Matrices

The real world applications of conventional antifouling biosensors based on gold-thiol (Au-S) interfaces are hampered by the progressive competitive displacement of key functionality by ubiquitous biothiols. To overcome this limitation, we introduce here novel platinum-selenium (Pt-Se) interfaces. Thiol displacement tests, antifouling analyses, and density functional theory calculations confirm markedly improved interfacial stability. This was then leveraged through the application of a seleno-multifunctional peptide platform, tailored to the detection of murine double minute 2, in biological samples. A derived amperometric sensing platform exhibited a notably lower detection limit and more accurate target quantification than that supported by analogous Au-S and Pt-S interfaces. We believe that this work broadens the scope of electrochemical sensor construction and holds significant promise for the development of high-fidelity impactful bioassay platforms.

Synthesis, characterization and evaluation of new anti-inflammatory iron charge transfer complexes

The novelty and the essential purpose of this research is the preparation of new anti-inflammatory iron complexes in water green solvent using critical micelle concentration of anionic surface active agent (SAA). Three new anti-inflammatory iron complexes have been prepared. Thiophene-electron (es) donor (D) Schiff base (2-(2-OH-benzylidene)-amino)-4, 5, 6, 7-tetrah ydrobenzo[b] thiophene-3-carbonitrile) has been prepared. Molecular structures of all samples were confirmed based on CNH analysis, 1H NMR and 13C NMR spectra. The molecular structure of Schiff base is further confirmed by computational chemistry using the DFT-B3LYP method, 6-31G (d) basis set. Observed and simulated 1H NMR, UV-Vis. IR/Raman spectra confirmed the molecular structure of D. This Schiff base is intercalated to ferric chloride (FeCl3) giving pure iron charge transfer complex (CTCs). In vitro and kinetic studies confirmed Fe-CTC complexes had (concentration-dependent) potent antimicrobial-, good anti-inflammatory activities. Free radical scavenging activity nitrous oxide (NO.) of Fe (III)CTCs is attributed to geometry Fe(III) ions as distorted octahedral (either monoclinic or triclinic single crystals) via functional groups (-C]N-O, NH2). Elemental analysis and EDS spectra confirmed strong binding between iron and hetero atoms (N, S, O) of D molecules.

Metal-Based Nanomaterials for the Sensing of NSAIDS

Cadmium sulfide and zinc oxide nanoparticles were prepared, characterized and used as electrode modifiers for the sensing of two non-steroidal anti-inflammatory drugs (NSAIDs): naproxen and mobic. The structural and morphological characterization of the synthesized nanoparticles was carried out by XRD, UV-Vis spectroscopy, FTIR and scanning electron microscopy. The electrode's enhanced surface area facilitated the signal amplification of the selected NSAIDs. The CdS-modified glassy carbon electrode (GCE) enhanced the electro-oxidation signals of naproxen to four times that of the bare GCE, while the ZnO-modified GCE led to a two-fold enhancement in the electro-oxidation signals of mobic. The oxidation of both NSAIDs occurred in a pH-dependent manner, suggesting the involvement of protons in their electron transfer reactions. The experimental conditions for the sensing of naproxen and mobic were optimized and, under optimized conditions, the modified electrode surface demonstrated the qualities of sensitivity and selectivity, and a fast responsiveness to the target NSAIDs.

Recent advances in electrochemical aptasensors and genosensors for the detection of pathogens

In recent years, pathogenic microorganisms have caused significant mortality rates and antibiotic resistance and triggered exorbitant healthcare costs. These pathogens often have high transmission rates within human populations. Rapid diagnosis is crucial in controlling and reducing the spread of pathogenic infections. The diagnostic methods currently used against individuals infected with these pathogens include relying on outward symptoms, immunological-based and, some biomolecular ones, which mainly have limitations such as diagnostic errors, time-consuming processes, and high-cost platforms. Electrochemical aptasensors and genosensors have emerged as promising diagnostic tools for rapid, accurate, and cost-effective pathogen detection. These bio-electrochemical platforms have been optimized for diagnostic purposes by incorporating advanced materials (mainly nanomaterials), biomolecular technologies, and innovative designs. This review classifies electrochemical aptasensors and genosensors developed between 2021 and 2023 based on their use of different nanomaterials, such as gold-based, carbon-based, and others that employed other innovative assemblies without the use of nanomaterials. Inspecting the diagnostic features of various sensing platforms against pathogenic analytes can identify research gaps and open new avenues for exploration.

