Simultaneous determination of cholesterol, ascorbic acid and uric acid as three essential biological compounds at a carbon paste electrode modified with copper oxide decorated reduced graphene oxide nanocomposite and ionic liquid

Chiral Effect on the Electrochemistry of Magnetic Ferrite Colloidal Nanocrystal Assembly Modified by Amino Acids

Chirality on the molecular or nanometer scale is particularly significant in chemistry, materials science, and biomedicine. Chiral electrochemical reactions on solid surfaces are currently a hot research topic. Herein, a chiral solid surface is constructed in aqueous solutions by mixing chiral molecules, d- and l-glutamic, with γ-Fe2O3 and Fe3O4 nanoparticles (NPs) and MnFe2O4 colloidal nanocrystal assembly (CNA). Cyclic voltammetry and differential pulse voltammetry measurements are conducted in a phosphate buffer solution (PBS) containing ascorbic acid (AA) or isoascorbic acid (IAA), and a chiral effect appears on the electroreduction of ferric ions of amino acid-modified magnetic samples. A negative or positive potential shift is observed, respectively, for magnetic structures modified by l- and d-glutamic acid in aqueous AA electrolyte, while the opposite is observed for these samples in IAA electrolyte. The reduction peak current increases by 0.8-1.2 times for the electrodes modified with l- and d-glutamate molecules, improving the electron transport efficiency. The chiral effect is absent when the electrolytes contain achiral uric acid or dopamine, or even chiral l-/d-/ld-tartaric acid. The chiral recognition between d-/l-glutamic acid and AA/IAA at the electrochemical interface is suggested to be related to their spinal configurations. These observations will be helpful for the rational design of inorganic functional chiral micro/nanostructures.

Electrochemical sensing of Hg(ii) in chicken liver and snail shell extract samples using novel modified SDA/MWCNT electrodes

Heavy metal ions (Hg(ii)) were detected in fresh chicken liver and snail shell extract samples using novel synthesised SDA/MWCNT-modified electrodes. The synthesized N,N'-bis(salicylaldehyde)-1,2-diaminobenzene (SDA) ligand was characterized via FT-IR, 1H-NMR, and 13C-NMR spectroscopy. The hydroxyl and imine functional groups present in SDA act as active sites and bind to the MWCNT surface. The surface morphology of the modified SDA/MWCNT electrode exhibited a star-like crystal structure and the preconcentration of Hg(ii)-SDA/MWCNTs lead to a crystal cloud structure, as characterized by SEM with EDX. The enhancement of current and conductance of the SDA/MWCNT- and MWCNT-modified electrode was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The conductance (σ) values for the MWCNT- and SDA/MWCNT-modified electrodes are 234.1 × 10-5 S cm-1 and 358.4 × 10-5 S cm-1, respectively, as determined by electrochemical impedance spectroscopy. Consequently, an electrochemical sensor with outstanding performance in terms of reproducibility, stability and anti-interference ability was fabricated. The stripping analysis of Hg(ii) was performed using square wave anodic stripping voltammetry (SWASV) and cyclic voltammetry (CV). Using SWASV, a linear range of Hg(ii) response was found to be 1.3 to 158 μg L-1, and the limit of detection (LOD) was 0.24 μg L-1. Finally, the results of the recovered value of Hg(ii) in freshly prepared chicken liver and snail shell extract samples by SWASV were compared with the atomic absorption spectroscopy (AAS) results.

"Two-in-One" PtPdCu Trimetallic Multifunctional Nanoparticles-Mediated Dual-Signal-Integrated Aptasensor for Ultradetection of Enrofloxacin

Balancing the accuracy and simplicity of aptasensors is a challenge in their construction. This study addresses this issue by leveraging the remarkable loading capacity and peroxidase-like catalytic activity of PtPdCu trimetallic nanoparticles, which reduces the reliance on precious metals. A dual-signal readout aptasensor for enrofloxacin (ENR) detection is designed, incorporating DNA dynamic network cascade reactions to further amplify the output signal. Exploiting the strong loading capacity of PtPdCu nanoparticles, they are self-assembled with thionine (Thi) to form a signal label capable of generating signals in two independent modes. The label exhibits excellent enzyme-like catalytic activity and enhances electron transfer capabilities. Differential pulse voltammetry (DPV) and square-wave voltammetry (SWV) are employed to independently read signals from the oxidation-reduction reaction of Thi and the catalytic oxidation of hydroquinone (HQ) to benzoquinone (BQ) by H2O2. The introduced DNA dynamic network cascade reaction modularizes sample processing and electrode surface signal generation, avoiding electrode contamination and efficiently increasing the output of the catalyzed hairpin assembly (CHA) cycle. Under optimized conditions, the developed aptasensor demonstrates detection limits of 0.112 (DPV mode) and 0.0203 pg/mL (SWV mode). Additionally, the sensor successfully detected enrofloxacin in real samples, expanding avenues for designing dual-mode signal amplification strategies.

