Fabricating BiOCl/BiVO4 nanosheets wrapped in a graphene oxide heterojunction composite for detection of an antihistamine in biological samples.

Antibiotics are essential medications for human and animal health, as they are used to battle urinary infections and bacterial diseases. Therefore, the rapid determination of antibiotic drugs in biological samples is necessary to address the current clinical challenge. Here, we developed a heterojunction ternary composite of BiOCl/BiVO4 nanosheets enriched with graphene oxide (BiOCl/BiVO4@GO) for accurate and minimal-level detection of an antihistamine (promethazine hydrochloride, PMZ) in urine samples. The BiOCl/BiVO4 nanosheets were prepared by a wet chemical approach using a deep eutectic green solvent. The spectroscopic and analytical methods verified the formation and interaction of the BiOCl/BiVO4@GO composite. Our results showed that the thoroughly exfoliated BiOCl/BiVO4@GO composite retained good electrical conductivity and fast charge transfer toward the electrode-electrolyte interface in neutral aqueous media. In addition, the experimental conditions were accurately optimized, and the BiOCl/BiVO4@GO composite showed excellent electrocatalytic activity toward the oxidation of PMZ. Indeed, the BiOCl/BiVO4@GO composite demonstrated a good linear response range (0.01-124.7 µM) and a detection level of 3.3 nM with a sensitivity of 1.586 µA µM-1 cm-2. In addition, the BiOCl/BiVO4@GO composite had excellent storage stability, good reproducibility, and reliable selectivity. Finally, the BiOCl/BiVO4@GO displayed a desirable recovery level of PMZ in urine samples for real-time monitoring.

Bismuth molybdate incorporated functionalized carbon nanofiber as an electrocatalytic tool for the pinpoint detection of organic pollutant in life samples.

Herein, we fabricated a feasible and accurate sensing platform for the quantification of toxic organic pollutant 2-nitroaniline (2-NA) in water samples through electrocatalyst made up of bismuth molybdate (Bi2MoO6, BMO) functionalized carbon nanofiber (f-CNF) modified electrode. The preparation of BMO/f-CNF composite is of two methods, such as co-precipitation (C-BMO/f-CNF) and ultrasonication method (U-BMO/f-CNF). The physicochemical properties of the composites were characterized by XRD, FTIR, Raman, BET, FE-SEM, and HR-TEM techniques. At U-BMO/f-CNF, the charge transfer resistance was low (Rct = 12.47 Ω) compared to C-BMO/f-CNF because nanosized U-BMO particles correctly aim at the defective sites of the f-CNF surface wall. Further, the electrocatalytic activity of C&U-BMO/f-CNF composites was examined by cyclic voltammetry (CV) and differential pulse voltammetry techniques (DPV) for the electrochemical detection of 2-nitroaniline (2-NA). The U-BMO/f-CNF/GCE shows a higher cathodic current, wide dynamic linear range of 0.01-168.01 µM, and superior electrocatalytic activity with a low detection limit (0.0437 µM) and good sensitivity (0.6857 µA µM-1 cm-2). The excellent selectivity nature of U-BMO/f-CNF/GCE was observed in the presence of various organic pollutants and a few toxic metal cations. The practical applicability such as stability, repeatability towards 2-NA outcomes with accepted results. Besides, the practical viability of as proposed U-BMO/f-CNF sensor was investigated in soil and lake water samples delivers good recovery results. Hence from these analyses, we conclude that U-BMO/f-CNF/GCE potential for the determination of hazardous environmental pollutant 2-NA.

Simultaneous electrochemical determination of nitrofurantoin and nifedipine with assistance of needle-shaped perovskite structure: barium stannate fabricated glassy carbon electrode.

