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Osteosarcoma, the most common bone cancer, leads to a poor survival rate of patients. Drug targeting employing hydroxyapatite (HAp)-based nanocarriers represents a fascinating choice for non-invasive treatment of osteosarcoma. Herein,...

β-Cyclodextrin (β-CD) is a nontoxic cyclic oligosachcharide that can encapsulate all or part of organic molecules of appropriate size and specific shape through noncovalent interaction. Herein, we report the influence of β-CD complex formation of an antipyrine derivative on its metal ion sensing behavior. In aqueous solution, the antipyrine shows a turn-on fluorescence sensing of vanadyl ion, and in cyclodextrin medium it senses aluminum ion. The compound shows an unusual fluorescence quenching on binding with β-cyclodextrin (log K SV = 2.34 ± 0.02). The differential metal ion sensing is due to the partial blocking of the chelating moiety by the cyclodextrin molecule. The structure of the antipyrine− cyclodextrin complex is optimized by two-dimensional rotating-frame Overhauser effect spectroscopy. The binding constant is determined by isothermal titration calorimetry (log K = 2.09 ± 0.004). The metal ion binding site is optimized by quanutm mechanical calculations. The lower limit of detection of vanadyl and aluminum ions, respectively, are 5 × 10 −8 and 5 × 10 −7 mol dm −3 . This is the first report of selectivity of two different cations by a chemosensor in water and in β-CD.

We report, in this paper, a benzothiazole derivative which shows selective binding of zinc ions among a pool of metal ions and the enhanced selectivity of the same metal ion by the derivative in its b-cyclodextrin bound form. The Zn 2+ ion binding is studied using UV-visible absorption and fluorescence spectroscopy.The stoichiometry and binding mode of the benzothiazole derivative-b-cyclodextrin complex are determined using 1D and 2D NMR spectroscopic analysis. The cyclodextrin molecule slides over the benzothiazole derivative and resides above the aminomethyl group linking the benzothiazole and dihydroxyphenyl moieties. The site of binding of the Zn 2+ ion with the compound remains the same both in the compound's free and cyclodextrin-complexed forms. Molecular modeling studies were also carried out in order to obtain more details about the cyclodextrin-compound and Zn 2+ -compound interactions, and their results are in close agreement with obtained experimental data.