title: Genospheres: self-assembling nucleic acid-lipid nanoparticles suitable for targeted gene delivery.
abstract: We describe the assembly of a cationic lipid-nucleic acid nanoparticle from a liquid monophase containing water and a water miscible organic solvent where both lipid and DNA components are separately soluble prior to their combination. Upon removal of the organic solvent, stable and homogenously sized (70-100 nm) lipid-nucleic acid nanoparticles (Genospheres) were formed. The low accessibility (<15%) of the nanoparticle-encapsulated DNA to a DNA intercalating dye indicated well-protected nucleic acids and high DNA incorporation efficiencies. It was demonstrated that Genospheres could be stably stored under a variety of conditions including a lyophilized state where no appreciable increase in particle size or DNA accessibility was observed following reconstitution. Finally, Genospheres were made target-specific by insertion of an antibody-lipopolymer (anti-HER2 scFv (F5)-PEG-DSPE) conjugate into the particle. The target specificity (>100-fold) in HER2 overexpressing SK-BR-3 breast cancer cells was dependent on the degree of PEGylation, where the incorporation of high amounts of PEG-lipid on the particle surface (up to 5 mol%) had only a minor effect on the transfection activity of the targeted Genospheres. In summary, this work describes a novel, readily scalable method for preparing highly stable immunotargeted nucleic acid delivery vehicles capable of achieving a high degree of specific transfection activity.
authors.affiliation: California Pacific Medical Center, San Francisco, CA 94080, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Hayes
authors.forename: D C
authors.initials: DC
authors.lastname: Drummond
authors.forename: D B
authors.initials: DB
authors.lastname: Kirpotin
authors.forename: W W
authors.initials: WW
authors.lastname: Zheng
authors.forename: C O
authors.initials: CO
authors.lastname: Noble
authors.forename: J W
authors.initials: JW
authors.lastname: Park
authors.forename: J D
authors.initials: JD
authors.lastname: Marks
authors.forename: C C
authors.initials: CC
authors.lastname: Benz
authors.forename: K
authors.initials: K
authors.lastname: Hong
mesh_terms: D004247:DNA / Q000008:administration & dosage*; D004337:Drug Carriers; D018390:Gene Targeting; D015316:Genetic Therapy / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D008081:Liposomes; D008854:Microscopy, Electron; D049329:Nanostructures; D036103:Nanotechnology / Q000379:methods*; D010714:Phosphatidylethanolamines; D011092:Polyethylene Glycols; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology*
chemical_list: D004247:DNA; D004337:Drug Carriers; D007135:Immunoglobulin Variable Region; D008081:Liposomes; D010714:Phosphatidylethanolamines; D011092:Polyethylene Glycols; D018719:Erb-b2 Receptor Tyrosine Kinases; C107570:polyethylene glycol-distearoylphosphatidylethanolamine