1
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Bose S, Wang H, Xu X, Gopinath A, Dasbiswas K. Elastic interactions compete with persistent cell motility to drive durotaxis. Biophys J 2024:S0006-3495(24)00633-7. [PMID: 39327734 DOI: 10.1016/j.bpj.2024.09.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2024] [Revised: 08/14/2024] [Accepted: 09/23/2024] [Indexed: 09/28/2024] Open
Abstract
Many animal cells that crawl on extracellular substrates exhibit durotaxis, i.e., directed migration toward stiffer substrate regions. This has implications in several biological processes including tissue development and tumor progression. Here, we introduce a phenomenological model for single-cell durotaxis that incorporates both elastic deformation-mediated cell-substrate interactions and the stochasticity of cell migration. Our model is motivated by a key observation in an early demonstration of durotaxis: a single, contractile cell at a sharp interface between a softer and a stiffer region of an elastic substrate reorients and migrates toward the stiffer region. We model migrating cells as self-propelling, persistently motile agents that exert contractile traction forces on their elastic substrate. The resulting substrate deformations induce elastic interactions with mechanical boundaries, captured by an elastic potential. The dynamics is determined by two crucial parameters: the strength of the cellular traction-induced boundary elastic interaction (A), and the persistence of cell motility (Pe). Elastic forces and torques resulting from the potential orient cells perpendicular (parallel) to the boundary and accumulate (deplete) them at the clamped (free) boundary. Thus, a clamped boundary induces an attractive potential that drives durotaxis, while a free boundary induces a repulsive potential that prevents antidurotaxis. By quantifying the steady-state position and orientation probability densities, we show how the extent of accumulation (depletion) depends on the strength of the elastic potential and motility. We compare and contrast crawling cells with biological microswimmers and other synthetic active particles, where accumulation at confining boundaries is well known. We define metrics quantifying boundary accumulation and durotaxis, and present a phase diagram that identifies three possible regimes: durotaxis, and adurotaxis with and without motility-induced accumulation at the boundary. Overall, our model predicts how durotaxis depends on cell contractility and motility, successfully explains some previous observations, and provides testable predictions to guide future experiments.
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Affiliation(s)
- Subhaya Bose
- Department of Physics, University of California, Merced, Merced, California
| | - Haiqin Wang
- Technion - Israel Institute of Technology, Haifa, Israel; Department of Physics and MATEC Key Lab, Guangdong Technion - Israel Institute of Technology, Shantou, Guangdong, China
| | - Xinpeng Xu
- Technion - Israel Institute of Technology, Haifa, Israel; Department of Physics and MATEC Key Lab, Guangdong Technion - Israel Institute of Technology, Shantou, Guangdong, China.
| | - Arvind Gopinath
- Department of Bioengineering, University of California, Merced, Merced, California.
| | - Kinjal Dasbiswas
- Department of Physics, University of California, Merced, Merced, California.
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2
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Pu R, Yang X, Mu H, Xu Z, He J. Current status and future application of electrically controlled micro/nanorobots in biomedicine. Front Bioeng Biotechnol 2024; 12:1353660. [PMID: 38314349 PMCID: PMC10834684 DOI: 10.3389/fbioe.2024.1353660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 01/09/2024] [Indexed: 02/06/2024] Open
Abstract
Using micro/nanorobots (MNRs) for targeted therapy within the human body is an emerging research direction in biomedical science. These nanoscale to microscale miniature robots possess specificity and precision that are lacking in most traditional treatment modalities. Currently, research on electrically controlled micro/nanorobots is still in its early stages, with researchers primarily focusing on the fabrication and manipulation of these robots to meet complex clinical demands. This review aims to compare the fabrication, powering, and locomotion of various electrically controlled micro/nanorobots, and explore their advantages, disadvantages, and potential applications.
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Affiliation(s)
- Ruochen Pu
- Jintan Hospital Affiliated to Jiangsu University, Changzhou, Jiangsu Province, China
- Shanghai Bone Tumor Institution, Shanghai, China
| | - Xiyu Yang
- Shanghai Bone Tumor Institution, Shanghai, China
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Haoran Mu
- Shanghai Bone Tumor Institution, Shanghai, China
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhonghua Xu
- Jintan Hospital Affiliated to Jiangsu University, Changzhou, Jiangsu Province, China
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jin He
- Jintan Hospital Affiliated to Jiangsu University, Changzhou, Jiangsu Province, China
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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3
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Zhang B, Glatz A, Aranson IS, Snezhko A. Spontaneous shock waves in pulse-stimulated flocks of Quincke rollers. Nat Commun 2023; 14:7050. [PMID: 37923744 PMCID: PMC10624688 DOI: 10.1038/s41467-023-42633-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 10/16/2023] [Indexed: 11/06/2023] Open
Abstract
Active matter demonstrates complex spatiotemporal self-organization not accessible at equilibrium and the emergence of collective behavior. Fluids comprised of microscopic Quincke rollers represent a popular realization of synthetic active matter. Temporal activity modulations, realized by modulated external electric fields, represent an effective tool to expand the variety of accessible dynamic states in active ensembles. Here, we report on the emergence of shockwave patterns composed of coherently moving particles energized by a pulsed electric field. The shockwaves emerge spontaneously and move faster than the average particle speed. Combining experiments, theory, and simulations, we demonstrate that the shockwaves originate from intermittent spontaneous vortex cores due to a vortex meandering instability. They occur when the rollers' translational and rotational decoherence times, regulated by the electric pulse durations, become comparable. The phenomenon does not rely on the presence of confinement, and multiple shock waves continuously arise and vanish in the system.
