Facile synthesis of mesoporous WS2 nanorods decorated N-doped RGO network modified electrode as portable electrochemical sensing platform for sensitive detection of toxic antibiotic in biological and pharmaceutical samples

A Novel Label-Free Electrochemical Immunosensor for the Detection of Thyroid Transcription Factor 1 Using Ribbon-like Tungsten Disulfide-Reduced Graphene Oxide Nanohybrids and Gold Nanoparticles

Thyroid transcription factor 1 (TTF1) is an important cancer-related biomarker for clinical diagnosis, especially for carcinomas of lung and thyroid origin. Herein, a novel label-free electrochemical immunosensor was prepared for TTF1 detection based on nanohybrids of ribbon-like tungsten disulfide-reduced graphene oxide (WS2-rGO) and gold nanoparticles (AuNPs). The proposed immunosensor employed H2O2 as the electrochemical probe because of the excellent peroxidase-like activity of ribbon-like WS2-rGO. The introduction of AuNPs not only enhanced the electrocatalytic activity of the immunosensor, but also provided immobilization sites for binding TTF1 antibodies. The electrochemical signals can be greatly amplified due to their excellent electrochemical performance, which realized the sensitive determination of TTF1 with a wide linear range of 0.025-50 ng mL-1 and a lower detection limit of 0.016 ng mL-1 (S/N = 3). Moreover, the immunosensor exhibited high selectivity, good reproducibility, and robust stability, as well as the ability to detect TTF1 in human serum with satisfactory results. These observed properties of the immunosensor enhance its potential practicability in clinical applications. This method can also be used for the detection of other tumor biomarkers by using the corresponding antigen-antibody complex.

Trends and prospects of 2-D tungsten disulphide (WS2) hybrid nanosystems for environmental and biomedical applications

Recently, 2D layered transition metal dichalcogenides (TMDCs) with their ultrathin sheet nanostructure and diversified electronic structure have drawn attention for various advanced applications to achieve high-performance parameters. Unique 2D TMDCs mainly comprise transition metal and chalcogen element where chalcogen element layers sandwich the transition metal element layer. In such a case, various properties can be enhanced and controlled depending on the targeted application. Among manipulative 2D TMDCs, tungsten disulphide (WS2) is one of the emerging nano-system due to its fascinating properties in terms of direct band gap, higher mobility, strong photoluminescence, good thermal stability, and strong magnetic field interaction. The advancement in characterization techniques, especially scattering techniques, can help in study of opto-electronic properties of 2D TMDCs along with determination of layer variations and investigation of defect. In this review, the fabrication and applications are well summarized to optimize an appropriate WS2-TMDCs assembly according to focused field of research. Here, the scientific investigations on 2D WS2 are studied in terms of its structure, role of scattering techniques to study its properties, and synthesis routes followed by its potential applications for environmental remediation (e.g., photocatalytic degradation of pollutants, gas sensing, and wastewater treatment) and biomedical domain (e.g., drug delivery, photothermal therapy, biomedical imaging, and biosensing). Further, a special emphasis is given to the significance of 2D WS2 as a substrate for surface-enhanced Raman scattering (SERS). The discussion is further extended to commercial and industrial aspects, keeping in view major research gaps in existing research studies.

Multifunctional Eu(III)-modified HOFs: roxarsone and aristolochic acid carcinogen monitoring and latent fingerprint identification based on artificial intelligence

The exploration of multifunctional materials and intelligent technologies used for fluorescence sensing and latent fingerprint (LFP) identification is a research hotspot of material science. In this study, an emerging crystalline luminescent material, Eu3+-functionalized hydrogen-bonded organic framework (Eu@HOF-BTB, Eu@1), is fabricated successfully. Eu@1 can emit purple red fluorescence with a high photoluminescence quantum yield of 36.82%. Combined with artificial intelligence (AI) algorithms including support vector machine, principal component analysis, and hierarchical clustering analysis, Eu@1 as a sensor can concurrently distinguish two carcinogens, roxarsone and aristolochic acid, based on different mechanisms. The sensing process exhibits high selectivity, high efficiency, and excellent anti-interference. Meanwhile, Eu@1 is also an excellent eikonogen for LFP identification with high-resolution and high-contrast. Based on an automatic fingerprint identification system, the simultaneous differentiation of two fingerprint images is achieved. Moreover, a simulation experiment of criminal arrest is conducted. By virtue of the Alexnet-based fingerprint analysis platform of AI, unknown LFPs can be compared with a database to identify the criminal within one second with over 90% recognition accuracy. With AI technology, HOFs are applied for the first time in the LFP identification field, which provides a new material and solution for investigators to track criminal clues and handle cases efficiently.

