Synthesis And Characterize Chiral DNA-schiff-base Fluorescent Probe For Zn²⁺

Schiff-base compounds have adjustable structure, stable property and good coordinating capability with different metal ions, so they are important fluoresent probe molecules. Utilizing DNA assembly, we synthesized single stranded DNA-Schiff-base fluorescent probe molecules Sn with chirality (S1 = D9-4M, S2 = D9-4H, S3 = D9-4C1, S4=D9-4T) and double stranded DNA-Schiff-base fluorescent probe molecules of Ln with chirality (L1 = D9-4M-D10-4M, L2 =D9-4H-D10-4H, L3 = D9-4Cl-D10-4Cl, L4 = D9-4T-D10-4T; D9 =C122H162O72N48P15, D10 = C122H165O75N45P15, 4M =2,6-diformyl-4-methylphenol, 4H = 2-hydroxyisophthaladehyde, 4C1 =2,6-diformyl-4-chlorophenol, 4T = 4-tert-butyl-2,6-diformylphenol).Their compositions and structures were characterized by UV-vis spectrum,gel-electrophoresis, Circular dichroism (CD) spectrum and mass spectrum. The results of fluorescence spectrum had shown that the probe had good response to Zn2+ and the LOD was all almost 10-7 mol/L. Job’s plot analysis indicated that Sn with Zn2+ form a complex of 1:2 stoichiometrica and Ln with Zn2+ form a complex of 1:4 stoichiometrica,which means schifft-base probe molecule binding with Zn2+ strongly.Zn2+-titration assay had shown that the probe molecule showed a good selectivity and high sensitivity for Zn2+ in comparison with Ag+, Cd2+,Cu2+, Mn2+, Ni2+, Hg2+, Na+, Fe3+, K+, Mg2+, Co2+ and Pb2+ metal ions. Accroding to the characteristics of Schiff-base compounds and DNA,the probe molecule owns good reversibility via adjusting pH of the system. When the pH of the Sn system was 5.0, and the pH of the Ln system was 5.4, the imine bond of Schifft-base probe molecule was broken and DNA molecule dissociated,which could be used as raw material to synthesize new pbobe molecule, and it could recycle for 4 times.