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Affiliation(s)
- Bo Zhang
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA.
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, and Department of Physics, Nanjing University, Nanjing, 210093, China.
| | - Andreas Glatz
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
- Department of Physics, Northern Illinois University, DeKalb, IL, 60115, USA
| | - Igor S Aranson
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, 16802, USA
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
- Department of Mathematics, Pennsylvania State University, University Park, PA, 16802, USA
| | - Alexey Snezhko
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA.
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4
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Kumar P, Tamayo J, Shiu RF, Chin WC, Gopinath A. Size-Dependent Diffusion and Dispersion of Particles in Mucin. Polymers (Basel) 2023; 15:3241. [PMID: 37571134 PMCID: PMC10422640 DOI: 10.3390/polym15153241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/17/2023] [Accepted: 07/17/2023] [Indexed: 08/13/2023] Open
Abstract
Mucus, composed significantly of glycosylated mucins, is a soft and rheologically complex material that lines respiratory, reproductive, and gastrointestinal tracts in mammals. Mucus may present as a gel, as a highly viscous fluid, or as a viscoelastic fluid. Mucus acts as a barrier to the transport of harmful microbes and inhaled atmospheric pollutants to underlying cellular tissue. Studies on mucin gels have provided critical insights into the chemistry of the gels, their swelling kinetics, and the diffusion and permeability of molecular constituents such as water. The transport and dispersion of micron and sub-micron particles in mucin gels and solutions, however, differs from the motion of small molecules since the much larger tracers may interact with microstructure of the mucin network. Here, using brightfield and fluorescence microscopy, high-speed particle tracking, and passive microrheology, we study the thermally driven stochastic movement of 0.5-5.0 μm tracer particles in 10% mucin solutions at neutral pH, and in 10% mucin mixed with industrially relevant dust; specifically, unmodified limestone rock dust, modified limestone, and crystalline silica. Particle trajectories are used to calculate mean square displacements and the displacement probability distributions; these are then used to assess tracer diffusion and transport. Complex moduli are concomitantly extracted using established microrheology techniques. We find that under the conditions analyzed, the reconstituted mucin behaves as a weak viscoelastic fluid rather than as a viscoelastic gel. For small- to moderately sized tracers with a diameter of lessthan 2 μm, we find that effective diffusion coefficients follow the classical Stokes-Einstein relationship. Tracer diffusivity in dust-laden mucin is surprisingly larger than in bare mucin. Probability distributions of mean squared displacements suggest that heterogeneity, transient trapping, and electrostatic interactions impact dispersion and overall transport, especially for larger tracers. Our results motivate further exploration of physiochemical and rheological mechanisms mediating particle transport in mucin solutions and gels.
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Affiliation(s)
- Parveen Kumar
- Department of Bioengineering, University of California Merced, Merced, CA 95343, USA; (P.K.); (J.T.)
| | - Joshua Tamayo
- Department of Bioengineering, University of California Merced, Merced, CA 95343, USA; (P.K.); (J.T.)
| | - Ruei-Feng Shiu
- Institute of Marine Environment and Ecology, National Taiwan Ocean University, Keelung 202301, Taiwan
| | - Wei-Chun Chin
- Department of Bioengineering, University of California Merced, Merced, CA 95343, USA; (P.K.); (J.T.)
| | - Arvind Gopinath
- Department of Bioengineering, University of California Merced, Merced, CA 95343, USA; (P.K.); (J.T.)
- Health Sciences Research Institute, University of California Merced, Merced, CA 95343, USA
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5
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Nazari F, Shoele K, Mohammadigoushki H. Helical Locomotion in Yield Stress Fluids. PHYSICAL REVIEW LETTERS 2023; 130:114002. [PMID: 37001094 DOI: 10.1103/physrevlett.130.114002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 01/27/2023] [Indexed: 06/19/2023]
Abstract
We report three stages for locomotion of a helical swimmer in yield stress fluids. In the first stage, the swimmer must overcome the material's yield strain to generate rotational motion. However, exceeding the first threshold is not sufficient for locomotion. Only when the viscous forces are sufficiently strong to plastically deform the material to a finite distance away from the swimmer will net locomotion occur. Once locomotion is underway in the third stage, the yield stress retards swimming at small pitch angles. Conversely, at large pitch angles, yield stress dominates the flow by enhancing swimming speed. Flow visualizations reveal a highly localized flow near the swimmer in yield stress fluids.