Recent advances in fluorescence-based chemosensing of organoarsenic feed additives using luminescence MOFs, COFs, HOFs, and QDs

Organoarsenics are low-toxicity compounds that are used widely as feed additives to promote livestock growth, enhance meat pigmentation, and fight against intestinal parasites. The organoarsenic compounds are commonly found in poultry waste and the degradation of organoarsenic produces the toxic carcinogen inorganic arsenic such as As(V) and As(III), which results in severe arsenic pollution of soil and groundwater. As a consequence, there exists a high necessity to develop suitable sensing methods for the trace detection and quantification of organoarsenic feed additives in wastewater. Among various detection methods, in particular, fluorescence-based sensing has become a popular and efficient method used extensively for sensing water contaminants and environmental contaminants. In the recent past, a wide variety of fluorescence chemosensors have been designed and employed for the efficient sensing and quantification of the concentration of organoarsenic feed additives in different environmental samples. This review article systematically highlights various fluorescence chemosensors reported to date for fluorescence-based sensing of organoarsenic feed additives. The fluorescence sensors discussed in this review are classified and grouped according to their structures and functions, and in each section, we provide a detailed report on the structure, photophysics, and fluorescence sensing properties of different chemosensors. Lastly, the future perspectives on the design and development of practically useful sensor systems for selective and discriminative sensing of organoarsenic compounds have been stated.

A novel electrochemical aptasensor based on eco-friendly synthesized titanium dioxide nanosheets and polyethyleneimine grafted reduced graphene oxide for ultrasensitive and selective detection of ciprofloxacin

Developing a rapid, sensitive, and efficient analytical method for the trace-level determination of highly concerning antibiotic ciprofloxacin (CIP) is desirable to guarantee the safety of human health and ecosystems. In this work, a novel electrochemical aptasensor based on polyethyleneimine grafted reduced graphene oxide and titanium dioxide (rGO/PEI/TiO2) nanocomposite was constructed for ultrasensitive and selective detection of CIP. Through the in-situ electrochemical oxidation of Ti3C2Tx nanosheets, TiO2 nanosheets with good electrochemical response were prepared in a more convenient and eco-friendly method. The prepared TiO2 nanosheets promote charge transferring on electrode interface, and [Fe(CN)6]3-/4- as electrochemical active substance can be electrostatically attracted by rGO/PEI. Thus, electrochemical detection signal of the aptasensor variates a lot after specific binding with CIP, achieving working dynamic range of 0.003-10.0 μmol L-1, low detection limit down to 0.7 nmol L-1 (S/N = 3) and selectivity towards other antibiotics. Additionally, the aptasensor exhibited good agreement with HPLC method at 95% confidence level, and achieved good recoveries (96.8-106.3%) in real water samples, demonstrating its suitable applicability of trace detection of CIP in aquatic environment.

Diclofenac-Impregnated Mesoporous Carbon-Based Electrode Material for the Analysis of the Arsenic Drug Roxarsone

This paper describes a novel electrode material, diclofenac-impregnated mesoporous carbon modified with a cationic surfactant, cetyltrimethylammonium bromide (DF-CMK-3/CTAB), for ultratrace analysis of the arsenic drug roxarsone (ROX). DF-CMK-3 amorphous carbon is a material with a high specific surface area and well-defined, hexagonally ordered, thin mesopores. The functional groups attached to the carbonaceous surface, such as chromene and pyron-like oxygen groups, lactam, and aromatic carbon rings, have the basic character and they can donate electrons. Modification of DF-CMK-3 with a CTAB layer significantly increases the analytical signal due to electrostatic interactions between the cationic surfactant and the anion form of ROX in the acidic medium. The voltammetric procedure at the glassy carbon sensor modified with DF-CMK-3/CTAB exhibited excellent sensitivity (limit of detection of 9.6 × 10-11 M) with a wide range of linearity from 5.0 × 10-10 to 1.0 × 10-4 M. Analysis of real samples (treated municipal wastewater and river water) showed recoveries from 96 to 102% without applying the complicated sample pretreatment step. The sensor demonstrated excellent sensitivity in the analysis of the arsenic drug ROX in the presence of interferences in environmental water samples.

