Spectrophotometric investigation on the interaction of toluidine blue with calf thymus DNA by cyclodextrin supramolecular |
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| Authors: | Zhenming Dong Wei Wang Guomei Zhang |
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| Affiliation: | 1. School of Chemistry and Chemical Engineering, Institute of Environmental Science, Shanxi University, Taiyuan, Chinagmzhang@sxu.edu.cn;3. School of Chemistry and Chemical Engineering, Institute of Environmental Science, Shanxi University, Taiyuan, China |
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| Abstract: | The interaction of toluidine blue (TB) with cyclodextrins (CDs), including β-cyclodextrin (β-CD) and carboxymethyl-β-cyclodextrin (CM-β-CD), and calf thymus DNA in aqueous solution is studied by ultraviolet-visible absorption and steady-state fluorescence technique. The interactive model of TB with double-stranded DNA has been investigated by means of the inclusive action of β-CD and CM-β-CD. Based on the changes of absorption, fluorescence and resonance light scattering (RLS) spectra, the intrinsic binding constant (Kap) and the binding site number (n) of TB with DNA and the inclusion complexes TB–CD with DNA are obtained in the case of 20 mmol L?1 Tris-HCl buffer solution (pH 7.2). According to the experimental results, it can be inferred that the interactive model of dimer TB with DNA is ‘electrostatic binding’, while the monomer TB with DNA is ‘intercalative binding’. |
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| Keywords: | DNA cyclodextrin toluidine blue supramolecular system |
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