1
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Cheon J, Son J, Lim S, Jeong Y, Park JH, Mitchell RJ, Kim JU, Jeong J. Motile bacteria crossing liquid-liquid interfaces of an aqueous isotropic-nematic coexistence phase. SOFT MATTER 2024; 20:7313-7320. [PMID: 39248026 DOI: 10.1039/d4sm00766b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/10/2024]
Abstract
In nature, bacteria often swim in complex fluids, but our understanding of the interactions between bacteria and complex surroundings is still evolving. In this work, rod-like Bacillus subtilis swims in a quasi-2D environment with aqueous liquid-liquid interfaces, i.e., the isotropic-nematic coexistence phase of an aqueous chromonic liquid crystal. Focusing on the bacteria motion near and at the liquid-liquid interfaces, we collect and quantify bacterial trajectories ranging across the isotropic to the nematic phase. Despite its small magnitude, the interfacial tension of the order of 10 μN m-1 at the isotropic-nematic interface justifies our observations that bacteria swimming more perpendicular to the interface have a higher probability of crossing the interface. Our force-balance model, considering the interfacial tension, further predicts how the length and speed of the bacteria affect their crossing behaviors. Investigating how a phase change affects bacterial motion, we also find, as soon as the bacteria cross the interface and enter the nematic phase, they wiggle less, but faster, and that this occurs as the flagellar bundles aggregate within the nematic phase. Given the ubiquity of multi-phases in biological environments, our findings will help to understand active transport across various phases.
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Affiliation(s)
- Jiyong Cheon
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea.
| | - Joowang Son
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea.
| | - Sungbin Lim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Yundon Jeong
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Jung-Hoon Park
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Robert J Mitchell
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Jaeup U Kim
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea.
| | - Joonwoo Jeong
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea.
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2
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Čopar S, Kos Ž. Many-defect solutions in planar nematics: interactions, spiral textures and boundary conditions. SOFT MATTER 2024; 20:6894-6906. [PMID: 39150404 DOI: 10.1039/d4sm00586d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
From incompressible flows to electrostatics, harmonic functions can provide solutions to many two-dimensional problems and, similarly, the director field of a planar nematic can be determined using complex analysis. We derive a closed-form solution for a quasi-steady state director field induced by an arbitrarily large set of point defects and circular inclusions with or without fixed rotational degrees of freedom, and compute the forces and torques acting on each defect or inclusion. We show that a complete solution must include two types of singularities, generating a defect winding number and its spiral texture, which have a direct effect on defect equilibrium textures and their dynamics. The solution accounts for discrete degeneracy of topologically distinct free energy minima which can be obtained by defect braiding. The derived formalism can be readily applied to equilibrium and slowly evolving nematic textures for active or passive fluids with multiple defects present within the orientational order.
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Affiliation(s)
- Simon Čopar
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia.
| | - Žiga Kos
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia.
- Department of Condensed Matter Physics, Jožef Stefan Institute, Ljubljana, Slovenia
- International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM2), Hiroshima University, Higashi-Hiroshima, Japan
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3
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Gautam B, Lintuvuori JS. Microswimmers Knead Nematics into Cholesterics. PHYSICAL REVIEW LETTERS 2024; 132:238301. [PMID: 38905647 DOI: 10.1103/physrevlett.132.238301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/30/2024] [Indexed: 06/23/2024]
Abstract
The hydrodynamic stresses created by active particles can destabilize orientational order present in the system. This is manifested, for example, by the appearance of a bend instability in active nematics or in quasi-two-dimensional living liquid crystals consisting of swimming bacteria in thin nematic films. Using large-scale hydrodynamics simulations, we study a system consisting of spherical microswimmers within a three-dimensional nematic liquid crystal. We observe a spontaneous chiral symmetry breaking, where the uniform nematic state is kneaded into a continuously twisting state, corresponding to a helical director configuration akin to a cholesteric liquid crystal. The transition arises from the hydrodynamic coupling between the liquid crystalline elasticity and the swimmer flow fields, leading to a twist-bend instability of the nematic order. It is observed for both pusher (extensile) and puller (contractile) swimmers. Further, we show that the liquid crystal director and particle trajectories are connected: in the cholesteric state the particle trajectories become helicoidal.
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Affiliation(s)
- Bhavesh Gautam
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33400 Talence, France
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4
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Zhang Z, Yang X, Zhao Y, Ye F, Shang L. Liquid Crystal Materials for Biomedical Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2300220. [PMID: 37235719 DOI: 10.1002/adma.202300220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 04/04/2023] [Indexed: 05/28/2023]
Abstract
Liquid crystal is a state of matter being intermediate between solid and liquid. Liquid crystal materials exhibit both orientational order and fluidity. While liquid crystals have long been highly recognized in the display industry, in recent decades, liquid crystals provide new opportunities into the cross-field of material science and biomedicine due to their biocompatibility, multifunctionality, and responsiveness. In this review, the latest achievements of liquid crystal materials applied in biomedical fields are summarized. The start is made by introducing the basic concepts of liquid crystals, and then shifting to the components of liquid crystals as well as functional materials derived therefrom. After that, the ongoing and foreseeable applications of liquid crystal materials in the biomedical field with emphasis put on several cutting-edge aspects, including drug delivery, bioimaging, tissue engineering, implantable devices, biosensing, and wearable devices are discussed. It is hoped that this review will stimulate ingenious ideas for the future generation of liquid crystal-based drug development, artificial implants, disease diagnosis, health status monitoring, and beyond.
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Affiliation(s)
- Zhuohao Zhang
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, and the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Xinyuan Yang
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, and the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yuanjin Zhao
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, and the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, School of Biological Science and Medical Engineering Southeast University, Nanjing, 210096, China
| | - Fangfu Ye
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang, 325001, China
| | - Luoran Shang
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, and the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, School of Biological Science and Medical Engineering Southeast University, Nanjing, 210096, China
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5
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Kim WS, Im JH, Kim H, Choi JK, Choi Y, Kim YK. Liquid Crystalline Systems from Nature and Interaction of Living Organisms with Liquid Crystals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2204275. [PMID: 35861641 DOI: 10.1002/adma.202204275] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/15/2022] [Indexed: 06/15/2023]
Abstract
Biomaterials, which are substances interacting with biological systems, have been extensively explored to understand living organisms and obtain scientific inspiration (such as biomimetics). However, many aspects of biomaterials have yet to be fully understood. Because liquid crystalline phases are ubiquitously found in biomaterials (e.g., cholesterol, amphiphile, DNA, cellulose, bacteria), therefore, a wide range of research has made attempts to approach unresolved issues with the concept of liquid crystals (LCs). This review presents these studies that address the interactive correlation between biomaterials and LCs. Specifically, intrinsic LC behavior of various biomaterials such as DNA, cellulose nanocrystals, and bacteriaare first introduced. Second, the dynamics of bacteria in LC media are addressed, with focus on how bacteria interact with LCs, and how dynamics of bacteria can be controlled by exploiting the characteristics of LCs. Lastly, how the strong correlation between LCs and biomaterials has been leveraged to design a new class of biosensors with additional functionalities (e.g., self-regulated drug release) that are not available in previous systems is reviewed. Examples addressed in this review convey the message that the intersection between biomaterials and LCs offers deep insights into fundamental understanding of biomaterials, and provides resources for development of transformative technologies.
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Affiliation(s)
- Won-Sik Kim
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jun-Hyung Im
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Hyein Kim
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jin-Kang Choi
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Yena Choi
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Young-Ki Kim
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
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6
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Goral M, Clement E, Darnige T, Lopez-Leon T, Lindner A. Frustrated 'run and tumble' of swimming Escherichia coli bacteria in nematic liquid crystals. Interface Focus 2022; 12:20220039. [PMID: 36330319 PMCID: PMC9560793 DOI: 10.1098/rsfs.2022.0039] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 09/05/2022] [Indexed: 10/16/2023] Open
Abstract
In many situations, bacteria move in complex environments, as soils, oceans or the human gut-track, where carrier fluids show complex structures associated with non-Newtonian rheology. Many fundamental questions concerning the ability to navigate in such environments remain unsolved. Recently, it has been shown that the kinetics of bacterial motion in structured fluids as liquid crystals (LCs) is constrained by the orientational molecular order (or director field) and that novel spatio-temporal patterns arise. A question unaddressed so far is how bacteria change swimming direction in such an environment. In this work, we study the swimming mechanism of a single bacterium, Esherichia coli, constrained to move along the director field of a lyotropic chromonic liquid crystal confined to a planar cell. Here, the spontaneous 'run and tumble' motion of the bacterium gets frustrated: the elasticity of the LC prevents flagella from unbundling. Interestingly, to change direction, bacteria execute a reversal motion along the director field, driven by the relocation of a single flagellum, a 'frustrated tumble'. We characterize this phenomenon in detail experimentally, exploiting exceptional spatial and temporal resolution of bacterial and flagellar dynamics, using a two colour Lagrangian tracking technique. We suggest a possible mechanism accounting for these observations.
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Affiliation(s)
- Martyna Goral
- Laboratoire de Physique et Mécanique des Milieux Hétérogènes, UMR 7636, CNRS, ESPCI Paris-PSL, Sorbonne Université, Université Paris Cité, 75005 Paris, France
- Laboratoire Gulliver, UMR 7083, CNRS, ESPCI Paris-PSL, 75005 Paris, France
| | - Eric Clement
- Laboratoire de Physique et Mécanique des Milieux Hétérogènes, UMR 7636, CNRS, ESPCI Paris-PSL, Sorbonne Université, Université Paris Cité, 75005 Paris, France
- Institut Universitaire de France (IUF), Paris, France
| | - Thierry Darnige
- Laboratoire de Physique et Mécanique des Milieux Hétérogènes, UMR 7636, CNRS, ESPCI Paris-PSL, Sorbonne Université, Université Paris Cité, 75005 Paris, France
| | - Teresa Lopez-Leon
- Laboratoire Gulliver, UMR 7083, CNRS, ESPCI Paris-PSL, 75005 Paris, France
| | - Anke Lindner
- Laboratoire de Physique et Mécanique des Milieux Hétérogènes, UMR 7636, CNRS, ESPCI Paris-PSL, Sorbonne Université, Université Paris Cité, 75005 Paris, France
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7
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Katuri J, Snezhko A, Sokolov A. Motility of acoustically powered micro-swimmers in a liquid crystalline environment. SOFT MATTER 2022; 18:8641-8646. [PMID: 36342339 DOI: 10.1039/d2sm01171a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Suspensions of microswimmers in liquid crystals demonstrate remarkably complex dynamics and serve as a model system for studying active nematics. So far, experimental realization of microswimmers suspended in liquid crystalline media has relied on biological microorganisms that impose strict limitations on the compatible media and makes it difficult to regulate activity. Here, we demonstrate that acoustically powered bubble microswimmers can efficiently self-propel in a lyotropic liquid crystal. The velocity of the swimmers is controlled by the amplitude of the acoustic field. Histograms of swimming directions with respect to the local nematic field reveal a bimodal distribution: the swimmers tend to either fully align with or swim perpendicular to the director field of the liquid crystal, occasionally switching between these two states. The bubble-induced streaming from a swimmer locally melts the liquid crystal and produces topological defects at the tail of the swimmer. We show that the defect proliferation rate increases with the angle between the swimmer's velocity and the local orientation of the director field.