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Affiliation(s)
- Farshad Nazari
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, Florida 32310, USA
| | - Kourosh Shoele
- Department of Mechanical Engineering, FAMU-FSU College of Engineering, Tallahassee, Florida 32310, USA
| | - Hadi Mohammadigoushki
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, Florida 32310, USA
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6
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Saud KT, Solomon MJ. Microdynamics of active particles in defect-rich colloidal crystals. J Colloid Interface Sci 2023; 641:950-960. [PMID: 36989821 DOI: 10.1016/j.jcis.2023.03.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 02/04/2023] [Accepted: 03/02/2023] [Indexed: 03/11/2023]
Abstract
HYPOTHESIS Because they are self-propulsive, active colloidal particles can interact with their environment in ways that differ from passive, Brownian particles. Here, we explore how interactions in different microstructural regions may contribute to colloidal crystal annealing. EXPERIMENTS We investigate active particles propagating in a quasi-2D colloidal crystal monolayer produced by alternating current electric fields (active-to-passive particle ratio ∼ 1:720). The active particle is a platinum Janus sphere propelled by asymmetric decomposition of hydrogen peroxide. Crystals are characterized for changes in void properties. The mean-squared-displacement of Janus particles are measured to determine how active microdynamics depend on the local microstructure, which is comprised of void regions, void-adjacent regions (defined as within three particle diameters of a void), and interstitial regions. FINDINGS At active particle energy EA = 2.55 kBT, the average void size increases as much as three times and the average void anisotropy increases about 40% relative to the passive case. The average microdynamical enhancement, <δ(t)>, of Janus particles in the crystal relative to an equivalent passive Janus particle is reduced compared to that of a free, active particle (<δ(t) > is 1.88 ± 0.04 and 2.66 ± 0.08, respectively). The concentration of active particles is enriched in void and void-adjacent regions. Active particles exhibit the greatest change in dynamics relative to the passive control in void-adjacent regions (<δ(t)> = 2.58 ± 0.06). The results support the conjecture that active particle microdynamical enhancement in crystal lattices is affected by local defect structure.
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Affiliation(s)
- Keara T Saud
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, United States; Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States
| | - Michael J Solomon
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States; Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, United States.
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7
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Chen Y, Wang L, Zhang TH. Tunable collective dynamics of ellipsoidal Quincke particles. SOFT MATTER 2023; 19:512-518. [PMID: 36541151 DOI: 10.1039/d2sm01238c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Collective behaviors in active systems become dramatically complicated in the presence of chirality. In this study, we show that ellipsoidal Quincke particles driven by an electric field exhibit flexible and tunable chirality because of the tilting of the spinning axis. As the tilting torque decreases with the increase of angular speed, the motion of individual particles transforms from localized circle motion to global rolling. However, because of the anisotropic shape and the resulting anisotropic polar interactions, it is dynamically easier for ellipsoids to bind and form rotating structures rather than to align their velocities. In dense systems, the suppression of velocity aligning produces transient dense clusters which produce dynamic heterogeneity. The formation and dissociation of dense clusters prohibit the emergence of large-scale collective motions and limit the amplitude of density fluctuations. These findings demonstrate that collective dynamics and thus the scale of density fluctuations in active systems with tunable chirality can be well controlled. This has potential applications in exploring disordered hyperuniform states.
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Affiliation(s)
- Yu Chen
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou, 215006, P. R. China.
- School of Physical Science and Technology, Soochow University, Suzhou, 215006, P. R. China
| | - Lei Wang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou, 215006, P. R. China.
- School of Physical Science and Technology, Soochow University, Suzhou, 215006, P. R. China
| | - Tian Hui Zhang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou, 215006, P. R. China.
- School of Physical Science and Technology, Soochow University, Suzhou, 215006, P. R. China
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8
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Kumar P, Chakrabarti R. Dynamics of self-propelled tracer particles inside a polymer network. Phys Chem Chem Phys 2023; 25:1937-1946. [PMID: 36541408 DOI: 10.1039/d2cp04253c] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The transport of tracer particles through mesh-like environments such as biological hydrogels and polymer matrices is ubiquitous in nature. These tracers can be passive, such as colloids, or active (self-propelled), for example, synthetic nanomotors or bacteria. Computer simulations in principle could be extremely useful in exploring the mechanism of the active transport of tracer particles through mesh-like environments. Therefore, we construct a polymer network on a diamond lattice and use computer simulations to investigate the dynamics of spherical self-propelled particles inside the network. Our main objective is to elucidate the effect of the self-propulsion on the tracer particle dynamics as a function of the tracer size and the stiffness of the polymer network. We compute the time-averaged mean-squared displacement (MSD) and the van-Hove correlations of the tracer. On the one hand, in the case of a bigger sticky particle, the caging caused by the network particles wins over the escape assisted by the self-propulsion. This results an intermediate-time subdiffusion. On the other hand, smaller tracers or tracers with high self-propulsion velocities can easily escape from the cages and show intermediate-time superdiffusion. The stiffer the network, the slower the dynamics of the tracer, and bigger tracers exhibit longer lived intermediate time superdiffusion, since the persistence time scales as ∼σ3, where σ is the diameter of the tracer. At the intermediate time, non-Gaussianity is more pronounced for active tracers. At the long time, the dynamics of the tracer, if passive or weakly active, becomes Gaussian and diffusive, but remains flat for tracers with high self-propulsion, accounting for their seemingly unrestricted motion inside the network.
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Affiliation(s)
- Praveen Kumar
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India.
| | - Rajarshi Chakrabarti
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India.