Smart and emerging point of care electrochemical sensors based on nanomaterials for SARS-CoV-2 virus detection: Towards designing a future rapid diagnostic tool

In the recent years, researchers from all over the world have become interested in the fabrication of advanced and innovative electrochemical and/or biosensors for respiratory virus detection with the use of nanotechnology. These fabricated sensors demonstrated a number of benefits, including precision, affordability, accessibility, and miniaturization which makes them a promising test method for point-of-care (PoC) screening for SARS-CoV-2 viral infection. In order to comprehend the principles of electrochemical sensing and the role of various types of sensing interfaces, we comprehensively explored the underlying principles of electroanalytical methods and terminologies related to it in this review. In addition, it is addressed how to fabricate electrochemical sensing devices incorporating nanomaterials as graphene, metal/metal oxides, metal organic frameworks (MOFs), MXenes, quantum dots, and polymers. We took an effort to carefully compile current developments, advantages, drawbacks, possible solutions in nanomaterials based electrochemical sensors.

A comprehensive exploration of tartrazine detection in food products: Leveraging fluorescence nanomaterials and electrochemical sensors: Recent progress and future trends

Azo dyes are widely used as food coloring agents because of their affordability and stability. Examples include brilliant blue, carmoisine, sunset yellow, allura red, and tartrazine (Tar), etc. Notably, Tar is often utilized in hazardous food goods. They are frequently flavoured and combined with food items, raising the likelihood and danger of exposure. Therefore, detecting Tar in food is crucial to prevent health risks. Fluorescence nanomaterials and electrochemical sensors, known for their high sensitivity, affordability, simplicity, and speed, have been widely adopted by researchers for Tar detection. This comprehensive paper delves into the detection of Tar in food products. It extensively covers the utilization of advanced carbon-based nanomaterials, including CDs, doped CDs, and functionalized CDs, for sensitive Tar detection. Additionally, the paper explores the application of electrochemical sensors. The paper concludes by addressing current challenges and prospects, emphasizing efforts to enhance sensitivity, and selectivity for improved food safety.

Investigating the Chemical Composition of Lepidium sativum Seeds and Their Ability to Safeguard against Monosodium Glutamate-Induced Hepatic Dysfunction

Monosodium glutamate (MSG) is one of the most frequently used food additives that endanger public health. The antioxidant, hyperlipidemic, and cytoprotective properties of Lepidium sativum seeds (LSS) as a natural remedy can minimize the harmful effects of MSG. This study investigated the potential protective effect of LSS against MSG-induced hepatotoxicity in rats. Male albino Sprague Dawley rats (n = 24) were equally divided into four groups for 30 days: the control group (G1) received a basal diet without supplement, group (G2) was fed a basal diet + MSG (30 g/kg b.w.) as a model group, group (G3) was fed a basal diet + MSG (30 g/kg b.w.) + LSS (30 g/kg b.w.), and group (G4) was fed a basal diet + MSG (30 g/kg b.w.) + LSS (60 g/kg b.w.). LSS enhanced serum alkaline phosphatase activity as well as total cholesterol, triglyceride, and glucose levels. It can decrease peroxide content in serum lipids and inhibit glutathione reductase and superoxide dismutase in hepatic cells. The dietary supplementation with LSS provided cytoprotection by enhancing the histoarchitecture of the liver and decreasing the number of apoptotic cells. Due to their antioxidant and anti-apoptotic properties, LSS effectively protect against the hepatotoxicity of MSG. These findings are of the highest significance for drawing attention to incorporating LSS in our food industry and as a health treatment in traditional medicine to combat MSG-induced hepatic abnormalities.

A three-dimensional composite film-modified electrode based on polyoxometalates and ionic liquid-decorated carbon nanotubes for the determination of L-tyrosine in food

A stable and innovative composite film-modified electrode based on Dawson polyoxometalates H8P2Mo16V2O62 (P2Mo16V2) and ionic liquid (BMIMBr)-decorated carbon nanotubes, annotated as PEI/(P2Mo16V2/BMIMBr-CNTs)8, has been constructed by using the layer-by-layer self-assembly (LBL) method for the determination of L-tyrosine. The combination of three active components not only offers higher conductivity to facilitate rapid electron transfer, but also avoids the accumulation of P2Mo16V2 to expand the contact area and increase the reactive active sites. The modified electrode exhibits outstanding sensing performance for determination of Tyr with wide linear determination range of 5.8×10-7 M ~ 1.2×10-4 M, low determination limit of 1.7×10-7M (S/N=3), high selectivity for common interferences, and excellent stability at the potential of +0.78 V (vs. Ag/AgCl (3 M KCl)). The relative standard deviation (RSD) of 4.3% for five groups of parallel experiments shows the satisfactory repeatability of PEI/(P2Mo16V2/BMIMBr-CNTs)8. In addition, for determination of Tyr, the PEI/(P2Mo16V2/BMIMBr-CNTs)8 shows good recoveries of 98.8-99.8% in meat floss, which can be feasible in practical application.