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Affiliation(s)
- Jaideep Katuri
- Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL, 60439, USA.
| | - Alexey Snezhko
- Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL, 60439, USA.
| | - Andrey Sokolov
- Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL, 60439, USA.
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8
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Chu G, Sohrabi F, Timonen JVI, Rojas OJ. Dispersing swimming microalgae in self-assembled nanocellulose suspension: Unveiling living colloid dynamics in cholesteric liquid crystals. J Colloid Interface Sci 2022; 622:978-985. [PMID: 35569411 DOI: 10.1016/j.jcis.2022.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/13/2022] [Accepted: 05/02/2022] [Indexed: 11/29/2022]
Abstract
Active matter comprises individual energy-consuming components that convert locally stored energy into mechanical motion. Among these, liquid crystal dispersed self-propelled colloids have displayed fascinating dynamic effects and nonequilibrium behaviors. In this work, we introduce a new type of active soft matter based on swimming microalgae and lyotropic nanocellulose liquid crystal. Cellulose is a kind of biocompatible polysaccharide that nontoxic to living biological colloids. In contrast to microalgae locomotion in isotropic and low viscosity media, we demonstrate that the propulsion force of swimming microalgae can overcome the stabilizing elastic force in cholesteric nanocellulose liquid crystal, with the displacement dynamics (gait, direction, frequency, and speed) be altered by the surrounding medium. Simultaneously, the active stress and shear flow exerted by swimming microalgae can introduce local perturbation in surrounding liquid crystal orientation order. The latter effect yields hydrodynamic fluctuations in bulk phase as well as layer undulations, helicoidal axis splay deformation and director bending in the cholesteric assembly, which finally followed by a recovery according to the inherent viscoelasticity of liquid crystal matrix. Our results point to an unorthodox design concept to generate a new type of hybrid soft matter that combines nontoxic cholesteric liquid crystal and active particles, which are expected to open opportunities in biosensing and biomechanical applications.
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Affiliation(s)
- Guang Chu
- Department of Bioproducts and Biosystems, Aalto University School of Chemical Engineering, Vuorimiehentie 1, 02510 Espoo, Finland.
| | - Fereshteh Sohrabi
- Department of Applied Physics, Aalto University School of Science, Puumiehenkuja 2, 02150 Espoo, Finland
| | - Jaakko V I Timonen
- Department of Applied Physics, Aalto University School of Science, Puumiehenkuja 2, 02150 Espoo, Finland
| | - Orlando J Rojas
- Department of Bioproducts and Biosystems, Aalto University School of Chemical Engineering, Vuorimiehentie 1, 02510 Espoo, Finland; Bioproducts Institute, Department of Chemical & Biological Engineering, Department of Chemistry and Department of Wood Science, 2360 East Mall, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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9
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Yao T, Kos Ž, Zhang QX, Luo Y, Steager EB, Ravnik M, Stebe KJ. Topological defect-propelled swimming of nematic colloids. SCIENCE ADVANCES 2022; 8:eabn8176. [PMID: 36001658 PMCID: PMC10939095 DOI: 10.1126/sciadv.abn8176] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
Topological defects on colloids rotating in nematic liquid crystals form far-from-equilibrium structures that perform complex swim strokes in which the defects periodically extend, depin, and contract. These defect dynamics propel the colloid, generating translation from rotation. The swimmer's speed and direction are determined by the topological defect's polarity and extent of elongation. Defect elongation is controlled by a rotating external magnetic field, allowing control over particle trajectories. The swimmers' translational motion relies on broken symmetries associated with lubrication forces between the colloid and the bounding surfaces, line tensions associated with the elongated defect, and anisotropic viscosities associated with the defect elongation adjacent to the colloid. The scattering or effective pair interaction of these swimmers is highly anisotropic, with polarization-dependent dimer stability and motion that depend strongly on entanglement and sharing of their extended defect structures. This research introduces transient, far-from-equilibrium topological defects as a class of virtual functional structures that generate modalities of motion and interaction.
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Affiliation(s)
- Tianyi Yao
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Žiga Kos
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Qi Xing Zhang
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yimin Luo
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, USA
| | - Edward B. Steager
- Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Miha Ravnik
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia
- Condensed Matter Physics Department, J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Kathleen J. Stebe
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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10
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Repula A, Abraham E, Cherpak V, Smalyukh II. Biotropic liquid crystal phase transformations in cellulose-producing bacterial communities. Proc Natl Acad Sci U S A 2022; 119:e2200930119. [PMID: 35671425 PMCID: PMC9214502 DOI: 10.1073/pnas.2200930119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 04/29/2022] [Indexed: 11/24/2022] Open
Abstract
Biological functionality is often enabled by a fascinating variety of physical phenomena that emerge from orientational order of building blocks, a defining property of nematic liquid crystals that is also pervasive in nature. Out-of-equilibrium, "living" analogs of these technological materials are found in biological embodiments ranging from myelin sheath of neurons to extracellular matrices of bacterial biofilms and cuticles of beetles. However, physical underpinnings behind manifestations of orientational order in biological systems often remain unexplored. For example, while nematiclike birefringent domains of biofilms are found in many bacterial systems, the physics behind their formation is rarely known. Here, using cellulose-synthesizing Acetobacter xylinum bacteria, we reveal how biological activity leads to orientational ordering in fluid and gel analogs of these soft matter systems, both in water and on solid agar, with a topological defect found between the domains. Furthermore, the nutrient feeding direction plays a role like that of rubbing of confining surfaces in conventional liquid crystals, turning polydomain organization within the biofilms into a birefringent monocrystal-like order of both the extracellular matrix and the rod-like bacteria within it. We probe evolution of scalar orientational order parameters of cellulose nanofibers and bacteria associated with fluid-gel and isotropic-nematic transformations, showing how highly ordered active nematic fluids and gels evolve with time during biological-activity-driven, disorder-order transformation. With fluid and soft-gel nematics observed in a certain range of biological activity, this mesophase-exhibiting system is dubbed "biotropic," analogously to thermotropic nematics that exhibit solely orientational order within a temperature range, promising technological and fundamental-science applications.
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Affiliation(s)
- Andrii Repula
- Department of Physics and Chemical Physics Program, University of Colorado, Boulder, CO 80309
| | - Eldho Abraham
- Department of Physics and Chemical Physics Program, University of Colorado, Boulder, CO 80309
| | - Vladyslav Cherpak
- Department of Physics and Chemical Physics Program, University of Colorado, Boulder, CO 80309
| | - Ivan I. Smalyukh
- Department of Physics and Chemical Physics Program, University of Colorado, Boulder, CO 80309
- Chirality Research Center, Hiroshima University, Higashi Hiroshima, Hiroshima 739-8526, Japan
- Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado, Boulder, CO 80309
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11
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Aranson IS. Bacterial active matter. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:076601. [PMID: 35605446 DOI: 10.1088/1361-6633/ac723d] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
Bacteria are among the oldest and most abundant species on Earth. Bacteria successfully colonize diverse habitats and play a significant role in the oxygen, carbon, and nitrogen cycles. They also form human and animal microbiota and may become sources of pathogens and a cause of many infectious diseases. Suspensions of motile bacteria constitute one of the most studied examples of active matter: a broad class of non-equilibrium systems converting energy from the environment (e.g., chemical energy of the nutrient) into mechanical motion. Concentrated bacterial suspensions, often termed active fluids, exhibit complex collective behavior, such as large-scale turbulent-like motion (so-called bacterial turbulence) and swarming. The activity of bacteria also affects the effective viscosity and diffusivity of the suspension. This work reports on the progress in bacterial active matter from the physics viewpoint. It covers the key experimental results, provides a critical assessment of major theoretical approaches, and addresses the effects of visco-elasticity, liquid crystallinity, and external confinement on collective behavior in bacterial suspensions.
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Affiliation(s)
- Igor S Aranson
- Departments of Biomedical Engineering, Chemistry, and Mathematics, Pennsylvania State University, University Park, PA 16802, United States of America
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12
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Sprenger AR, Bair C, Löwen H. Active Brownian motion with memory delay induced by a viscoelastic medium. Phys Rev E 2022; 105:044610. [PMID: 35590653 DOI: 10.1103/physreve.105.044610] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 04/11/2022] [Indexed: 01/17/2023]
Abstract
By now active Brownian motion is a well-established model to describe the motion of mesoscopic self-propelled particles in a Newtonian fluid. On the basis of the generalized Langevin equation, we present an analytic framework for active Brownian motion with memory delay assuming time-dependent friction kernels for both translational and orientational degrees of freedom to account for the time-delayed response of a viscoelastic medium. Analytical results are obtained for the orientational correlation function, mean displacement, and mean-square displacement which we evaluate in particular for a Maxwell fluid characterized by a kernel which decays exponentially in time. Further, we identify a memory-induced delay between the effective self-propulsion force and the particle orientation which we quantify in terms of a special dynamical correlation function. In principle, our predictions can be verified for an active colloidal particle in various viscoelastic environments such as a polymer solution.
