Surface Recognition and Complexations Between Synthetic Poly(ribo)nucleotides and Neutral Phospholipids and Their Implications in Lipofection

Thermodynamic features related to preparation and use of self-assemblies formed betweenmultilamellar and unilamellar zwitterionic liposomes and polynucleotides with various conformationand sizes are presented. the divalent metal cation or surfactant-induced adsorption, aggregation andadhesion between single- and double-stranded polyribonucleotides and phosphatidylcholine vesicles wasfollowed by differential adiabatic scanning microcalorimetry. nucleic acid condensation and compactionmediated by mg2+ and n-alkyl-n,n,n-trimetylammoniunl ions (cntma, n=12), regarding to interfacialinteraction with unilamellar vesicles. microcalorimetric measurements ofsynthetic phospholipid vesiclesand poly(ribo)nucleotides and their ternary complexes with inorganic cations were used to build thethermodynamic model of their structural transitions. the increased thermal stability of the phospholipidbilayers is achieved by affecting their melting transition temperature by nucleic acid induced electrostaticcharge screening. measurements give evidence for the stabilization of polynucleotide helices upontheir association with liposomes in the presence of divalent metal cations. such an induced aggregationof vesicles either leads to heterogeneous multilamellar dna-lipid arrangements, or to dna-inducedbilayer destabilization and lipid fusion. in contrast, stable monodispersed complexes are formed aftercompaction of dna with surfactant, followed by the addition of vesicles. surfactants bind to dna ina cooperative manner and increased number of nucleic acid-bound cl2tma leads to a rise in the sizeof the resulting dna-surfactant complexes, due to their aggregation. the formation of these bundlesis governed by both elctrostatic and hydrophobic interactions of surfactant chains, the reaction beingmediated by condensed counterions, steric hindrance or by intrinsic chain flexibility. in here, furtheremployment of these polyelectrolyte nanostructures as an improved formulation in therapeutic genedelivery trials, as well as in dna chromatography is discussed..