Molybdenum-doped BiVO4 thin films: Facile preparation via hot-spin coating method and the relationship between surface statistical parameters and photoelectrochemical activity.

Molybdenum-doped BiVO4 thin films were uniformly coated on indium-doped tin oxide (ITO) substrates via a facile modified hot spin coating (HSC) technique. The prepared layers were used as photoanode in a photoelectrochemical (PEC) cell. Different percentage of Mo dopant was examined to maximize the photo-current density (J) of the layers. The highest J value (872 ± 8 µA/cm2) was obtained by 5 atomic% of Mo doping. After that, the surface topographies of these samples were changed by varying the initial precursor concentration from 27 to 80 mM. The relation between surface topographies and the PEC activity of Mo-doped BiVO4 thin films was investigated from microscopic point of view by calculating the surface roughness exponent of α, and a mechanism for the PEC activity of Mo-doped BiVO4 photoanodes was proposed accordingly. The sample with a small roughness exponent provided a surface with jagged microscopic fluctuations which may trap the air molecules between the electrolyte and sample surface, hindering the fine atomic interaction for photo-generated electron-hole transition. Therefore, the layer with the highest roughness exponent (2α = 0.48 ± 0.03), which means the smoother microscopic surface and better interfacial contact with the electrolyte, exhibited the best PEC activity.

Revolutionizing cancer monitoring with carbon-based electrochemical biosensors.

Cancer monitoring plays a critical role in improving patient outcomes by providing early detection, personalized treatment options, and treatment response tracking. Carbon-based electrochemical biosensors have emerged in recent years as a revolutionary technology with the potential to revolutionize cancer monitoring. These sensors are useful for clinical applications because of their high sensitivity, selectivity, rapid response, and compatibility with miniaturized equipment. This review paper gives an in-depth look at the latest developments and the possibilities of carbon-based electrochemical sensors in cancer surveillance. The essential principles of carbon-based electrochemical sensors are discussed, including their structure, operating mechanisms, and critical qualities that make them suited for cancer surveillance. Furthermore, we investigate their applicability in detecting specific cancer biomarkers, evaluating therapy responses, and detecting cancer recurrence early. Additionally, a comparison of carbon-based electrochemical sensor performance measures, including sensitivity, selectivity, accuracy, and limit of detection, is presented in contrast to existing monitoring methods and upcoming technologies. Finally, we discuss prospective tactics, future initiatives, and commercialization opportunities for improving the capabilities of these sensors and integrating them into normal clinical practice. The review highlights the potential impact of carbon-based electrochemical sensors on cancer diagnosis, treatment, and patient outcomes, as well as the importance of ongoing research, collaboration, and validation studies to fully realize their potential in revolutionizing cancer monitoring.

Employing Pd nanoparticles decorated on halloysite nanotube/carbon composite for electrochemical aptasensing of HER2 in breast cancer patients.

An effective biosensing platform is described based on halloysite nanotube/carbon composite decorated with Pd nanoparticles (HNT/C@Pd NPs). A novel electrochemical aptasensor was designed using the proposed nano-platform to determine human epidermal growth factor receptor 2 (HER2), a breast cancer biomarker. Inherently, aptasensing interfaces provide high sensitivity and selectivity for tumor markers owing to the high specific surface area of HNT/C and good conductivity stems from deposition of Pd NPs into HNT/C composite. With a correlation coefficient of 0.996, the electrochemical aptasensor demonstrated a wide linear range from 0.03 ng/mL to 9 ng/mL. The limit of detection (LOD) of the established assay was 8 pg/mL based on S/N = 3 method. Further, the designed biosensor demonstrated acceptable selectivity, good reproducibility, and high stability. The applicability of the impedimetric sensor in human serum samples was also examined and compared to enzyme-linked immunosorbent assay (ELISA) assay (p-value >0.05). Based on the results, it was found that the proposed methodology can be used in quantification of breast cancer markers for early diagnosis and treatment.

Evaluation of thallium ion as an effective ion in human health using an electrochemical sensor.