Nanotechnology-assisted treatment of pharmaceuticals contaminated water

The presence of pharmaceutical compounds in wastewater due to an increase in industrialization and urbanization is a serious health concern. The demand for diverse types of pharmaceutical compounds is expected to grow as there is continuous improvement in the global human health standards. Discharge of domestic pharmaceutical personal care products and hospital waste has aggravated the burden on wastewater management. Further, the pharmaceutical water is toxic not only to the aquatic organism but also to terrestrial animals coming in contact directly or indirectly. The pharmaceutical wastes can be removed by adsorption and/or degradation approach. Nanoparticles (NPs), such as 2D layers materials, metal-organic frameworks (MOFs), and carbonaceous nanomaterials are proven to be more efficient for adsorption and/or degradation of pharmaceutical waste. In addition, inclusion of NPs to form various composites leads to improvement in the waste treatment efficacy to a greater extent. Overall, carbonaceous nanocomposites have advantage in the form of being produced from renewable resources and the nanocomposite material is biodegradable either completely or to a great extent. A comprehensive literature survey on the recent advancement of pharmaceutical wastewater is the focus of the present article.

Machine learning-guided the fabrication of nanozyme based on highly-stable violet phosphorene decorated with phosphorus-doped hierarchically porous carbon microsphere for portable intelligent sensing of mycophenolic acid in silage

Violet phosphorene (VP) have been proved to be more stable than black phosphorene, but few reports for its application in electrochemical sensors. In this study, a highly-stable VP decorated with phosphorus-doped hierarchically porous carbon microsphere (PCM) with multiple enzyme-like activities as a nanozyme sensing platform for portable intelligent analysis of mycophenolic acid (MPA) in silage with machine learning (ML) assistance is successfully fabricated. The pore size distribution on the PCM surface is discussed using N2 adsorption tests, and morphological characterization indicates that the PCM is embedded in the layers of lamellar VP. The affinity of the VP-PCM nanozyme obtained under the guidance of the ML model reaches Km = 12.4 μmol/L for MPA. The VP-PCM/SPCE for the efficient detection of MPA exhibits high sensitivity, a wide detection range of 2.49 μmol/L - 71.14 μmol/L with a low limit of detection of 18.7 nmol/L. The proposed ML model with high prediction accuracy (R2 = 0.9999, MAPEP = 0.0081) assists the nanozyme sensor for intelligent and rapid quantification of MPA residues in corn silage and wheat silage with satisfactory recoveries of 93.33%-102.33%. The excellent biomimetic sensing properties of the VP-PCM nanozyme are driving the development of a novel MPA analysis strategy assisted by ML in the context of production requirements of livestock safety.

Polyester fabric-based nano copper-polyhedral oligomeric silsesquioxanes sorbent for thin film extraction of non-steroidal anti-inflammatory drugs

In this study, in-situ preparation of copper nanoparticles under sonoheating conditions followed by coating on commercial polyester fabric is reported. Through the self-assembly interaction of thiol groups and copper nanoparticles, the modified polyhedral oligomeric silsesquioxanes (POSS) was deposited on the fabric's surface. In the next step, radical thiol-ene click reactions were implemented to create more layers of POSSs. Subsequently, the modified fabric was applied for sorptive thin film extraction of non-steroidal anti-inflammatory drugs (NSAIDs) including naproxen, ibuprofen, diclofenac, and mefenamic acid from urine samples, followed by high-performance liquid chromatography equipped with a UV detector. The morphology of the prepared fabric phase was characterized by scanning electron microscopy, water angle contact, energy dispersive spectrometry mapping, analysis of nitrogen adsorption-desorption isotherms, and attenuated total reflectance Fourier transform infrared spectroscopy. The significant extraction parameters, including the acidity of the sample solution, desorption solvent and its volume, extraction time, and desorption time, were investigated using the one-variable-at-a-time approach. Under the optimal condition, NSAIDs' detection limit was 0.3-1 ng mL^-1 with a wide linear range of 1-1000 ng mL^-1. The recovery values were between 94.0% and 110.0%, with relative standard deviations of less than 6.3%. The prepared fabric phase exhibited acceptable repeatability, stability, and sorption property toward NSAIDs in urine samples.

