Browsing by Author "Onani, Martin O"

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    Biomolecular affinities and cytotoxicity of copper(I) and silver(I) phosphine–pyridinyl complexes against CACO-2 and CASKI cell lines
    (John Wiley and Sons Inc, 2025) Meyer, Miche D; Sibuyi, Nicole R. S; Onani, Martin O
    A series of three copper (I) and three silver (I) complexes with the general formula [M L(PPh3)2]NO3, (M = Cu for complexes 1–3 and Ag for complexes 4–6) are synthesized by reacting copper(I) or silver(I)-nitrate and triphenylphosphine with the bidentate ligands, (E)-1-(pyridin-2-yl)-N-(o-tolyl)methanimine L1, (E)-N-isopropyl-1-(pyridine-2-yl)methanimine L2, or (E)-N-(2,6-dimethylphenyl)-1-(pyridine-2-yl)methanimine L3. The structures of these complexes are elucidated using a combination of NMR spectroscopy, FTIR, UV–visible, mass spectrometry, elemental analysis, and single-crystal X-ray diffraction. Structural analysis revealed that the Schiff bases coordinate to the metal centers in a bidentate fashion, with triphenylphosphine occupying the remaining coordination sites in complexes 1, 2, and 5. In contrast, in complexes 3, 4, and 6, one coordination site is occupied by a nitrate anion instead of triphenylphosphine. All six complexes exhibit a distorted tetrahedral geometry around the metal center, as confirmed by τ4 values ranging from 0.54 to 0.87. Binding studies with calf-thymus DNA demonstrated that complexes 1–6 interact via intercalation, with complex 5 exhibiting the highest binding constant. Furthermore, all complexes showed strong binding affinity toward bovine serum albumin. Cytotoxicity studies revealed significant cytotoxicity of complexes 1–6 against human colon adenocarcinoma (Caco-2) and human cervical epidermoid carcinoma (Caski) cell lines.
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    Synthesis and cytotoxic evaluation of gum arabic surface modified cadmium telluride quantum dots
    (American Scientific Publishers, 2020) Edwina, Uzunuigbe O; Kiplagat, Ayabei; Sibuyi, Nicole R. S.; Meyer, Mervin; Kappo, Abidemi Paul; Onani, Martin O
    Water-soluble cadmium telluride (CdTe) quantum dots (QDs) were capped with gum Arabic (GA) is a non-toxic, water-soluble glycoprotein polymer commonly used in the food and pharmaceutical industries. The GA was used to stabilise cadmium telluride quantum dots (GA-QDs) and provides functional groups for other molecules such as nucleic acids, peptides and antibodies to be attached to the QDs for biological and biomedical applications. In this study, the GA was used to cap and stabilise QDs using two different methods. These QDs were characterised using Ultraviolet-visible (UV-vis) and Photoluminescence (PL) spectroscopy, X-powder ray diffraction (XRD), High-resolution transmission electron microscopy, zeta potential and particle size distributions. Cytotoxicity of these QDs was also investigated using four different human cell lines; HeLa, MCF-7, PC-3 and U87 cancer cells.