Tungsten-based Nanomaterials in the Biomedical Field: A Bibliometric Analysis of Research Progress and Prospects

Tungsten-based nanomaterials (TNMs) with diverse nanostructures and unique physicochemical properties have been widely applied in the biomedical field. Although various reviews have described the application of TNMs in specific biomedical fields, there are still no comprehensive studies that summarize and analyze research trends of the field as a whole. To identify and further promote the development of biomedical TNMs, a bibliometric analysis method is used to analyze all relevant literature on this topic. First, general bibliometric distributions of the dataset by year, country, institute, referenced source, and research hotspots are recognized. Next, a comprehensive review of the subjectively recognized research hotspots in various biomedical fields, including biological sensing, anticancer treatments, antibacterials, and toxicity evaluation, is provided. Finally, the prospects and challenges of TNMs are discussed to provide a new perspective for further promoting their development in biomedical research.

Glassy Carbon Modified with Cationic Surfactant (GCE/CTAB) as Electrode Material for Fast and Simple Analysis of the Arsenic Drug Roxarsone

For the fast and simple sensing of the arsenic drug roxarsone (ROX), the development of a glassy carbon electrode (GCE) modified with cationic surfactant (cetyltrimethylammonium bromide, CTAB) material is critical. The CTAB-modified glassy carbon electrode, in contrast to the unmodified one, showed excellent behavior for electrochemical reduction of ROX using cyclic voltammetry (CV) and square-wave adsorptive stripping voltammetry (SWAdSV) techniques. CV studies reveal an irreversible reduction process of NO₂ to NH-OH in the ROX molecule in NaAc-HAc buffer (pH = 5.6). The electrode material was characterized using CV and electrochemical impedance spectroscopy. The experiments show that the surfactant-modified material has faster electron transfer and a higher active surface area, and permits a diffusion-adsorption-controlled process. After optimization, the SWAdSV procedure with GCE/CTAB has linear ranges of 0.001-0.02 and 0.02-20 µM, and a detection limit of 0.13 nM. Furthermore, the procedure successfully determined roxarsone in river water samples.

Two-Dimensional Non-Carbon Materials-Based Electrochemical Printed Sensors: An Updated Review

Recently, there has been increasing interest in electrochemical printed sensors for a wide range of applications such as biomedical, pharmaceutical, food safety, and environmental fields. A major challenge is to obtain selective, sensitive, and reliable sensing platforms that can meet the stringent performance requirements of these application areas. Two-dimensional (2D) nanomaterials advances have accelerated the performance of electrochemical sensors towards more practical approaches. This review discusses the recent development of electrochemical printed sensors, with emphasis on the integration of non-carbon 2D materials as sensing platforms. A brief introduction to printed electrochemical sensors and electrochemical technique analysis are presented in the first section of this review. Subsequently, sensor surface functionalization and modification techniques including drop-casting, electrodeposition, and printing of functional ink are discussed. In the next section, we review recent insights into novel fabrication methodologies, electrochemical techniques, and sensors' performances of the most used transition metal dichalcogenides materials (such as MoS₂, MoSe₂, and WS₂), MXenes, and hexagonal boron-nitride (hBN). Finally, the challenges that are faced by electrochemical printed sensors are highlighted in the conclusion. This review is not only useful to provide insights for researchers that are currently working in the related area, but also instructive to the ones new to this field.

Graphene-based electrochemical sensors for antibiotic detection in water, food and soil: A scientometric analysis in CiteSpace (2011-2021)

The residues of antibiotics in the environment pose a potential health hazard, so highly sensitive detection of antibiotics has always appealed to analytical chemists. With the widespread use of new low-dimensional materials, graphene-modified electrochemical sensors have emerged as an excellent candidate for highly sensitive detection of antibiotics. Graphene, its derivatives and its composites have been used in this field of exploration in the last decade. In this review, we have not only described the field using traditional summaries, but also used bibliometrics to quantify the development of the field. The literature between 2011 and 2021 was included in the analysis. Also, the sensing performance and detection targets of different sensors were compared. We were able to trace not only the flow of research themes, but also the future areas of development. Graphene is a material that has a high potential to be used on a large scale in the preparation of electrochemical sensors. How to design a sensor with selectivity and low cost is the key to bring this material from the laboratory to practical applications.