Green synthesis of Au@g-C3N4 nanocomposite using Hyssopus officinalis extract and its sensing application for vortioxetine determination

Herein, we introduce a stable and green Au@g-C3N4 nanocomposite as a selective electrochemical sensor for vortioxetine (VOR) determination. The electrochemical behavior of VOR on the developed electrode was investigated through cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), and chronoamperometry. The Au@g-C3N4 nanocomposite was thoroughly observed by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and scanning electron microscopy. The Au@g-C3N4 nanocomposite had a higher conductivity and a narrower band gap than pure g-C3N4, causing higher electrochemical activity for VOR detection. Moreover, Au@g-C3N4 on the glassy carbon electrode (Au@g-C3N4/GCE) monitored a low level of VOR with high efficiency and low interference as an environmentally friendly processing approach. Interestingly, the as-fabricated sensor exhibited an ultrahigh selectivity for recognizing VOR with a detection limit (LOD) of 3.2 nM. Furthermore, the developed sensor was applied to determine VOR in pharmaceutical and biological samples, which indicated a high selectivity in the presence of interferences. This study suggests new insights into the phytosynthesis synthesis of nanomaterials with excellent biosensing applications.

Miniaturized Rapid Electrochemical Immunosensor Based on Screen Printed Carbon Electrodes for Mycobacterium tuberculosis Detection

In 2019, over 21% of an estimated 10 million new tuberculosis (TB) patients were either not diagnosed at all or diagnosed without being reported to public health authorities. It is therefore critical to develop newer and more rapid and effective point-of-care diagnostic tools to combat the global TB epidemic. PCR-based diagnostic methods such as Xpert MTB/RIF are quicker than conventional techniques, but their applicability is restricted by the need for specialized laboratory equipment and the substantial cost of scaling-up in low- and middle-income countries where the burden of TB is high. Meanwhile, loop-mediated isothermal amplification (LAMP) amplifies nucleic acids under isothermal conditions with a high efficiency, helps in the early detection and identification of infectious diseases, and can be performed without the need for sophisticated thermocycling equipment. In the present study, the LAMP assay was integrated with screen-printed carbon electrodes and a commercial potentiostat for real time cyclic voltammetry analysis (named as the LAMP-Electrochemical (EC) assay). The LAMP-EC assay was found to be highly specific to TB-causing bacteria and capable of detecting even a single copy of the Mycobacterium tuberculosis (Mtb) IS6110 DNA sequence. Overall, the LAMP-EC test developed and evaluated in the present study shows promise to become a cost-effective tool for rapid and effective diagnosis of TB.

Three-Dimensional Electrochemical Sensors for Food Safety Applications

Considering the increasing concern for food safety, electrochemical methods for detecting specific ingredients in the food are currently the most efficient method due to their low cost, fast response signal, high sensitivity, and ease of use. The detection efficiency of electrochemical sensors is determined by the electrode materials' electrochemical characteristics. Among them, three-dimensional (3D) electrodes have unique advantages in electronic transfer, adsorption capacity and exposure of active sites for energy storage, novel materials, and electrochemical sensing. Therefore, this review begins by outlining the benefits and drawbacks of 3D electrodes compared to other materials before going into more detail about how 3D materials are synthesized. Next, different types of 3D electrodes are outlined together with common modification techniques for enhancing electrochemical performance. After this, a demonstration of 3D electrochemical sensors for food safety applications, such as detecting components, additives, emerging pollutants, and bacteria in food, was given. Finally, improvement measures and development directions of electrodes with 3D electrochemical sensors are discussed. We think that this review will help with the creation of new 3D electrodes and offer fresh perspectives on how to achieve extremely sensitive electrochemical detection in the area of food safety.

A CaCuSi4O10/GCE electrochemical sensor for detection of norfloxacin in pharmaceutical formulations

This study reports on a calcium copper tetrasilicate (CaCuSi₄O₁₀)/glassy carbon electrode (GCE) electrochemical sensor developed for rapid sensing and quantification of an antibacterial drug, norfloxacin, using both cyclic voltammetry and differential pulse voltammetry. The sensor was fabricated by modifying a glassy carbon electrode with the CaCuSi₄O₁₀. Electrochemical impedance spectroscopy was performed and the Nyquist plot showed that the CaCuSi₄O₁₀/GCE had a lower charge transfer resistance of 22.1 Ω cm² compared to the GCE with a charge transfer resistance of 43.5 Ω cm². Differential pulse voltammetry showed that the optimum pH for the electrochemical detection of norfloxacin in potassium phosphate buffer solution (PBS) electrolyte was pH 4.5 and an irreversible oxidative peak was found at 1.067 V. Two linear ranges were established at 0.01 to 0.55 μM and 0.55 μM to 82.1 μM, and the limit of detection was ca. 0.0046 μM. We further demonstrated that the electrochemical oxidation was controlled by both diffusion and adsorption processes. The sensor was investigated in the presence of interferents and was found to be selective toward norfloxacin. The pharmaceutical drug analysis was done to establish method reliability and a significantly low standard deviation of 2.3% was achieved. The results suggest that the sensor can be applied in the detection of norfloxacin.