Exposure to thallium (Tl), a noxious heavy metal, poses significant health risks to both humans and animals upon ingestion. Therefore, monitoring Tl levels in the environment is crucial to prevent human exposure and reduce the risk of developing severe health problems. This paper presents the development of a highly sensitive Tl ions sensor through surface modification of a glassy carbon electrode with a nanocomposite comprising MnO2 magnetic sepiolite and multi-walled carbon nanotubes (MnO2@Fe3O4/Sep/MWCNT/GCE). Multiple methodologies were employed to assess the performance of the newly developed sensor. By employing square wave anodic stripping voltammetry (SWASV) to optimize the measurement conditions, notable enhancements were observed in the stripping peak currents of Tl (I) on the MnO2@Fe3O4/Sep/MWCNT/GCE surface. The effectiveness of the nanocomposite in facilitating electron transfer between the Tl (I) ions (guest) and the electrode (host) was demonstrated from the enhanced signals observed at the different modified electrode surfaces under optimal conditions. The developed sensor displayed a wide linear range of 0.1-1500 ppb for Tl (I) and a low detection limit of 0.03 ppb for Tl (I). It was found to be selective for Tl (I) ions while remaining unaffected by interfering non-target ions in the presence of the target ions. Despite its simple preparation procedure, the modified electrode exhibited high stability and excellent reproducibility for measuring Tl (I). The outstanding electroanalytical performances of the MnO2@Fe3O4/Sep/MWCNT/GCE electrode enabled its successful use as an ultrasensitive sensor for determining trace amounts of Tl in environmental samples.

Follow up of the prostate cancer treatment based on a novel sensing method for anti-prostate cancer drug (flutamide).

In this work, novel modified electrode (MXene/MIL-101(Cr)/GCE) are manufactured through simple layer-by-layer immobilization procedure. The fabricated electrochemical sensor was utilized for electrochemical sensing of flutamide in biological fluids. The immobilization of both MXene and metal-organic framework (MOF) materials on the electrode surface could improve the electrochemical performance of the modified glassy carbon electrode (GCE) towards flutamide due to the synergic effects. The established sensor illustrated the significant sensing ability for the determination of flutamide. The influence of solution pH and volume ratio of MXene/MIL-101(Cr) on electrochemical performance of the modified GCE was researched and optimized. The sensor demonstrated a favorable detection limit of 0.009 µM and a linear range of 0.025-100 µM using differential pulse voltammetry (DPV) technique. The suggested assay illustrated an excellent sensing efficiency towards flutamide in body fluids with recoveries ranging from 97.7% to 102.5%, which indicates its potential in real matrices. In addition, the MXene/MIL-101(Cr)/GCE was illustrated some advantages including simple preparation, good selectivity and reproducibility, and rapid flutamide detection.

Development of an impedimetric sensor for susceptible detection of melatonin at picomolar concentrations in diverse pharmaceutical and human specimens.

Our investigation aimed to create and manufacture an electrochemical impedance sensor with the purpose of improving the detection efficiency of melatonin (ME). To achieve this objective, we employed gold nanoparticles coated on polydopamine formed in glassy carbon electrodes (AuNPs/PDA/GCE) as a means to enhance the sensor's capabilities. A novel approach employing the signal-off strategy and electrochemical impedance spectroscopy (EIS) technique was utilized to determine ME. When the AuNPs/PDA/GCE electrode was immersed in a buffered solution containing ME, and the oxidation current of AuNPs was recorded, it was observed that the oxidation current of AuNPs decreased upon the introduction of ME molecules. The decrease in electrical current can be ascribed to the inhibitory impact of ME molecule adsorption on the electrode surface with applying -0.2 V for 150 s in acetate buffer solution (ABS) (pH, 5) through various mechanisms, which hinders the electron transfer process crucial for AuNPs oxidation. Consequently, by utilizing EIS, various concentrations of ME were quantified spanning from 1 to 18 pM. Moreover, the ME sensor achieved an impressive detection limit of 0.32 pM, indicating its remarkable sensitivity in detecting low concentrations of ME. Importantly, these novel sensors demonstrated exceptional attributes in terms of sensitivity, specificity, stability, and repeatability. The outstanding performance of these sensors, coupled with their desirable attributes, establishes their considerable potential for a wide range of practical applications. These applications encompass various fields such as clinical diagnostics, pharmaceutical analysis, environmental monitoring, and industrial quality control, where accurate and sensitive detection of ME is of utmost importance.

