title: Direct formation of giant vesicles from synthetic polypeptides.
abstract: This report describes direct formation of giant vesicles from a series of poly(L-lysine)-block-poly(L-phenylalanine) (PLL-b-PPA) block copolymers from their water solution. These polymers are prepared by successive ring-opening polymerization (ROP) of the two alpha-amino acid N-carboxyanhydrides and then removing the side chain protecting groups by acidolysis. The structures of the copolymers are confirmed by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and size exclusion chromatography (SEC). The vesicles are studied by atomic force microscopy (AFM), field emission scanning electron microscopy (ESEM), and confocal laser scanning microscopy (CLSM). Rhodamine B is used as a fluorescent probe to confirm the existence of the vesicle with an aqueous interior. The vesicle size is in the range 0.55-6 microm, depending on the absolute and relative lengths of the two blocks, on initial polymer concentration, and on solution pH. The vesicles are still stable in water for 2 months after preparation. Addition of the copolymer to DNA solution results in complex formation with it. The complex assumes the morphology of irregular particles of less than 2 microm. It is expected to be used in drug and gene delivery.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.forename: Xuesi
authors.initials: X
authors.lastname: Chen
authors.forename: Chao
authors.initials: C
authors.lastname: Deng
authors.forename: Haijun
authors.initials: H
authors.lastname: Yu
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Xie
authors.forename: Xiabin
authors.initials: X
authors.lastname: Jing
mesh_terms: D002152:Calorimetry, Differential Scanning; D004247:DNA / Q000737:chemistry; D016503:Drug Delivery Systems; D018014:Gene Transfer Techniques; D006863:Hydrogen-Ion Concentration; D018625:Microscopy, Atomic Force; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D011107:Polylysine / Q000138:chemical synthesis / Q000737:chemistry*; D012235:Rhodamines / Q000737:chemistry
chemical_list: D010455:Peptides; D012235:Rhodamines; D011107:Polylysine; C012001:polyphenylalanine; D004247:DNA; C029773:rhodamine B