Recent Advances in Electrochemical Immunosensors with Nanomaterial Assistance for Signal Amplification

Electrochemical immunosensors have attracted immense attention due to the ease of mass electrode production and the high compatibility of the miniature electric reader, which is beneficial for developing point-of-care diagnostic devices. Electrochemical immunosensors can be divided into label-free and label-based sensing strategies equipped with potentiometric, amperometric, voltammetric, or impedimetric detectors. Emerging nanomaterials are frequently used on electrochemical immunosensors as a highly rough and conductive interface of the electrodes or on nanocarriers of immobilizing capture antibodies, electroactive mediators, or catalyzers. Adopting nanomaterials can increase immunosensor characteristics with lower detection limits and better sensitivity. Recent research has shown innovative immobilization procedures of nanomaterials which meet the requirements of different electrochemical immunosensors. This review discusses the past five years of advances in nanomaterials (metal nanoparticles, metal nanostructures, carbon nanotubes, and graphene) integrated into the electrochemical immunosensor. Furthermore, the new tendency and endeavors of nanomaterial-based electrochemical immunosensors are discussed.

Simultaneous Voltammetric Determination of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Using a Modified Carbon Paste Electrode and Chemometrics

This work presents the simultaneous quantification of four non-steroidal anti-inflammatory drugs (NSAIDs), paracetamol, diclofenac, naproxen, and aspirin, in mixture solutions, by a laboratory-made working electrode based on carbon paste modified with multi-wall carbon nanotubes (MWCNT-CPE) and Differential Pulse Voltammetry (DPV). Preliminary electrochemical analysis was performed using cyclic voltammetry, and the sensor morphology was studied by scanning electronic microscopy and electrochemical impedance spectroscopy. The sample set ranging from 0.5 to 80 µmol L^-1 was prepared using a complete factorial design (3⁴) and considering some interferent species such as ascorbic acid, glucose, and sodium dodecyl sulfate to build the response model and an external randomly subset of samples within the experimental domain. A data compression strategy based on discrete wavelet transform was applied to handle voltammograms' complexity and high dimensionality. Afterward, Partial Least Square Regression (PLS) and Artificial Neural Networks (ANN) predicted the drug concentrations in the mixtures. PLS-adjusted models (n = 12) successfully predicted the concentration of paracetamol and diclofenac, achieving correlation values of R ≥ 0.9 (testing set). Meanwhile, the ANN model (four layers) obtained good prediction results, exhibiting R ≥ 0.968 for the four analyzed drugs (testing stage). Thus, an MWCNT-CPE electrode can be successfully used as a potential sensor for voltammetric determination and NSAID analysis.

Nanomaterials-based electrochemical sensors for the detection of natural antioxidants in food and biological samples: research progress

