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Titolo:
Modulating artificial membrane morphology: pH-induced chromatic transitionand nanostructural transformation of a bolaamphiphilic conjugated polymer from blue helical ribbons to red nanofibers
Autore:
Song, J; Cheng, Q; Kopta, S; Stevens, RC;
Indirizzi:
Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA Univ Calif Berkeley Berkeley CA USA 94720 Mat Sci, Berkeley, CA 94720 USA
Titolo Testata:
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
fascicolo: 14, volume: 123, anno: 2001,
pagine: 3205 - 3213
SICI:
0002-7863(20010411)123:14<3205:MAMMPC>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
ATOMIC-FORCE MICROSCOPY; LIPID TUBULES; SUPRAMOLECULAR ASSEMBLIES; DIACETYLENIC ALDONAMIDES; MOLECULAR ARCHITECTURE; LIPOSOMES; ACID; VESICLES; PHASE; ORDER;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
59
Recensione:
Indirizzi per estratti:
Indirizzo: Cheng, Q Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA Univ Calif Berkeley Berkeley CA USA 94720 Berkeley, CA 94720 USA
Citazione:
J. Song et al., "Modulating artificial membrane morphology: pH-induced chromatic transitionand nanostructural transformation of a bolaamphiphilic conjugated polymer from blue helical ribbons to red nanofibers", J AM CHEM S, 123(14), 2001, pp. 3205-3213

Abstract

Design and characterization of helical ribbon assemblies of a bolaamphiphilic conjugated polymer and their color-coded transformation into nanofibersare described. An L-glutamic acid modified bolaamphiphilic diacetylene lipid was synthesized and self-assembled into right-handed helical ribbons with micron scale length and nano scale thickness under mild conditions. The ribbon structures were further stabilized by polymerizing well-aligned diacetylene units to form bisfunctional polydiacetylenes (PDAs). Transitions from flat sheets to helical ribbons and tubes were observed by transmission electron microscopy. The helical ribbons appear to originate from the ruptureof flat sheets along domain edges and the peeling off between stacked lipid layers. These results point to the applicability of chiral packing theoryin bolaamphiphilic supramolecular assemblies. Contact mode atomic force microscopy observations revealed that high order existed in the surface packing arrangement. Hexagonal and pseudorectangular packings were observed in flat and twisted regions of the ribbons, respectively, suggesting a correlation between microscopic morphologies and nanoscopic packing arrangements. The tricarboxylate functionalities of the bolaamphiphilic lipid provide a handle for the manipulation of the bisfunctional PDAs' morphology. Increasingsolution pH caused the fraying of helical ribbons into nanofibers accompanied by a sharp blue-to-red chromatic transition. A dramatic change in circular dichroism spectra was observed during this process, suggesting the lossof chirality in packing. A model is proposed to account for the pH-inducedmorphological change and chromatic transition. The color-coded transition between two distinct microstructures would be useful in the design of sensors and other "smart" nanomaterials requiring defined molecular templates.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/04/20 alle ore 19:10:54