Homodimeric monomethine cyanine dyes as fluorescent probes of biopolymers

The fluorescence properties of newly synthesized homodimeric monomethine cy anine dyes in the presence of biopolymers are investigated. They do not flu oresce in TE buffer and bidistilled water but become strongly fluorescent ( Q(p) = 0.3-0.9) in the region 530-650 nm when bound to dsDNA and ssDNA. The detection limit of dsDNA is about 1.7 ng/ml. Some of dyes studied are able to distinguish between dsDNA and ssDNA, RNA, BSA in solution and gel elect rophoresis. The influence of different factors (temperature, pH and viscosi ty of the medium, presence of histone) on the formation of the dye-biopolym er complexes is investigated. The results of steady-state and dynamic fluor escence measurements concerning the different types of binding between dyes and biopolymers show that the new dyes cue applicable in molecular biology as highly sensitive fluorescence labels. (C) 2000 Elsevier Science B.V. Al l rights reserved.