Antioxidants are healthy substances that are beneficial to the human body and exist mainly in natural and synthetic forms. Among many kinds of antioxidants, the natural antioxidants have great applications in many fields such as food chemistry, medical care, and clinical application. In recent years, many efforts have been made for the determination of natural antioxidants. Nano-electrochemical sensors combining electrochemistry and nanotechnology have been widely used in the determination of natural antioxidants due to their unique advantages. Therefore, a large number of nanomaterials such as metal oxide, carbon materials, and conducting polymer have attracted much attention in the field of electrochemical sensors due to their good catalytic effect and stable performance. This review mainly introduces the construction of electrochemical sensors based on different nanomaterials, such as metallic nanomaterials, metal oxide nanomaterials, carbon nanomaterials, metal-organic frameworks, polymer nanomaterials, and other nanocomposites, and their application to the detection of natural antioxidants, including ascorbic acid, phenolic acids, flavonoid, tryptophan, citric acid, and other natural antioxidants. In the end, the limitations of the existing nano-sensing technology, the latest development trend, and the application prospect for various natural antioxidant substances are summarized and analyzed. We expect that this review will be helpful to researchers engaged in electrochemical sensors.

Atropine-Phosphotungestate Polymeric-Based Metal Oxide Nanoparticles for Potentiometric Detection in Pharmaceutical Dosage Forms

The new research presents highly conductive polymeric membranes with a large surface area to volume ratio of metal oxide nanoparticles that were used to determine atropine sulfate (AT) in commercial dosage forms. In sensing and biosensing applications, the nanomaterials zinc oxide (ZnONPs) and magnesium oxide (MgONPs) were employed as boosting potential electroactive materials. The electroactive atropine phosphotungstate (AT-PT) was created by combining atropine sulfate and phosphotungstic acid (PTA) and mixing it with polymeric polyvinyl chloride (PVC) with the plasticizer o-nitrophenyl octyl ether (o-NPOE). The modified sensors AT-PT-ZnONPs or AT-PT-MgONPs showed excellent selectivity and sensitivity for the measurements of atropine with a linear concentration range of 6.0 × 10⁻⁸ − 1.0 × 10⁻³ and 8.0 × 10⁻⁸ − 1.0 × 10⁻³ mol L⁻¹ with regression equations of E_(mV) = (56 ± 0.5) log [AT] − 294 and E_(mV) = (54 ± 0.5) log [AT] − 422 for AT-PT-NPs or AT-PT-MgONPs sensors, respectively. The AT-PT coated wire sensor, on the other hand, showed a Nernstian response at 4.0 × 10⁻⁶ − 1.0 × 10⁻³ mol L⁻¹ and a regression equation E_(mV) = (52.1 ± 0.2) log [AT] + 198. The methodology-recommended guidelines were used to validate the suggested modified potentiometric systems against various criteria.

Electrochemical sensing system for the analysis of emerging contaminants in aquatic environment: A review

This survey distinguishes understudied spaces of arising impurity research in wastewaters and the habitat, and suggests bearing for future checking. Thinking about the impeding effect of toxins on human wellbeing and biological system, their discovery in various media including water is fundamental. This review sums up and assesses the latest advances in the electrochemical detecting of emerging contaminants (ECs). This survey is expected to add to the advancement in electrochemical applications towards the ECs. Different electrochemical insightful procedures like Amperometry, Voltammetry has been examined in this overview. The improvement of cutting edge nanomaterial-based electrochemical sensors and biosensors for the discovery of drug compounds has accumulated monstrous consideration because of their benefits, like high affectability and selectivity, continuous observing, and convenience has been reviewed in this survey. This survey likewise features the diverse electrochemical treatment procedures accessible for the removal of ECs.

The influence of iodide on the solution-phase growth of Cu microplates: a multi-scale theoretical analysis from first principles

We use first-principles density functional theory (DFT) to quantify the role of iodide in the solution-phase growth of Cu microplates. Our calculations show that a Cu adatom binds more strongly to hcp hollow sites than fcc hollow sites on iodine-covered Cu(111) - the basal facet of two-dimensional (2D) Cu plates. This feature promotes the formation of stacking faults during seed and plate which, in turn, promotes 2D growth. We also found that iodine adsorption leads to strong Cu atom binding and prohibitively slow diffusion of Cu atoms on Cu(100) - a feature that promotes Cu atom accumulation on the {100} site facets of a growing 2D plate. Incorporating these insights into analog experiments, in which we initiated the growth of Cu plates from small seeds consisting of magnetic spheres, we confirmed that two or more stacking faults are required for lateral plate growth, consistent with prior studies. Moreover, plates can take on a variety of shapes during growth: from triangular and truncated triangular to round and hexagonal - consistent with experiment. Using absorbing Markov chain calculations, we assessed the propensity for 2D vs. 3D kinetic growth of the plates. At experimental temperatures, we predict plates can grow to achieve lateral dimensions in the 1-10 micron range, as observed in experiments.