Novel biosynthesis of gold nanoparticles for multifunctional applications: Electrochemical detection of hydrazine and treatment of gastric cancer.

In this work, an environmentally friendly strategy was used to synthesize gold nanoparticles (Au NPs) using Olea europaea (olive) fruit. Transmission electron microscopy (TEM), UV-Vis spectroscopy, X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) were used to characterize the physicochemical properties of the synthesized NPs. An Au NPs modified glassy carbon electrode was used to investigate the direct electrochemical oxidation of hydrazine. The suggested hydrazine sensor has good performance, such as a wide linear range (2.5-275 µM), low limit of detection (0.09 µM), notable selectivity and excellent reproducibility (RSD = 2.2%). The in-vitro cytotoxicity of three human cancer cell lines (KATOIII, NCI-N87, and SNU-16) was also explored with various concentrations of Au NPs prepared from olive fruit extract. Bio-synthesized Au NPs were found to have cytotoxic properties against gastric cancer in humans based on MTT assay protocol. The obtained results show that green synthesized Au NPs can be successfully employed in electrochemical sensing and cancer treatment applications.

Application of Co3O4 nanocrystal/rGO for simultaneous electrochemical detection of cadmium and lead in environmental waters.

Sensing of cadmium (Cd) and lead (Pb) in environmental samples is crucial for identifying potential health risks associated with exposure to these heavy metals as well as understanding the extent of heavy metal contamination in different environments and its impact on the ecosystem. The present study elucidates the development of a novel electrochemical sensor that can detect Cd (II) and Pb (II) ions simultaneously. This sensor is fabricated using reduced graphene oxide (rGO) and cobalt oxide nanocrystals (Co3O4 nanocrystals/rGO). The characterization of Co3O4 nanocrystals/rGO was done by using various analytical techniques. The incorporation of cobalt oxide nanocrystals with intense absorption properties results in an amplification of the electrochemical current generated on the surface of the sensor by heavy metals. This, when coupled with the unique properties of the GO layer, enables the identification of trace levels of Cd (II) and Pb (II) in the surrounding environment. The electrochemical testing parameters were meticulously optimized to obtain high sensitivity and selectivity. The Co3O4 nanocrystals/rGO sensor exhibited exceptional performance in detecting Cd (II) and Pb (II) within a concentration range of 0.1-450 ppb. Notably, the limits of detection (LOD) for Pb (II) and Cd (II) were found to be highly impressive at 0.034 ppb and 0.062 ppb, respectively. The Co3O4 nanocrystals/rGO sensor integrated with the SWASV method displayed notable resistance to interference and exhibited consistent reproducibility and stability. Therefore, the suggested sensor has the potential to serve as a technique for detecting both ions in aqueous samples using SWASV analysis.

A new formulation of Ni/Zn bi-metallic nanocomposite and evaluation of its applications for pollution removal, photocatalytic, electrochemical sensing, and anti-breast cancer.