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Affiliation(s)
- Alexander R Sprenger
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Christian Bair
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Hartmut Löwen
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
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13
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Faidiuk Y, Skivka L, Zelena P, Tereshchenko O, Buluy O, Pergamenshchik VM, Nazarenko V. Anchoring-induced nonmonotonic velocity versus temperature dependence of motile bacteria in a lyotropic nematic liquid crystal. Phys Rev E 2021; 104:054603. [PMID: 34942701 DOI: 10.1103/physreve.104.054603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 09/27/2021] [Indexed: 11/07/2022]
Abstract
The elastic and viscous properties of lyotropic chromonic liquid crystals have a very sharp, often exponential temperature dependence. Self-propelled bacteria swimming in this viscoelastic medium induce director deformations which can strongly influence their velocity, and we study the temperature behavior of their motility in the whole range of the nematic phase. We observe experimentally that, with increasing temperature, while the viscosity drops exponentially and the frequency of the flagellum rotation grows linearly, the swimmers' speed first conventionally increases but then, above some crossover temperature, slows down and at the same time bacteria-induced director distortions become visible. It is shown that the physics behind this temperature-driven effect is in a sharp rise in the ability of the bacterium's flagellum to induce director deformations. As temperature increases, the splay and bend elastic constants sharply decrease and the anchoring extrapolation length of the flagellum surface gets shorter and shorter. At the crossover temperature the resulting effective anchoring effect dominates the fast dropping viscosity and the distortion strengthens. As a result, a fraction of the torque the flagellum applies for the propulsion is spent for the elastic degrees of freedom, which results in a bacterium slowdown. To find the director distortions, the flagellum is presented as a collection of anchoring-induced elastic monopoles, and the bacterium velocity is found from the balance of the energy spent for the propulsion and the viscous drag and nematodynamic dissipation.
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Affiliation(s)
- Yu Faidiuk
- ESC Institute of Biology and Medicine, Taras Shevchenko National University, Kyiv 03022, Ukraine.,D.K. Zabolotny Institute of Microbiology and Virology, NASU, Kyiv 03680, Ukraine
| | - L Skivka
- ESC Institute of Biology and Medicine, Taras Shevchenko National University, Kyiv 03022, Ukraine
| | - P Zelena
- ESC Institute of Biology and Medicine, Taras Shevchenko National University, Kyiv 03022, Ukraine
| | | | - O Buluy
- Institute of Physics, NASU, Kyiv 03028, Ukraine
| | | | - V Nazarenko
- Institute of Physics, NASU, Kyiv 03028, Ukraine
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14
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Abstract
Smart soft materials are envisioned to be the building blocks of the next generation of advanced devices and digitally augmented technologies. In this context, liquid crystals (LCs) owing to their responsive and adaptive attributes could serve as promising smart soft materials. LCs played a critical role in revolutionizing the information display industry in the 20th century. However, in the turn of the 21st century, numerous beyond-display applications of LCs have been demonstrated, which elegantly exploit their controllable stimuli-responsive and adaptive characteristics. For these applications, new LC materials have been rationally designed and developed. In this Review, we present the recent developments in light driven chiral LCs, i.e., cholesteric and blue phases, LC based smart windows that control the entrance of heat and light from outdoor to the interior of buildings and built environments depending on the weather conditions, LC elastomers for bioinspired, biological, and actuator applications, LC based biosensors for detection of proteins, nucleic acids, and viruses, LC based porous membranes for the separation of ions, molecules, and microbes, living LCs, and LCs under macro- and nanoscopic confinement. The Review concludes with a summary and perspectives on the challenges and opportunities for LCs as smart soft materials. This Review is anticipated to stimulate eclectic ideas toward the implementation of the nature's delicate phase of matter in future generations of smart and augmented devices and beyond.
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Affiliation(s)
- Hari Krishna Bisoyi
- Advanced Materials and Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, United States
| | - Quan Li
- Advanced Materials and Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, United States.,Institute of Advanced Materials, School of Chemistry and Chemical Engineering, and Jiangsu Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing 211189, China
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15
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Farazin A, Mohammadimehr M, Ghasemi AH, Naeimi H. Design, preparation, and characterization of CS/PVA/SA hydrogels modified with mesoporous Ag 2O/SiO 2 and curcumin nanoparticles for green, biocompatible, and antibacterial biopolymer film. RSC Adv 2021; 11:32775-32791. [PMID: 35493577 PMCID: PMC9042220 DOI: 10.1039/d1ra05153a] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 09/19/2021] [Indexed: 12/12/2022] Open
Abstract
One of the most significant factors affecting the rapid and effective healing of wounds is the application of appropriate wound dressings. In the present study, novel antibacterial wound dressings are fabricated that consist of Chitosan (CS)/Polyvinyl alcohol (PVA)/Sodium Alginate (SA), which are all biocompatible, functionalized with mesoporous Ag2O/SiO2 and curcumin nanoparticles as reinforcements. In this research nanocomposites are fabricated (0 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt% of Ag2O/SiO2). After the composition of nanocomposites using the cross-linked technique, Fourier Transform Infrared (FT-IR) spectroscopy is performed to confirm the functional groups that are added to the polymer at each step. X-ray diffraction (XRD) is done to show the crystallinity of Ag2O/SiO2. Field emission scanning electron microscopy (FE-SEM) studies are performed to demonstrate the morphology of the structure, Energy-dispersive X-ray spectroscopy (EDS) is done to examine the elements in the wound dressing and atomic force microscopy (AFM) study is performed to show surface roughness and pores. Then the nanocomposites with different weight percentages are cultured in three bacteria called Acinetobacter baumannii, Staphylococcus epidermidis, and Proteus mirabilis, all three of which cause skin infections. Finally, by performing the tensile test, the results related to the tensile strength of the wound dressings are examined. The results show that with the increase of Ag2O/SiO2, the mechanical properties, as well as the healing properties of the wound dressing, have increased significantly. Fabricating these nanocomposites helps a lot in treating skin infections.
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Affiliation(s)
- Ashkan Farazin
- Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan P.O. Box 87317-53153 Kashan Iran
| | - Mehdi Mohammadimehr
- Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan P.O. Box 87317-53153 Kashan Iran
| | - Amir Hossein Ghasemi
- Department of Organic Chemistry, Faculty of Chemistry, University of Kashan P.O. Box 87317-53153 Kashan Iran
| | - Hossein Naeimi
- Department of Organic Chemistry, Faculty of Chemistry, University of Kashan P.O. Box 87317-53153 Kashan Iran
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16
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Senyuk B, Mundoor H, Smalyukh II, Wensink HH. Nematoelasticity of hybrid molecular-colloidal liquid crystals. Phys Rev E 2021; 104:014703. [PMID: 34412251 DOI: 10.1103/physreve.104.014703] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/25/2021] [Indexed: 11/07/2022]
Abstract
Colloidal rods immersed in a thermotropic liquid-crystalline solvent are at the basis of so-called hybrid liquid crystals, which are characterized by tunable nematic fluidity with symmetries ranging from conventional uniaxial nematic or antinematic to orthorhombic [Mundoor et al., Science 360, 768 (2018)SCIEAS0036-807510.1126/science.aap9359]. We provide a theoretical analysis of the elastic moduli of such systems by considering interactions between the individual rods with the embedding solvent through surface-anchoring forces, as well as steric and electrostatic interactions between the rods themselves. For uniaxial systems, the presence of colloidal rods generates a marked increase of the splay elasticity, which we found to be in quantitative agreement with experimental measurements. For orthorhombic hybrid liquid crystals, we provide estimates of all 12 elastic moduli and show that only a small subset of those elastic constants play a relevant role in describing the nematoelastic properties. The complexity and possibilities related to identifying the elastic moduli in experiments are briefly discussed.
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Affiliation(s)
- B Senyuk
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - H Mundoor
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - I I Smalyukh
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.,Department of Electrical, Computer, and Energy Engineering, Materials Science and Engineering Program and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.,Chemical Physics Program, Departments of Chemistry and Physics, University of Colorado, Boulder, Colorado 80309, USA.,Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado, Boulder, Colorado 80309, USA
| | - H H Wensink
- Laboratoire de Physique des Solides, Université Paris-Saclay & CNRS, UMR 8502, 91405 Orsay, France
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17
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Chaudhuri S, Saha A, Basu S. An opinion on the multiscale nature of Covid-19 type disease spread. Curr Opin Colloid Interface Sci 2021; 54:101462. [PMID: 33967585 PMCID: PMC8088079 DOI: 10.1016/j.cocis.2021.101462] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recognizing the multiscale, interdisciplinary nature of the Covid-19 transmission dynamics, we discuss some recent developments concerning an attempt to construct a disease spread model from the flow physics of infectious droplets and aerosols and the frequency of contact between susceptible individuals with the infectious aerosol cloud. Such an approach begins with the exhalation event-specific, respiratory droplet size distribution (both airborne/aerosolized and ballistic droplets), followed by tracking its evolution in the exhaled air to estimate the probability of infection and the rate constants of the disease spread model. The basic formulations and structure of submodels, experiments involved to validate those submodels, are discussed. Finally, in the context of preventive measures, respiratory droplet-face mask interactions are described.
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Affiliation(s)
- Swetaprovo Chaudhuri
- Institute for Aerospace Studies, University of Toronto, Toronto, ON M3H 5T6, Canada
| | - Abhishek Saha
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Saptarshi Basu
- Department of Mechanical Engineering, Indian Institute of Science, Bengaluru, KA 560012, India
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18
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Lavrentovich OD. Design of nematic liquid crystals to control microscale dynamics. LIQUID CRYSTALS REVIEWS 2021; 8:59-129. [PMID: 34956738 PMCID: PMC8698256 DOI: 10.1080/21680396.2021.1919576] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/11/2021] [Indexed: 05/25/2023]
Abstract
The dynamics of small particles, both living such as swimming bacteria and inanimate, such as colloidal spheres, has fascinated scientists for centuries. If one could learn how to control and streamline their chaotic motion, that would open technological opportunities in the transformation of stored or environmental energy into systematic motion, with applications in micro-robotics, transport of matter, guided morphogenesis. This review presents an approach to command microscale dynamics by replacing an isotropic medium with a liquid crystal. Orientational order and associated properties, such as elasticity, surface anchoring, and bulk anisotropy, enable new dynamic effects, ranging from the appearance and propagation of particle-like solitary waves to self-locomotion of an active droplet. By using photoalignment, the liquid crystal can be patterned into predesigned structures. In the presence of the electric field, these patterns enable the transport of solid and fluid particles through nonlinear electrokinetics rooted in anisotropy of conductivity and permittivity. Director patterns command the dynamics of swimming bacteria, guiding their trajectories, polarity of swimming, and distribution in space. This guidance is of a higher level of complexity than a simple following of the director by rod-like microorganisms. Namely, the director gradients mediate hydrodynamic interactions of bacteria to produce an active force and collective polar modes of swimming. The patterned director could also be engraved in a liquid crystal elastomer. When an elastomer coating is activated by heat or light, these patterns produce a deterministic surface topography. The director gradients define an activation force that shapes the elastomer in a manner similar to the active stresses triggering flows in active nematics. The patterned elastomer substrates could be used to define the orientation of cells in living tissues. The liquid-crystal guidance holds a major promise in achieving the goal of commanding microscale active flows.
