Studies on DNA, complexed by surfactants or modified with pyrene

This work consists of several parts. It was initiated by Giese’s electon or hole transfer
through DNA using a modified thymidine as a photon triggered radical injector. Taken
the gained knowlegde, that has been collected over years from the series of Tstar
experiments in DNA fragments (oligonucleotides) in solution in account, this work
describes in the first part the changing of the surrounding media. By complexing the
polyanionic backbone of DNA or oligonucleotides with amphiphilic, cationic surfactants
(Surfactant-DNA complex, SDC), water as media could be exchanged by alcohols such
es methanol or propanol. DNA can thereby be dissolved in organic solvents. Surfactants
like dimethylditetradecylammonium chloride (DMDTAB) were used for experiments on
the T star.
During gathering the knowlegde of how to handle the complexes, we started to complex
salmon DNA with a hole series of surfactants of aliphatic as well as aromatic and
polyaromatic nature. Cationic surfactants (trimethylammonim heads) were synthesisied
containing moieties like pyrene, anthracene and substituted derivatives, naphthalimide,
carbazole, umbelliferone, phthalimide and coumarin to change the physical and spectral
properties of the resulting DNA complexes.
The complex of DNA and cetylammonium bromide (CTAB) was spun into fibres with
diameters of 300 - 500 nm by electrospinning. In this way stable, self-assembling
nanomaterials have been produced.
An other part of this work deals with the photophysical and photochemical properties of
DNA, modifed with pyrene. Pyrene has been incorporated as pyrene deoxyribose
nucleoside, replacing only one nucleobase as well as a diamide, replacing the nucleobase
and a sugar moiety into oligomers. This pyrene modified strands have been irradiated
with UV light and the degradation has been analysed using HPLC and Maldi-ToF.