DNA-surfactant complexes

Determinations of the degree of DNA entrapment show loading efficiency (LE) values of CTAB-DNA particles higher than 99%, confirming the effectiveness of DNA entrapment in the surfactant solution. DNA loads of up to 2% were achieved. The binding of CTAB to DNA depends of the secondary structure of the polyelectrolyte. Quantification of the surfactant-DNA complexes in the particles shows significative differences (52% versus 79% in particles formed with native ds-DNA and denatured ss-DNA, respectively). 

Mel nikov, S.M., Sergeyev, V.G. and Yoshikawa, K. (1997c) Cooperation between salt induced coil-globule transition in single duplex DNA complexed with cationic surfactant and sphere-rod transition of surfactant micelles. Prog. Colloid. Polym. Sci., 106, 209-214. 

Polymer-based delivery systems (Fig. 11.1) include polymer-protein conjugates, polymer-drug conjugates, micelles consisting of polymeric surfactants, and complexes of cationic polymers and DNA (polyplexes).26... 

Since the early years of DNA complexation with cationic polymers, pioneers from the field of polyelectrolyte complexes between surfactants and/or polymers led solid physico-chemical studies on the complexation of DNA with polymers. But it is only more recently, with the rise of more precise instruments for physico-chemical characterization and appropriate biochemical and biophysical techniques, that the published studies are allowing a direct link to be drawn between physico-chemical characteristics (such as size, charge, etc.) of the DNA/polymer (mostly polycations) complexes, also called polyplexes, and their in vitro and in vivo properties, thus allowing tremendous progresses in the quest towards polyplexes for gene therapy and their application beyond research laboratories. 

The resistance of lipoplexes formed from compounds LI and L2 and plasmid DNA was studied by electrophoretic retardation assays. Initial complexation experiments showed that all compounds were able to form full lipid/DNA complexes despite the presence of fluorinated regions near the headgroup. Fluorinated lipoplexes were formed with an excess of pure compounds LI and L2 and their integrity was tested with anionic, cationic, or neutral surfactants. When lipoplexes were analyzed by agarose... 

Abstract A linear DNA can be dissolved in nonaqueous low-polar organic solvents by forming complexes between DNA and cationic surfactants. The data of high-rate sedimentation, UV-spectrometric and circular dichroism measurements show that the DNA complexes with surfactant in chloroform, heptane and cyclohexane are individual components with a 1 1 stoichiometry. The DNA molecules passing to the organic phase retain a double-stranded helix conformation. By... 

Cooperation between salt induced globulesingle duplex DNA complexed with cationic surfactant and sphorofod transition of surfactant micelles... 

Fig. 16 Idealised model for self-assembly process of DNA-surfactant cation complexes. (Reproduced with permission from American Chemical Society and [17])...

Colloidal systems with a cationic poly(lactide-co-glycolide) (PLGA) surface containing microparticles coated with a cationic cetyltrimethylammonium bromide surfactant by a solvent evaporation process were also reported to deliver DNA vaccine [122]. However, the microparticles attached to DNA complexes were weak as the cationic surfactant was physically adsorbed onto the microparticle surface [123],... 

Complexes of the [Ru(bpy)2L] " type in which L is a phen-based ligand are discussed next. Perchlorate salts of [Ru(bpy)2(phen)] + and [Ru(bpy)2(5-Mephen)] + have been prepared and structurally characterized. The steric strain within the coordination sphere is relieved in part by twisting of each bpy ligand. Time-resolved resonance Raman spectroscopy has been used to investigate the localization of the excited electron in the MLCT state of [Ru(bpy)2(4,7-Ph2-phen)] In neutral micelles, the electron is localized on the bpy ligands, but in the presence of DNA and anionic surfactants, it is localized on 4,7-Ph2phen when the complex is in aqueous... 

DNA has also been immobilized on Au electrode by its interaction with gem-ini surfactants [216]. Moreover, inclusion complexes of viologen-attached alkanethi-ols and a- and /J-cyclodextrins that spontaneously assemble on Au electrodes have been studied [217, 218]. 

Self-organization systems under thermodynamic control (spontaneous processes with a negative free-energy change), such as supramolecular complexes, crystallization, surfactant aggregation, certain nano-structures, protein folding, protein assembly, DNA duplex. 

Yamasaki, Y., Hirano, K., Morishima, K., Mizuno, A., Arai, F. and Yoshikawa, K. (1998) Optical trapping of single DNA molecule complexed with cationic surfactant. Forma, 13, 397-403. 

Liu, F., Yang, J.P., Huang, L. and Liu, D. (1996a) Effect of non-ionic surfactants on the formation of DNA/emulsion complexes and emulsion-mediated gene transfer. Pharm. Res., 13, 1642-1646. 

Charged solutes in electrolyte solutions that are electrokinetically driven through channels with nanoscale widths exhibit unique transport characteristics that may enable rapid and efficient separations under a variety of physiological and environmental conditions. Many biomolecules, including DNA, proteins, and peptides, are charged or can be complexed with charged surfactant molecules. Manipulating the velocity of biomolecules by variation in flow pressure or electric fields in channels of nanoscopic widths will enable efficient separations that are not possible in micro- or macroscopic channels. 

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