Effect of binding mode on the photoluminescence of CTMA-DNA doped with (E)-2-(2-(4-(diethylamino)styryl)-4H-pyran-4-ylidene)malononitrile

Purified natural DNA extracted from Salmon sperm can only be dissolved in water; it is not soluble in any other organic solvent. Therefore, in this study, the structure of DNA was modified and its solubility was changed. The preparation of organic-soluble DNA was carried out by precipitating the purified DNA in water with the cationic surfactant cetyltrimethylammonium chloride (CTMA). The resulting DNA-lipid complex shows good solubility in alcohol, which allows the fabrication of thin films for studying the photophysical properties of DNA in a solid state. The absorption and photoluminescence (PL) behaviors of CTMA-DNA and polymethylmethacrylate (PMMA) doped with (E)-2-(2-(4-(diethylamino)styryl)-4H-pyran-4-ylidene)malononitrile (DCM) were investigated. In addition, different PL spectral behaviors with differing concentrations of DCM in two different host materials were observed. These behaviors were explained by a mechanism based on intercalation or groove binding of fluorescent dye into the base pairs or aliphatic side-chain moieties of CTMA-DNA.