title: Hyperbranched polyglycerol-based lipids via oxyanionic polymerization: toward multifunctional stealth liposomes.
abstract: We describe the synthesis of linear-hyperbranched lipids for liposome preparation based on linear poly(ethylene glycol) (PEG) and hyperbranched polyglycerol (PG). Molecular weights were adjusted to values around 3000 g/mol with varying degrees of polymerization of the linear and the branched segments in analogy to PEG-based stealth lipids; polydispersities were generally low and below 1.3. The hydrophobic anchors were introduced into the lipid structures as initiators for the anionic polymerization of ethylene oxide and are either based on cholesterol or on different aliphatic glyceryl ethers. Complete incorporation of the apolar initiators was evidenced by MALDI-ToF analysis at all stages of the reaction. The linear-hyperbranched polyether lipid is incorporated as the polyfunctional shell in liposome formulations together with 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). The resulting liposomes were subsequently characterized via dynamic light scattering (DLS) and small angle neutron scattering (SANS) as well as transmission electron microscopy (TEM), demonstrating the formation of unilamellar liposomes in the size range of 40 to 50 nm.
authors.affiliation: Institute of Organic Chemistry, Johannes Gutenberg-Universitat, Duesbergweg 10-14, Mainz, Germany.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Hofmann
authors.forename: Frederik
authors.initials: F
authors.lastname: Wurm
authors.forename: Eva
authors.initials: E
authors.lastname: Hühn
authors.forename: Thomas
authors.initials: T
authors.lastname: Nawroth
authors.forename: Peter
authors.initials: P
authors.lastname: Langguth
authors.forename: Holger
authors.initials: H
authors.lastname: Frey
mesh_terms: D000838:Anions; D005990:Glycerol / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes; D009682:Magnetic Resonance Spectroscopy; D011108:Polymers / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000838:Anions; D008055:Lipids; D008081:Liposomes; D011108:Polymers; C043941:polyglycerol; D005990:Glycerol