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Hierarchical organization of chiral rafts in colloidal membranes (2014)

P. Sharma ; A. Ward ; T. Gibaud ; [et al.]

Nature Publishing Group (NPG)

In: Nature. 513(7516): 77-80. doi: 10.1038/nature13694.

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Publication Date: 2014-09-05

Description: Liquid-liquid phase separation is ubiquitous in suspensions of nanoparticles, proteins and colloids. It has an important role in gel formation, protein crystallization and perhaps even as an organizing principle in cellular biology. With a few notable exceptions, liquid-liquid phase separation in bulk proceeds through the continuous coalescence of droplets until the system undergoes complete phase separation. But when colloids, nanoparticles or proteins are confined to interfaces, surfaces or membranes, their interactions differ fundamentally from those mediated by isotropic solvents, and this results in significantly more complex phase behaviour. Here we show that liquid-liquid phase separation in monolayer membranes composed of two dissimilar chiral colloidal rods gives rise to thermodynamically stable rafts that constantly exchange monomeric rods with the background reservoir to maintain a self-limited size. We visualize and manipulate rafts to quantify their assembly kinetics and to show that membrane distortions arising from the rods' chirality lead to long-range repulsive raft-raft interactions. Rafts assemble into cluster crystals at high densities, but they can also form bonds to yield higher-order structures. Taken together, our observations demonstrate a robust membrane-based pathway for the assembly of monodisperse membrane clusters that is complementary to existing methods for colloid assembly in bulk suspensions. They also reveal that chiral inclusions in membranes can acquire long-range repulsive interactions, which might more generally have a role in stabilizing assemblages of finite size.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sharma, Prerna -- Ward, Andrew -- Gibaud, T -- Hagan, Michael F -- Dogic, Zvonimir -- England -- Nature. 2014 Sep 4;513(7516):77-80. doi: 10.1038/nature13694.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Department of Physics, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, USA [2]. ; Laboratoire de Physique, Ecole Normale Superieure de Lyon, Universite de Lyon I, CNRS/UMR 5672, 46 allee d'Italie, 69007 Lyon, France. ; Department of Physics, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25186901" target="_blank"〉PubMed〈/a〉

Print ISSN: 0028-0836

Electronic ISSN: 1476-4687

Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics

Published by Nature Publishing Group (NPG)

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Reconfigurable self-assembly through chiral control of interfacial tension (2012)

T. Gibaud ; E. Barry ; M. J. Zakhary ; [et al.]

Nature Publishing Group (NPG)

In: Nature. 481(7381): 348-51. doi: 10.1038/nature10769.

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Publication Date: 2012-01-06

Description: From determining the optical properties of simple molecular crystals to establishing the preferred handedness in highly complex vertebrates, molecular chirality profoundly influences the structural, mechanical and optical properties of both synthetic and biological matter on macroscopic length scales. In soft materials such as amphiphilic lipids and liquid crystals, the competition between local chiral interactions and global constraints imposed by the geometry of the self-assembled structures leads to frustration and the assembly of unique materials. An example of particular interest is smectic liquid crystals, where the two-dimensional layered geometry cannot support twist and chirality is consequently expelled to the edges in a manner analogous to the expulsion of a magnetic field from superconductors. Here we demonstrate a consequence of this geometric frustration that leads to a new design principle for the assembly of chiral molecules. Using a model system of colloidal membranes, we show that molecular chirality can control the interfacial tension, an important property of multi-component mixtures. This suggests an analogy between chiral twist, which is expelled to the edges of two-dimensional membranes, and amphiphilic surfactants, which are expelled to oil-water interfaces. As with surfactants, chiral control of interfacial tension drives the formation of many polymorphic assemblages such as twisted ribbons with linear and circular topologies, starfish membranes, and double and triple helices. Tuning molecular chirality in situ allows dynamical control of line tension, which powers polymorphic transitions between various chiral structures. These findings outline a general strategy for the assembly of reconfigurable chiral materials that can easily be moved, stretched, attached to one another and transformed between multiple conformational states, thus allowing precise assembly and nanosculpting of highly dynamical and designable materials with complex topologies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gibaud, Thomas -- Barry, Edward -- Zakhary, Mark J -- Henglin, Mir -- Ward, Andrew -- Yang, Yasheng -- Berciu, Cristina -- Oldenbourg, Rudolf -- Hagan, Michael F -- Nicastro, Daniela -- Meyer, Robert B -- Dogic, Zvonimir -- R01 EB002583/EB/NIBIB NIH HHS/ -- England -- Nature. 2012 Jan 4;481(7381):348-51. doi: 10.1038/nature10769.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉The Martin Fisher School of Physics, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22217941" target="_blank"〉PubMed〈/a〉

