摘要(英) |
Self-propelled micro-swimmers are biological organisms or synthetic objects that propel themselves through the surrounding fluids. Examples are swimming fish, flying birds, or various swimming bacteria such as Escherichia coli and the green alga Chlamydomonas reinhardtii, etc. In the microscale living system, most of self-propelled bacteria have the same pattern of motion, which they move along one direction with linear motion, after a period of time, they stop suddenly and turn to another direction, and then they repeat the same process. This motion mode is called run-and-tumble motion. The trajectory of its motion is linear in a short interval, then punctuated by sudden and rapid randomizations in direction. However, the motion of the particles will be affect by Brownian motion in microscopic study. The particle will change the direction of the movement because rotational Brownian motion. In other words, the particle won’t move straightly before it tumbles.
In this study, dissipative particle dynamics (DPD) is employed to simulate the rod-like self-propelled nano-swimmers in bounded/unbounded system. For the unbounded system, it is found that the longer nano-rods have the lower rotational diffusivity (Dθ), and the lower translational diffusivity (D). It means, the longer nano-rods need more time to change the direction of the movement, and the rate of the diffusion is lower. Additionally, the nano-rods become the self-propelled nano-swimmers from the active force (FA). The rotational diffusivity of the nano-swimmers is the same as the nano-rods. Both the square of the amount of active force and the time of the nano-swimmers changing the direction of the movement are directly proportional to the diffusivity of the nano-swimmers. For the sedimentation equilibrium, it is found that the sedimentation length of the nano-swimmers is higher than the nano-rod. In addition, the nano-swimmers exhibit polar order under gravity. It means, the nano-swimmers proceed toward reverse direction of gravity. |
參考文獻 |
[1] M. Doi; S. F. Edwards, The Theory of Polymer Dynamics.
[2] H. C. Berg, E. coli in Motion. Springer: New York, 2003; p 134.
[3] H. C. Berg; D. A. Brown, Chemotaxis in Escherichia coli analyzed by three-dimensional tracking. Annual Review of Plant Physiology and Plant Molecular Biology 1974, 19, 55-78.
[4] J. Gray, The movement of sea-urchin spermatozoa. Journal of Experimental Biology 1955, 32, 775-801.
[5] E. H. Harris, Chlamydomonas as a model organism. Annual review of plant biology 2001, 52 (1), 363-406.
[6] Alexander A. Solovev; Samuel Sanchez; Oliver G. Schmidt, Collective behaviour of self-propelled catalytic micromotors. Nanoscale 2013, 5 (4), 1284-1293.
[7] Timothy R. Kline; Walter F. Paxton; Thomas E. Mallouk; Ayusman Sen, Catalytic Nanomotors: Remote-Controlled Autonomous Movement of Striped Metallic Nanorods. Angew. Chem. Int. Ed. 2005, 44, 744 –746.
[8] J. Tailleur; M. E. Cates, Statistical mechanics of interacting run-and-tumble bacteria. Physical Review Letters 2008, 100 (21).
[9] Jonathan Saragosti; Pascal Silberzan; Axel Buguin, Modeling E. coli Tumbles by Rotational Diffusion. Implications for Chemotaxis. Plos One 2012, 7 (4).
[10] M. E. Cates, Diffusive transport without detailed balance in motile bacteria: does microbiology need statistical physics? , Rep. Prog. Phys. 2012, 75 (4).
[11] Aparna Baskaran; M. Cristina Marchettia, Statistical mechanics and hydrodynamics of bacterial suspensions. Proceedings of the National Academy of Sciences of the United States of America 2009, 106 (37), 15567-15572.
[12] Yashodhan Hatwalne; Sriram Ramaswamy; Madan Rao; R. Aditi Simha, Rheology of active-particle suspensions. Physical Review Letters 2004, 92 (11), 118101
[13] Salima Rafai; Levan Jibuti; Philippe Peyla, Effective Viscosity of Microswimmer Suspensions. Physical Review Letters 2010, 104 (9), 098102.
[14] Patrick T. Underhill; Juan P. Hernandez-Ortiz; Michael D. Graham, Diffusion and spatial correlations in suspensions of swimming particles. Physical Review Letters 2008, 100 (24), 248101.
[15] Jonathan R. Howse; Richard A. L. Jones; Anthony J. Ryan; Tim Gough; Reza Vafabakhsh; Ramin Golestanian, Self-motile colloidal particles: From directed propulsion to random walk. Physical Review Letters 2007, 99 (4), 048102.
[16] Jeremie Palacci; Cecile Cottin-Bizonne; Christophe Ybert; Lyderic Bocquet, Sedimentation and effective temperature of active colloidal suspensions. Physical Review Letters 2010, 105 (8), 088304.