Nanocomposites have gained attention due to their variety of applications in different fields. In this research, we have reported a green synthesis of a bi-metallic nanocomposite of nickel and zinc using an aqueous extract of Citrus sinensis in the presence of chitosan (Ni/Zn@orange/chitosan). The nanocomposite was characterized using different techniques. We have examined various applications for Ni/Zn@orange/chitosan. The NPs were manufactured in spherical morphology with a particle range size of 17.34-90.51 nm. Ni/Zn@orange/chitosan showed an acceptable ability to remove dyes of Congo red and methyl orange from an aqueous solution after 80 min furthermore, it uptaking the drug mefenamic acid from a solution. Ni/Zn@orange/chitosan also exhibited great photocatalytic activity in synthesizing benzimidazole using benzyl alcohol and o-phenylenediamine. Ni/Zn@orange/chitosan was found as a potent electrochemical sensor to determine glucose. In the molecular and cellular section of the current research, the cells with composite nanoparticles were studied by MTT way about the anti-breast adenocarcinoma potentials malignant cell lines. The IC50 of composite nanoparticles were 320, 460, 328, 500, 325, 379, 350, and 396 µg/mL concering RBA, NMU, SK-BR-3, CAMA-1, MCF7, AU565, MDA-MB-468, and Hs 281.T breast adenocarcinoma cell lines, respectively. The results revealed the newly synthesized nanocomposite is a potent photocatalyst, dye pollution removal agent, and an acceptable new drug to treat breast cancer.

A strategy for As(III) determination based on ultrafine gold nanoparticles decorated on magnetic graphene oxide.

In this work, a new dendrimer modified magnetic graphene oxide (GO) was used as a substrate for electrodeposition of Au nanoparticles. The modified magnetic electrode was employed for sensitive measuring of As(III) ion as a well-established human carcinogen. The prepared electrochemical device exhibits excellent activity towards As(III) detection using the square wave anodic stripping voltammetry (SWASV) protocol. At optimum conditions (deposition potential at -0.5 V for 100 s in 0.1 M acetate buffer with pH 5.0), a linear range from 1.0 to 125.0 µgL-1 with a low detection limit (calculated by S/N = 3) of 0.47 µg L-1 was obtained. In addition to the simplicity and sensitivity of the proposed sensor, its high selectivity against some major interfering agents, such as Cu(II) and Hg(II) makes it an appreciable sensing tool for the screening of As(III). In addition, the sensor revealed satisfactory results for detection of As(III) in different water samples, and the accuracy of obtained data were confirmed by inductively coupled plasma atomic emission spectroscopy (ICP-AES) setup. Accounting for the high sensitivity, remarkable selectivity and good reproducibility, the established electrochemical strategy has great potential for analysis of As(III) in environmental matrices.

Calf thymus ds-DNA intercalation with pendimethalin herbicide at the surface of ZIF-8/Co/rGO/C3N4/ds-DNA/SPCE; A bio-sensing approach for pendimethalin quantification confirmed by molecular docking study.

Pendimethalin (PND) is a herbicide that is regarded to be possibly carcinogenic to humans and toxic to the environment. Herein, we fabricated a highly sensitive DNA biosensor based on ZIF-8/Co/rGO/C3N4 nanohybrid modification of a screen-printed carbon electrode (SPCE) to monitor PND in real samples. The layer-by-layer fabrication pathway was conducted to construct ZIF-8/Co/rGO/C3N4/ds-DNA/SPCE biosensor. The physicochemical characterization techniques confirmed the successful synthesis of ZIF-8/Co/rGO/C3N4 hybrid nanocomposite, as well as the appropriate modification of the SPCE surface. The utilization of ZIF-8/Co/rGO/C3N4 nanohybrid as a modifier was analyzed using. The electrochemical impedance spectroscopy results showed that the modified SPCE exhibited significantly lowered charge transfer resistance due to the enhancement of its electrical conductivity and facilitation of the transfer of charged particles. The proposed biosensor successfully quantified PND in a wide concentration range of 0.01-35 µM, with a limit of detection (LOD) value of 8.0 nM. The PND monitoring capability of the fabricated biosensor in real samples including rice, wheat, tap, and river water samples was verified with a recovery range of 98.2-105.6%. Moreover, to predict the interaction sites of PND herbicide with DNA, the molecular docking study was performed between the PND molecule and two sequence DNA fragments and confirmed the experimental findings. This research sets the stage for developing highly sensitive DNA biosensors that will be used to monitor and quantify toxic herbicides in real samples by fusing the advantages of nanohybrid structures with crucial knowledge from a molecular docking investigation.

