@article{GehneFlehrKienzleretal.2012,
  author    = {Gehne, S{\"o}ren and Flehr, Roman and Kienzler, Andrea Altevogt Nee and Berg, Maik and Bannwarth, Willi and Kumke, Michael Uwe},
  title     = {Dye dynamics in three-color FRET samples},
  series = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  volume    = {116},
  journal   = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  number    = {35},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1520-6106},
  doi       = {10.1021/jp3064273},
  pages     = {10798 -- 10806},
  year      = {2012},
  abstract  = {Time-resolved emission data (fluorescence decay and fluorescence depolarization) of two three-color Forster resonance energy transfer (tc-FRET) systems consisting of a carbostyril donor (D), a ruthenium complex (Ru) as relay dye, and a Cy5 derivative (Cy) or, optionally, an anthraquinone quencher (Q) were carefully analyzed using advanced distribution analysis models. Thereby, it is possible to get information on the flexibility and mobility of the chromophores which are bound to double stranded (ds) DNA. Especially the distance distribution based on the analysis of the fluorescence depolarization is an attractive approach to complement data of fluorescence decay time analysis. The distance distributions extracted from the experimental data were in excellent agreement with those determined from accessible volume (AV) simulations. Moreover, the study showed that for tc-FRET systems the combination of dyes emitting on different time scales (e.g., nanoseconds vs microseconds) is highly beneficial in the distribution analysis of time-resolved luminescence data in cases where macromolecules such as DNA are involved. Here, the short lifetimes can yield information on the rotation of the dye molecule itself and the long lifetime can give insight in the overall dynamics of the macromolecule.},
  language  = {en}
}
@article{GehneSydowDatheetal.2013,
  author    = {Gehne, S{\"o}ren and Sydow, Karl and Dathe, Margitta and Kumke, Michael Uwe},
  title     = {Characterization of cell-penetrating lipopeptide micelles by spectroscopic methods},
  series = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  volume    = {117},
  journal   = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  number    = {46},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1520-6106},
  doi       = {10.1021/jp406053g},
  pages     = {14215 -- 14225},
  year      = {2013},
  abstract  = {The transport of bioactive compounds to the site of action is a great challenge. A promising approach to overcome application-related problems is the development of targeting colloidal transport systems, such as micelles which are equipped with uptake mediating moieties. Here, we investigated a set of novel lipopeptides which exhibit a surfactant-like structure due to attachment of two palmitoyl chains to the Nterminus of cationic or anionic amino acid sequences. We analyzed the association behavior of these lipopeptides by using 5(6)-carboxyfluorescein (CF)-labeled derivatives as a fluorescent probe and different spectroscopic methods such as fluorescence anisotropy and fluorescence correlation spectroscopy (FCS). The photophysical properties as well as the diffusion and rotational movements of the CF-labeled lipopeptides were exploited to determine the cmc and the size of the micelles consisting of lipopeptides. We could distinguish cationic and anionic lipopeptides by their association behavior and by studying the interactions with mouse brain capillary endothelial cells (b.end3). The cationic derivatives turned out to be very strong surfactants with a very low cmc in the micromolar range (0.5-14 mu M). The unique combination of micelle-forming property and cell-penetrating ability can pave the road for the development of a novel class of efficient drug carrier systems.},
  language  = {en}
}
@article{KienzlerFlehrGehneetal.2012,
  author    = {Kienzler, Andrea Altevogt Nee and Flehr, Roman and Gehne, S{\"o}ren and Kumke, Michael Uwe and Bannwarth, Willi},
  title     = {Verification and biophysical characterization of a New Three-Color Forster Resonance-Energy-Transfer (FRET) System in DNA},
  series = {Helvetica chimica acta},
  volume    = {95},
  journal   = {Helvetica chimica acta},
  number    = {4},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0018-019X},
  doi       = {10.1002/hlca.201100460},
  pages     = {543 -- 555},
  year      = {2012},
  abstract  = {We report on a new three-color FRET system consisting of three fluorescent dyes, i.e., of a carbostyril (=quinolin-2(1H)-one)-derived donor D, a (bathophenanthroline)ruthenium complex as a relay chromophore A1, and a Cy dye as A2 (FRET=Forster resonance-energy-transfer) (cf. Fig. 1). With their widely matching spectroscopic properties (cf. Fig. 2), the combination of these dyes yielded excellent FRET efficiencies. Furthermore, fluorescence lifetime measurements revealed that the long fluorescence lifetime of the Ru complex was transferred to the Cy dye offering the possibility to measure the whole system in a time-resolved mode. The FRET system was established on double-stranded DNA (cf. Fig. 3) but it should also be generally applicable to other biomolecules.},
  language  = {en}
}