Synthesis And Fluorescence Sensing Behavior Of Symmetrical Cyanine Dyes With Naphthalene Diphenol As Linker

In recent years,the fluorescence imaging technology has been widely used to detect physiological processes in living system due to its advantages of high spatial-temporal resolution,high sensitivity,low background interference and non-invasive detection.The key of the fluorescence imaging technology is fluorescence probe.In order to avoid the interference of background fluorescence and the damage of high energy to cells,the emission wavelength of fluorescent probe used in living cells or in vivo imaging should be as long as possible.Among many fluorescent probe molecules,streptocyanines dyes have attracted much attention due to their excellent photophysical properties and biocompatibility.Reasonably design the structure of cyanine and achieve the goal of diversification and modified have become one of the hot.In this paper,aromatic groups were introduced into the streptocyanines conjugated chain of traditional cyanine,and different groups containing phenols(phenol or naphthol derivatives)were used as potential donor units to construct indole(or thiophene)double receptor conjugated system to improve the spectral properties of dye molecules,and further study their spectral changes in different biological environments.The main work of this paper is as follows:(1)A series of cyanine fluorescent probes Cy-I,Cy-B and Cy-C were synthesized by Knoevenagel condensation of 1,2,3,3-tetramethyl-3h-indole and 3-ethyl-2-methyl benzothiazole with naphthalene diphenol and resorcinal aldehyde,respectively.The correlation between the density of electron cloud in the structure and the cationic and basic properties of the compounds was summarized by ~1H NMR analysis and spectral changes.Furthermore,the sensing properties of cyanine dyes Cy-I and Cy-B to environmental viscosity were investigated by comparing the UV and fluorescence spectra.Cy-I can located in lysosome and monitoring the change of mitochondrial viscosity.(2)Based on the condensation reaction of 2,3-Dihydroxynaphthalene-1,4-dicarbaldehyde and 4-methylpyeidine derivatives,we designed and synthesized the nucleic acid fluorescent probe Cy-P.The chemical sensing behavior of the probe with ct-DNA and RNA were systematically studied by UV-vis spectrum and fluorescence emission spectrum.The results showed that the probe Cy-P had strong interaction with ct-DNA and RNA,and the fluorescence emission intensity was greatly reduced.DNA heat-denaturalization experiment showed that the binding mode between probe Cy-P with ct-DNA was electrostatic interaction.