Ultrasensitive detection of four organic arsenic compounds at the same time using a five-link cardboard-based assay

In order to effectively control the excessive use of organic arsenic reagents in livestock and poultry products, there is an urgent need to develop a method for rapid detection of multiple organic arsenic reagents. In this study, two haptens were designed and derivatized around the structural formula of roxarsone, and a highly-sensitive group-selective mAb 3F2 was prepared, which can simultaneously detect roxarsone, 4-aminophenylarsonic acid, 2-aminophenylarsonic acid and phenylarsonic acid. We further developed a colloidal gold immunochromatographic test strip (ICS) and prepared a five-link card that can simultaneously detect four organic arsenics in chicken and pork samples. Its quantitative detection limits (LOQ) for the four compounds in chicken and pork samples were 0.06 and 0.32 ng/mL, 0.11 and 0.29 ng/mL, 0.34 and 0.99 ng/mL, and 0.88 and 1.5 ng/mL, respectively. This multi-ICS detection provides a powerful tool for the on-site detection and rapid screening of organic arsenic reagents in actual samples.

Electrochemical Sensing of Roxarsone on Natural Biomass-Derived Two-Dimensional Carbon Material as Promising Electrode Material

Herein, we report the electrochemical detection of roxarsone (ROX) on a two-dimensional (2D) activated carbon (AC)-modified glassy carbon electrode (GCE). Meso/microporous 2D-AC is synthesized from a natural biomass Desmostachya bipinnata, commonly known as Kusha in India. This environment-friendly material is synthesized by chemical activation using potassium hydroxide (KOH) and used as a sensitive electrochemical platform for the determination of ROX. It is an arsenic-based medicine, also used as a coccidiostat drug. It is widely used in poultry production as a feed additive to increase weight gain and improve feed efficiency. Long-term exposure to arsenic leads to serious health problems in humans and demands an urgent call for sensitive detection of ROX. Therefore, the green synthesis of 2D-AC is introduced as new carbon support for the electrochemical sensing of ROX. It provides a large surface area and efficiently supports enhanced electron transfer. Its electrocatalytic activity is seen in potassium ferri/ferrocyanide by cyclic voltammetry, where the 2D-AC-modified GCE delivered five to six times higher electrochemical performance as compared to the unmodified GCE. Electrochemical impedance spectroscopy is also performed to show that the prepared material has faster electron transfer and permits a diffusion-controlled process. It works well in real samples and also on disposable screen-printed carbon electrodes, thereby showing great potential for its application in clinical diagnosis. Our results exemplify a modest and innovative style for the synthesis of excellent electrode material in the electrochemical sensing platform and thus offer an inexpensive and highly sensitive novel approach for the electrochemical sensing of ROX and other similar drugs.

Electrochemical Behavior of Three-Dimensional Cobalt Manganate with Flowerlike Structures for Effective Roxarsone Sensing

Rational design and construction of the finest electrocatalytic materials are important for improving the performance of electrochemical sensors. Spinel bioxides based on cobalt manganate (CoMn₂O₄) are of particular importance for electrochemical sensors due to their excellent catalytic performance. In this study, three-dimensional CoMn₂O₄ with the petal-free, flowerlike structure is synthesized by facile hydrothermal and calcination methods for the electrochemical sensing of roxarsone (RXS). The effect of calcination temperature on the characteristics of CoMn₂O₄ was thoroughly studied by in-depth electron microscopic, spectroscopic, and analytical methods. Compared to previous reports, CoMn₂O₄-modified screen-printed carbon electrodes display superior performance for the RXS detection, including a wide linear range (0.01-0.84 μM; 0.84-1130 μM), a low limit of detection (0.002 μM), and a high sensitivity (33.13 μA μM^-1 cm^-2). The remarkable electrocatalytic performance can be attributed to its excellent physical properties, such as good conductivity, hybrid architectures, high specific surface area, and rapid electron transportation. More significantly, the proposed electrochemical sensor presents excellent selectivity, good stability, and high reproducibility. Besides, the detection of RXS in river water samples using the CoMn₂O₄-based electrochemical sensor shows satisfactory recovery values in the range of 98.00-99.80%. This work opens a new strategy to design an electrocatalyst with the hybrid architecture for high-performance electrochemical sensing.

