Department of Physical Chemistry, University of Umeå, S-901 87, Umeå, Sweden.
J Fluoresc. 1995 Sep;5(3):279-84. doi: 10.1007/BF00723899.
We report on the properties of 1,32-dihydroxy-dotriacontane-bis-rhodamine 101 ester (Rh101C32Rh101) in lipid bilayers of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and in liquid solvents. The results are compared with those of rhodamine 101 octadecanyl ester (Rh101C18). Both molecules are solubilized in the lipid bilayer and the Rh101 moieties are anchored in the lipid-water interface, so that the electronic transition dipole moments (S 0 ↔S 1) are oriented preferentially in the plane of the bilayer. At low concentrations of the dyes in lipid bilayers of DOPC, the fluorescence relaxation is single exponential with a lifetime of τ=4.9±0.2 ns. The relative fluorescence quantum yield of ΦC32/ΦC18 ≈ 0.95 in DOPC vesicles. These results strongly suggest that only a small fraction of the Rh101C32Rh101 molecules are quenched, by, for example, intra- or intermolecular dimers in the ground state at mole fractions of less than 0.1% in the lipid bilayers. For Rh101C32Rh101 in lipid vesicles, the steady-state and time-resolved fluorescence anisotropies are compatible with efficient intramolecular electronic energy transfer. It is concluded that nearly every Rh101C32Rh101 molecule is spanning across the lipid bilayer of DOPC.
我们报告了 1,32-二羟基-三十二烷双罗丹明 101 酯（Rh101C32Rh101）在 1,2-二油酰基-sn-甘油-3-磷酸胆碱（DOPC）脂质双层中和在液体溶剂中的性质。结果与罗丹明 101 十八烷基酯（Rh101C18）的结果进行了比较。这两种分子都溶解在脂质双层中，Rh101 部分锚定在脂质-水界面，使得电子跃迁偶极矩（S0↔S1）优先取向于双层平面。在 DOPC 脂质双层中染料的低浓度下，荧光弛豫是单指数的，寿命τ=4.9±0.2ns。在 DOPC 囊泡中，ΦC32/ΦC18 的相对荧光量子产率≈0.95。这些结果强烈表明，只有一小部分 Rh101C32Rh101 分子被猝灭，例如，在脂质双层中摩尔分数小于 0.1%的基态下的分子内或分子间二聚体。对于 Rh101C32Rh101 在脂质囊泡中，稳态和时间分辨荧光各向异性与有效的分子内电子能量转移兼容。可以得出结论，几乎每个 Rh101C32Rh101 分子都跨越了 DOPC 的脂质双层。