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9
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Ignés-Mullol J, Sagués F. Experiments with active and driven synthetic colloids in complex fluids. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2022.101636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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10
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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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11
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Self-assembly in binary mixtures of spherical colloids. Adv Colloid Interface Sci 2022; 308:102748. [DOI: 10.1016/j.cis.2022.102748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/16/2022] [Accepted: 07/29/2022] [Indexed: 11/18/2022]
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12
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Kamdar S, Shin S, Leishangthem P, Francis LF, Xu X, Cheng X. The colloidal nature of complex fluids enhances bacterial motility. Nature 2022; 603:819-823. [PMID: 35355005 DOI: 10.1038/s41586-022-04509-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 02/03/2022] [Indexed: 12/24/2022]
Abstract
The natural habitats of microorganisms in the human microbiome, ocean and soil ecosystems are full of colloids and macromolecules. Such environments exhibit non-Newtonian flow properties, drastically affecting the locomotion of microorganisms1-5. Although the low-Reynolds-number hydrodynamics of swimming flagellated bacteria in simple Newtonian fluids has been well developed6-9, our understanding of bacterial motility in complex non-Newtonian fluids is less mature10,11. Even after six decades of research, fundamental questions about the nature and origin of bacterial motility enhancement in polymer solutions are still under debate12-23. Here we show that flagellated bacteria in dilute colloidal suspensions display quantitatively similar motile behaviours to those in dilute polymer solutions, in particular a universal particle-size-dependent motility enhancement up to 80% accompanied by a strong suppression of bacterial wobbling18,24. By virtue of the hard-sphere nature of colloids, whose size and volume fraction we vary across experiments, our results shed light on the long-standing controversy over bacterial motility enhancement in complex fluids and suggest that polymer dynamics may not be essential for capturing the phenomenon12-23. A physical model that incorporates the colloidal nature of complex fluids quantitatively explains bacterial wobbling dynamics and mobility enhancement in both colloidal and polymeric fluids. Our findings contribute to the understanding of motile behaviours of bacteria in complex fluids, which are relevant for a wide range of microbiological processes25 and for engineering bacterial swimming in complex environments26,27.
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Affiliation(s)
- Shashank Kamdar
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - Seunghwan Shin
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | | | - Lorraine F Francis
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - Xinliang Xu
- Complex Systems Division, Beijing Computational Science Research Center, Beijing, China. .,Department of Physics, Beijing Normal University, Beijing, China.
| | - Xiang Cheng
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA.
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13
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Choudhary A, Stark H. On the cross-streamline lift of microswimmers in viscoelastic flows. SOFT MATTER 2021; 18:48-52. [PMID: 34878484 DOI: 10.1039/d1sm01339d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The current work studies the dynamics of a microswimmer in pressure-driven flow of a weakly viscoelastic fluid. Employing a second-order fluid model, we show that a self-propelling swimmer experiences a viscoelastic swimming lift in addition to the well-known passive lift that arises from its resistance to shear flow. Using the reciprocal theorem, we evaluate analytical expressions for the swimming lift experienced by neutral and pusher/puller-type swimmers and show that they depend on the hydrodynamic signature associated with the swimming mechanism. We find that, in comparison to passive particles, the focusing of neutral swimmers towards the centerline can be significantly accelerated, while for force-dipole swimmers no net modification in cross-streamline migration occurs.
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Affiliation(s)
- Akash Choudhary
- Institute of Theoretical Physics, Technische Universität Berlin, 10623 Berlin, Germany.
| | - Holger Stark
- Institute of Theoretical Physics, Technische Universität Berlin, 10623 Berlin, Germany.
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14
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Dhatt-Gauthier K, Livitz D, Bishop KJM. Automating Bayesian inference and design to quantify acoustic particle levitation. SOFT MATTER 2021; 17:10128-10139. [PMID: 34729575 DOI: 10.1039/d1sm01116b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Self-propulsion of micro- and nanoparticles powered by ultrasound provides an attractive strategy for the remote manipulation of colloidal matter using biocompatible energy inputs. Quantitative understanding of particle motion and its dependence on size, shape, and composition requires accurate characterization of the acoustic field, which depends sensitively on the experimental setup. Here, we show how automated experiments based on Bayesian inference and design can accurately and efficiently characterize the acoustic field within resonant chambers used to propel acoustic nanomotors. Repeated cycles of observation, inference, and design (OID) are guided by a physical model that describes the rate at which levitating particles approach the nodal plane. Using video microscopy, we observe the relaxation of tracer particles to this plane following the application of the acoustic field. We use sequential Monte Carlo methods to infer model parameters such as the amplitude and frequency of the resonant chamber while accounting for particle-level measurement noise and population-level heterogeneity in the field. Guided by simulated outcomes, we select the optimal design for the next experiment as to maximize the information gain in the relevant parameters. We show how this iterative process serves to discriminate between competing hypotheses and efficiently converges to accurate parameter estimates using only few automated experiments. We discuss the need for model criticism to ensure the validity of the guiding model throughout automated cycles of observation, inference, and design. This work demonstrates how Bayesian methods can learn the parameters of nonlinear, hierarchical models used to describe video microscopy data of active colloids.
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Affiliation(s)
| | - Dimitri Livitz
- Department of Chemical Engineering, Columbia University, New York, NY, USA.
| | - Kyle J M Bishop
- Department of Chemical Engineering, Columbia University, New York, NY, USA.
