Self-Assembled Complexes of Synthetic Polypeptides and Oppositely Charged Low Molecular Weight Surfactants. Solid-State Properties

Ponomarenko, Ekaterina A.; Waddon, A. J.; Bakeev, Kirill N.; Tirrell, David A.; MacKnight, William J.

doi:10.1021/ma951088h

Cited by 102 publications

(133 citation statements)

References 35 publications

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“…An even more efficient way to design the final structures of the complexes consists in tailoring the molecular architecture of the polyelectrolyte template. The initial works have focused on linear polyelectrolytes and alkyl tail surfactants, [3] and has successively extended to macromolecular polyelectrolytes with diverse and complex molecular architectures such as branched polyeletrolytes, [4] peptidic polymers with secondary a-helices structures, [5,6] DNA [7,8,9] or other types of rod-like polyelectrolytes.…”

Section: Introductionmentioning

confidence: 99%

Functional Columnar Liquid Crystalline Phases From Ionic Complexes of Dendronized Polymers and Sulfate Alkyl Tails

Canilho¹,

Kasëmi

Schlüter

et al. 2008

Macromolecular Symposia

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Summary:We describe how cationic dendronized polymers of generations 1, and 2 and anionic monoalkyl tails can be combined by supramolecular ionic complexation into comb-like liquid crystalline polymers. The final structures in bulk of these supramolecular complexes were studied by differential scanning calorimetry (DSC), cross-polarized optical microscopy (CPOM), small angle x-rays scattering (SAXS) and transmission electron microscopy (TEM). The combination of these techniques allowed elucidating (i) that these complexes exhibit thermotropic behaviour, (ii) that various liquid crystalline structures in the 3-5 nm length scale can be obtained such as columnar rectangular, columnar tetragonal, columnar hexagonal and lamellar, depending both on alkyl tail length and polymer generation, (iii) that although the alkyl tails represent the majority phase in the columnar phases, they form the cylindric domains, and the dendronized polymers occupy the continuous domains. Therefore, upon selective cleavage of the alkyl tails in the columnar phases, the present self-assembly approach may constitute an efficient strategy towards the formation of porous organic matrices with ultra-dense pore size in the range of 2 to 4 nm.

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Section: Introductionmentioning

confidence: 99%

Functional Columnar Liquid Crystalline Phases From Ionic Complexes of Dendronized Polymers and Sulfate Alkyl Tails

Canilho¹,

Kasëmi

Schlüter

et al. 2008

Macromolecular Symposia

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“…Estos compuestos se caracterizan por la tendencia a adoptar estructuras ordenadas tanto en estado sólido como en disolventes orgánicos. Así, en los complejos ATMA·PAGA las cadenas de polipéptido adoptan una conformación de hélice α similar a la esquematizada en la Figura 9b [59,60] . Estudios computacionales basados en técni-cas tanto cuánticas como clásicas han permitido profundizar en determinados aspectos microscópicos de este tipo de complejos autoasociados [61][62][63][64] .…”

Section: Análisis De Las Interacciones Específicas En Complejos Análiunclassified

Aplicaciones de los métodos computacionales al estudio de la estructura y propiedades de polímeros

Alemán

Muñoz‐Guerra

2003

Polímeros

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IntroducciónLa aparición de ordenadores en el mundo de la química es relativamente reciente. Sin embargo, debido al rápido aumento de su potencia, se han convertido en una herramienta de gran valor para el estudio y comprensión de los sistemas químicos. Su uso abarca desde la creación y administración de bases de datos a la simulación computacional a escala atómica de procesos químicos y físicos. De hecho, a lo largo de las últimas dos décadas la química computacional ha evolucionado hasta convertirse en una potente herramienta que no solo permite a los investigadores racionalizar los resultados extraídos de la experimentación, sino también obtener un tipo de información absolutamente inasequible para las metodologías experimentales. La calidad de los resultados obtenidos ha permitido que las técnicas computacionales se hayan generalizado a diversos campos de la Química y la Biología, por ejemplo la Química Orgánica e Inorgánica, la Farmacología, o la Biología Molecular. Recientemente ha sido la Ciencia de los Polímeros la que de forma decidida ha incorporado su uso al estudio de los polímeros sintéticos.Las propiedades de cualquier material polimérico están directa o indirectamente ligadas a su estructura molecular. Es decir, son una consecuencia de la estructuración de las macromoléculas que constituyen un determinado material y, en muchos casos, son un reflejo de los procesos dinámi-cos que se dan a escala molecular. Entender y racionalizar la estructura de un material debe permitir comprender el origen de sus propiedades físicas. De ahí que el estudio de la estructura molecular de los materiales poliméricos -escala microscópica-y su relación con las propiedades observables -escala macroscópica-se haya convertido en uno de los campos de investigación que más interés despierta. En este sentido resulta evidente la importancia de abordar estos estudios mediante técnicas computacionales basadas en la simulación molecular, ya que estas permitirán obtener detalles a nivel atómico que son difíciles cuando no imposibles de investigar desde un punto de vista experimental. Aplicaciones de los Métodos Computacionales al Estudio de la Estructura y Propiedades de Polímeros Carlos Alemán, Sebastián Muñoz-Guerra Departament d'Enginyeria Química, Universitat Politécnica de Catalunya, EspañaResumo: En este trabajo se revisan las técnicas de simulación molecular más habituales y potentes para la descripción de los polímeros a escala atómica y molecular, las cuales se han clasificado en cuánticas o clásicas dependiendo de cómo se describen las interacciones entre las partículas. Se presentan asimismo diversas aplicaciones de dichas metodologías, realizadas en nuestro laboratorio, en el contexto del estudio de la estructura y propiedades de polímeros. En particular, se muestran aplicaciones de las técnicas clásicas a la determinación de estructuras cristalinas, a estudio del plegamiento lamelar de los nylons, a la estabilidad de las estructuras supramoleculares observadas en algunos complejos tensioactivo·polielectrolito y a la ...