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Affiliation(s)
- Oleg D Lavrentovich
- Advanced Materials and Liquid Crystal Institute, Department of Physics, Materials Science Graduate Program, Kent State University, Kent, OH 44242, USA
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19
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Mandal S, Mazza MG. Multiparticle collision dynamics simulations of a squirmer in a nematic fluid. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:64. [PMID: 33939056 PMCID: PMC8093181 DOI: 10.1140/epje/s10189-021-00072-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 04/16/2021] [Indexed: 05/26/2023]
Abstract
We study the dynamics of a squirmer in a nematic liquid crystal using the multiparticle collision dynamics (MPCD) method. A recently developed nematic MPCD method [Phys. Rev. E 99, 063319 (2019)] which employs a tensor order parameter to describe the spatial and temporal variations of the nematic order is used to simulate the suspending anisotropic fluid. Considering both nematodynamic effects (anisotropic viscosity and elasticity) and thermal fluctuations, in the present study, we couple the nematic MPCD algorithm with a molecular dynamics (MD) scheme for the squirmer. A unique feature of the proposed method is that the nematic order, the fluid, and the squirmer are all represented in a particle-based framework. To test the applicability of this nematic MPCD-MD method, we simulate the dynamics of a spherical squirmer with homeotropic surface anchoring conditions in a bulk domain. The importance of anisotropic viscosity and elasticity on the squirmer's speed and orientation is studied for different values of self-propulsion strength and squirmer type (pusher, puller or neutral). In sharp contrast to Newtonian fluids, the speed of the squirmer in a nematic fluid depends on the squirmer type. Interestingly, the speed of a strong pusher is smaller in the nematic fluid than for the Newtonian case. The orientational dynamics of the squirmer in the nematic fluid also shows a non-trivial dependence on the squirmer type. Our results compare well with existing experimental and numerical data. The full particle-based framework could be easily extended to model the dynamics of multiple squirmers in anisotropic fluids.
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Affiliation(s)
- Shubhadeep Mandal
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
- Max-Planck-Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077, Göttingen, Germany
| | - Marco G Mazza
- Max-Planck-Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077, Göttingen, Germany.
- Interdisciplinary Centre for Mathematical Modelling and Department of Mathematical Sciences, Loughborough University, Leicestershire LE11 3TU, Loughborough, United Kingdom.
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20
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Abstract
Nematic and columnar phases of lyotropic chromonic liquid crystals (LCLCs) have been long studied for their fundamental and applied prospects in material science and medical diagnostics. LCLC phases represent different self-assembled states of disc-shaped molecules, held together by noncovalent interactions that lead to highly sensitive concentration and temperature dependent properties. Yet, microscale insights into confined LCLCs, specifically in the context of confinement geometry and surface properties, are lacking. Here, we report the emergence of time dependent textures in static disodium cromoglycate (DSCG) solutions, confined in PDMS-based microfluidic devices. We use a combination of soft lithography, surface characterization, and polarized optical imaging to generate and analyze the confinement-induced LCLC textures and demonstrate that over time, herringbone and spherulite textures emerge due to spontaneous nematic (N) to columnar M-phase transition, propagating from the LCLC-PDMS interface into the LCLC bulk. By varying the confinement geometry, anchoring conditions, and the initial DSCG concentration, we can systematically tune the temporal dynamics of the N- to M-phase transition and textural behavior of the confined LCLC. Overall, the time taken to change from nematic to the characteristic M-phase textures decreased as the confinement aspect ratio (width/depth) increased. For a given aspect ratio, the transition to the M-phase was generally faster in degenerate planar confinements, relative to the transition in homeotropic confinements. Since the static molecular states register the initial conditions for LC flows, the time dependent textures reported here suggest that the surface and confinement effects—even under static conditions—could be central in understanding the flow behavior of LCLCs and the associated transport properties of this versatile material.
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21
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Eun J, Cheon J, Kim SJ, Shin TJ, Jeong J. Lyotropic Chromonic Liquid Crystals and Their Impurities Reveal the Importance of the Position of Functional Groups in Self-Assembly. J Phys Chem B 2020; 124:9246-9254. [PMID: 32960600 DOI: 10.1021/acs.jpcb.0c07163] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We study the effect of purification and impurities on the self-assembly and phase behavior of lyotropic chromonic liquid crystals (LCLCs). LCLC molecules in water stack to form aggregates; then, the elongated nanoaggregates align to make liquid crystalline phases. Utilizing multiple experimental techniques, we unveil impurities in commercial Sunset Yellow FCF (SSY), a representative LCLC, and how the precipitation-based purification promotes the formation of the aggregates and mesophase. We further explore the roles of intrinsic impurities, i.e., byproducts of the SSY synthesis, whose molecular structures are almost identical to that of SSY but differ only in the number and position of sulfonate groups. Combining quantum chemical calculations of molecular structures and experimental investigation of aggregate structures and phase behavior, we propose that the impurities of the planar shapes behave as planar SSY, i.e., participating in aggregate formation, whereas the nonplanar one disrupts the nematic phase. These results highlight the critical roles of the impurities and deepen our understanding of self-assembled aggregates and their aligned mesophases.
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Affiliation(s)
- Jonghee Eun
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Jiyong Cheon
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Sung-Jo Kim
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Tae Joo Shin
- UNIST Central Research Facilities & School of Natural Science, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Joonwoo Jeong
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
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22
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Krajnik Ž, Kos Ž, Ravnik M. Spectral energy analysis of bulk three-dimensional active nematic turbulence. SOFT MATTER 2020; 16:9059-9068. [PMID: 32901629 DOI: 10.1039/c9sm02492a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We perform energy spectrum analysis of the active turbulence in a 3D bulk active nematic using continuum numerical modelling. Specifically, we calculate the spectra of the two main energy contributions - kinetic energy and nematic elastic energy - and combine this with the geometrical analysis of the nematic order and flow fields, based on direct defect tracking and calculation of autocorrelations. We show that the active nematic elastic energy is concentrated at scales corresponding to the effective defect-to-defect separation, scaling with activity as ∼ζ0.5, whereas the kinetic energy is largest at somewhat larger scales of typically several 100 nematic correlation lengths. Nematic biaxiality is shown to have no role in active turbulence at most length scales, but can affect the nematic elastic energy by an order of magnitude at scales of the active defect core size. The effect of an external aligning field on the 3D active turbulence is explored, showing a transition from an effective active turbulent to an aligned regime. The work is aimed at providing a contribution towards understanding active turbulence in general three-dimensions, from the perspective of main energy-relevant mechanisms at different length scales of the system.
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Affiliation(s)
- Žiga Krajnik
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia.
| | - Žiga Kos
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia.
| | - Miha Ravnik
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia. and JoŽef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
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23
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Akdeniz B, Batir O, Bukusoglu E. Identification and sorting of particle chirality using liquid crystallinity. J Colloid Interface Sci 2020; 574:11-19. [PMID: 32298977 DOI: 10.1016/j.jcis.2020.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/30/2020] [Accepted: 04/01/2020] [Indexed: 10/24/2022]
Abstract
Particles dispersed in liquid crystals (LCs) have been shown to assemble due to the elastic interactions arising from the molecular anisotropy. Studies have shown that the alignment of the particles within LCs were strongly dependent on the surface director of LCs on particles. Different from the past studies involving particles with degenerate planar anchoring of LCs, this study shows that the azimuthal surface director can be used to control and finely tune the positioning of the particles in LCs. Specifically, polymeric particles with two flat surfaces that mediate parallel or non-parallel (chiral) anchoring were synthesized and dispersed in nematic 5CB with spatial variations in the director profile. Besides demonstration of their positioning, it was observed that the particles with same chiral handedness with the LC twist were distributed within the LC film, whereas particles with opposite handedness were repelled from the LC medium due to the elastic energy contributions. In addition, a pronounced effect of the surface anchoring of the particles were present on their orientation during non-equilibrium events such as sedimentation. Overall, the studies presented here will find potential use in sensors, separations, optics or soft robotic applications that will take advantages of chirality or chiral interactions.
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Affiliation(s)
- Burak Akdeniz
- Department of Chemical Engineering, Middle East Technical University, Dumlupinar Bulvari No. 1, Çankaya, Ankara 06800, Turkey
| | - Ozge Batir
- Department of Chemical Engineering, Middle East Technical University, Dumlupinar Bulvari No. 1, Çankaya, Ankara 06800, Turkey
| | - Emre Bukusoglu
- Department of Chemical Engineering, Middle East Technical University, Dumlupinar Bulvari No. 1, Çankaya, Ankara 06800, Turkey.
