title: Nanospheres with polymerization ability coated by polyrotaxane.
abstract: BETA-cyclodextrin (beta-CD)-based nanosphere 1 initiated the oligomerization of delta-valerolactone (delta-VL) on the surface of 1 to give oligo(delta-VL)-tethered beta-CD nanosphere 2 in bulk. Atomic force microscopy indicated that the molecular size of 2 is twice that of 1. The addition of alpha-CD to 2 leads to the formation of poly-pseudo-rotaxane on the surface of 2 to give a nanosphere with poly-pseudo-rotaxane (alpha-CD[symbol: see text]2). 2D-NOESY NMR experiments showed correlation peaks between the inner protons of alpha-CD and the oligo(delta-VL) chains in an aqueous solution, indicating that the oligo(delta-VL) chains are included in the alpha-CD cavity. Alpha-CD[symbol: see text]2 has a core of beta-CDs with poly-pseudo-rotaxanes on the surface. It should be noted that 2 did not show polymerization ability for delta-VL, but after the formation of poly-pseudo-rotaxanes, oligo(delta-VL) of alpha-CD[symbol: see text]2 repropagated upon the addition of delta-VL. Alpha-CD[symbol: see text]2 is significantly larger than nanospheres 1 and 2. Additionally, postpolymerization increases the size of alpha-CD[symbol: see text]2. These behaviors are reminiscent of the function of a spherical virus, which forms an ordered spherical structure and releases RNA chains from the capsid surface.
authors.affiliation: Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Motofumi
authors.initials: M
authors.lastname: Osaki
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Takashima
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: Akira
authors.initials: A
authors.lastname: Harada
mesh_terms: D003505:Cyclodextrins / Q000138:chemical synthesis* / Q000737:chemistry; D054118:Nanospheres; D010316:Particle Size; D020442:Poloxamer / Q000138:chemical synthesis* / Q000737:chemistry; D011753:Pyrones / Q000737:chemistry; D043862:Rotaxanes / Q000138:chemical synthesis* / Q000737:chemistry; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D003505:Cyclodextrins; D011753:Pyrones; D043862:Rotaxanes; C475673:polyrotaxane; D014867:Water; D020442:Poloxamer; C052207:delta-valerolactone