A needle-shaped perovskite, barium stannate (BaSnO3), was synthesized via a co-precipitation technique for the simultaneous electrochemical determination of antibiotic drug nitrofurantoin (NFTO) and pericardial drug nifedipine (NFP). The spectroscopic and microscopic result confirms that as-prepared BaSnO3 particles formed with desired crystalline nature, functional group, pore size, pore diameter, and fine needle-like morphology. The simultaneous electrochemical detection of the two pharmaceutical compounds was examined via cyclic voltammetry (CV) and differential pulse voltammetry (DPV) technique using BaSnO3-modified glassy carbon electrode (BaSnO3/GCE) at a potential range from +0.4 to - 1.2 V. The discrete and simultaneous detection of NFTO and NFP at the BaSnO3 sensor exhibits higher catalytic activity in terms of cathodic current and cathodic potential compared to bare GCE. DPV results of the BaSnO3 sensor provide improved linear ranges and limits of detection for NFTO (0.01-42.65 µM; 42.65-557.65 µM, 0.062 µM, respectively) and NFP (0.01-697.65 µM, 0.0168 µM, respectively). Besides, the BaSnO3-fabricated sensor exhibits good sensitivity, reproducibility, and repeatability. The modified electrode shows excellent recoveries of NFTO (97.0-100.7%) and NFP (98.7-101.3%) in plasma, urine, and milk samples with an acceptable relative standard deviation (RSD) of 1.6-4.8%. Graphical abstract Needle-shaped BaSnO3 perovskite material for simultaneous electrochemical sensing of pharmaceutical drugs.

Exploring the photochemosensitivity by novel cysteine-based mixed ligand complexes.

A new series of cysteine-based metal(II) complexes with 2,2'-bipyridine or 1,10-phenanthroline as co-ligand have been prepared and characterized. Their DNA binding and cleavage properties have been studied. The analytical and spectroscopic data of complexes 1-18 reveal that the complexes adopt an octahedral geometry around the central metal ion in which the cysteine is coordinated through NS and NN atoms, respectively. Spectroscopic titration and viscosity measurements reveal that the complexes bind to DNA through an intercalative mode. Electrophoresis measurements exhibit that they cleave pBR322 DNA efficiently in the presence of 3-mercaptopropionic acid (MPA), probably via hydrolytic mechanism with the involvement of (•)OH. The in vitro anticancer activities indicate that the Cu(II) complexes are active against four selected human tumor cell lines. Furthermore, it is remarkable that all the complexes exhibit significant photocytotoxicity against human breast cancer cell lines (MCF-7) with a potency more than the widely used drugs photofrin and cisplatin indicating that they have the potential to act as effective anticancer drugs in a dose-dependent manner.

Efficient interrupting skills of amino acid metallointercalators with DNA at physiological pH: evaluation of biological assays.

The 4-aminoantipyrine derivatives (NO2, OCH3) and their mixed-ligand complexes with amino acids have been synthesized and investigated for their binding with CT DNA using UV-visible spectroscopy, cyclic voltammetry, and viscosity measurements under physiological conditions of pH (stomach 4.7; blood 7.4). The results from all techniques i.e. binding constant (Kb), and free energy change (ΔG) were in good agreement and inferred spontaneous compound-DNA complexes formation via intercalation. Among all the compounds 1 and 4 showed comparatively greater binding at pH 7.4 as evident from its greater Kb values. All the complexes exhibit oxidative cleavage of supercoiled (SC) pBR322 plasmid DNA in the presence of H2O2 as an activator. It is remarkable that at 25µM concentration 1 and 4 completely degrade SC DNA into undetectable minor fragments and thus they act as efficient chemical nucleases. Among the new complexes, complexes 1 and 4 have highest potential against all the microorganisms tested. The results of the above biological experiments also reveal that the choice of different metal ions has little influence on the DNA binding, DNA cleavage and antimicrobial assay.

Photo biological activation of NSO donor mixed-ligand complexes: in vivo and preclinical perspectives.

Pyrazolone incorporating N-acetylcysteine (NAC) mixed-ligand complexes are described as promising anti-inflammatory, anticonvulsant, SODs mimetic and cytotoxic compounds possibly due to its antioxidant profile. In this study, we have evaluated the pharmacologic activity, antioxidant and toxicological profiles of compounds (1-6). Among them, compounds 1 and 4 were haemobiocompatible than the others. Both complexes 1 and 4 display efficient photo-nuclease activity upon irradiation with UV-A light of 365 nm and red light of 647 nm as compared with others. Mechanistic studies reveal that the DNA cleavage oxidative pathway involves H2O2 and singlet oxygen as the reactive oxygen species. Interestingly, both compounds 1 and 4, show non-toxic effects in vitro to human normal lymphocyte cells, revealing that they are selective in killing only the cancer cells as expected for a better drug. In addition, considering the safety profile, these compounds are promising as preventive and/or therapeutic agents against oxidative damage.