Rh single-atom nanozymes for efficient ascorbic acid oxidation and detection

The management of ascorbic acid (AA) in biological fluids is of significant importance for body functions and human health, yet challenging due to the lack of high-performance sensing catalysts. Herein, we report the design of Rh single-atom nanozymes (Rh SAzymes) by mimicking the active sites of ascorbate peroxidase toward efficient electrocatalytic oxidation and detection of AA. Benefiting from the enzyme-mimicking single-atom coordination, the Rh SAzyme exhibits an unprecedented electrocatalytic activity for AA oxidation with an onset potential as low as 0.02 V (vs. Ag/AgCl). Combined with the screen-printing technology, a miniaturized Rh SAzyme biosensor was firstly constructed for tracking dynamic trends of AA in the human subject and detecting AA content in nutritional products. The as-prepared biosensor exhibits excellent detection performances with a wide linear range of 10.0 μM-53.1 mM, a low detection limit of 0.26 μM, and a long stability of 28 days. This work opens a door for the design of artificial single-atom electrocatalysts to mimic natural enzymes and their subsequent application in biosensors.

An Efficient Electrochemical Biosensor to Determine 1,5-Anhydroglucitol with Persimmon-Tannin-Reduced Graphene Oxide-PtPd Nanocomposites

1,5-Anhydroglucitol (1,5-AG) is a sensitive biomarker for real-time detection of diabetes mellitus. In this study, an electrochemical biosensor to specifically detect 1,5-AG levels based on persimmon-tannin-reduced graphene oxide-PtPd nanocomposites (PT-rGO-PtPd NCs), which were modified onto the surface of a screen-printed carbon electrode (SPCE), was designed. The PT-rGO-PtPd NCs were prepared by using PT as the film-forming material and ascorbic acid as the reducing agent. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-vis), and X-ray diffraction (XRD) spectroscopy analysis were used to characterise the newly synthesised materials. PT-rGO-PtPd NCs present a synergistic effect not only to increase the active surface area to bio-capture more targets, but also to exhibit electrocatalytic efficiency to catalyze the decomposition of hydrogen peroxide (H₂O₂). A sensitive layer is formed by pyranose oxidase (PROD) attached to the surface of PT-rGO-PtPd NC/SPCE. In the presence of 1,5-AG, PROD catalyzes the oxidization of 1,5-AG to generate 1,5-anhydrofuctose (1,5-AF) and H₂O₂ which can be decomposed into H₂O under the synergistic catalysis of PT-rGO-PtPd NCs. The redox reaction between PT and its oxidative product (quinones, PTox) can be enhanced simultaneously by PT-rGO-PtPd NCs, and the current signal was recorded by the differential pulse voltammetry (DPV) method. Under optimal conditions, our biosensor shows a wide range (0.1-2.0 mg/mL) for 1,5-AG detection with a detection limit of 30 μg/mL (S/N = 3). Moreover, our electrochemical biosensor exhibits acceptable applicability with recoveries from 99.80 to 106.80%. In summary, our study provides an electrochemical method for the determination of 1,5-AG with simple procedures, lower costs, good reproducibility, and acceptable stability.

Electrochemical devices for cholesterol detection

Cholesterol can be considered as a biomarker of illnesses such as heart and coronary artery diseases or arteriosclerosis. Therefore, the fast determination of its concentration in blood is interesting as a means of achieving an early diagnosis of these unhealthy conditions. Electrochemical sensors and biosensors have become a potential tool for selective and sensitive detection of this biomolecule, combining the analytical advantages of electrochemical techniques with the selective recognition features of modified electrodes. This review covers the different approaches carried out in the development of electrochemical sensors for cholesterol, differentiating between enzymatic biosensors and non-enzymatic systems, highlighting lab-on-a-chip devices. A description of the different modification procedures of the working electrode has been included and the role of the different functional materials used has been discussed.

A Carbon Paste Electrode Modified by Bentonite and l-Cysteine for Simultaneous Determination of Ascorbic and Uric Acids: Application in Biological Fluids

A novel modification of a paste carbon electrode by Bentonite (Bent) and l-Cysteine (l-Cyst) was carried out for uric acid (UA) and ascorbic acid (AA) detection and quantification. Morphological and compositional characterization of the electrode surface were carried out using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopic analysis (EDS). Cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques were used to analyze UA and AA. The obtained sensor shows a good stability, sensibility, selectivity, and regeneration ability. Accordingly, the limit of detection (LOD) is found to be 0.031 μm and 9.6 μm for UA and AA, respectively. A good linearity in the range of 0.1 to 100 μm for UA and 10 to 1000 μm for AA was obtained. The peak-to-peak separation of UA-AA (ΔE_UA-AA ) was determined to be 330 mV. In addition, the sensor is applied successfully to monitor UA and AA in serum samples.

Sensitive and Rapid Detection of Aspartic Acid with Co3O4-ZnO Nanorods Using Differential Pulse Voltammetry

Herein, the detection of aspartic acid by doped Co₃O₄-ZnO nanorod materials was proposed using differential pulse voltammetry. The nano-composite metal oxide was synthesized by the wet precipitation method in basic media. Aspartic acid is a non-essential amino acid naturally synthesized in the body with lot of health significance, including as a biomarker for several health deficiencies. The synthesized composite Co₃O₄-ZnO nanorod was well-investigated by using FESEM, XRD, XPS, FTIR, UV/vis., EIS, and CV. The synthesized composite exhibited a low limit of detection (0.03 µM, high sensitivity (0.0014 µA µM^-1 cm^-2) and wide linear range (0.05-50 µM) for aspartic acid. The substrate, the Co₃O₄-ZnO nanorod, enhanced the electro-catalytic oxidation of aspartic acid as a result of its catalytic and conductivity properties. The developed sensor based on Co₃O₄-ZnO has a repeatable, reproducible and stable current response for aspartic acid. Additionally, other electroactive compounds did not interfere with the sensor's current response. The suitability of the developed sensor for real sample analysis was also established. Therefore, this study proposed the potential use of Co₃O₄-ZnO nanorod material in healthcare management for the maintenance of human well-being.

