[Accumulation of oxacarbocyanine dyes with different length of the alkyl chain in marrow cells and hepatocytes].

The incorporation of the fluorescent probe 3,3-dialkyloxacarbocyanine bromide H-510 (where alkyl is ethyl- (C2), nonyl- (C9), or octadecyl (C18) groups) into cells of different kind has been explored. It has been revealed that the length of alkyl chains significantly influences the dynamics and mechanisms of accumulation of the probe by the cells. It has been found by microfluorimetry that all probe species have similar spectral characteristics in bone marrow cells, indicating that all probes, independently on their lipophilic properties, are incorporated into micelle-like structures formed probably by cell phospholipids. Spectroscopy experiments have shown that, in hepatocytes, the fluorescent probes 3,3-diethyloxacarbocyanine bromide (H-510/C2) and 3,3-dinonyloxacarbocyanine bromide (H-510/C9) are mainly accumulated in weakly polar media (nonpolar and weakly polar lipids of these cells). The luminescence maximum of the H-510/C18 probe in hepatocytes is blue-shifted and coincides with that in an albumin solution. We suppose that the incorporation of the probe into cells occurs by endocytosis when the probe binds to surface proteins.

Specificity of cyanine dye L-21 aggregation in solutions with nucleic acids.

Optical spectroscopy experiments were used to study the features of cyanine dye 3,3'-dimethyl-9-(2-thienyl)-thiacarbocyanine iodide (L-21) aggregation in binary solutions DMF:Tris-HCl buffer (pH = 8) containing nucleic acids (DNA or RNA). The appearance of absorption and luminescence bands associated with J-aggregates and dimers that are formed within the minor groove of DNA has been observed. The model of L-21 J-aggregate structure is proposed. It has been found that dimers are the building blocks of L-21 J-aggregates. Disorientation in dimers caused by the minor groove curvature is reason of observation of Davydov splitting in absorption spectrum of L-21 J-aggregates. In the solution containing DNA the absorption and luminescence bands of L-21 J-aggregates exhibit the specific properties that allows the dye L-21 to be used as a fluorescent probe for DNA detection.