Keywords: Amino Acid Substitution ; Bacteriophage M13/*chemistry/genetics ; Biomechanical Phenomena ; Colloids/chemistry ; Computer Simulation ; Microscopy, Electron, Transmission ; Oils/chemistry ; Stereoisomerism ; Surface Tension ; Surface-Active Agents/chemistry ; Water/chemistry

Print ISSN: 0028-0836

Electronic ISSN: 1476-4687

Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics

Published by Nature Publishing Group (NPG)

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Spontaneous motion in hierarchically assembled active matter (2012)

T. Sanchez ; D. T. Chen ; S. J. DeCamp ; [et al.]

Nature Publishing Group (NPG)

In: Nature. 491(7424): 431-4. doi: 10.1038/nature11591.

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Publication Date: 2012-11-09

Description: With remarkable precision and reproducibility, cells orchestrate the cooperative action of thousands of nanometre-sized molecular motors to carry out mechanical tasks at much larger length scales, such as cell motility, division and replication. Besides their biological importance, such inherently non-equilibrium processes suggest approaches for developing biomimetic active materials from microscopic components that consume energy to generate continuous motion. Being actively driven, these materials are not constrained by the laws of equilibrium statistical mechanics and can thus exhibit sought-after properties such as autonomous motility, internally generated flows and self-organized beating. Here, starting from extensile microtubule bundles, we hierarchically assemble far-from-equilibrium analogues of conventional polymer gels, liquid crystals and emulsions. At high enough concentration, the microtubules form a percolating active network characterized by internally driven chaotic flows, hydrodynamic instabilities, enhanced transport and fluid mixing. When confined to emulsion droplets, three-dimensional networks spontaneously adsorb onto the droplet surfaces to produce highly active two-dimensional nematic liquid crystals whose streaming flows are controlled by internally generated fractures and self-healing, as well as unbinding and annihilation of oppositely charged disclination defects. The resulting active emulsions exhibit unexpected properties, such as autonomous motility, which are not observed in their passive analogues. Taken together, these observations exemplify how assemblages of animate microscopic objects exhibit collective biomimetic properties that are very different from those found in materials assembled from inanimate building blocks, challenging us to develop a theoretical framework that would allow for a systematic engineering of their far-from-equilibrium material properties.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3499644/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3499644/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sanchez, Tim -- Chen, Daniel T N -- DeCamp, Stephen J -- Heymann, Michael -- Dogic, Zvonimir -- 5K25GM8561/GM/NIGMS NIH HHS/ -- K25 GM085613/GM/NIGMS NIH HHS/ -- T32 EB009419/EB/NIBIB NIH HHS/ -- England -- Nature. 2012 Nov 15;491(7424):431-4. doi: 10.1038/nature11591. Epub 2012 Nov 7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Martin Fisher School of Physics, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23135402" target="_blank"〉PubMed〈/a〉

Print ISSN: 0028-0836

Electronic ISSN: 1476-4687

Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics

Published by Nature Publishing Group (NPG)

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Cilia-like beating of active microtubule bundles (2011)

T. Sanchez ; D. Welch ; D. Nicastro ; [et al.]

American Association for the Advancement of Science (AAAS)

In: Science. 333(6041): 456-9. doi: 10.1126/science.1203963.

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Publication Date: 2011-07-23

Description: The mechanism that drives the regular beating of individual cilia and flagella, as well as dense ciliary fields, remains unclear. We describe a minimal model system, composed of microtubules and molecular motors, which self-assemble into active bundles exhibiting beating patterns reminiscent of those found in eukaryotic cilia and flagella. These observations suggest that hundreds of molecular motors, acting within an elastic microtubule bundle, spontaneously synchronize their activity to generate large-scale oscillations. Furthermore, we also demonstrate that densely packed, actively bending bundles spontaneously synchronize their beating patterns to produce collective behavior similar to metachronal waves observed in ciliary fields. The simple in vitro system described here could provide insights into beating of isolated eukaryotic cilia and flagella, as well as their synchronization in dense ciliary fields.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3172966/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3172966/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sanchez, Timothy -- Welch, David -- Nicastro, Daniela -- Dogic, Zvonimir -- 5K25GM85613/GM/NIGMS NIH HHS/ -- 5R01GM083122/GM/NIGMS NIH HHS/ -- K25 GM085613/GM/NIGMS NIH HHS/ -- K25 GM085613-01/GM/NIGMS NIH HHS/ -- K25 GM085613-02/GM/NIGMS NIH HHS/ -- K25 GM085613-03/GM/NIGMS NIH HHS/ -- K25 GM085613-04/GM/NIGMS NIH HHS/ -- K25 GM085613-05/GM/NIGMS NIH HHS/ -- R01 GM083122/GM/NIGMS NIH HHS/ -- R01 GM083122-01/GM/NIGMS NIH HHS/ -- R01 GM083122-02/GM/NIGMS NIH HHS/ -- R01 GM083122-03/GM/NIGMS NIH HHS/ -- R01 GM083122-03S1/GM/NIGMS NIH HHS/ -- R01 GM083122-03S2/GM/NIGMS NIH HHS/ -- R01 GM083122-04/GM/NIGMS NIH HHS/ -- T32 GM007596/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2011 Jul 22;333(6041):456-9. doi: 10.1126/science.1203963.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, Brandeis University, 415 South Street, Waltham, MA 02454, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21778400" target="_blank"〉PubMed〈/a〉

