Synthesis, Absorption and Fluorescence Spectral Characteristics of Trinucleus Dimethine Cyanine Dyes as Fluorescent Probes for DNA Detection

The preparation of six trinucleus dimethine cyanine dyes with pyridine nucleus obtained by the condensation of trimethylpyridinium iodides with heterocyclic aromatic aldehyde was described. The absorption and fluorescence properties of the dyes were studied in different polarity solvents. Blue shift of the maxima absorption of the dyes was observed with the increase of solvents polarity. The fluorescence properties of the dyes in solution and in presence of DNA were studied. Significant enhancement of the fluorescent quantum yield was observed in four dyes in the presence of DNA. Specially, one of six dyes emitted weak fluorescence in Tris-HCl buffer, but displayed bright fluorescence in the presence of DNA.