Recent Patents and Potential Applications of Homogenisation Techniques in Drug Delivery Systems

BACKGROUND

The term homogenise means "to force or provide coalesce". Homogenisation is a process to attain homogenous particle size. The objective of the homogenisation process is to use fluid force to split the fragments or tiny particles contained in the fluids into very small dimensions and form a sustainable dispersion suitable for further production.

METHODS

The databases were collected through Scopus, google patent, science web, google scholar, PubMed on the concept of homogenisation. The data obtained were systematically investigated.

RESULTS

The present study focus on the use of the homogenisation in drug delivery system. The aim of homogenisation process is to achieve the particle size in micro-and nano- range as it affects the different parameters in the formulation and biopharmaceutical profile of the drug. The particle size reduction plays a key role in influencing drug dissolution and absorption. The reduced particle size enhances the stability and therapeutic efficacy of the drug. Homogenization technology ensures to achieve effective, clinically efficient and targeted drug delivery with the minimal side effect.

CONCLUSION

Homogenization technology has been shown to be an efficient and easy method of size reduction to increase solubility and bioavailability, stability of drug carriers. This article gives an overview of the process attributes affecting the homogenization process, the patenting of homogeniser types, design, the geometry of valves and nozzles and its role in drug delivery.

Functionalization of Graphene Derivatives with Conducting Polymers and Their Applications in Uric Acid Detection

In this article, we review recent progress concerning the development of sensorial platforms based on graphene derivatives and conducting polymers (CPs), alternatively deposited or co-deposited on the working electrode (usually a glassy carbon electrode; GCE) using a simple potentiostatic method (often cyclic voltammetry; CV), possibly followed by the deposition of metallic nanoparticles (NPs) on the electrode surface (ES). These materials have been successfully used to detect an extended range of biomolecules of clinical interest, such as uric acid (UA), dopamine (DA), ascorbic acid (AA), adenine, guanine, and others. The most common method is electrochemical synthesis. In the composites, which are often combined with metallic NPs, the interaction between the graphene derivatives-including graphene oxide (GO), reduced graphene oxide (RGO), or graphene quantum dots (GQDs)-and the CPs is usually governed by non-covalent functionalization through π-π interactions, hydrogen bonds, and van der Waals (VW) forces. The functionalization of GO, RGO, or GQDs with CPs has been shown to speed up electron transfer during the oxidation process, thus improving the electrochemical response of the resulting sensor. The oxidation mechanism behind the electrochemical response of the sensor seems to involve a partial charge transfer (CT) from the analytes to graphene derivatives, due to the overlapping of π orbitals.

Sodium Dodecyl Sulfate-Mediated Graphene Sensor for Electrochemical Detection of the Antibiotic Drug: Ciprofloxacin

The present study involves detecting and determining CIP by a new electrochemical sensor based on graphene (Gr) in the presence of sodium dodecyl sulfate (SDS) employing voltammetric techniques. Surface morphology studies of the sensing material were analyzed using a scanning electron microscope (SEM) and atomic force microscope (AFM). In the electroanalysis of CIP at the developed electrode, an enhanced anodic peak response was recorded, suggesting the electro-oxidation of CIP at the electrode surface. Furthermore, we evaluated the impact of the electrolytic solution, scan rate, accumulation time, and concentration variation on the electrochemical behavior of CIP. The possible electrode mechanism was proposed based on the acquired experimental information. A concentration variation study was performed using differential pulse voltammetry (DPV) in the lower concentration range, and the fabricated electrode achieved a detection limit of 2.9 × 10^-8 M. The proposed sensor detected CIP in pharmaceutical and biological samples. The findings displayed good recovery, with 93.8% for tablet analysis and 93.3% to 98.7% for urine analysis. The stability of a developed electrode was tested by inter- and intraday analysis.

Ultrafast construction of 3D ultrathin NiCo-LDH@Cu heteronanosheet array by plasma magnetron sputtering for non-enzymatic glucose sensing in beverage and human serum

In this work, a 3D ultra-thin NiCo-LDH nanosheet array coated Cu nanoparticles on carbon cloth (NiCo-LDH@Cu NSA/CC) was ultrafast synthesized by plasma magnetron sputtering for the first time. This method has low toxicity and is easy to operate. As a durable and efficient 3D heteronanoarray electrocatalyst for glucose detection, NiCo-LDH@Cu NSA/CC has higher stable conductivity and faster electron transport rate than NiCo-LDH NSA/CC and Cu nanoparticles, which work through synergistic effect to form a high-performance sensing platform. The NiCo-LDH@Cu NSA/CC heteronanosheet structure has good electrocatalytic performance for glucose oxidation, with the sensitivity of the two linear ranges (0.001-1 mmol L^-1 and 1-6 mmol L^-1) being 9710 μA L mmol^-1 cm^-2 and 4870 μA L mmol^-1 cm^-2, respectively, and the detection limit (LOD) is 157 nmol L^-1 (S/N = 3). The sensor has been successfully applied to detect glucose in beverages and serum.

