Synthesis of a tubular polymer from threaded cyclodextrins

Harada, Akira; Li, Jun; Kamachi, Mikiharu

doi:10.1038/364516a0

Cited by 601 publications

(377 citation statements)

References 8 publications

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“…This is an example of the organic nanotubes that possess the CD-inclusion complex on the tubular surface (for CD molecular tubes, see ref. 31). The inclusion of hydrophobic pyrene into the cavity of CD is expected to make the focal moiety hydrophilic because of the hydrophilic outer surface of CD, and consequently the volume ratio of the hydrophilic and hydrophobic moieties of the building blocks is changed.…”

Section: Resultsmentioning

confidence: 99%

Cyclodextrin-covered organic nanotubes derived from self-assembly of dendrons and their supramolecular transformation

Park

Lee

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

132

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The dendritic building blocks with a focal pyrene unit self-organize into vesicles in aqueous phase. The in situ inclusion of the focal pyrene units into the cavity of ␤-or ␥-cyclodextrin (CD) induces self-assembled organic nanotubes with an average outer diameter of Ϸ45 nm and inner diameter of 22 nm. The surface of the nanotube is covered with CD. Therefore, the functional group on the surface of the nanotube is controlled simply by modifying the functionality of CD. The removal of CD from the nanotube with poly(propylene glycol) reversibly generates vesicles. This work provides an efficient methodology not only to create an additional class of CD-covered organic nanotubes but also to exhibit reversible transformation of nanotubes and vesicles triggered by the motifs of dendron self-assembly, CD inclusion, and pseudorotaxane formation.vesicle ͉ amphiphile S elf-assembly and transformation of biological or synthetic macromolecules in a wide range of scientific fields are crucial subjects for the achievement of well defined nanostructures and the precise control of the function of supramolecules at the molecular level (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). A multitude of biological or chemical assemblies including vesicle, tubule, fibril, and viral helical coats perform numerous biochemical operations in nature. In particular, vesicular and tubular assemblies are of much interest because of their unique characteristics as a biomimetic system, carrier for drug or gene, biochemical sensor, electronic or photonic material, nanoreactor, and template for hybrid structure (9-18). Therefore, in these viewpoints, self-assembly of synthetic building blocks by noncovalent interactions is expected to provide a unique methodology for creating supramolecular functional materials (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27).Self-organization of dendrons (6) into supramolecular assemblies has been demonstrated in a thermotropic fashion (19,27), in aqueous phase (21-25), in organic media (20,22,23,26), and at solid-liquid interface (26). Recently, we reported that the amide dendrons can self-organize in various conditions to exhibit a multiplicity of architectures and functions (22-26). For the preparation of self-assembling nanomaterials, we designed the amide dendritic building blocks consisting of amide branches for hydrogen bonding, carboxyl functionality at the focal point, and alkyl tails for the stabilization of assembled structures by van der Waals interaction (22). Particularly, it was suggested that the dimeric form of the amide dendron, induced by secondary interactions such as hydrogen bonding and -interaction at the focal functional units, is the primary building block in the self-aggregation process in organic media (22,23,26). In addition, the amphiphilic nature of these amide dendritic building blocks provides an opportunity for the formation of various self-assembled nanostructures in aqueous phase. For example, we reported that the transition of the self-organiz...

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Section: Resultsmentioning

confidence: 99%

Cyclodextrin-covered organic nanotubes derived from self-assembly of dendrons and their supramolecular transformation

Park

Lee

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

132

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“…When the hydroxyl groups are chemically modified by using bi-functional reagents, CDs in the polyrotaxanes can be intraor intermolecularly crosslinked. In the former case, Harada et al crosslinked adjacent CDs in the polyrotaxanes, and then hydrolyzed the terminal bulky-blocking groups to prepare a tubular conjugate, named molecular tube (MT) [23]. Our group prepared MT with very narrow molecular weight distribution and clarified thermodynamic properties of the inclusion complexation with sodium alkyl sulfonates [24,25].…”