[17] I. Theurkauff; C. Cottin-Bizonne; J. Palacci; C. Ybert; L. Bocquet, Dynamic Clustering in Active Colloidal Suspensions with Chemical Signaling. Physical Review Letters 2012, 108 (26), 268303.
[18] Mihaela Enculescu; Holger Stark, Active Colloidal Suspensions Exhibit Polar Order under Gravity. Physical Review Letters 2011, 107 (5), 058301.
[19] Min Jun Kim; Kenneth S. Breuer, Enhanced diffusion due to motile bacteria. Physics of Fluids 2004, 16 (9), L78-L81.
[20] Peter Galajda; Juan Keymer; Paul Chaikin; Robert Austin, A wall of funnels concentrates swimming bacteria. J. Bacteriol. 2007, 189 (23), 8704-8707.
[21] J. Tailleur; M. E. Cates, Sedimentation, trapping, and rectification of dilute bacteria. Epl 2009, 86 (6), 60002.
[22] M. B. Wan; C. J. Olson Reichhardt; Z. Nussinov; C. Reichhardt1, Rectification of swimming bacteria and self-driven particle systems by arrays of asymmetric barriers. Physical Review Letters 2008, 101 (1), 018102.
[23] Mew-Bing Wan; YongSeok Jho, Directed motion of elongated active polymers. Soft Matter 2013, 9 (12), 3255-3261.
[24] R. Di Leonardo; L. Angelani; D. Dell’Arciprete; G. Ruocco; V. Iebba; S. Schippa; M. P. Conte; F. Mecarini; F. De Angelis; E. Di Fabrizio, Bacterial ratchet motors. Proceedings of the National Academy of Sciences of the United States of America 2010, 107 (21), 9541-9545.
[25] Allison P. Berke; Linda Turner; Howard C. Berg; Eric Lauga, Hydrodynamic attraction of swimming microorganisms by surfaces. Physical Review Letters 2008, 101 (3), 038102.
[26] Jane Hill; Ozge Kalkanci; Jonathan L. McMurry; Hur Koser, Hydrodynamic surface interactions enable Escherichia coli to seek efficient routes to swim upstream. Physical Review Letters 2007, 98 (6), 068101.
[27] R.W. Nash; R. Adhikari; J. Tailleur; M. E. Cates, Run-and-Tumble Particles with Hydrodynamics: Sedimentation, Trapping, and Upstream Swimming. Physical Review Letters 2010, 104 (25), 258101.
[28] J. Schwarz-Linek; C. Valeriani; A. Cacciuto y; M. E. Cates; D. Marenduzzo; A. N. Morozov; W. C. K. Poon, Phase separation and rotor self-assembly in active particle suspensions. Proceedings of the National Academy of Sciences of the United States of America 2012, 109 (11), 4052-4057.
[29] Julian Bialke; Thomas Speck; Hartmut Lowen, Crystallization in a Dense Suspension of Self-Propelled Particles. Physical Review Letters 2012, 108 (16), 168301.
[30] Idan Tuval; Luis Cisneros; Christopher Dombrowski; Charles W. Wolgemuth; John O. Kessler; Raymond E. Goldstein, Bacterial swimming and oxygen transport near contact lines. Proceedings of the National Academy of Sciences of the United States of America 2005, 102 (7), 2277-2282.
[31] P. J. Hoogerbrugge; J. Koelman, Simulating microscopic hydrodynamic phenomena with dissipative particle dynamics. Europhysics Letters 1992, 19 (3), 155-160.
[32] R. D. Groot; P. B. Warren, Dissipative particle dynamics: Bridging the gap between atomistic and mesoscopic simulation. J. Chem. Phys. 1997, 107 (11), 4423-4435.
[33] P. Espanol; P. Warren, Statistical-mechanics of dissipative particle dynamics. Europhysics Letters 1995, 30 (4), 191-196.
[34] Jonathan B. Gibson; Ke Chen; Simon Chynoweth, Simulation of particle adsorption onto a polymer-coated surface using the dissipative particle dynamics method. J. Colloid Interface Sci. 1998, 206 (2), 464-474.
[35] M. P. Allen; D. J. Tildesley, Computer simulation of liquids. Oxford university press: New York, 1989; p 385.
[36] Robert D. Groot; Timothy J. Madden, Dynamic simulation of diblock copolymer microphase separation. J. Chem. Phys. 1998, 108 (20), 8713-8724.
[37] D. C. Rapaport, The art of molecular dynamics simulation. Cambridge University Press: Cambridge, 2004; p 564.
[38] D. Frenkel; B. Smit, Understanding molecular simulation: from algorithms to applications. Academic press: San Diego, 2001; p 443
[39] J. Perrin., Mouvement brownien et realite moleculaire. Ann. Chim. Phys. 1909, 18, 5-104.
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