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24
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Nayani K, Córdova-Figueroa UM, Abbott NL. Steering Active Emulsions with Liquid Crystals. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6948-6956. [PMID: 31804839 DOI: 10.1021/acs.langmuir.9b02975] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Colloids dispersed in liquid crystals (LCs) diffuse preferentially along the LC director because this direction of displacement generates the lowest hydrodynamic drag. In this article, we report on the active transport of micrometer-sized nematic droplets of 4'-pentyl-4-biphenylcarbonitrile (5CB) propelled through a continuous LC phase formed from aqueous solutions of disodium cromoglycate (DSCG) by Marangoni stresses (generated through the addition of sodium dodecyl sulfate (SDS)). We observe the nematic droplets to exhibit motion guided by the continuous LC phase, but in contrast to passive diffusion, the LC droplets move preferentially in a direction perpendicular to the continuous-phase LC director. Our results suggest that the LC droplets, with internal symmetry broken by the Marangoni flow, interact through orientation-dependent van der Waals forces with the LC continuous phase, biasing the orientation of the droplets and the direction of propulsion orthogonal to the far-field director of the continuous LC phase. This proposal is supported by measurements of the orientations of droplets of 5CB and 4-ethoxy-4'-(6-acryloyloxyhexyloxy) azobenzene (RM257) polymerized in a preradial director configuration, which reveal the polymerized droplets to adopt orientations that are biased toward the perpendicular of the far-field DSCG director. Additionally, we demonstrate that preferential motion parallel to the continuous-phase LC director is recovered when using self-propelled isotropic oil droplets. We also observe periodic changes in the instantaneous velocities of LC droplets. We show the changes to correlate with the formation and detachment of satellite droplets, consistent with the solubilization of the nematic oil into surfactant assemblies near the trailing edge of the droplets and their accumulation near a stagnation region downstream of the droplet. Overall, our results provide fundamental insights into ways in which LC ordering can change the dynamics of active colloidal systems and hint at principles by which the motion of active colloids can be steered.
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Affiliation(s)
- Karthik Nayani
- Department of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Ubaldo M Córdova-Figueroa
- Department of Chemical Engineering, University of Puerto Rico-Mayagüez, Mayagüez 00682, Puerto Rico, United States
| | - Nicholas L Abbott
- Department of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
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25
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Dhakal NP, Jiang J, Guo Y, Peng C. Self-Assembly of Aqueous Soft Matter Patterned by Liquid-Crystal Polymer Networks for Controlling the Dynamics of Bacteria. ACS APPLIED MATERIALS & INTERFACES 2020; 12:13680-13685. [PMID: 32118403 DOI: 10.1021/acsami.0c00746] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The study of controlling the molecular self-assembly of aqueous soft matter is a fundamental scheme across multiple disciplines such as physics, chemistry, biology, and materials science. In this work, we use liquid-crystal polymer networks (LCNs) to control the superstructures of one aqueous soft material called lyotropic chromonic liquid crystals (LCLCs), which shows spontaneous orientational order by stacking the plank-like molecules into elongated aggregates. We synthesize a layer of patterned LCN films by a nematic liquid-crystal host in which the spatially varying molecular orientations are predesigned by plasmonic photopatterning. We demonstrate that the LCLC aggregates are oriented parallel to the polymer filaments of the LCN film. This patterned aqueous soft material shows immediate application for controlling the dynamics of swimming bacteria. The demonstrated control of the supramolecular assembly of aqueous soft matter by using a stimuli-responsive LCN film will find applications in designing dynamic advanced materials for bioengineering applications.
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Affiliation(s)
- Netra Prasad Dhakal
- Department of Physics and Materials Science, The University of Memphis, Memphis, Tennessee 38152, United States
| | - Jinghua Jiang
- Department of Physics and Materials Science, The University of Memphis, Memphis, Tennessee 38152, United States
| | - Yubing Guo
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, United States
| | - Chenhui Peng
- Department of Physics and Materials Science, The University of Memphis, Memphis, Tennessee 38152, United States
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26
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Samantaray K, Mishra SR, Purohit G, Mohanty PS. AC Electric Field Mediated Assembly of Bacterial Tetrads. ACS OMEGA 2020; 5:5881-5887. [PMID: 32226868 PMCID: PMC7098059 DOI: 10.1021/acsomega.9b04124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 02/25/2020] [Indexed: 05/10/2023]
Abstract
Understanding spatiotemporal organization in bacteria under an external AC electric field is not only very interesting from a perspective of studying assembly and disassembly in a model biofilm but also provides insight into the intricate role of anisotropic interaction with bacterial dynamics that can generate interesting complex structures. In the current study, using confocal microscopy, we demonstrate such complex assemblies of monodisperse tetrad clusters of Micrococcus luteus, an environmental bacterium synthesized under a controlled growth condition. These clusters under the AC field produce a range of interesting structures such as chains, double helix, and bundles, which are instantaneously reversible when the field is switched off. Our studies can provide important insights into the natural organization of the clustered bacterium (with relevance in biofilm-like states) and generate strategies for biomaterial fabrication with a switchable functionality.
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Affiliation(s)
- Kunal Samantaray
- School of Biotechnology and School of Chemical Technology, Kalinga Institute of Industrial Technology (KIIT), Deemed to be University, Bhubaneswar 751024, India
| | - Samir R Mishra
- School of Biotechnology and School of Chemical Technology, Kalinga Institute of Industrial Technology (KIIT), Deemed to be University, Bhubaneswar 751024, India
| | - Gopal Purohit
- School of Biotechnology and School of Chemical Technology, Kalinga Institute of Industrial Technology (KIIT), Deemed to be University, Bhubaneswar 751024, India
| | - Priti S Mohanty
- School of Biotechnology and School of Chemical Technology, Kalinga Institute of Industrial Technology (KIIT), Deemed to be University, Bhubaneswar 751024, India
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27
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Naskar S, Saurabh S, Jang YH, Lansac Y, Maiti PK. Liquid crystal ordering of nucleic acids. SOFT MATTER 2020; 16:634-641. [PMID: 31840704 DOI: 10.1039/c9sm01816f] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Several analytical calculations and computer simulations propose that cylindrical monodispersive rods having an aspect ratio (ratio of length to diameter) greater than 4 can exhibit liquid crystal (LC) ordering. But, recent experiments demonstrated the signature of LC ordering in systems of 4- to 20-base pair (bp) long nucleic acids (NAs) that do not satisfy the shape anisotropy criterion. Mechanisms of end-to-end adhesion and stacking have been proposed to explain this phenomenon. In this study, using all-atom molecular dynamics (MD) simulation, we explicitly verify the end-to-end stacking of double-stranded RNA (dsRNA) and demonstrate the LC ordering at the microscopic level. Using umbrella sampling (US) calculation, we quantify the potential of mean force (PMF) between two dsRNAs for various reaction coordinates (RCs) and compare our results with previously reported PMFs for double-stranded DNA (dsDNA). The PMF profiles demonstrate the anisotropic nature of inter-NA interaction. We find that, like dsDNA, dsRNA also prefers to stack on top of each other while repelling sideways, leading to the formation of supra-molecular-columns that undergo LC ordering at high NA volume fraction (φ). We also demonstrate and quantify the nematic ordering of the RNAs using several hundred nanosecond-long MD simulations that remain almost invariant for different initial configurations and under different external physiological conditions.
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Affiliation(s)
- Supriyo Naskar
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
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28
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Guo Y, Shahsavan H, Davidson ZS, Sitti M. Precise Control of Lyotropic Chromonic Liquid Crystal Alignment through Surface Topography. ACS APPLIED MATERIALS & INTERFACES 2019; 11:36110-36117. [PMID: 31532609 DOI: 10.1021/acsami.9b12943] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Many emerging applications, such as water-based electronic devices and biological sensors, require local control of anisotropic properties. Lyotropic chromonic liquid crystals (LCLCs) are an exciting class of materials, which are usually biocompatible and provide uniaxial anisotropy through a director field but, to date, remain difficult to control. In this work, we introduce a simple strategy to realize an arbitrary orientation of LCLCs director field in two dimensions (2D). Our alignment strategy relies on surface topographical micro/nanostructures fabricated by two-photon laser writing. We show that the alignment of LCLCs can be: (a) precisely controlled with a remarkable pixel resolution of 2.5 μm and (b) patterned into an arbitrary 2D alignment (e.g., +2 topological defect) by a pixelated design and arrangement of micro/nanostructures. Using a similar strategy, we achieve a patternable homeotropic alignment of LCLCs with nanopillars. Finally, we demonstrate that a self-assembled three-dimensional alignment of LCLCs can be obtained due to the versatility of our alignment strategy. Our demonstration of LCLC director field control, which is not only straightforward to achieve but also compatible with other conventional micro/nanofabrication techniques, will provide new opportunities for the manufacturing of LC-based electronic and biological devices.
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Affiliation(s)
- Yubing Guo
- Physical Intelligence Department , Max Planck Institute for Intelligent Systems , 70569 Stuttgart , Germany
| | - Hamed Shahsavan
- Physical Intelligence Department , Max Planck Institute for Intelligent Systems , 70569 Stuttgart , Germany
| | - Zoey S Davidson
- Physical Intelligence Department , Max Planck Institute for Intelligent Systems , 70569 Stuttgart , Germany
| | - Metin Sitti
- Physical Intelligence Department , Max Planck Institute for Intelligent Systems , 70569 Stuttgart , Germany
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Kim YK, Noh J, Nayani K, Abbott NL. Soft matter from liquid crystals. SOFT MATTER 2019; 15:6913-6929. [PMID: 31441481 DOI: 10.1039/c9sm01424a] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Liquid crystals (LCs) are fluids within which molecules exhibit long-range orientational order, leading to anisotropic properties such as optical birefringence and curvature elasticity. Because the ordering of molecules within LCs can be altered by weak external stimuli, LCs have been widely used to create soft matter systems that respond optically to electric fields (LC display), temperature (LC thermometer) or molecular adsorbates (LC chemical sensor). More recent studies, however, have moved beyond investigations of optical responses of LCs to explore the design of complex LC-based soft matter systems that offer the potential to realize more sophisticated functions (e.g., autonomous, self-regulating chemical responses to mechanical stimuli) by directing the interactions of small molecules, synthetic colloids and living cells dispersed within the bulk of LCs or at their interfaces. These studies are also increasingly focusing on LC systems driven beyond equilibrium states. This review presents one perspective on these advances, with an emphasis on the discovery of fundamental phenomena that may enable new technologies. Three areas of progress are highlighted; (i) directed assembly of amphiphilic molecules either within topological defects of LCs or at aqueous interfaces of LCs, (ii) templated polymerization in LCs via chemical vapor deposition, an approach that overcomes fundamental challenges related to control of LC phase behavior during polymerization, and (iii) studies of colloids in LCs, including chiral colloids, soft colloids that are strained by LCs, and active colloids that are driven into organized states by dissipation of energy (e.g. bacteria). These examples, and key unresolved issues discussed at the end of this perspective, serve to convey the message that soft matter systems that integrate ideas from LC, surfactant, polymer and colloid sciences define fertile territory for fundamental studies and creation of future transformative technologies.
