title: Tailoring micrometer-long high-integrity 1D array of superparamagnetic nanoparticles in a nanotubular protein jacket and its lateral magnetic assembling behavior.
abstract: Tailoring of a micrometer-long one-dimensional (1D) array of superparamagnetic iron oxide nanoparticles (SNPs) was achieved by Mg(2+)-mediated supramolecular polymerization of a SNP-containing chaperonin protein (GroELMC⊃SNP). The inclusion complex GroELMC⊃SNP formed when ligand-modified SNPs were mixed with GroELMC, a GroEL mutant having multiple merocyanine (MC) units at its apical domains. Upon mixing with MgCl2 in phosphate buffer, GroELMC⊃SNP polymerized via the formation of multiple MC-Mg(2+)-MC coordination bonds, yielding thermodynamically stable micrometer-long nanotubes encapsulating 1D-arrayed SNPs (NTGroEL⊃SNP). When the NTGroEL⊃SNP nanotubes in phosphate buffer were incubated in a 0.5 T magnetic field, they began to assemble laterally and then organized into thick 1D bundles, where longer nanotubes were more preferentially incorporated. When the applied magnetic field was turned off, such bundles disassembled back to the individual 1D nanotubes. Lateral assembly of 1D SNP arrays in a magnetic field has been theoretically predicted but never been proven experimentally.
authors.affiliation: †RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.|‡Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
authors.forename: Seunghyun
authors.initials: S
authors.lastname: Sim
authors.affiliation: †RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Daigo
authors.initials: D
authors.lastname: Miyajima
authors.affiliation: §Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Niwa
authors.affiliation: §Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Taguchi
authors.affiliation: †RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.|‡Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
authors.forename: Takuzo
authors.initials: T
authors.lastname: Aida
mesh_terms: D001578:Benzopyrans / Q000737:chemistry; D018834:Chaperonin 60 / Q000737:chemistry* / Q000235:genetics; D005290:Ferric Compounds / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry; D060328:Magnetic Phenomena; D008958:Models, Molecular; D008968:Molecular Conformation; D009154:Mutation; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation*; D043942:Nanotubes / Q000737:chemistry*
chemical_list: D001578:Benzopyrans; D018834:Chaperonin 60; D005290:Ferric Compounds; D007211:Indoles; C548873:merocyanine; C000499:ferric oxide