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15
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Piras CC, Smith DK. Self-Propelling Hybrid Gels Incorporating an Active Self-Assembled, Low-Molecular-Weight Gelator. Chemistry 2021; 27:14527-14534. [PMID: 34339068 PMCID: PMC8597049 DOI: 10.1002/chem.202102472] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Indexed: 01/25/2023]
Abstract
Hybrid gel beads based on combining a low-molecular-weight gelator (LMWG) with a polymer gelator (PG) demonstrate an enhanced ability to self-propel in water, with the LMWG playing an active role. Hybrid gel beads were loaded with ethanol and shown to move in water owing to the Marangoni effect changes in surface tension caused by the expulsion of ethanol - smaller beads move farther and faster than larger beads. Flat shapes of the hybrid gel were cut using a "stamp" - circles moved the furthest, whereas stars showed more rotation on their own axes. Comparing hybrid LMWG/PG gel beads with PG-only beads demonstrated that the LMWG speeds up the beads, enhancing the rate of self-propulsion. Self-assembly of the LMWG into a "solid-like" network prevents its leaching from the gel. The LMWG also retains its own unique function - specifically, remediating methylene blue pollutant dye from basic water as a result of noncovalent interactions. The mobile hybrid beads accumulate this dye more effectively than PG-only beads. Self-propelling gel beads have potential applications in removal/delivery of active agents in environmental or biological settings. The ability of self-assembling LMWGs to enhance mobility and control removal/delivery suggests that adding them to self-propelling systems can add significant value.
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Affiliation(s)
- Carmen C. Piras
- Department of ChemistryUniversity of YorkHeslingtonYorkYO10 5DDUK
| | - David K. Smith
- Department of ChemistryUniversity of YorkHeslingtonYorkYO10 5DDUK
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16
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Singh J, Patteson AE, Torres Maldonado BO, Purohit PK, Arratia PE. Bacterial activity hinders particle sedimentation. SOFT MATTER 2021; 17:4151-4160. [PMID: 33881035 DOI: 10.1039/d0sm02115f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Sedimentation in active fluids has come into focus due to the ubiquity of swimming micro-organisms in natural and industrial processes. Here, we investigate sedimentation dynamics of passive particles in a fluid as a function of bacteria E. coli concentration. Results show that the presence of swimming bacteria significantly reduces the speed of the sedimentation front even in the dilute regime, in which the sedimentation speed is expected to be independent of particle concentration. Furthermore, bacteria increase the dispersion of the passive particles, which determines the width of the sedimentation front. For short times, particle sedimentation speed has a linear dependence on bacterial concentration. Mean square displacement data shows, however, that bacterial activity decays over long experimental (sedimentation) times. An advection-diffusion equation coupled to bacteria population dynamics seems to capture concentration profiles relatively well. A single parameter, the ratio of single particle speed to the bacteria flow speed can be used to predict front sedimentation speed.
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Affiliation(s)
- Jaspreet Singh
- Department of Mechanical Engineering & Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | | | - Bryan O Torres Maldonado
- Department of Mechanical Engineering & Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Prashant K Purohit
- Department of Mechanical Engineering & Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Paulo E Arratia
- Department of Mechanical Engineering & Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA.
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17
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Lee JG, Al Harraq A, Bishop KJM, Bharti B. Fabrication and Electric Field-Driven Active Propulsion of Patchy Microellipsoids. J Phys Chem B 2021; 125:4232-4240. [PMID: 33876931 PMCID: PMC8279480 DOI: 10.1021/acs.jpcb.1c01644] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Active colloids are a synthetic analogue
of biological microorganisms
that consume external energy to swim through viscous fluids. Such
motion requires breaking the symmetry of the fluid flow in the vicinity
of a particle; however, it is challenging to understand how surface
and shape anisotropies of the colloid lead to a particular trajectory.
Here, we attempt to deconvolute the effects of particle shape and
surface anisotropy on the propulsion of model ellipsoids in alternating
current (AC) electric fields. We first introduce a simple process
for depositing metal patches of various shapes on the surfaces of
ellipsoidal particles. We show that the shape of the metal patch is
governed by the assembled structure of the ellipsoids on the substrate
used for physical vapor deposition. Under high-frequency AC electric
field, ellipsoids dispersed in water show linear, circular, and helical
trajectories which depend on the shapes of the surface patches. We
demonstrate that features of the helical trajectories such as the
pitch and diameter can be tuned by varying the degree of patch asymmetry
along the two primary axes of the ellipsoids, namely longitudinal
and transverse. Our study reveals the role of patch shape on the trajectory
of ellipsoidal particles propelled by induced charge electrophoresis.
We develop heuristics based on patch asymmetries that can be used
to design patchy particles with specified nonlinear trajectories.
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Affiliation(s)
- Jin Gyun Lee
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Ahmed Al Harraq
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Kyle J M Bishop
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Bhuvnesh Bharti
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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18
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Fatehiboroujeni S, Gopinath A, Goyal S. Three-dimensional nonlinear dynamics of prestressed active filaments: Flapping, swirling, and flipping. Phys Rev E 2021; 103:013005. [PMID: 33601644 DOI: 10.1103/physreve.103.013005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 12/24/2020] [Indexed: 11/07/2022]
Abstract
Initially straight slender elastic filaments or rods with constrained ends buckle and form stable two-dimensional shapes when prestressed by bringing the ends together. Beyond a critical value of this prestress, rods can also deform off plane and form twisted three-dimensional equilibrium shapes. Here, we analyze the three-dimensional instabilities and dynamics of such deformed filaments subject to nonconservative active follower forces and fluid drag. We find that softly constrained filaments that are clamped at one end and pinned at the other exhibit stable two-dimensional planar flapping oscillations when active forces are directed toward the clamped end. Reversing the directionality of the forces quenches the instability. For strongly constrained filaments with both ends clamped, computations reveal an instability arising from the twist-bend-activity coupling. Planar oscillations are destabilized by off-planar perturbations resulting in twisted three-dimensional swirling patterns interspersed with periodic flipping or reversal of the swirling direction. These striking swirl-flip transitions are characterized by two distinct timescales: the time period for a swirl (rotation) and the time between flipping events. We interpret these reversals as relaxation oscillation events driven by accumulation of torsional energy. Each cycle is initiated by a fast jump in torsional deformation with a subsequent slow decrease in net torsion until the next cycle. Our work reveals the rich tapestry of spatiotemporal patterns when weakly inertial strongly damped rods are deformed by nonconservative active forces. Taken together, our results suggest avenues by which prestress, elasticity, and activity may be used to design synthetic macroscale pumps or mixers.