Keywords: Axoneme/physiology ; Cilia/chemistry/*physiology ; Flagella/chemistry/physiology ; Kinesin/*metabolism ; Microtubules/chemistry/*physiology/ultrastructure ; Models, Biological ; Molecular Motor Proteins/*metabolism ; Movement ; Polyethylene Glycols

Print ISSN: 0036-8075

Electronic ISSN: 1095-9203

Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics

Published by American Association for the Advancement of Science (AAAS)

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Topology and dynamics of active nematic vesicles (2014)

F. C. Keber ; E. Loiseau ; T. Sanchez ; [et al.]

American Association for the Advancement of Science (AAAS)

In: Science. 345(6201): 1135-9. doi: 10.1126/science.1254784.

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Publication Date: 2014-09-06

Description: Engineering synthetic materials that mimic the remarkable complexity of living organisms is a fundamental challenge in science and technology. We studied the spatiotemporal patterns that emerge when an active nematic film of microtubules and molecular motors is encapsulated within a shape-changing lipid vesicle. Unlike in equilibrium systems, where defects are largely static structures, in active nematics defects move spontaneously and can be described as self-propelled particles. The combination of activity, topological constraints, and vesicle deformability produces a myriad of dynamical states. We highlight two dynamical modes: a tunable periodic state that oscillates between two defect configurations, and shape-changing vesicles with streaming filopodia-like protrusions. These results demonstrate how biomimetic materials can be obtained when topological constraints are used to control the non-equilibrium dynamics of active matter.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4401068/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4401068/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Keber, Felix C -- Loiseau, Etienne -- Sanchez, Tim -- DeCamp, Stephen J -- Giomi, Luca -- Bowick, Mark J -- Marchetti, M Cristina -- Dogic, Zvonimir -- Bausch, Andreas R -- T32 EB009419/EB/NIBIB NIH HHS/ -- New York, N.Y. -- Science. 2014 Sep 5;345(6201):1135-9. doi: 10.1126/science.1254784.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, Technische Universitat Munchen, 85748 Garching, Germany. Institute for Advanced Study, Technische Universitat Munchen, 85748 Garching, Germany. ; Department of Physics, Technische Universitat Munchen, 85748 Garching, Germany. ; Department of Physics, Brandeis University, Waltham, MA 02474, USA. ; SISSA International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, Italy. Instituut-Lorentz for Theoretical Physics, Leiden University, 2333 CA Leiden, Netherlands. ; Physics Department and Syracuse Biomaterials Institute, Syracuse University, Syracuse, NY 13244, USA. ; Institute for Advanced Study, Technische Universitat Munchen, 85748 Garching, Germany. Department of Physics, Brandeis University, Waltham, MA 02474, USA. ; Department of Physics, Technische Universitat Munchen, 85748 Garching, Germany. abausch@mytum.de.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25190790" target="_blank"〉PubMed〈/a〉

Print ISSN: 0036-8075

Electronic ISSN: 1095-9203

Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics

Published by American Association for the Advancement of Science (AAAS)

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Electronic Resource

Concentration-dependent sedimentation of colloidal rods (2000)

Dogic, Z.

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 113 (2000), S. 8368-8380

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ISSN: 1089-7690

Source: AIP Digital Archive

Topics: Physics , Chemistry and Pharmacology

Notes: In this paper we first develop an approximate theory for the leading order concentration dependence of the sedimentation coefficient for rodlike colloids/polymers/macromolecules. To first order in volume fraction cursive-phi of rods, the sedimentation coefficient is written as 1+αcursive-phi. For large aspect ratios L/D (L is the rod length, D its thickness) α is found to vary like ∝(L/D)2/ln(L/D). This theoretical prediction is compared to experimental results. Then, experiments on fd virus are described, both in the isotropic and nematic phase. First-order in concentration results for this very long and thin (semiflexible) rod are in agreement with the above-mentioned theoretical prediction. Sedimentation profiles for the nematic phase show two sedimentation fronts. This result indicates that the nematic phase becomes unstable with the respect to isotropic phase during sedimentation. © 2000 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.1308107

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