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Affiliation(s)
- Young-Ki Kim
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, New York 14853, USA. and Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyengbuk 37673, Korea
| | - JungHyun Noh
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, New York 14853, USA.
| | - Karthik Nayani
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, New York 14853, USA.
| | - Nicholas L Abbott
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, New York 14853, USA.
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Dadalyan T, Galstian T. Local pulses of electrical potential can induce long-range transient excitations in self-aligned molecular films. Sci Rep 2019; 9:12346. [PMID: 31451713 PMCID: PMC6710425 DOI: 10.1038/s41598-019-48836-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 08/07/2019] [Indexed: 11/09/2022] Open
Abstract
Natural liquids can contain self-aligned molecules (such as liquid crystals and biological membranes) which give them unique properties of anisotropic diffusion, coupling between the molecular orientation and flow, etc. Here, we describe the observation of new phenomena in those materials: long-distance transport and molecular orientation waves that are induced by pulses of spatially localized electrical potential. As a result, the morphological properties of the material are significantly altered well beyond the reach of the electrical field. The local dielectric torque-induced reduction of the effective molecular volume and corresponding pressure gradients are in the origin of these phenomena. Our observations are made for electric fields that are an order of magnitude smaller than those present in biological membranes. Thus, this discovery may have important impact on the understanding of the operation of these membranes and on the dynamics of action potential propagation in neural cells. The corresponding possible influence of observed excitation mechanisms on the ionic gates and the role of myelin sheath are discussed.
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Affiliation(s)
- T Dadalyan
- Center for Optics, Photonics and Laser, Department of Physics, Engineering Physics and Optics, Université Laval. 2375 Rue de la Terrasse, Québec (Qc), G1V 0A6, Canada.,Yerevan State University, 1 Alek Manukyan St, Yerevan, 0025, Armenia
| | - T Galstian
- Center for Optics, Photonics and Laser, Department of Physics, Engineering Physics and Optics, Université Laval. 2375 Rue de la Terrasse, Québec (Qc), G1V 0A6, Canada.
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31
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Lee H, Sunkara V, Cho YK, Jeong J. Effects of poly(ethylene glycol) on the wetting behavior and director configuration of lyotropic chromonic liquid crystals confined in cylinders. SOFT MATTER 2019; 15:6127-6133. [PMID: 31290906 DOI: 10.1039/c9sm00927b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We investigate the effects of poly(ethylene glycol) (PEG) doping on nematic lyotropic chromonic liquid crystals (LCLCs) confined in a cylindrical cavity. First, PEG added to Sunset Yellow (SSY) renders confining glass surfaces nemato-phobic by adsorption. We also confirm that the grafting of PEG to bare glass surfaces changes them from nemato-philic to nemato-phobic. This change in the wetting behavior affects how nematic director configurations form and relax. Additionally, we observe that PEG-doped nematic SSY retains the double-twist director configuration as in the PEG-free case. However, the PEG-doped nematic SSY is accompanied by unprecedented domain-wall-like defects and heterogeneity in the director configuration. We propose multiple hypotheses on how PEG changes the director configuration, including the formation of meta-stable director configurations.
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Affiliation(s)
- Hyesong Lee
- Department of Physics, School of Natural Science, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
| | - Vijaya Sunkara
- Center for Soft and Living Matter, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Yoon-Kyoung Cho
- Center for Soft and Living Matter, Institute for Basic Science, Ulsan 44919, Republic of Korea and Department of Biomedical Engineering, School of Life Science, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Joonwoo Jeong
- Department of Physics, School of Natural Science, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea. and Center for Soft and Living Matter, Institute for Basic Science, Ulsan 44919, Republic of Korea
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32
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Abstract
Mucus plays crucial roles in higher organisms, from aiding fertilization to protecting the female reproductive tract. Here, we investigate how anisotropic organization of mucus affects bacterial motility. We demonstrate by cryo electron micrographs and elongated tracer particles imaging, that mucus anisotropy and heterogeneity depend on how mechanical stress is applied. In shallow mucus films, we observe bacteria reversing their swimming direction without U-turns. During the forward motion, bacteria burrowed tunnels that last for several seconds and enable them to swim back faster, following the same track. We elucidate the physical mechanism of direction reversal by fluorescent visualization of the flagella: when the bacterial body is suddenly stopped by the mucus structure, the compression on the flagellar bundle causes buckling, disassembly and reorganization on the other side of the bacterium. Our results shed light into motility of bacteria in complex visco-elastic fluids and can provide clues in the propagation of bacteria-born diseases in mucus.
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Zhao J, Gulan U, Horie T, Ohmura N, Han J, Yang C, Kong J, Wang S, Xu BB. Advances in Biological Liquid Crystals. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1900019. [PMID: 30892830 DOI: 10.1002/smll.201900019] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 02/17/2019] [Indexed: 06/09/2023]
Abstract
Biological liquid crystals, a rich set of soft materials with rod-like structures widely existing in nature, possess typical lyotropic liquid crystalline phase properties both in vitro (e.g., cellulose, peptides, and protein assemblies) and in vivo (e.g., cellular lipid membrane, packed DNA in bacteria, and aligned fibroblasts). Given the ability to undergo phase transition in response to various stimuli, numerous practices are exercised to spatially arrange biological liquid crystals. Here, a fundamental understanding of interactions between rod-shaped biological building blocks and their orientational ordering across multiple length scales is addressed. Discussions are made with regard to the dependence of physical properties of nonmotile objects on the first-order phase transition and the coexistence of multi-phases in passive liquid crystalline systems. This work also focuses on how the applied physical stimuli drives the reorganization of constituent passive particles for a new steady-state alignment. A number of recent progresses in the dynamics behaviors of active liquid crystals are presented, and particular attention is given to those self-propelled animate elements, like the formation of motile topological defects, active turbulence, correlation of orientational ordering, and cellular functions. Finally, future implications and potential applications of the biological liquid crystalline materials are discussed.
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Affiliation(s)
- Jianguo Zhao
- Quanzhou Institute of Equipment Manufacturing, Haixi Institutes, Chinese Academy of Sciences, Quanzhou, 362200, China
- Third Institute of Physics-Biophysics, University of Göttingen, 37077, Göttingen, Germany
| | - Utku Gulan
- Institute of Environmental Engineering, ETH Zurich, 8093, Zurich, Switzerland
| | - Takafumi Horie
- Department of Chemical Science and Engineering, Kobe University, Kobe, 657-8501, Japan
| | - Naoto Ohmura
- Department of Chemical Science and Engineering, Kobe University, Kobe, 657-8501, Japan
| | - Jun Han
- Quanzhou Institute of Equipment Manufacturing, Haixi Institutes, Chinese Academy of Sciences, Quanzhou, 362200, China
| | - Chao Yang
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
| | - Jie Kong
- Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Science, Northwestern Polytechnical University, Xi'an, 710072, China
| | - Steven Wang
- School of Engineering, Newcastle University, Newcastle Upon Tyne, NE1 7RU, UK
| | - Ben Bin Xu
- Mechanical and Construction Engineering, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
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34
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Zhou S. Recent progresses in lyotropic chromonic liquid crystal research: elasticity, viscosity, defect structures, and living liquid crystals. LIQUID CRYSTALS TODAY 2019. [DOI: 10.1080/1358314x.2018.1570593] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Shuang Zhou
- Physics Department, University of Massachusetts, Amherst, MA, USA
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35
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Abstract
Active matter is a wide class of nonequilibrium systems consisting of interacting self-propelled agents transducing the energy stored in the environment into mechanical motion. Numerous examples range from microscopic cytoskeletal filaments and swimming organisms (bacteria and unicellular algae), synthetic catalytic nanomotors, colloidal self-propelled Janus particles, to macroscopic bird flocks, fish schools, and even human crowds. Active matter demonstrates a remarkable tendency toward self-organization and development of collective states with the long-range spatial order. Furthermore, active materials exhibit properties that are not present in traditional materials like plastics or ceramics: self-repair, shape change, and adaptation. A suspension of microscopic swimmers, such as motile bacteria or self-propelled colloids (active suspensions), is possibly the simplest and the most explored realization of active matter. Recent studies of active suspensions revealed a wealth of unexpected behaviors, from a dramatic reduction of the effective viscosity, enhanced mixing and self-diffusion, rectification of chaotic motion, to artificial rheotaxis (drift against the imposed flow) and cross-stream migration. To date, most of the studies of active matter are performed in isotropic suspending medium, like water with the addition of some "fuel", e.g., nutrient for bacteria or H2O2 for catalytic bimetallic AuPt nanorods. A highly structured anisotropic suspending medium represented by lyotropic liquid crystal (water-soluble) opens enormous opportunities to control and manipulate active matter. Liquid crystals exhibit properties intermediate between solid and liquids; they may flow like a liquid but respond to deformations as a solid due to a crystal-like orientation of molecules. Liquid crystals doped by a small amount of active component represent a new class of composite materials (living liquid crystals or LLCs) with unusual mechanical and optical properties. LLCs demonstrate a variety of highly organized dynamic collective states, spontaneous formation of dynamic textures of topological defects (singularities of local molecular orientation), controlled and reconfigurable transport of cargo particles, manipulation of individual trajectories of microswimmers, and many others. Besides insights into fundamental mechanisms governing active materials, living liquid crystals may have intriguing applications, such as the design of new classes of soft adaptive bioinspired materials capable to respond to physical and chemical stimuli, such as light, magnetic, and electric fields, mechanical shear, airborne pollutants, and bacterial toxins. This Account details the most recent developments in the field of LLCs and discusses how the anisotropy of liquid crystals can be harnessed to control and manipulate active materials.