A Review on Electrochemical Sensors and Biosensors Used in Assessing Antioxidant Activity

Currently, there is growing interest in screening and quantifying antioxidants from biological samples in the quest for natural and effective antioxidants to combat free radical-related pathological complications. Antioxidants play an important role in human health and provide a defense against many diseases. Due to the valuable dietary role of these compounds, the analysis and determination of their amount in food is of particular importance. In recent years, many attempts have been made to provide simple, fast, and economical analytical approaches for the on-site detection and determination of antioxidant activity in food antioxidants. In this regard, electrochemical sensors and biosensors are considered promising tools for antioxidant research due to their high sensitivity, fast response time, and ease of miniaturization; thus, they are used in a variety of fields, including food analysis, drug screening, and toxicity research. Herein, we review the recent advances in sensors and biosensors for the detection of antioxidants, underlying principles, and emphasizing advantages, along with limitations regarding the ability to discriminate between the specific antioxidant or quantifying total antioxidant content. In this work, both direct and indirect methods for antioxidants detecting with electrochemical sensors and biosensors are analyzed in detail. This review aims to prove how electrochemical sensors and biosensors represent reliable alternatives to conventional methods for antioxidant analysis.

MXene-based electrochemical sensors for detection of environmental pollutants: A comprehensive review

Since the discovery of MXenes at Drexel University in the United States in 2011, there has been extensive research regarding various applications of MXenes including environmental remediation. MXenes with a general formula of M_n+1X_nT_x are a class of two-dimensional (2D) transition metal carbides, carbonitrides, and nitrides with unique chemical and physical characteristics as nanomaterials. MXenes feature characteristics such as high conductivity, hydrophobicity, and large specific surface areas that are attracting attention from researchers in many fields including environmental water engineering such as desalination and wastewater treatment as well as designing and building efficient sensors to detect hazardous pollutants in water. In this study, we review recent developments in MXene-based nanocomposites for electrochemical (bio) sensing with a particular focus on the detection of hazardous pollutants, such as organic components, pesticides, nitrite, and heavy metals. Integration of these 2D materials in electrochemical enzyme-based and affinity-based biosensors for environmental pollutants is also discussed. In addition, a summary of the key challenges and future remarks are presented. Although this field is relatively new, future research on biosensors of MXene-based nanocomposites need to exploit the remarkable properties of these 2D materials.

Functionalized Multi-Walled Carbon Nanotube–Based Aptasensors for Diclofenac Detection

Driven by the increasing concern about the risk of diclofenac (DCF) residues as water pollutants in the aqueous environment and the growing need for its trace determination, a simple but sensitive electrochemical aptasensor for the trace detection of DCF was developed. To construct the aptasensor, the amine-terminated DCF aptamer was covalently immobilized on the surface of the carboxylic acid–functionalized multi-walled carbon nanotube (f-MWCNT)–modified glassy carbon electrode (GCE) through EDC/NHS chemistry. The f-MWCNTs provide a reliable matrix for aptamer immobilization with high grafting density, while the aptamer serves as a biorecognition probe for DCF. The obtained aptasensor was incubated with DCF solutions at different concentrations and was then investigated by electrochemical impedance spectroscopy (EIS). It displays two linear ranges of concentration for DCF detection, from 250 fM to 1pM and from 1 pM to 500 nM with an extremely low detection limit of 162 fM. Also, the developed biosensor shows great reproducibility, acceptable stability, and reliable selectivity. Therefore, it offers a simple but effective aptasensor construction strategy for trace detection of DCF and is anticipated to show great potential for environmental applications.