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Affiliation(s)
- Soheil Fatehiboroujeni
- Department of Mechanical Engineering, University of California, Merced, California 95343, USA
| | - Arvind Gopinath
- Department of Bioengineering, University of California, Merced, California 95343, USA
| | - Sachin Goyal
- Department of Mechanical Engineering, University of California, Merced, California 95343, USA and Health Sciences Research Institute, University of California, Merced, California 95343, USA
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19
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Yang S, Huang M, Zhao Y, Zhang HP. Controlling Cell Motion and Microscale Flow with Polarized Light Fields. PHYSICAL REVIEW LETTERS 2021; 126:058001. [PMID: 33605769 DOI: 10.1103/physrevlett.126.058001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/26/2020] [Accepted: 12/21/2020] [Indexed: 06/12/2023]
Abstract
We investigate how light polarization affects the motion of photoresponsive algae, Euglena gracilis. In a uniformly polarized field, cells swim approximately perpendicular to the polarization direction and form a nematic state with zero mean velocity. When light polarization varies spatially, cell motion is modulated by local polarization. In such light fields, cells exhibit complex spatial distribution and motion patterns which are controlled by topological properties of the underlying fields; we further show that ordered cell swimming can generate directed transporting fluid flow. Experimental results are quantitatively reproduced by an active Brownian particle model in which particle motion direction is nematically coupled to local light polarization.
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Affiliation(s)
- Siyuan Yang
- School of Physics and Astronomy and Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Mingji Huang
- School of Physics and Astronomy and Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yongfeng Zhao
- School of Physics and Astronomy and Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
| | - H P Zhang
- School of Physics and Astronomy and Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
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20
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Chelakkot R, Hagan MF, Gopinath A. Synchronized oscillations, traveling waves, and jammed clusters induced by steric interactions in active filament arrays. SOFT MATTER 2021; 17:1091-1104. [PMID: 33289748 DOI: 10.1039/d0sm01162b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Autonomous active, elastic filaments that interact with each other to achieve cooperation and synchrony underlie many critical functions in biology. The mechanisms underlying this collective response and the essential ingredients for stable synchronization remain a mystery. Inspired by how these biological entities integrate elasticity with molecular motor activity to generate sustained oscillations, a number of synthetic active filament systems have been developed that mimic oscillations of these biological active filaments. Here, we describe the collective dynamics and stable spatiotemporal patterns that emerge in such biomimetic multi-filament arrays, under conditions where steric interactions may impact or dominate the collective dynamics. To focus on the role of steric interactions, we study the system using Brownian dynamics, without considering long-ranged hydrodynamic interactions. The simulations treat each filament as a connected chain of self-propelling colloids. We demonstrate that short-range steric inter-filament interactions and filament roughness are sufficient - even in the absence of inter-filament hydrodynamic interactions - to generate a rich variety of collective spatiotemporal oscillatory, traveling and static patterns. We first analyze the collective dynamics of two- and three-filament clusters and identify parameter ranges in which steric interactions lead to synchronized oscillations and strongly occluded states. Generalizing these results to large one-dimensional arrays, we find rich emergent behaviors, including traveling metachronal waves, and modulated wavetrains that are controlled by the interplay between the array geometry, filament activity, and filament elasticity. Interestingly, the existence of metachronal waves is non-monotonic with respect to the inter-filament spacing. We also find that the degree of filament roughness significantly affects the dynamics - specifically, filament roughness generates a locking-mechanism that transforms traveling wave patterns into statically stuck and jammed configurations. Taken together, simulations suggest that short-ranged steric inter-filament interactions could combine with complementary hydrodynamic interactions to control the development and regulation of oscillatory collective patterns. Furthermore, roughness and steric interactions may be critical to the development of jammed spatially periodic states; a spatiotemporal feature not observed in purely hydrodynamically interacting systems.
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Affiliation(s)
- Raghunath Chelakkot
- Department of Physics, Indian Institute of Technology Bombay, Mumbai, India.