Recent advances in electrochemical sensor developments for detecting emerging pollutant in water environment

In the latest times, considerable studies have been performed closer to detecting emerging pollutant such as paracetamol in wastewater. Electrochemical sensor developments have recently started to determine in fewer concentrations effectively. The detection of paracetamol using standard protocols corresponding to electroanalytical techniques has a greater impact noticed in directing the detecting process toward biosensors. Non-enzymatic sensors are the peak of all electro analysis approaches. Functionalized materials, such as metal oxide nanoparticles, conducting polymers, and carbon-based materials for electrode surface functionalization have been used to create a fortification for distributing passive enzyme-free biosensors. Synergic effects are possible by enhancing loading capacity and mass transfer of reactants for attaining high analytical sensitivity using a variety of nanomaterials with large surface areas. The main focus of this study is to address the prevailing issues in the identification of paracetamol with the tasks in the non-enzymatic sensors field, followed by the useful methods of electro analysis studies.

Recent advances in electrochemical-based sensors amplified with carbon-based nanomaterials (CNMs) for sensing pharmaceutical and food pollutants

Foodborne-related infections due to additives and pollutants pose a considerable task for food processing enterprises. Therefore, the competent, cost-effective, and quick investigation of nutrition additives and contaminants is essential to reduce the threat of public fitness problems. The electrochemical sensor (ECS) shows facile and potent analytical approaches desirable for food protection and quality inspection over traditional methods. The consequence of a broad display of nanomaterials has paved the path for their relevance in designing high-performance ECSs appliances for medical diagnostics and conditions and food protection. This review article has discussed the importance of electrochemical-based sensors amplified with carbon-based nanomaterials (CNMs). Initially, we have demonstrated the types of pharmaceutical and food/agriculture pollutants (such as pesticides, heavy metals, antibiotics and other medical drugs) present in water. Subsequently, we have compiled the information on electrochemical techniques (such as voltammetric and electrochemical impedance spectroscopy) and their crucial parameters for detecting pollutants. Further, the applications of CNMs for sensing pharmaceutical and food pollutants have been demonstrated in detail. Finally, the topic has been concluded with existing challenges and future prospects.

Electrochemical detection of nicotine at a carbon Nanofiber-Poly(amidoamine) dendrimer modified glassy carbon electrode

Development of electrochemical sensors for important drugs such nicotine (an addictive drug) is important for the society. This study reports the electrochemical detection of nicotine at a carbon nanofiber/poly (amidoamine) dendrimer modified glassy carbon electrode. The carbon nanofiber (CNF) modified GCE was prepared by drop-coating followed by the electrodeposition of generation 4 poly (amidoamine) succinamic acid dendrimer (PAMAM) to form the sensor - CNF-PAMAM GCE. Characterization of prepared materials and modified electrodes was carried out using Fourier transmission infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The CNF-PAMAM composite was confirmed by microscopy. A marked reduction in charge transfer resistance and increase in current of the CNF-PAMAM GCE in comparison to the bare electrode showed a synergic improvement electrochemical response because of the CNF-PAMAM nanocomposite. The CNF-PAMAM demonstrated an enhanced performance in the oxidation of nicotine in comparison to the bare GCE by shifting the anodic potential E_pa of nicotine from 0.9 V to 0.8 V. The electrochemical sensor achieved a detection limit (LOD) of 0.02637 μM in the concentration range of 0.4815-15.41 μM of nicotine in 0.1 M PBS at pH 7.5. The sensor ability to determine nicotine in real samples was assessed in cigarettes obtaining recovery percentages of 88.00 and 97.42%. The sensor demonstrated selectivity toward nicotine in the presence of interferences. Finally, the method was validated by ultraviolet-visible spectroscopy analysis.

Application of carbon nanotubes in sensing/monitoring of pancreas and liver cancer

Liver and pancreatic tumors are among the third leading causes of cancer-associated death worldwide. In addition to poor prognosis, both cancer types are diagnosed at advanced and metastatic stages without typical prior symptoms. Unfortunately, the existing theranostic approaches are inefficient in cancer diagnosis and treatment. Carbon nanotubes (CNTs) have attracted increasing attention in this context due to their distinct properties, including variable functionalization capability, biocompatibility, and excellent thermodynamic and optical features. As a consequence, they are now regarded as one of the most promising materials for this application. The current review aims to summarize and discuss the role of CNT in pancreatic and liver cancer theranostics. Accordingly, the breakthroughs achieved so far are classified based on the cancer type and analyzed in detail. The most feasible tactics utilizing CNT-based solutions for both cancer diagnosis and treatment are presented from the biomedical point of view. Finally, a future outlook is provided, which anticipates how the R&D community can build on the already developed methodologies and the subsequent biological responses of the pancreatic and liver cancer cells to the directed procedures.

