title: Transformable core-corona nanoparticles: Simultaneous change of core morphology and corona wettability in response to temperature.
abstract: We prepared transformable thermoresponsive nanoparticles with variable core softness, controlled by the nanoparticle core's glass transition temperature (Tg). The nanoparticles were prepared by the dispersion copolymerization of butyl methacrylate (BMA) and/or methyl methacrylate (MMA) with a poly(N-isopropylacrylamide) (PNIPAAm) macromonomer in a polar solvent. The shape of the nanoparticle core changed with temperature. We then prepared poly(vinyl alcohol) (PVA) films with dispersed thermoresponsive nanoparticles, to elongate the nanoparticles through a uniaxial stretching of the films at 60°C. In this manner, the nanoparticle shape changed from spherical to rod-like morphologies, depending on the degree of film extension. Additionally, the rod-shaped nanoparticles only changed back to spheres with temperature modulation. The nanoparticle core's Tg value affected the rate of its physical transformation from rods to spheres at 37°C, with a slower rate observed for increased Tg. As the nanorod shape change was relatively minor at 37°C, we could control the shape of these transformable nanoparticles under various physiological conditions, a highly desirable feature for drug delivery applications.
authors.affiliation: Department of Materials Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Matsuyama
authors.affiliation: Department of Materials Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Kimura
authors.affiliation: Department of Materials Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Taka-Aki
authors.initials: TA
authors.lastname: Asoh
authors.affiliation: Department of Materials Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Materials Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan. Electronic address: kikuchia@rs.noda.tus.ac.jp.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kikuchi
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D058105:Polymerization; D013696:Temperature; D017155:Wettability
chemical_list: D000180:Acrylic Resins; C052970:poly-N-isopropylacrylamide
keywords: Atom transfer radical polymerization; Macromonomer method; Nanoparticle; Poly(N-isopropyl acrylamide); Transformable