Anionic lipoplex

Patil SD, Rhodes DG, Burgess DJ (2005) Biophysical characterization of anionic lipoplexes. Biochim Biophys Acta 1711(1) 1—11... 

C. Srinivasan, D.J. Burgess, Optimization and characterization of anionic lipoplexes for gene delivery, J. Control Release 136 (2009) 62-70. 

S.D. Patil, D.G. Rhodes, D.J. Burgess, Biophysical characterization of anionic lipoplexes,... 

An alternative to the conventional PEG-PE was to incorporate between the PEG and the lipidic chain, a linker bearing anionic charges conveniently positioned in order to interact with the free amines of the cationic lipid within the lipoplexes (8). 

Nicolazzi C, et al. Anionic polyethyleneglycol lipids added to cationic lipoplexes increase their plasmatic circulation time. J Control Rel 2003 429. 

Fig. 25 (a) DNA release from EDOPC-DNA lipoplexes after addition of negatively charged lipid dispersion, as monitored by FRET (CM, oleic acid DOPA, dioleoyl phosphatidic acid DOPG, dioleoyl phosphatidylglycerol CL, cardiolipin DOPS, dioleoyl phosphatidylserine PI, phospha-tidylinositol). (b) Fraction of released DNA from EDOPC lipoplexes 10 min after addition of the respective anionic liposomes (c) X-ray diffraction patterns of mixtures of EDOPC and anionic liposome dispersions the respective structures are shown schematically on the left side (reproduced with permission from [98] copyright (2004) Biophysical Society)... 

Cellular anionic lipids have a twofold effect on DNA release from the lipo-plexes. They compensate the cationic lipid surface charge and eliminate the electrostatically driven DNA binding to the membrane interface, and they also disrupt the lipoplex structure and facilitate DNA departure into the solution by inducing formation of nonlamellar phases upon mixing with the lipoplex lipids. 

Tarahovsky YS, Koynova R, MacDonald RC (2004) DNA release from lipoplexes by anionic lipids correlation with lipid mesomorphism, interfacial curvature, and membrane fusion. Biophys J 87 1054—1064... 

M. Cadet, R.T. Ibad, J. Seguin, D. Scher-man, and M. Bessodes. 2003. Anionic polyethyleneglycol lipids added to cationic lipoplexes increase their plasmatic circulation time./. Control. Release 88 429 -43. 

To reach this goal, we have designed tunable anionic pH sensitive lipoplexes. These complexes are anionic at physiological pH and pegylated to improve their circulation time, as compared to cationic lipoplexes (22). Moreover, they become cationic at pH under 6, in order to promote efficient tumor cell internalization, since it is widely recognized that extracellular pH is acidic in ischemic tumor tissue (see Scheme 1). 

Lipoplexes were prepared in tris-maleate 25 mM, glucose 2.5% with a charge ratio cationic lipid/anionic lipid=6, which corresponds to a ratio total lipid to DNA= 12. 

Mignet N, Richard C, Seguin J, Largeau C, Bessodes M, Scherman D (2008) Anionic pH-sensitive pegylated lipoplexes to deliver DNA to the tumors. Int J Pharm 361(1-2) 194-201... 

Lipoplexes are prepared by the interaction of anionic nucleic acids with the surface of cationic lipid to afford multilamellar lipid-nucleic acid complexes. Cationic liposomes can protect nucleic acids from serum nucleases and facilitate the cellular uptake and release of nucleic acids into the cytosol [218]. Pedroso et al. [219] have extensively discussed the structure-activity relationships of cationic lipo-some/DNA complexes and the key formulation parameters influencing the properties of lipoplexes. In addition, optimization of the cationic liposomal complexes for in vivo application has been reviewed by Smyth [220]. 

Cationic lipids and polymers interact and self-assemble with anionic nucleic acids in the form of complexes, named lipoplexes and polyplexes, respectively. Polyplexes are nanoscale complexes obtained by cationic polymers and... 

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... 

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