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21
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Thamizhanban A, Balaji S, Lalitha K, Prasad YS, Prasad RV, Kumar RA, Maheswari CU, Sridharan V, Nagarajan S. Glycolipid-Based Oleogels and Organogels: Promising Nanostructured Structuring Agents. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:14896-14906. [PMID: 33284625 DOI: 10.1021/acs.jafc.0c02936] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Over the past few decades, the scientific community is actively involved in the development of edible structuring agents suitable for food, cosmetics, agricultural, pharmaceutical, and biotechnology applications. In particular, edible oil structuring using simple amphiphiles would be the best alternative for the currently used trans and saturated fatty acids, which cause deleterious health effects and cardiovascular problems. In this report, we have made an attempt to address the aforementioned consequences, by synthesizing a new class of structuring agents by a judicious combination of δ-gluconolactone and ricinoleic acid, compounds classified as GRAS, using simple steps in good yield. To our delight, the synthesized glycolipids self-assemble in a wide variety of vegetable oils and commercially viable glycerol, ethylene glycol, and polyethylene glycol via various intermolecular interactions to form a gel. The morphology of molecular gels was investigated by optical microscopy and FESEM analysis, which reveal the existence of a tubular architecture with a diameter ranging from 75 to 150 nm. Rheological studies disclosed the viscoelastic nature, thermal processability, and thixotropic behavior of both oleogels and organogels. Altogether, self-assembled oleogel and organogel reported in this paper would potentially be used in food, agricultural, cosmetics, pharmaceutical, and biotechnological applications.
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Affiliation(s)
- Ayyapillai Thamizhanban
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
| | - Srikanth Balaji
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
| | - Krishnamoorthy Lalitha
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
| | - Yadavali Siva Prasad
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
| | - R Vara Prasad
- Department of Chemistry, National Institute of Technology Warangal, Warangal 506004, Telangana, India
| | - R Arun Kumar
- Department of Chemistry, National Institute of Technology Warangal, Warangal 506004, Telangana, India
| | - C Uma Maheswari
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
| | - Vellaisamy Sridharan
- Department of Chemistry and Chemical Sciences, Central University of Jammu, Rahya-Suchani (Bagla), District-Samba, Jammu 181143, India
| | - Subbiah Nagarajan
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
- Department of Chemistry, National Institute of Technology Warangal, Warangal 506004, Telangana, India
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22
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Liao X, Purohit PK, Gopinath A. Extensions of the worm-like-chain model to tethered active filaments under tension. J Chem Phys 2020; 153:194901. [PMID: 33218239 DOI: 10.1063/5.0025200] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Intracellular elastic filaments such as microtubules are subject to thermal Brownian noise and active noise generated by molecular motors that convert chemical energy into mechanical work. Similarly, polymers in living fluids such as bacterial suspensions and swarms suffer bending deformations as they interact with single bacteria or with cell clusters. Often, these filaments perform mechanical functions and interact with their networked environment through cross-links or have other similar constraints placed on them. Here, we examine the mechanical properties-under tension-of such constrained active filaments under canonical boundary conditions motivated by experiments. Fluctuations in the filament shape are a consequence of two types of random forces-thermal Brownian forces and activity derived forces with specified time and space correlation functions. We derive force-extension relationships and expressions for the mean square deflections for tethered filaments under various boundary conditions including hinged and clamped constraints. The expressions for hinged-hinged boundary conditions are reminiscent of the worm-like-chain model and feature effective bending moduli and mode-dependent non-thermodynamic effective temperatures controlled by the imposed force and by the activity. Our results provide methods to estimate the activity by measurements of the force-extension relation of the filaments or their mean square deflections, which can be routinely performed using optical traps, tethered particle experiments, or other single molecule techniques.
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Affiliation(s)
- Xinyu Liao
- Graduate Group in Applied Mathematics and Computational Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Prashant K Purohit
- Graduate Group in Applied Mathematics and Computational Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Arvind Gopinath
- Department of Bioengineering, University of California Merced, Merced, California 95343, USA
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23
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Mallory SA, Bowers ML, Cacciuto A. Universal reshaping of arrested colloidal gels via active doping. J Chem Phys 2020; 153:084901. [PMID: 32872893 DOI: 10.1063/5.0016514] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Colloids that interact via a short-range attraction serve as the primary building blocks for a broad range of self-assembled materials. However, one of the well-known drawbacks to this strategy is that these building blocks rapidly and readily condense into a metastable colloidal gel. Using computer simulations, we illustrate how the addition of a small fraction of purely repulsive self-propelled colloids, a technique referred to as active doping, can prevent the formation of this metastable gel state and drive the system toward its thermodynamically favored crystalline target structure. The simplicity and robust nature of this strategy offers a systematic and generic pathway to improving the self-assembly of a large number of complex colloidal structures. We discuss in detail the process by which this feat is accomplished and provide quantitative metrics for exploiting it to modulate the self-assembly. We provide evidence for the generic nature of this approach by demonstrating that it remains robust under a number of different anisotropic short-ranged pair interactions in both two and three dimensions. In addition, we report on a novel microphase in mixtures of passive and active colloids. For a broad range of self-propelling velocities, it is possible to stabilize a suspension of fairly monodisperse finite-size crystallites. Surprisingly, this microphase is also insensitive to the underlying pair interaction between building blocks. The active stabilization of these moderately sized monodisperse clusters is quite remarkable and should be of great utility in the design of hierarchical self-assembly strategies. This work further bolsters the notion that active forces can play a pivotal role in directing colloidal self-assembly.