A novel platform based on CoMn2O4-rGO/1-ethyl-3-methylimidazolium chloride modified carbon paste electrode for voltammetric detection of pethidine in the presence morphine and olanzapine

The present work focuses on the development of a new electrochemical platform based on CoMn₂O₄-rGO/1-ethyl-3-methylimidazolium chloride modified carbon paste electrode (CoMn₂O₄-rGO/IL/CPE) for electrochemical determination of pethidine in the presence of biological species. For the first time, the electrooxidation mechanism of pethidine in presences of morphine and olanzapine is investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) technologies. The as-synthesized CoMn₂O₄-rGO nanocomposites are characterized by physicochemical measurements such as X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared (FT-IR). The obtained results illustrated synergistic interactions between rGO and CoMn₂O₄ structures. Also, to investigate the electrode charge-transfer resistances, electrochemical features of the resulting nanocomposites are studied via electrochemical impedance spectroscopy (EIS) analysis. Based on the result, three segmented linear ranges are observed over the range 0.08-900 μM and detection limit of 0.024 μM. Over the 10.0-40.0 μM ranges of pethidine in phosphate buffer solution (PBS-pH 7.0), suitable diffusion coefficient of 5.67 × 10^-7 cm² s^-1 is evaluated by chronoamperometry technique (CHA). Finally, the CoMn₂O₄-rGO/IL/CPE with high sensitivity, selectivity and repeatability is successfully used for determination of pethidine in real sample and drug formulation.

A caffeic acid electrochemical sensor amplified with GNR/CoFe2O4@NiO and 1-Ethyl-3-methylimidazolium acetate; a new perspective for food analysis

Determining Caffeic acid is important as an antioxidant compound in food. In this study, caffeic acid (CA) was measured using a carbon paste electrode modified with GNR/CoFe₂O₄@NiO and 1-Ethyl-3-methylimidazolium acetate (EMIM Ac) as ion liquid. A simple sensor showed a higher current than a bare carbon paste; thus, it can be said that the modified electrode has a higher sensitivity for detecting CA. The linear range of this sensor and its detection limit was equal to 0.01-100.0 μM and 0.01 μM, respectively. Moreover, the developed electrode indicated outstanding selectivity in the presence of several interferences, high sensitivity, reproducibility, and long-term stability. The percentage recovery of CA obtained with the developed sensor affirmed its reliability for CA determination in real samples. The modified sensor's accuracy was confirmed to identify this analyte according to the results.

Highly Selective and Sensitive Voltammetric Method for the Detection of Catechol in Tea and Water Samples Using Poly(gibberellic acid)-Modified Carbon Paste Electrode

Despite the wide range of applications of catechol (CC) in agrochemical, petrochemical, textile, cosmetics, and pharmaceutical industries, its exposure to the environment leads to health issues as it is carcinogenic. This increased the concern over the risk of exposure level of CC in the environment, and monitoring its level has become critical. In this work, we report the fabrication of poly-gibberellic acid-modified carbon paste electrode (PGBAMCPE) to be a simple, viable, and effective electrochemical electrode for the determination of CC. This was synthesized by a simple electropolymerization method by the cyclic voltammetry (CV) technique. The electrodes were characterized by field emission electron microscopy, energy-dispersive X-ray spectroscopy, and electrochemical impedance spectroscopy. Compared to the bare carbon paste electrode, the sensitivity for CC fortified at PGBAMCPE in both CV and differential pulse voltammetry (DPV). We succeeded attaining a lower detection limit of 0.57 μM by the DPV method. The developed electrode was observed to be highly conductive, transducing, stable, and reproducible and was highly selective with anti-interfering properties from the determination of CC with hydroquinone simultaneously. The applicability of the electrode was confirmed from the detection CC in tea and water samples with good recoveries. This substantiates that PGBAMCPE is promising and consistent for the rapid monitoring of CC-contaminated area and clinical diagnosis.

Precise and quick detection of ascorbic acid and eugenol in fruits, pharmaceuticals and medicinal herbs using hydroxyapatite-titanium dioxide nanocomposite-based electrode

Ascorbic acid (AA) and eugenol (EUG) are well-known antioxidants found in several fruits, spices and herbs. In particular, the EUG, one of the major phytocompounds present in clove, acts as pro-oxidant or anti-oxidant depending on its concentration. Considering the medical importance of AA and EUG and its extensive usage in the form of food and medicine, we have developed a voltammetric sensor based on hydroxyapatite-TiO₂ composite modified GCE for their selective and simultaneous determination over very wide linear range of 2.78-2490 µM for AA and 1.4-78 µM for EUG with the LODs of 63.3 nM and 94 nM respectively. Practical applicability of the prepared electrode has been demonstrated by detecting AA and EUG in lemon juice, vitamin tablet, clove oil and Kabasura Kudineer, an herbal decoction used as an immunity booster against number of diseases including Covid-19. The proposed HAP-TiO₂/GCE shall be useful for food and pharmaceutical industries.