Section: Introductionmentioning

confidence: 99%

Hydrogels having tubular α-cyclodextrin structure: effect of nano-tube structure on long alkyl chain partitions

Ooya

Kobayashi

Ichi

et al. 2003

Science and Technology of Advanced Materials

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New hydrogels having the tubular structure of a-cyclodextrins (a-CDs) crosslinked by poly(ethylene glycol) (PEG) (MT-PEG hydrogels) were prepared by using a hydrolyzable polyrotaxane. The hydrolyzable polyrotaxane, in which many a-CDs are threaded onto a PEG chain capped by a hydrolyzable ester moiety, was used to form a tubular structure in the hydrogel. After crosslinking with another PEG chain, the ester linkage in the polyrotaxane was hydrolyzed in 1N NaOH. This led to exposing hydrophobic cavity of a-CDs. The tubular-structured hydrogel incorporated sodium dodecyl sulfate (SDS) much faster than normally crosslinked a-CDs hydrogel (a-CD-PEG hydrogel). Furthermore, partition coefficient (K) of SDS to the MT-PEG hydrogel was two times larger than the a-CD-PEG hydrogel. These results suggest that the tubular structure of a-CDs, made from a template of the polyrotaxane, is much more attractive to include SDS in the a-CD cavities. Unsaturated fatty acids (palmitoleic acid (C16:1) and oleic acid (C18:1)) were also effectively incorporated into the tubularstructured hydrogel during 6 days. The K value of C16:1 was as the same order in magnitude as C18:1. Thus, the tubular structure of a-CDs was advantageous to incorporate long alkyl chains into the hydrophobic cavity of a-CDs in aqueous conditions. q

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“…[11] During the synthesis of supramolecular nanorod aggregates in an aqueous solution, the nanorod dissociates to form into vesicle structures due to the CD introduction. [12] For example, Harada et al prepared CD-reliant polypseudorotaxanes and polyrotaxanes through threading of several CD components onto a polymer chain [13][14][15][16] and then combined them into molecular tubes through the covalent crosslink of adjoining CD components in a polyrotaxane. [6,16,17] Pistolis and co-worker reported the formation of nanotube in b-CD and g-CD due to the intermolecular hydrogen bonding formation between adjacent CDs.…”

Section: Introductionmentioning

confidence: 99%

Nanorod formation of cyclodextrin-covered sudan dyes through supramolecular self-assembly

Sankaranarayanan

Rajendiran

2013

Journal of Experimental Nanoscience

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Cyclodextrin-covered sudan III (SDIII) and sudan IV (SDIV) dyes produced various nanostructures such as pseudorotaxanes through supramolecular self-assembly, studied by absorption, fluorescence, time-resolved fluorescence, SEM, TEM, FT-IR, DSC, PXRD and 1 H NMR. Solvent study shows that azo-hydrazo tautomer is present in sudan dyes. Absorption and fluorescence spectroscopy data gave evidence for the formation of 1:2 inclusion complexes. Big nanorod ($36 nm) surrounded by small nanorod ($3 nm) was identified in SDIV/a-CD complexes. This confirms that the rigid molecular nanorod aggregates of a-CD and b-CD complexes are formed through the initial formation of smaller nanorods. An unequal morphology noticed in SDIII/CD suggests that the 1:2 inclusion complexes were self-assembled into irregular arrangement. The thermodynamic parameters (DH, DG and DS) of inclusion processes were determined from semi-empirical PM3 calculations.

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Synthesis of a tubular polymer from threaded cyclodextrins

Cited by 601 publications

References 8 publications

Cyclodextrin-covered organic nanotubes derived from self-assembly of dendrons and their supramolecular transformation

Cyclodextrin-covered organic nanotubes derived from self-assembly of dendrons and their supramolecular transformation

Hydrogels having tubular α-cyclodextrin structure: effect of nano-tube structure on long alkyl chain partitions

Nanorod formation of cyclodextrin-covered sudan dyes through supramolecular self-assembly

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