A new fluorescent probe for studies of interactions between hydrophobic oligonucleotides and cellular membranes

The synthesis of a new fluorescently labeled medium-sensitive lipophilic ol igonucleotide is reported. A fluorescent chalcone chromophore was introduce d between the 5' end of the nucleic acid and the fatty hydrocarbon chains. A blue shift of both absorption and emission wavelength maxima results from a transfer of the chromophore to a more hydrophobic medium or upon binding of the conjugate to unilamellar vesicles of egg phosphatidyl choline. Thes e conjugates could be used as markers for cell uptake studies of lipophilic nucleic acid derivatives.