State-of-art advances on removal, degradation and electrochemical monitoring of 4-aminophenol pollutants in real samples: A review.

p_Aminophenol, namely 4-aminophenol (4-AP), is an aromatic compound including hydroxyl and amino groups contiguous together on the benzene ring, which are suitable chemically reactive, amphoteric, and alleviating agents in nature. Amino phenols are appropriate precursors for synthesizing oxazoles and oxazines. However, since the toxicity of aniline and phenol can harm human and herbal organs, it is essential to improve a reliable technique for the determination of even a trace amount of amino phenols, as well as elimination or (bio)degradation/photodegradation of it to protect both the environment and people's health. For this purpose, various analytical methods have been suggested up till now, including spectrophotometry, liquid chromatography, spectrofluorometric and capillary electrophoresis, etc. However, some drawbacks such as the requirement of complex instruments, high costs, not being portable, slow response time, low sensitivity, etc. prevent them to be employed in a wide range and swift in-situ applications. In this regard, besides the efforts such as (bio)degradation/photodegradation or removal of 4-AP pollutants from real samples, electroanalytical techniques have become a promising alternative for monitoring them with high sensitivity. In this review, it was aimed to emphasize and summarize the recent advances, challenges, and opportunities for removal, degradation, and electrochemical sensing 4-AP in real samples. Electroanalytical monitoring of amino phenols was reviewed in detail and explored the various types of electrochemical sensors applied for detecting and monitoring in real samples. Furthermore, the various technique of removal and degradation of 4-AP in industrial and urban wastes were also deliberated. Moreover, deep criticism of multifunctional nanomaterials to be utilized as a catalyst, adsorbent/biosorbent, and electroactive material for the fabrication of electrochemical sensors was covered along with their unique properties. Future perspectives and conclusions were also criticized to pave the way for further studies in the field of application of up-and-coming nanostructures in environmental applications.

A novel γ‒BMO@BMWO Z‒Scheme heterojunction for promotion photocatalytic performance: Nanofibers thin film by Co‒axial‒electrospun.

Bismuth molybdate has three phases α-Bi2MoO6, ß-Bi2Mo2O9, and γ- Bi2Mo3O12, each of which has unique properties that distinguish them from each other. Among them, Bi2MoO6 and Bi2Mo3O12 have the most stability. In this research, γ-Bi2MoO6@Bi2Mo2.66W0.34O12 core‒shell nanofibers were deposited on the stainless steel mesh as effective and low‒cost substrate. The co‒axial electrospinning as a simple method was applied to form nanofibers on the substrate. Both of the abovementioned bismuth molybdates contents include different crystal facets, controlling the Red‒Ox properties. α-Bi2MoO6 possesses the vast numbers of oxygen vacancies in Mo-O bonding makes the oxidant {100} crystal facet. Likewise, γ‒Bi2Mo2.66W0.34O12 contains brittle facet of {010} with high concentration of Oxygen vacancies resulted in oxidative capability of the core‒shell composite. The obtained data indicated the key role of OH radical through photocatalytic reactions and a new heterojunction having direct Z‒scheme standing.

Multifaceted role of polyphenols in the treatment and management of neurodegenerative diseases.

Neurodegenerative diseases (NDDs) are conditions that cause neuron structure and/or function to deteriorate over time. Genetic alterations may be responsible for several NDDs. However, a multitude of physiological systems can trigger neurodegeneration. Several NDDs, such as Huntington's, Parkinson's, and Alzheimer's, are assigned to oxidative stress (OS). Low concentrations of reactive oxygen and nitrogen species are crucial for maintaining normal brain activities, as their increasing concentrations can promote neural apoptosis. OS-mediated neurodegeneration has been linked to several factors, including notable dysfunction of mitochondria, excitotoxicity, and Ca2+ stress. However, synthetic drugs are commonly utilized to treat most NDDs, and these treatments have been known to have side effects during treatment. According to providing empirical evidence, studies have discovered many occurring natural components in plants used to treat NDDs. Polyphenols are often safer and have lesser side effects. As, epigallocatechin-3-gallate, resveratrol, curcumin, quercetin, celastrol, berberine, genistein, and luteolin have p-values less than 0.05, so they are typically considered to be statistically significant. These polyphenols could be a choice of interest as therapeutics for NDDs. This review highlighted to discusses the putative effectiveness of polyphenols against the most prevalent NDDs.