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“…The birefringence persisted until 37 8C, confirming that the second endothermic transition observed in the DSC experiments (arrow in Figure 2 (Figure 3 c). These values corresponded to repeat distances of 4.6 and 3.8 , respectively, and were typical of alkyl tail-tail [10] and polyethylene glycol (PEG) chain-chain interactions. [11] These peaks persisted up to a temperature of about 40 8C, indicating that they were associated specifically with the liquid-crystalline order of the protein fluid.…”

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confidence: 91%

Solvent‐Free Protein Liquids and Liquid Crystals

Perriman

Cölfen²,

Hughes

et al. 2009

Angewandte Chemie

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Nanostructures such as functionalized nanoparticles and superlattices have wide-ranging applications in diverse areas. [1][2][3][4] Although these materials are invariably used in the form of aqueous/organic dispersions, ultrathin films, or bulk powders, Giannellis and co-workers have recently pioneered an approach to preparing functionalized inorganic nanostructures with liquidlike behavior. [5,6] These are produced by electrostatically grafting an organic canopy layer onto the surface of charged nanoparticles of silica, [7] iron oxides, [7] and titania [8] for example, to provide a fluidization medium for the preparation of solvent-free nanoparticle ionic fluids. Like nanoscale objects in general, proteins exhibit persistent structures with dimensions that exceed the range of their intermolecular forces, such that liquid-vapor co-existence is unattainable.[9] As a consequence, solid-state proteins sublime at low pressures or thermally degrade under ambient conditions: thus, there are no known liquid proteins in the absence of solvent.Herein, we report, to our knowledge, the first example of a solvent-free liquid protein. Specifically, we report the preparation and properties of a protein melt based on a stoichiometric ferritin-polymer nanoscale construct with surface modifications that extend the range of intermolecular interactions to a length scale that is commensurate with fluidity in the absence of water. Moreover, we show that these spherically shaped nano-constructs undergo anisotropic ordering during melting at 30 8C to produce a viscoelastic protein liquid that exhibits thermotropic liquid-crystalline behavior, and which subsequently transforms to a Newtonian fluid at temperatures above 40 8C and is stable up to a temperature of 405 8C. The method, which utilizes the sitespecificity of surface amino acid residues and high degree of uniformity in ferritin molecular architecture to produce discrete single-component ferritin-polymer constructs (Supporting Information, Figure S1), should be readily accessible to exploitation as a facile route to solvent-free liquid proteins and enzymes in general.Electrostatically induced complexation of cationized ferritin (C-Fn), comprising approximately 240 covalently coupled N,N-dimethyl-1,3-propanediamine (DMPA) groups per molecule (10 DMPA per subunit; Supporting Information, Figure S2 Protein melts were prepared in the absence of water by lyophilization of the aqueous [C-Fn][S] solutions to produce a low-density solid that was subsequently annealed at 50 8C to produce a transparent, viscous, red liquid that remained fluid when cooled to room temperature, but re-solidified at À50 8C (Figure 1). TEM studies of the melt revealed discrete electron-dense nanoparticles, approximately 8 nm in diameter, indicating that the protein nanostructure remained structurally intact in the liquid state (Supporting Information, Figure S4). The melts were readily soluble in water or dichloromethane. Thermogravimetric analysis of the melt gave a water content of less than 2 % and a resid...

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Self-Assembled Complexes of Synthetic Polypeptides and Oppositely Charged Low Molecular Weight Surfactants. Solid-State Properties

Cited by 102 publications

References 35 publications

Functional Columnar Liquid Crystalline Phases From Ionic Complexes of Dendronized Polymers and Sulfate Alkyl Tails

Functional Columnar Liquid Crystalline Phases From Ionic Complexes of Dendronized Polymers and Sulfate Alkyl Tails

Aplicaciones de los métodos computacionales al estudio de la estructura y propiedades de polímeros

Solvent‐Free Protein Liquids and Liquid Crystals

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