An electrochemical sensing platform with a molecularly imprinted polymer based on chitosan-stabilized metal@metal-organic frameworks for topotecan detection.

The present study aims to develop an electroanalytical method to determine one of the most significant antineoplastic agents, topotecan (TPT), using a novel and selective molecular imprinted polymer (MIP) method for the first time. The MIP was synthesized using the electropolymerization method using TPT as a template molecule and pyrrole (Pyr) as the functional monomer on a metal-organic framework decorated with chitosan-stabilized gold nanoparticles (Au-CH@MOF-5). The materials' morphological and physical characteristics were characterized using various physical techniques. The analytical characteristics of the obtained sensors were examined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). After all characterizations and optimizing the experimental conditions, MIP-Au-CH@MOF-5 and NIP-Au-CH@MOF-5 were evaluated on the glassy carbon electrode (GCE). MIP-Au-CH@MOF-5/GCE indicated a wide linear response of 0.4-70.0 nM and a low detection limit (LOD) of 0.298 nM. The developed sensor also showed excellent recovery in human plasma and nasal samples with recoveries of 94.41-106.16 % and 95.1-107.0 %, respectively, confirming its potential for future on-site monitoring of TPT in real samples. This methodology offers a different approach to electroanalytical procedures using MIP methods. Moreover, the high sensitivity and selectivity of the developed sensor were illustrated by the ability to recognize TPT over potentially interfering agents. Hence, it can be speculated that the fabricated MIP-Au-CH@MOF-5/GCE may be utilized in a multitude of areas, including public health and food quality.

A reusable and sensitive electrochemical sensor for determination of Allura red in the presence of Tartrazine based on functionalized nanodiamond@SiO2@TiO2; an electrochemical and molecular docking investigation.

A sensitive and novel electrochemical sensor for the detection of Allura Red (AR) in the presence of tartrazine (TRZ) was fabricated using a screen-printed electrode modified by functionalized nanodiamond covered using silicon dioxide and titanium dioxide nanoparticles (F-nanodiamond@SiO2@TiO2/SPE). Scanning electron microscopy (SEM), brunauer-Emmett-teller (BET), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR) techniques were performed to characterize the as-synthesized Fnanodiamond@SiO2@TiO2 nanocomposite. The as-fabricated electrode demonstrated two wide dynamic ranges of 0.01-0.12 and 0.12-8.65 µM with a limit of detection (LOD) as low as 1.22 nM. Moreover, the modified electrode exhibits excellent repeatability, reproducibility, reusability, selectivity, and stability with high sensitivity of 44.3 µA µM-1 cm-1, offering good prospects in the simple, cost-effective, and rapid assessment of their total concentration. The successful detection of AR and TRZ, simultaneously and individually in food samples, revealed the applicability of the sensor in the determination of AR and TRZ with satisfactory recovery. Therefore, these advantages provide an excellent possibility for the smart monitoring of AR and TRZ in the future. In the final step, the preferential intercalative binding mode of Allura red with ds-DNA was approved for the first time by a molecular docking study. This study paves the way for engineering highly sensitive DNA biosensors to monitor azo dye compounds by combining the benefits of nanocomposites and valuable information of a molecular docking study.

A reusable and sensitive electrochemical sensor for determination of idarubicin in environmental and biological samples based on NiFe2O4 nanospheres anchored N-doped graphene quantum dots composite; an electrochemical and molecular docking investigation.

An ultrasensitive and selective voltammetric sensor with ultra-trace level detection limit is introduced for idarubicin (IDA) determination in real samples. The as-synthesized nanocomposite was characterized by several techniques, including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, Energy-dispersive X-ray spectroscopy (EDX), and Field emission scanning electron microscopy (FE-SEM). The electrocatalytic performance of the developed electrode was observed by cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), and chronoamperometry. The limit of detection (LOD) of the developed sensor for idarubicin is 1.0 nM, and the response is found to be in the dynamic concentration range of 0.01-1.9 µmol/L in a Britton-Robinson buffer (B-R, pH = 6.0). Moreover, the fabricated electrode illustrated high selectivity with good repeatability and reproducibility for diagnosing idarubicin as an anthracycline antileukemic drug. Furthermore, to evaluate the validity of the recommended method, three real samples, including human plasma, urine, and water samples, were analyzed with satisfactory recovery and compared with high-performance liquid chromatography (HPLC). The minor groove-binding mode of interaction was also supported by docking simulation studies, emphasizing that IDA can bind to ds-DNA preferably and confirmed experimental results. The reduced assay time and the possibility of measuring a single sample with another anticancer drug without any interference are significant advantages compared to the HPLC. The developed and validated sensor could be a valuable point-of-care diagnostic tool for IDA quantification in patients.

Sensing of Acetaminophen Drug Using Zn-Doped Boron Nitride Nanocones: a DFT Inspection.

During environmental testing, scientists face the problem of developing and designing a new type of sensor electrode with distinguished stability, high activity, and cost-effectiveness to detect acetaminophen (ACE). Density functional theory (DFT) calculations were used to investigate the interaction and electrical response of Zn-doped and pristine boron nitride nanocones (BNNCs) with and to ACE with the disclination angle of 240°. The adsorption energy for ACE in the Zn-doped was - 56.94 kJ.mol-1. This value for BNNCs was approximately - 26.11 kJ.mol-1. Furthermore, after the adsorption of ACE, the value of band gap (Eg) for Zn-doped BNNCs decreased significantly (from 4.01 to 3.10 eV), thereby increasing the electrical conductivity. However, Eg value of the pristine BNNCs decreased marginally after the adsorption of ACE. Compared with the pristine BNNCs, the Zn-doped BNNCs could be considered promising materials for the detection of ACE and could be employed in electronic sensors. In the Zn-doped BNNCs, the molecular and electrostatic interactions and the creation of Zn-O bond played key roles in the adsorption of ACE. The Zn-doped BNNCs had other merits such as slight recovery time which was approximately 7.09 ms for the desorption of ACE at ambient temperature.