Cationic polymers, at physiological pH, are used to condense anionic nucleic acids, as healing agent, into nano-sized particle-like complexes called “polyplexes”, through self-assembly driven by electrostatic interactions. By compressing DNA molecules to a relatively small size, cellular internalization is facilitated and, thus, transfection efficacy is improved.New non-viral vector formulations are proposed for gene therapy.Cationic liquid-crystal polymers, synthetized as cholesteric and biocompatible, are directly complexed with polynucleotides of increasing complexity (both single and double stranded)or with two kinds of deoxyribonucleic acid (Plasmid PBR322 and calf-thymus DNA). Structural information of thepolyplexes is studied by SAXS at the BM16 beamline at ESRF.The radii of gyration (Rg) of the Cholesteric Liquid-Crystal Polymer aggregates and polyplexes suspended in TAE, have been calculated from the slope of the corresponding Guinier plots Ln (I) vs q2 (slope = Rg2/3). Information about the shape is estimated by plotting I(q) vs q*Rg.Fractal nature is also analyzed from Porod plots[Ln I(q)-B] vs Ln (q).The interaction between the new cationic cholesteric liquid-crystal polymers and oligonucleotides and DNA is confirmed in all the studied cases.Peer reviewe