ZIF-67 MOF-derived Co nanoparticles supported on N-doped carbon skeletons for the amperometric determination of hydrogen peroxide

ZIF-67-derived Co nanoparticles supported on N-doped carbon skeletons have been prepared from melamine foam (Co-NPs/NCs) for non-enzymatic electrochemical H₂O₂ detection. The synthesis of Co-NPs/NCs was demonstrated via calcination treatment using melamine foam (MF) and ZIF-67 as precursors. The experimental results show that Co-NPs/NCs composites exhibit eminent catalytic activity toward specific determination of H₂O₂ with high selectivity and sensitivity (252.43 and 203.88 μA mM^-1 cm^-2), low LOD (0.12 μM), and wide linear ranges (10-2080 and 2080-11,800 μM). The excellent performance might be ascribed to the synergetic effects of MOF and N-doped carbon skeletons. The carbon skeletons serve as a conductive bridge and provide a large specific surface area, which can facilitate electron transfer and well disperse nanoparticles. This non-enzymatic electrochemical sensor based on Co-NPs/NCs can successfully detect H₂O₂ secreted by living cells, indicating its great potential in the early diagnosis and pathological exploration of disease.

Synthesis and characterization of bipyridine cobalt(ii) complex modified graphite screen printed electrode: an electrochemical sensor for simultaneous detection of acetaminophen and naproxen

The new Co(ii) compound [Co(5,5'-dmbpy)2(NCS)2] (a1) was prepared by reacting Co(NO3)2·6H2O, 5,5'-dimethyl-2,2'-bipyridine ligand, and Na(SCN). The nano-scale size of [Co(5,5'-dmbpy)2(NCS)2] (a1) was synthesized using sonochemical process. The size of the nanoparticles (a2) was ∼13 ± 2 nm. We have also provided a new platform of electrochemical sensing for simultaneous detection of acetaminophen and naproxen using (a2) surface modified graphite screen printed electrode (SPE) in 0.1 M phosphate buffer solution (PBS, pH 7.0). In contrast to bare SPE, the modified SPE could significantly improve the electrooxidation activity of acetaminophen along with the rise in the current of an anodic peak. The peak currents acquired using differential pulse voltammetry (DPV) raised linearly with the raising of acetaminophen concentration and the sensor had a detection range over the concentration range of 0.009-325.0 μM, with a detection limit of 5.0 nM (S/N = 3). In the case of naproxen peak, currents of naproxen oxidation at the modified SPE were linearly dependent on the naproxen amounts in the range of 1.0-500.0 μM. The detection limit (S/N = 3) was calculated to be 0.03 μM. The DPV responses show that the peaks of acetaminophen and naproxen oxidation were vividly separated from one other with a potential difference of 410 mV between them. The low detection limit, high sensitivity, and stability made the relevant electrode applicable for the analysis of acetaminophen and naproxen in real samples. Further, its practical applicability was reliable and desirable in the analysis of pharmaceutical compounds and biological fluids. The benefits of using this modified electrode for the determination of analytes are compared with other works in the manuscript.

Ultrasonication and hydrothermal assisted synthesis of cloud-like zinc molybdate nanospheres for enhanced detection of flutamide

Ultrasonication is one of the emerging probes for nanoparticles synthesis as well as promoting the material property by treasuring the precious time during a chemical reaction. In this present work, we successfully designed a cloud-like α-ZnMoO₄ nanospheres (ZMNS) using ultrasound assistance (bath sonication with the power of 60 W and frequency of 37/80 kHz) hydrothermal method for catalyzing the effective electrochemical determination of anti-androgen drug candidate flutamide (FLT). The crystallinity and phase purity were investigated using powder X-ray diffractometric analysis. The FTIR and Raman spectra information were compared to detect the possible bonding in ZMNS. The texture and surface morphology were studied using Field emission scanning electron microscope and High-resolution Transmission electron microscope images. The presence of the elements (Zn, Mo and O) and the absence of any other impurities were monitored and confirmed using EDAX analysis. The fabrication of ZMNS modified GCE was performed carefully. Additionally, the ZMNS modified glassy carbon electrode (GCE) exhibits superior electrocatalytic activity by means of higher cathodic peak current towards the detection of FLT. The fashioned electrode attained two wide linear response ranges (0.1 to 73 µM; 111 to 1026 µM) with a lower detection limit of about 33 nM correspondingly. Furthermore, the fabricated sensor displayed excellent sensitivity of 1.095 µA µM^-1 cm^-2 and good selectivity for FLT sensing even in the existence of similar interfering compounds and biomolecules. Along with that, the designed sensor executed noticeable reproducibility, repeatability, and enduring stability.