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Affiliation(s)
- Igor S. Aranson
- Departments of Biomedical Engineering, Chemistry and Mathematics, Pennsylvania State University, University Park, Pennsylvania 16802, United States
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36
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Yuan Y, Abuhaimed GN, Liu Q, Smalyukh II. Self-assembled nematic colloidal motors powered by light. Nat Commun 2018; 9:5040. [PMID: 30487599 PMCID: PMC6261955 DOI: 10.1038/s41467-018-07518-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 11/02/2018] [Indexed: 01/07/2023] Open
Abstract
Biological motors are marvels of nature that inspire creation of their synthetic counterparts with comparable nanoscale dimensions, high efficiency and diverse functions. Molecular motors have been synthesized, but obtaining nanomotors through self-assembly remains challenging. Here we describe a self-assembled colloidal motor with a repetitive light-driven rotation of transparent micro-particles immersed in a liquid crystal and powered by a continuous exposure to unstructured ~1 nW light. A monolayer of azobenzene molecules defines how the liquid crystal's optical axis mechanically couples to the particle's surface, as well as how they jointly rotate as the light's polarization changes. The rotating particle twists the liquid crystal, which changes polarization of traversing light. The resulting feedback mechanism yields a continuous opto-mechanical cycle and drives the unidirectional particle spinning, with handedness and frequency robustly controlled by polarization and intensity of light. Our findings may lead to opto-mechanical devices and colloidal machines compatible with liquid crystal display technology.
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Affiliation(s)
- Ye Yuan
- Department of Physics, University of Colorado, Boulder, CO, 80309, USA
| | | | - Qingkun Liu
- Department of Physics, University of Colorado, Boulder, CO, 80309, USA
| | - Ivan I Smalyukh
- Department of Physics, University of Colorado, Boulder, CO, 80309, USA. .,Soft Materials Research Center and Materials Science and Engineering Program, Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO, 80309, USA. .,Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado, Boulder, CO, 80309, USA.
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37
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Soni H, Pelcovits RA, Powers TR. Enhancement of Microorganism Swimming Speed in Active Matter. PHYSICAL REVIEW LETTERS 2018; 121:178002. [PMID: 30411941 DOI: 10.1103/physrevlett.121.178002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Indexed: 06/08/2023]
Abstract
We study a swimming undulating sheet in the isotropic phase of an active nematic liquid crystal. Activity changes the effective shear viscosity, reducing it to zero at a critical value of activity. Expanding in the sheet amplitude, we find that the correction to the swimming speed due to activity is inversely proportional to the effective shear viscosity. Our perturbative calculation becomes invalid near the critical value of activity; using numerical methods to probe this regime, we find that activity enhances the swimming speed by an order of magnitude compared to the passive case.
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Affiliation(s)
- Harsh Soni
- School of Engineering, Brown University, Providence, Rhode Island 02912, USA
| | - Robert A Pelcovits
- Department of Physics, Brown University, Providence, Rhode Island 02012, USA
| | - Thomas R Powers
- School of Engineering, Brown University, Providence, Rhode Island 02912, USA
- Department of Physics, Brown University, Providence, Rhode Island 02012, USA
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38
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Koumakis N, Devailly C, Poon WCK. Motile bacteria in a critical fluid mixture. Phys Rev E 2018; 97:062604. [PMID: 30011513 DOI: 10.1103/physreve.97.062604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Indexed: 11/07/2022]
Abstract
We studied the swimming of Escherichia coli bacteria in the vicinity of the critical point in a solution of the nonionic surfactant C_{12}E_{5} in buffer solution. In phase-contrast microscopy, each swimming cell produces a transient trail behind itself lasting several seconds. Comparing quantitative image analysis with simulations show that these trails are due to local phase reorganization triggered by differential adsorption. This contrasts with similar trails seen in bacteria swimming in liquid crystals, which are due to shear effects. We show how our trails are controlled, and use them to probe the structure and dynamics of critical fluctuations in the fluid medium.
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Affiliation(s)
- Nick Koumakis
- SUPA and School of Physics & Astronomy, The University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh EH9 3FD, Scotland, United Kingdom
| | - Clémence Devailly
- SUPA and School of Physics & Astronomy, The University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh EH9 3FD, Scotland, United Kingdom
| | - Wilson C K Poon
- SUPA and School of Physics & Astronomy, The University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh EH9 3FD, Scotland, United Kingdom
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39
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Ferreiro-Córdova C, Toner J, Löwen H, Wensink HH. Long-time anomalous swimmer diffusion in smectic liquid crystals. Phys Rev E 2018; 97:062606. [PMID: 30011607 DOI: 10.1103/physreve.97.062606] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Indexed: 06/08/2023]
Abstract
The dynamics of self-locomotion of active particles in aligned or liquid crystalline fluids strongly deviates from that in simple isotropic media. We explore the long-time dynamics of a swimmer moving in a three-dimensional smectic liquid crystal and find that the mean-square displacement transverse to the director exhibits a distinct logarithmic tail at long times. The scaling is distinctly different from that in an isotropic or nematic fluid and hints at the subtle but important role of the director fluctuation spectrum in governing the long-time motility of active particles. Our findings are based on a generic hydrodynamic theory and Brownian dynamics computer simulation of a three-dimensional soft mesogen model.
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Affiliation(s)
- Claudia Ferreiro-Córdova
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - John Toner
- Department of Physics and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, USA
| | - Hartmut Löwen
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Henricus H Wensink
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
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40
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Elementary Flow Field Profiles of Micro-Swimmers in Weakly Anisotropic Nematic Fluids: Stokeslet, Stresslet, Rotlet and Source Flows. FLUIDS 2018. [DOI: 10.3390/fluids3010015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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41
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Ibanez ACS, Marji E, Luk YY. Cromoglycate mesogen forms isodesmic assemblies promoted by peptides and induces aggregation of a range of proteins. RSC Adv 2018; 8:29598-29606. [PMID: 35547307 PMCID: PMC9085300 DOI: 10.1039/c8ra05226c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/05/2018] [Indexed: 11/21/2022] Open
Abstract
Disodium cromoglycate (5′DSCG) belongs to a class of nonamphiphilic molecules that form nematic chromonic liquid crystals in aqueous solutions. As the concentration increases, it is believed that the molecules first form isodesmic assemblies in water, which further align to form liquid crystal phases. However, the reports on isodesmic assemblies of 5′DSCG have been scarce. Herein, we show that the presence of peptides can promote the isodesmic assembly of 5′DSCG over a broad range of concentrations before reaching the liquid crystal phase. The presence of peptides can lower the 5′DSCG concentration in the aqueous solution to ∼1.5 wt% (from 11–12 wt%, forming a nematic liquid crystal phase) for isodesmic assembly formation. This result indicates a demixing between 5′DSCG and peptides in aqueous solution. We further explored this demixing mechanism to precipitate a wide range of proteins, namely, lectin A, esterase, lipase, bovine serum albumin, trypsin, and a pilin protein from bacterium Pseudomonas aeruginosa. We found that 5′DSCG caused the aggregation of all these proteins except trypsin. These results, along with past findings, suggest that 5′DSCG isodesmic assemblies have the potential to assist in protein purification and crystallization. 5′DSCG molecules form isodesmic assembly in the presence of peptides, and cause a wide range of proteins to aggregate.![]()
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Affiliation(s)
| | - Elaine Marji
- Chemistry Department
- Syracuse University
- Syracuse
- USA
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42
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Duchesne I, Galstian T, Rainville S. Transient locking of the hook procures enhanced motility to flagellated bacteria. Sci Rep 2017; 7:16354. [PMID: 29180634 PMCID: PMC5703839 DOI: 10.1038/s41598-017-16562-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 11/14/2017] [Indexed: 11/09/2022] Open
Abstract
Flagellated bacteria often proliferate in inhomogeneous environments, such as biofilms, swarms and soil. In such media, bacteria are observed to move efficiently only if they can get out of "dead ends" by changing drastically their swimming direction, and even to completely reverse it. Even though these reorientations are ubiquitous, we have only recently begun to describe and understand how they happen. In the present work, we visualized the flagella of bacteria swimming in a soft agar solution. The surprising observation that the filaments do not rotate while being flipped from one side of the cell to the other suggests that reversals are driven directly by the motor rather than by the thrust created by the rotating filament. This was confirmed by observing bacteria in a liquid crystal, where the linear movement of bacteria greatly simplifies the analysis. These observations suggest that the reversal and reorientation processes involve a temporary locking of the flagellum's hook, which is the normally flexible joint between the rotary motor and the long helical filament that propels the cell. This newly described locked-hook mode occurs only when the motor switches to a clockwise rotation. That correlates with other phenomena that are triggered by a switch in one direction and not the other.
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Affiliation(s)
- Ismaël Duchesne
- Department of Physics, Engineering Physics and Optics, Center for Optics, Photonics and Lasers, Laval University, Quebec city, G1V 0A6, Canada
| | - Tigran Galstian
- Department of Physics, Engineering Physics and Optics, Center for Optics, Photonics and Lasers, Laval University, Quebec city, G1V 0A6, Canada
| | - Simon Rainville
- Department of Physics, Engineering Physics and Optics, Center for Optics, Photonics and Lasers, Laval University, Quebec city, G1V 0A6, Canada.
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43
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Adhyapak TC, Jabbari-Farouji S. Flow properties and hydrodynamic interactions of rigid spherical microswimmers. Phys Rev E 2017; 96:052608. [PMID: 29347781 DOI: 10.1103/physreve.96.052608] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Indexed: 06/07/2023]
Abstract
We analyze a minimal model for a rigid spherical microswimmer and explore the consequences of its extended surface on the interplay between its self-propulsion and flow properties. The model is the first order representation of microswimmers, such as bacteria and algae, with rigid bodies and flexible propelling appendages. The flow field of such a microswimmer at finite distances significantly differs from that of a point-force (Stokeslet) dipole. For a suspension of microswimmers, we derive the grand mobility matrix that connects the motion of an individual swimmer to the active and passive forces and torques acting on all the swimmers. Our investigation of the mobility tensors reveals that hydrodynamic interactions among rigid-bodied microswimmers differ considerably from those among the corresponding point-force dipoles. Our results are relevant for the study of collective behavior of hydrodynamically interacting microswimmers by means of Stokesian dynamics simulations at moderate concentrations.
