title: Anionic liposome template synthesis of raspberry-like hollow silica particle under ambient conditions with basic catalyst.
abstract: Hollow silica particle was obtained with a vesicle template synthesis in water under ambient conditions in the presence of ammonia. Biomimetic vesicles, liposomes were used, which consisted of a zwitterionic phospholipid, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and a tiny amount of charged amphiphiles, hexadecylamine (HDA) or dicetylphosphate (DCP). Aggregation of silica occurred for DPPC or cationic DPPC/HDA liposome, whereas well-dispersed hollow silica particle could be obtained for anionic DPPC/DCP liposome. The hollow particle synthesized with the anionic liposome had single-layered and raspberry-like structures. Electrostatic repulsion between anionic vesicles maintained stable dispersion of the as-synthesized particles during the reaction. Formation of the raspberry-like morphology is explained by silica particle precipitation selectively induced around the liposomes under basic conditions due to affinity of silica precursors for the liposomes. Synthesis of well-dispersed hollow silica particle with a raspberry-like morphology is the first report in vesicle template syntheses.
authors.affiliation: Department of Chemical Engineering, Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai, Japan.
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Ishii
authors.forename: Kumi
authors.initials: K
authors.lastname: Sato
authors.forename: Daisuke
authors.initials: D
authors.lastname: Nagao
authors.forename: Mikio
authors.initials: M
authors.lastname: Konno
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D000838:Anions; D002384:Catalysis; D008081:Liposomes / Q000138:chemical synthesis / Q000737:chemistry* / Q000648:ultrastructure; D010755:Organophosphates / Q000737:chemistry; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*; D012996:Solutions; D055672:Static Electricity; D013535:Suspensions
chemical_list: D000838:Anions; D008081:Liposomes; D010755:Organophosphates; D012996:Solutions; D013535:Suspensions; D015060:1,2-Dipalmitoylphosphatidylcholine; C002290:dicetylphosphate; D012822:Silicon Dioxide