Application of BiNPs/MWCNTs-PDA/GC sensor to measurement of Tl (1) and Pb (II) using stripping voltammetry.

Herein, simultaneous determination of Tl (1) and Pb (II) has been carried out at the surface of a modified glassy carbon electrode with polydopamine functionalized multi-walled carbon nanotubes- BiNPs nanocomposite (BiNPs/MWCNTs-PDA/GC) using square-wave anodic stripping voltammetry (SWASV) technique. The morphologies, composition and, electrochemical properties of the BiNPs/MWCNTs-PDA/GC were characterized by scanning electron microscopy (SEM), transition electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDX), electrochemical impedance spectroscopy (EIS) and, SWASV. The parameters affecting the stripping current response were investigated and optimized. The large specific area of MWCNTs and good electro-conductibility of BiNPs causes the BiNPs/MWCNTs-PDA/GC electrode to exhibit an excellent electro-catalytic effect with good separation peaks for Tl and Pb oxidation compared to bare GCE under the optimal conditions. The proposed sensor showed wide leaner ranges from 0.4-100 ppb and 100-400 ppb for Tl (I) and Pb (II). Low detection limits of 0.04 ppb for Tl (I) and 0.07 ppb for Pb (II) were achieved. The efficiency of the electrode after thirty days of storage in ambient conditions without using it and also with the ability to reuse for 16 days did not decrease significantly. In addition, the modified electrode with simple preparation method showed good reproducibility, and high selectivity for measuring target ions. The method was successfully implemented for the simultaneous determination of Tl (I) and Pb (II) in tap, mineral and waste water samples with acceptable recovery (from 99.1-103.2 for Tl (I) and 98.4-100.4 for Pb (II)).

Recent advances in carbon nanomaterials-based electrochemical sensors for food azo dyes detection.

Azo dyes as widely applied food colorants are popular for their stability and affordability. On the other hand, many of these dyes can have harmful impacts on living organs, which underscores the need to control the content of this group of dyes in food. Among the various analytical approaches for detecting the azo dyes, special attention has been paid to electro-analytical techniques for reasons such as admirable sensitivity, excellent selectivity, reproducibility, miniaturization, green nature, low cost, less time to prepare and detect of specimens and the ability to modify the electrode. Satisfactory results have been obtained so far for carbon-based nanomaterials in the fabrication of electrochemical sensing systems in detecting the levels of these materials in various specimens. The purpose of this review article is to investigate carbon nanomaterial-supported techniques for electrochemical sensing systems on the analysis of azo dyes in food samples in terms of carbon nanomaterials used, like carbon nanotubes (CNT) and graphene (Gr).

Determination of D&C Red 33 and Patent Blue V Azo dyes using an impressive electrochemical sensor based on carbon paste electrode modified with ZIF-8/g-C3N4/Co and ionic liquid in mouthwash and toothpaste as real samples.

Synthetic azo dyes are widely used in a variety of industries, but many of them pose a risk to human health, particularly when consumed in large quantities. As a result, their existence in products should be closely monitored. D&C red 33 and Patent Blue V are mostly used in cosmetics, especially in toothpaste and mouthwashes. A novel carbon paste electrode modified with ZIF-8/g-C3N4/Co nanocomposite and 1-methyl-3-butylimidazolium bromide as an ionic liquid was employed as a highly sensitive reproducible electrochemical sensor for the simultaneous determination of these common dyes. ZIF structure has unique properties such as high surface area, suitable conductivity, and excellent porosity. The electrochemical behavior of the suggested electrode was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). To characterize the synthesized nanocomposites, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were applied to investigate the structure of nanocomposites. Under the optimized conditions, the modified sensor offered a wide linear concentration range 0.08-10 µM (R2 = 0.9906) and 10-900 µM (R2 = 0.9932) with a low limit of detection of 0.034 µM. The value of diffusion coefficient (D), and the electron transfer coefficient (α) was calculated to be 310 × 10-5, and 0.9 respectively. This technique offered a successful performance for the determination of target analyte in the real samples with acceptable results between 96% and 107%.

