title: Oligonucleotide lipoplexes: the influence of oligonucleotide composition on complexation.
abstract: Despite extensive investigations into oligonucleotide lipoplexes, virtually no work has addressed whether the physicochemical properties of these assemblies vary as a function of the constituent oligonucleotide (ODN) sequence and/or composition. The present study was aimed at answering this question. To this end, we complexed N-(1-(2,3-dioleoyloxy)propyl)-N,N,N-trimethylammonium chloride (DOTAP) liposomes, in dispersion, with either 18-mer phosphorothiote homo-oligonucleotides composed of either adenine, thymidine or cytosine; or one of three structurally related 18-mer phosphorothioate oligonucleotides (S-ODNs) (G3139, its reverse sequence and its two-base mismatch). After ODN addition to vesicles at different mole ratios, changes in pH and electrical surface potential at the lipid-water interface were analyzed by using the fluorophore heptadecyl-7-hydroxycoumarin while particle size distributions were analyzed by static-light scattering. The results indicate that each homo-oligonucleotide does indeed exhibit different complexation behavior. In particular, the maximal level of DOTAP neutralization by the polyadenine S-ODN is much lower than that for the two other homo-oligonucleotides and hence its lipoplex is much more positively charged. Much smaller electrostatic differences are also apparent between lipoplexes formed from each of the G3139-related ODNs. This paper identifies nucleotide base selection and sequence as a variable that can affect the physicochemical properties of oligonucleotide lipoplexes and hence probably their transfection competency.
authors.affiliation: Advanced Technology Center, Chaim Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: V M
authors.initials: VM
authors.lastname: Meidan
authors.forename: J
authors.initials: J
authors.lastname: Glezer
authors.forename: N
authors.initials: N
authors.lastname: Amariglio
authors.forename: J S
authors.initials: JS
authors.lastname: Cohen
authors.forename: Y
authors.initials: Y
authors.lastname: Barenholz
mesh_terms: D005229:Fatty Acids, Monounsaturated; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D008081:Liposomes / Q000737:chemistry*; D008564:Membrane Potentials; D016376:Oligonucleotides, Antisense / Q000737:chemistry*; D010316:Particle Size; D000644:Quaternary Ammonium Compounds; D055672:Static Electricity; D013873:Thionucleotides / Q000737:chemistry*; D014468:Umbelliferones
chemical_list: D005229:Fatty Acids, Monounsaturated; D005456:Fluorescent Dyes; D008081:Liposomes; D016376:Oligonucleotides, Antisense; D000644:Quaternary Ammonium Compounds; D013873:Thionucleotides; D014468:Umbelliferones; C031827:4-heptadecylumbelliferone; C408162:oblimersen; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane