Dicationic (also known as gemini or dimeric) bis-alkylimidazolium surfactants belong to a group of non-viral transfection systems proposed for the successful introduction of different types of nucleic acids (i.e., siRNA, DNA oligomers, and plasmid DNA) into living cells.
Dimeric cationic surfactants (gemini-type) are a group of amphiphilic compounds with potential use in gene therapy as effective carriers for nucleic acid transfection (i.e., siRNA, DNA, and plasmid DNA). Our studies have shown the formation of lipoplexes composed of alkanediyl-α,ω-bis[(oxymethyl)dimethyldodecylammonium] chlorides and selected 21-base-pair nucleic acid (dsDNA and siRNA) oligomers. To examine the structure and physicochemical properties of these systems, optical microscopy, circular dichroism spectroscopy (CD), small-angle X-ray scattering of synchrotron radiation (SR-SAXS), and agarose gel electrophoresis (AGE) were used. The lengths of spacer groups of the studied surfactants had a significant influence on the surfactants’ complexing properties. The lowest charge ratio (p/n) at which stable lipoplexes were observed was 1.5 and the most frequently occurring microstructure of these lipoplexes were cubic and micellar phases for dsDNA and siRNA, respectively. The cytotoxicity tests on HeLa cells indicated the non-toxic concentration of surfactants to be at approximately 10 µM. The dicationic gemini surfactants studied form complexes with siRNA and dsDNA oligomers; however, the complexation process is more effective towards siRNA. Therefore these systems could be applied as transfection systems for therapeutic nucleic acids.
Carbon nanotubes
and a number of other carbon nanomaterials have
a tendency to aggregate, which often resulted in difficulties of dispersion
of these nanomaterials in aqueous solutions. The ability of dicationic
(gemini) surfactants to disperse multiwall carbon nanotubes in water
and the dynamic processes taking place at the water–multiwall
carbon nanotubes (MWCTs) interface are studied. Stable dispersions
of multiwall carbon nanotubes with selected gemini surfactants (1,1′-(1,6-hexanediyl)bis(3-alkyloxymethylimidazolium)
dichlorides) were prepared and characterized by nuclear magnetic relaxation
dispersion (NMRD), NMR diffusometry, scanning and transmission electron
microscopy, and Fourier transform infrared spectroscopy. The addition
of multiwall carbon nanotubes to aqueous solutions of studied gemini
surfactants leads to significant paramagnetic enhancement of the spin–lattice
relaxation processes, which gets more pronounced with increasing concentration
of well-dispersed MWNTs in water. The dominant role of outer sphere
(OS) relaxation mechanism in total observed R
1, governed by two-dimensional diffusion of water on the carbon
nanotube surface in the vicinity of paramagnetic centers incorporated
in the MWCNTs’ sidewalls (mainly of iron origin), was assumed
to explain NMRD data. The NMR diffusion experiments confirm the existence
of restricted water diffusion in the studied supernatants. The NMR
diffusion results are consistent with the FTIR and NMR proton spin–lattice
relaxation dispersion in which the more effective R
1 dispersion noticed for the sample with IMIC6C12 was
ascribed to the better accessibility of water molecules to the surface
of the MWCNTs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.