A green and sensitive guanine-based DNA biosensor for idarubicin anticancer monitoring in biological samples: A simple and fast strategy for control of health quality in chemotherapy procedure confirmed by docking investigation.

Drug efficiency can be considerably boosted while adverse effects can be reduced by precisely monitoring the concentration of anti-cancer drugs. Thus, one of the most important parameters for human health is the monitoring and detection of anticancer drugs during chemotherapy treatment. Herein, a glassy carbon electrode (GCE) was modified by Pt- and Pd-incorporated ZnO nanoparticles-decorated single-wall carbon nanotubes (Pt-Pd-ZnO/SWCNTs) nanocomposites, and ds-DNA (Calf Thymus) that was a biological recognition element, and it was aimed to be utilized as an ultrasensitive and effective electroanalytical biosensor for idarubicin (IDR) monitoring. Various physicochemical characterization techniques including transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray spectroscopy (EDS) were used to investigate the morphology and structure of the Pt-Pd-ZnO/SWCNTs nanocomposite, which was produced via straightforward chemical precipitation combined with the one-pot method. The layer-by-layer modification technique was implemented to fabricate the ds-DNA/Pt-Pd-ZnO/SWCNTs/GCE to be further utilized as a voltammetric sensor for sensitive monitoring of idarubicin in biological fluids and pharmaceutical substances. The electroanalytical method implemented to detect idarubicin was based to detect the ds-DNA's guanine base signal on the surface of the modified electrode in the absence and presence of the anticancer drug. The results explicated that the developed biosensor performed well in determining idarubicin in concentrations ranging from 1.0 nM to 65 µM, with a detection limit of 0.8 nM. The idarubicin detection ability of the modified electrode in real samples was evaluated, and the recovery data was acquired in the range of 98.0% and 104.75%. In the final step, the preferential intercalative binding mode of idarubicin drug with ds-DNA was approved by molecular docking study. This study paves the way for engineering highly sensitive DNA biosensors to be employed in the monitoring of anticancer drugs by combining the benefits of nanocomposites and valuable information of a molecular docking study.

Preparation of GO/Fe3O4@PMDA/AuNPs nanocomposite for simultaneous determination of As3+ and Cu2+ by stripping voltammetry.

One of the critical challenges in the simultaneous determination of As3+ and Cu2+ by stripping voltammetry is the overlapping of their oxidation peaks. Therefore, the engineering of nanostructured sensors in order to uplift their electrochemical performance is a significant issue for the codetection of As3+ and Cu2+. Herein, we modified a glassy carbon electrode with a new nanocomposite based on poly methyldopa along with gold nanoparticles immobilized on the surface of magnetic graphene oxide (GCE/GO/Fe3O4@PMDA/AuNPs) that can determine As3+ and Cu2+ with great sensitivity. Optimization of the measurement conditions by square wave stripping voltammetry (SWSV) caused the oxidation peaks of As3+ and Cu2+ to be distinguished significantly from each other, while the peak currents of As3+ and Cu2+ increased 9-12 fold, respectively, compared to the bare electrode. The proposed electrode exhibits low detection limits (S/N ≥ 3): 0.15 ppb for As3+ and 0.11 ppb for Cu2+. The GCE/GO/Fe3O4@PMDA/AuNPs also has good linearity over a wide concentration range from 5 to 500 ppb for As3+ and 0.5-750 ppb for Cu2+. The good recovery values were obtained for the analysis of As3+ and Cu2+ in pool and drinking water samples.