Abstract |
Oligonucleotides (ODNs) are short (up to 30 bases) fragments of
single-stranded nucleic acids that are used as sequence specific regulators of
gene expression and anti-sense based therapeutics. ODNs are frequently
aggregated with particulates in order to improve their pharmacological
characteristics. Complexes of ODN and lipid aggregates are among the most
commonly mentioned in the literature. In order to control the formation and final
properties of such aggregates, a detailed description of how ODN interacts with
the lipid surface is needed. In this paper, we present the results of fluorescence
measurements regarded an association of 20 base ODN, labelled with
fluorescein, and a lipid surface containing various amount of positive charge.
Unilamellar lipid vesicles were formed from egg phosphatidylcholine (PC) and
various amounts of the cationic lipid 1,2-dioleoyl-3-trimethylammoniumpropane
(DOTAP). It was found that about 20 mol% of DOTAP in the lipid
bilayer suffices to obtain complete ODN association. This result was further
confirmed via measurements performed by fluorescence correlation
spectroscopy (FCS). These in turn showed that the diffusion time of labelled
ODN in the presence of cationic liposomes decreases. Also, the particle number and count rate were reduced, concurring with conclusions derived from steadystate
fluorescence spectroscopy results. |
Address and Contact Information |
1Institute of Physics, Wrocław University of Technology, Wybrzeże
Wyspiańskiego 27, 50-370 Wrocław, Poland, 2Centre for Molecular and
Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112,
90-363 Łódź, Poland, 3J. Heyrovský Institute of Physical Chemistry, Academy
of Sciences of the Czech Republic and Center for Complex Molecular Systems
and Biomolecules, Dolejškova 3, CZ-18223 Prague, Czech Republic, 4Academic
Centre for the Biotechnology of Lipids Aggregates, Przybyszewskiego 63/67,
51-148, Wrocław, Poland * Corresponding author
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