Development and Optimization of Electrochemical Method for Determination of Vitamin C

The focus of this work was to develop a simple electrochemical method for the determination of vitamin C (VitC) by using a specially constructed microelectrode made from pyrolytic graphite sheet (PGS). A procedure for quantifying VitC in a real sample was established. VitC shows a single quasi-reversible reaction. The method was optimized, and analytical determination was performed by using cyclic voltammetry and square wave voltammetry for electroanalytical purposes. The obtained results show a linear response of the PGS electrode in a wide concentrations range. For the lower concentration range, 0.18–7.04 µg L−1, the sensitivity is 11.7 µAcm−2/mgL−1, while for the higher concentration range, 10.6–70.4 µg L−1, the sensitivity is 134 µAcm−2/mgL−1, preserving the linearity of 0.998 and 0.999. The second objective was to determine the effect of the addition of five different types of “green” biowaste on plant growth, VitC content, and antioxidant activity in arugula (Eruca sativa L.) using the developed method. After three weeks of cultivation, small differences in growth and large differences in certain nutritional characteristics were observed. The addition of black coffee makes the soil slightly alkaline and causes a significant increase in VitC content and antioxidant activity.

Electrochemical sensors based on carbon nanostructures for the analysis of bisphenol A-A review

Overuse of Bisphenol A (BPA), a proven endocrine disruptor, has become a serious public health problem across the world. It has the potential to harm both the environment and human health, notably reproductive disorders, heart disease, and diabetes. Accordingly, much attention has been paid to the detection of BPA to promote food safety and environmental health. Carbon based nanostructures have proven themselves well in a variety of applications, such as energy storage, catalysis and sensors, due to their remarkable properties. Therefore, researchers have recently focused on fabricating electrochemical BPA sensors based on carbon nanostructures due to their unique advantages, such as real-time monitoring, simplicity, high selectivity, high sensitivity and easy operation. The purpose of the current review was to summarize the recent findings on carbon nanostructures for electrochemically sensing the BPA, as well as relevant future prospects and ongoing challenges.

Disposable stochastic sensors for fast analysis of ibuprofen, ketoprofen, and flurbiprofen in their topical pharmaceutical formulations

Three disposable stochastic sensors based on maltodextrin (dextrose equivalent = 4-7) and nanostructures (copper monolayer, carbon monolayer and carbon-copper composite layer) deposited using cold plasma on copy paper were proposed for the fast analysis of ibuprofen, ketoprofen and flurbiprofen in pharmaceutical formulation samples. The widest linear concentration ranges recorded were: for ibuprofen 1 fmol/L - 1 mmol/L when the disposable stochastic sensor based on carbon monolayer was used, for ketoprofen 1 fmol/L - 1 mmol/L when the disposable stochastic sensors based on copper monolayer and carbon-copper composite layer were used, and for flurbiprofen 1 fmol/L - 10 mmol/L when the disposable stochastic sensor based on carbon-copper composite layer was used. The lowest limit of detection recorded for each non-steroidal anti-inflammatory drug was 1 fmol/L.

Simultaneous detection of carmoisine and tartrazine in food samples using GO-Fe3O4-PAMAM and ionic liquid based electrochemical sensor

This study was performed to investigate the simultaneous detection of carmoisine and tartrazine, two food azo dyes, with a new voltammetric sensor based on graphene oxide-Fe3O4 (GO-Fe3O4) nanocomposite functionalized with fourth-generation poly(amidoamine) (G4 PAMAM) dendrimers (GO-Fe3O4-G4 PAMAM) and ionic liquid (IL) modified carbon paste electrode (GO-Fe3O4-G4 PAMAM/ILCPE). The GO-Fe3O4-G4 PAMAM was synthesized and characterized by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), vibrating-sample magnetometer (VSM), and fourier transform infrared (FT-IR) techniques. Cyclic voltammetry (CV) was used to evaluate the electrochemical behavior of carmoisine, revealing the good electrocatalytic function of GO-Fe3O4-G4 PAMAM/ILCPE. Linear response from 0.1 to 170.0 μM was obtained based on carmoisine electrochemical oxidation through differential pulse voltammetry (DPV). The limit of detection (LOD) value obtained was 0.02 μM. Also, the GO-Fe3O4-G4 PAMAM/ILCPE was used for the simultaneous determination of carmoisine and tartrazine. In co-existence system containing carmoisine and tartrazine, the developed sensor exhibited well-defined and separate DPV peaks (i.e., 770 mV) for carmoisine and tartrazine. Besides, repeatability, reproducibility and stability studies were performed. Additionally, the analytical application of this sensor was demonstrated by determination of carmoisine and tartrazine in food samples including lemon juice and powdered juice.

Fast screening method for early diagnostic of gastric cancer based on utilization of a chitosan - S-doped graphene - based needle stochastic sensors

Needle stochastic sensors were developed for the assay of carbohydrate antigen 19-9 (CA 19-9) and carcinoembryonic antigen (CEA) in different biological samples (e.g., whole blood, tissues, urine, and saliva). Sulfur doped graphene powders were modified with chitosan; paraffin oil was added to form a homogeneous paste that was used as active side of the stochastic sensors. High sensitivities and low limits of determination were achieved for the assay of CA19-9 and CEA in biological samples. The validation of the proposed screening method (which is utilizing the stochastic sensors as screening tools) was made by using real biological samples obtained from confirmed patients with gastric cancer; very good correlations for the concentrations of CEA and CA19-9 were obtained using the needle stochastic sensors.