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Copper levels in biological fluids are associated with Wilson's, Alzheimer's, Menke's, and Parkinson's diseases, making them good biochemical markers for these diseases. This study introduces a miniaturized screen-printed electrode (SPE) for the potentiometric determination of copper(II) in some biological fluids. Manganese(III) oxide nanoparticles (Mn2O3-NPs), dispersed in Nafion, are drop-casted onto a graphite/PET substrate, serving as the ion-to-electron transducer material. The solid-contact material is then covered by a selective polyvinyl chloride (PVC) membrane incorporated with 18-crown-6 as a neutral ion carrier for the selective determination of copper(II) ions. The proposed electrode exhibits a Nernstian response with a slope of 30.2 ± 0.3 mV/decade (R2 = 0.999) over the linear concentration range 5.2 × 10–9 – 6.2 × 10–3 mol/l and a detection limit of 1.1 × 10–9 mol/l (69.9 ng/l). Short-term potential stability is evaluated using constant current chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS). A significant improvement in the electrode capacitance (91.5 μF) is displayed due to the use of Mn2O3-NPs as a solid contact. The presence of Nafion, with its high hydrophobicity properties, eliminates the formation of the thin water layer, facilitating the ion-to-electron transduction between the sensing membrane and the conducting substrate. Additionally, it enhances the adhesion of the polymeric sensing membrane to the solid-contact material, preventing membrane delamination and increasing the electrode's lifespan. The high selectivity, sensitivity, and potential stability of the proposed miniaturized electrode suggests its use for the determination of copper(II) ions in human blood serum and milk samples. The results obtained agree fairly well with data obtained by flameless atomic absorption spectrometry. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel transition metal chelates based on a bidentate NO-donor Schiff base ligand were efficiently synthesized. • DFT analyses for geometrical optimization of the synthesized compounds. • Biological studies including antimicrobial and anti-proliferative activities of the synthesized compounds. • Intercalative binding with macromolecular biological receptors was supported by molecular docking studies. • Correlation between the estimated DFT data and molecular docking results. It is crucial to establish a correlation between the chemical structure of transition metal chelates and their anticipated biological activity to create efficient bioinorganic medications. Thus, new bivalent transition metal chelates; M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II), were easily synthesized from an innovative bidentate NO-donor Schiff base ligand (HL). A comprehensive series of physicochemical techniques like FT-IR, 1H NMR, ESR, TGA and UV–Vis spectroscopy was used to characterize the synthesized compounds. The metal is evidently coupled to two ligands through the deprotonated enolic oxygen and nitrogen atoms of imine groups in all chelates. The obtained analytical and spectroscopic data revealed that the chelates of Mn(II), Co(II), Ni(II) and Cu(II) adopted octahedral structures with two coordinated water molecules. On the other hand, the Zn(II) chelate was found to be a tetrahedron, while the Cd(II) one was a distorted tetrahedron. The energy optimized geometry of HL and some of its chelates as well as their quantum reactivity descriptors were estimated by DFT analysis. The antimicrobial and cytotoxicity screening exhibited that the compounds were bioactive with various biological activities. In addition, the binding interaction characteristics of the ligand and the Cu(II), Zn(II) and Cd(II) chelates were validated by molecular docking processes using three macromolecular biological receptors (Aureolysin, Staphylococcus Aureus metalloproteinase (1BQB), a penicillin-binding protein 3 from Escherichia Coli (4PJP) and a B-DNA (1BNA). The biological findings were correlated with the calculated DFT data and molecular docking results. [ABSTRACT FROM AUTHOR]

In this research, CuFe2O4 nanoparticles were synthesized by co-precipitation methods and modified by coating with thiophene for removal of Hg(II) ions from aqueous solution. CuFe2O4 nanoparticles, with and without thiophene, were characterized by x-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), energy dispersive x-ray (EDX), high-resolution transmission electron microscopy (HRTEM) and Brunauer–Emmett–Teller (BET). Contact time, adsorbent dose, solution pH, adsorption kinetics, adsorption isotherm and recyclability were studied. The maximum adsorption capacity towards Hg2+ ions was 7.53 and 208.77 mg/g for CuFe2O4 and CuFe2O4@Polythiophene composite, respectively. Modification of CuFe2O4 nanoparticles with thiophene revealed an enhanced adsorption towards Hg2+ removal more than CuFe2O4 nanoparticles. The promising adsorption performance of Hg2+ ions by CuFe2O4@Polythiophene composite generates from soft acid–soft base strong interaction between sulfur group of thiophene and Hg(II) ions. Furthermore, CuFe2O4@Polythiophene composite has both high stability and reusability due to its removal efficiency, has no significant decrease after five adsorption–desorption cycles and can be easily removed from aqueous solution by external magnetic field after adsorption experiments took place. Therefore, CuFe2O4@Polythiophene composite is applicable for removal Hg(II) ions from aqueous solution and may be suitable for removal other heavy metals. [ABSTRACT FROM AUTHOR]