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Affiliation(s)
- Tapan Chandra Adhyapak
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7-9, 55128 Mainz, Germany
| | - Sara Jabbari-Farouji
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7-9, 55128 Mainz, Germany
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44
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Mangal R, Nayani K, Kim YK, Bukusoglu E, Córdova-Figueroa UM, Abbott NL. Active Janus Particles at Interfaces of Liquid Crystals. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:10917-10926. [PMID: 28850782 DOI: 10.1021/acs.langmuir.7b02246] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report an investigation of the active motion of silica-palladium Janus particles (JPs) adsorbed at interfaces formed between nematic liquid crystals (LCs) and aqueous phases containing hydrogen peroxide (H2O2). In comparison to isotropic oil-aqueous interfaces, we observe the elasticity and anisotropic viscosity of the nematic phase to change qualitatively the active motion of the JPs at the LC interfaces. Although contact line pinning on the surface of the JPs is observed to restrict out-of-plane rotational diffusion of the JPs at LC interfaces, orientational anchoring of nematic LCs on the silica (planar) and palladium (homeotropic) hemispheres biases JP in-plane orientations to generate active motion almost exclusively along the director of the LC at low concentrations of H2O2 (0.5 wt %). In contrast, displacements perpendicular to the director exhibit the characteristics of Brownian diffusion. At higher concentrations of H2O2 (1-3 wt %), we observe an increasing population of JPs propelled parallel and perpendicular to the LC director in a manner consistent with active motion. In addition, under these conditions, we also observe a subpopulation of JPs (approximately 10%) that exhibit active motion exclusively perpendicular to the LC director. These results are discussed in light of independent measurements of the distribution of azimuthal orientations of the JPs at the LC interfaces and calculations of the elastic energies that bias JP orientations. We also contrast our observations at LC interfaces to past studies of self-propulsion of particles within and at the interfaces of isotropic liquids.
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Affiliation(s)
- Rahul Mangal
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Karthik Nayani
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Young-Ki Kim
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Emre Bukusoglu
- Chemical Engineering Department, Middle East Technical University , Ankara 06800, Turkey
| | - Ubaldo M Córdova-Figueroa
- Department of Chemical Engineering, University of Puerto Rico - Mayagüez , Mayagüez 00681, Puerto Rico
| | - Nicholas L Abbott
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , 1415 Engineering Drive, Madison, Wisconsin 53706, United States
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45
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Lintuvuori JS, Würger A, Stratford K. Hydrodynamics Defines the Stable Swimming Direction of Spherical Squirmers in a Nematic Liquid Crystal. PHYSICAL REVIEW LETTERS 2017; 119:068001. [PMID: 28949617 DOI: 10.1103/physrevlett.119.068001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Indexed: 06/07/2023]
Abstract
We present a study of the hydrodynamics of an active particle-a model squirmer-in an environment with a broken rotational symmetry: a nematic liquid crystal. By combining simulations with analytic calculations, we show that the hydrodynamic coupling between the squirmer flow field and liquid crystalline director can lead to reorientation of the swimmers. The preferred orientation depends on the exact details of the squirmer flow field. In a steady state, pushers are shown to swim parallel with the nematic director while pullers swim perpendicular to the nematic director. This behavior arises solely from hydrodynamic coupling between the squirmer flow field and anisotropic viscosities of the host fluid. Our results suggest that an anisotropic swimming medium can be used to characterize and guide spherical microswimmers in the bulk.
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Affiliation(s)
- J S Lintuvuori
- Laboratoire Ondes et Matière d'Aquitaine, Université de Bordeaux & CNRS, 33405 Talence, France
| | - A Würger
- Laboratoire Ondes et Matière d'Aquitaine, Université de Bordeaux & CNRS, 33405 Talence, France
| | - K Stratford
- EPCC, University of Edinburgh, EH9 3FD, Edinburgh, United Kingdom
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46
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Peng C, Guo Y, Turiv T, Jiang M, Wei QH, Lavrentovich OD. Patterning of Lyotropic Chromonic Liquid Crystals by Photoalignment with Photonic Metamasks. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1606112. [PMID: 28295687 DOI: 10.1002/adma.201606112] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/28/2016] [Indexed: 06/06/2023]
Abstract
Controlling supramolecular self-assembly in water-based solutions is an important problem of interdisciplinary character that impacts the development of many functional materials and systems. Significant progress in aqueous self-assembly and templating has been demonstrated by using lyotropic chromonic liquid crystals (LCLCs) as these materials show spontaneous orientational order caused by unidirectional stacking of plank-like molecules into elongated aggregates. In this work, it is demonstrated that the alignment direction of chromonic assemblies can be patterned into complex spatially-varying structures with very high micrometer-scale precision. The approach uses photoalignment with light beams that exhibit a spatially-varying direction of light polarization. The state of polarization is imprinted into a layer of photosensitive dye that is protected against dissolution into the LCLC by a liquid crystalline polymer layer. The demonstrated level of control over the spatial orientation of LCLC opens opportunities for engineering materials and devices for optical and biological applications.
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Affiliation(s)
- Chenhui Peng
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH, 44242, USA
| | - Yubing Guo
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH, 44242, USA
| | - Taras Turiv
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH, 44242, USA
| | - Miao Jiang
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH, 44242, USA
| | - Qi-Huo Wei
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH, 44242, USA
| | - Oleg D Lavrentovich
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH, 44242, USA
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47
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Samantaray K, Bhol P, Sahoo B, Barik SK, Jathavedan K, Sahu BR, Suar M, Bhat SK, Mohanty PS. Template-Free Assembly in Living Bacterial Suspension under an External Electric Field. ACS OMEGA 2017; 2:1019-1024. [PMID: 30023626 PMCID: PMC6044750 DOI: 10.1021/acsomega.6b00541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/06/2017] [Indexed: 05/04/2023]
Abstract
Although template-assisted self-assembly methods are very popular in materials and biological systems, they have certain limitations such as lack of tunability and switchable functionality because of the irreversible association of cells and their matrix components. With an aim to achieve more tunability, we have made an attempt to investigate the self-assembly behavior of rod-shaped living bacteria subjected to an external alternating electric field using confocal microscopy. We demonstrate that rod-shaped living bacteria dispersed in a low salinity aqueous medium form different types of reversible freely suspended structures when subjected to an external alternating electric field. At low field strength, an oriented phase is observed where individual bacterium orients with its major axis aligned along the field direction. At intermediate field strength, bacteria align in the form of one-dimensional (1D) chains that lie along the field direction. Further, at high field strength, more bacteria associate with these 1D chains laterally to form a two-dimensional (2D) array. At higher bacterial concentration, these field-induced 2D arrays extend to form three-dimensional columnar structures. These results are discussed in the context of previously reported studies on bacterial self-assembly.
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Affiliation(s)
- Kunal Samantaray
- School
of Biotechnology and School of Applied Sciences, KIIT University, Bhubaneswar 751024, India
| | - Prachi Bhol
- School
of Biotechnology and School of Applied Sciences, KIIT University, Bhubaneswar 751024, India
| | - Bhabani Sahoo
- Institute
of Life Science, Bhubaneswar 751023, India
| | - Subrat Kumar Barik
- School
of Biotechnology and School of Applied Sciences, KIIT University, Bhubaneswar 751024, India
| | - Kiran Jathavedan
- Polymer
Science & Engineering Division, CSIR-National
Chemical Laboratory, Pune 411008, India
| | - Bikash Ranjan Sahu
- School
of Biotechnology and School of Applied Sciences, KIIT University, Bhubaneswar 751024, India
| | - Mrutyunjay Suar
- School
of Biotechnology and School of Applied Sciences, KIIT University, Bhubaneswar 751024, India
| | - Suresh K. Bhat
- Polymer
Science & Engineering Division, CSIR-National
Chemical Laboratory, Pune 411008, India
| | - Priti Sundar Mohanty
- School
of Biotechnology and School of Applied Sciences, KIIT University, Bhubaneswar 751024, India
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48
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Lee BK, Kim SJ, Lev B, Kim JH. Motion of a colloidal particle in a nonuniform director field of a nematic liquid crystal. Phys Rev E 2017; 95:012709. [PMID: 28208466 DOI: 10.1103/physreve.95.012709] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Indexed: 11/07/2022]
Abstract
We investigate the dynamics of a single spherical particle immersed in a nematic liquid crystal. A nonuniform director field is imposed on the substrate by a stripe alignment pattern with splay deformation. The particle of homeotropic anchoring at the surface is accompanied by hyperbolic hedgehog or Saturn-ring defects. The particle motion is dependent on the defect structure. We study the two types of motions theoretically and confirm the obtained results experimentally. The particle accompanied by a hyperbolic hedgehog defect is pulled to a deformed region to relax the elastic deformation energy. The motion occurs in the direction heading the hyperbolic hedgehog defect of a particle in a twist region. The position exhibits a weak S-shaped change as a function of time. The particle accompanied by a Saturn-ring defect shows insignificant motion due to its relatively small deformation energy.
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Affiliation(s)
- Beom-Kyu Lee
- Department of Physics, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea
| | - Sung-Jo Kim
- Department of Physics, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea
| | - Bohdan Lev
- Department of Physics, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea.,Bogolyubov Institute for Theoretical Physics of the NAS of Ukraine, Metrolohichna Street 14-b, Kiev 03680, Ukraine
| | - Jong-Hyun Kim
- Department of Physics, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea
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49
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van der Asdonk P, Kouwer PHJ. Liquid crystal templating as an approach to spatially and temporally organise soft matter. Chem Soc Rev 2017; 46:5935-5949. [DOI: 10.1039/c7cs00029d] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Liquid crystal templating: an emerging technique to organise and control soft matter at multiple length scales.
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Affiliation(s)
- Pim van der Asdonk
- Radboud University
- Institute for Molecules and Materials
- 6525 AJ Nijmegen
- The Netherlands
| | - Paul H. J. Kouwer
- Radboud University
- Institute for Molecules and Materials
- 6525 AJ Nijmegen
- The Netherlands
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50
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Peng C, Turiv T, Guo Y, Wei QH, Lavrentovich OD. Command of active matter by topological defects and patterns. Science 2016; 354:882-885. [DOI: 10.1126/science.aah6936] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 10/21/2016] [Indexed: 11/03/2022]
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