title: Thermosensitive pluronic micelles stabilized by shell cross-linking with gold nanoparticles.
abstract: Gold nanoparticles were employed to prepare shell cross-linked Pluronic micelles that exhibit a reversibly thermosensitive swelling/shrinking behavior. Two terminal hydroxyl groups of Pluronic F127 were thiol-functionalized to form self-assembling Pluronic micelles in aqueous solution with exposed -SH groups in an outer shell layer. The thiol groups present in the outer shell were cross-linked by gold nanoparticles synthesized through NaBH4 reduction of gold precursor anions. The resultant shell cross-linked gold-Pluronic micelles exhibited a temperature-dependent volume transition: their hydrodynamic diameter was changed from 157.1 +/- 15.6 nm at 15 degrees C to 53.4 +/- 5.5 nm at 37 degrees C as determined by dynamic light scattering. The critical micelle temperature measured by a pyrene solubilization technique suggested that the reversible swelling/shrinking behavior of the micelles was caused by hydrophobic interactions of cross-linked or grafted Pluronic copolymer chains in the micelle structure with increasing temperature. Transmission electron microscopy directly revealed that the shell cross-linked micelles were indeed produced by gold nanoparticles covalently clustered on the surface. These novel self-assembled organic/inorganic hybrid micelles would hold great potential for diagnostic and therapeutic applications.
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, South Korea.
authors.forename: Ki Hyun
authors.initials: KH
authors.lastname: Bae
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Choi
authors.forename: Sung Young
authors.initials: SY
authors.lastname: Park
authors.forename: Yuhan
authors.initials: Y
authors.lastname: Lee
authors.forename: Tae Gwan
authors.initials: TG
authors.lastname: Park
mesh_terms: D001894:Borohydrides / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006358:Hot Temperature; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008823:Micelles; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D020442:Poloxamer / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013499:Surface Properties
chemical_list: D001894:Borohydrides; D008823:Micelles; D013438:Sulfhydryl Compounds; D020442:Poloxamer; D006046:Gold; C025364:sodium borohydride