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Affiliation(s)
- S A Mallory
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - M L Bowers
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - A Cacciuto
- Department of Chemistry, Columbia University, New York, New York 10027, USA
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24
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Han K, Shields CW, Bharti B, Arratia PE, Velev OD. Active Reversible Swimming of Magnetically Assembled "Microscallops" in Non-Newtonian Fluids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:7148-7154. [PMID: 32011137 DOI: 10.1021/acs.langmuir.9b03698] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Miniaturized devices capable of active swimming at low Reynolds numbers are of fundamental importance and possess potential biomedical utility. The design of colloidal microswimmers requires not only miniaturizing reconfigurable structures but also understanding their interactions with media at low Reynolds numbers. We investigate the dynamics of "microscallops" made of asymmetric magnetic cubes, which are assembled and actuated using magnetic fields. One approach to achieving directional propulsion is to break the symmetry of the viscous forces by coupling the reciprocal motions of such microswimmers with the nonlinear rheology inherent in non-Newtonian fluids. When placed in shear-thinning fluids, the local viscosity gradient resulting from nonuniform shear stresses exerted by time-asymmetric strokes of the microscallops generates propulsive thrust through an effect we term "self-viscophoresis". Surprisingly, we found that the direction of propulsion changes with the size and structure of these assemblies. We analyze the origins of their directional propulsion and explain the variable propulsion direction in terms of multiple counterbalancing domains of shear dissipation around the microscale structures. The principles governing the locomotion of these microswimmers may be extended to other reconfigurable microbots assembled from colloidal-scale units.
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Affiliation(s)
- Koohee Han
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Charles Wyatt Shields
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80303, United States
| | - Bhuvnesh Bharti
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Paulo E Arratia
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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25
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Wu Z, Chen Y, Mukasa D, Pak OS, Gao W. Medical micro/nanorobots in complex media. Chem Soc Rev 2020; 49:8088-8112. [PMID: 32596700 DOI: 10.1039/d0cs00309c] [Citation(s) in RCA: 124] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Medical micro/nanorobots have received tremendous attention over the past decades owing to their potential to be navigated into hard-to-reach tissues for a number of biomedical applications ranging from targeted drug/gene delivery, bio-isolation, detoxification, to nanosurgery. Despite the great promise, the majority of the past demonstrations are primarily under benchtop or in vitro conditions. Many developed micro/nanoscale propulsion mechanisms are based on the assumption of a homogeneous, Newtonian environment, while realistic biological environments are substantially more complex. Moving toward practical medical use, the field of micro/nanorobotics must overcome several major challenges including propulsion through complex media (such as blood, mucus, and vitreous) as well as deep tissue imaging and control in vivo. In this review article, we summarize the recent research efforts on investigating how various complexities in biological environments impact the propulsion of micro/nanoswimmers. We also highlight the emerging technological approaches to enhance the locomotion of micro/nanorobots in complex environments. The recent demonstrations of in vivo imaging, control and therapeutic medical applications of such micro/nanorobots are introduced. We envision that continuing materials and technological innovations through interdisciplinary collaborative efforts can bring us steps closer to the fantasy of "swallowing a surgeon".
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Affiliation(s)
- Zhiguang Wu
- Andrew and Peggy Cherng Department of Medical Engineering, California Institute of Technology, Pasadena, CA, USA.
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26
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Spreading of biologically relevant liquids over the laser textured surfaces. J Colloid Interface Sci 2020; 567:224-234. [PMID: 32058172 DOI: 10.1016/j.jcis.2020.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/02/2020] [Accepted: 02/03/2020] [Indexed: 12/21/2022]
Abstract
HYPOTHESIS The distribution of biological objects upon the spreading of biologically relevant dispersions over laser textured surfaces is affected by the dispersion composition and substrate chemistry and roughness. EXPERIMENTS To examine the role of the substrate texture in biologically relevant liquid spreading, the dynamic behavior of droplets of water and dispersions of bacterial cells and viruses and dynamic behavior of droplet/air surface tension were addressed. A new procedure to simultaneously distinguish three different spreading fronts was developed. FINDINGS The study of spreading of water and the biologically relevant liquids over the laser textured substrate indicate the development of three spreading fronts associated with the movement of bulk droplet base, the flow along the microchannels, and the nanotexture impregnation. The anisotropy of spreading for all types of liquid fronts was found. Despite the expected difference in the rheological behavior of water and the biologically relevant liquids, the spreading of all tested liquids was successfully described by power-law fits. The droplet base spreading for all tested liquids followed the Tanner law. The advancing of water and dispersions in the microchannels along both fast and slow axes was described by Washburn type behavior. The impregnation of the nanotexture by water and biologically relevant liquids demonstrated universality in power fit description with an exponent n = 0.23.
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27
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Wang W, Lv X, Moran JL, Duan S, Zhou C. A practical guide to active colloids: choosing synthetic model systems for soft matter physics research. SOFT MATTER 2020; 16:3846-3868. [PMID: 32285071 DOI: 10.1039/d0sm00222d] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Synthetic active colloids that harvest energy stored in the environment and swim autonomously are a popular model system for active matter. This emerging field of research sits at the intersection of materials chemistry, soft matter physics, and engineering, and thus cross-talk among researchers from different backgrounds becomes critical yet difficult. To facilitate this interdisciplinary communication, and to help soft matter physicists with choosing the best model system for their research, we here present a tutorial review article that describes, in appropriate detail, six experimental systems of active colloids commonly found in the physics literature. For each type, we introduce their background, material synthesis and operating mechanisms and notable studies from the soft matter community, and comment on their respective advantages and limitations. In addition, the main features of each type of active colloid are summarized into two useful tables. As materials chemists and engineers, we intend for this article to serve as a practical guide, so those who are not familiar with the experimental aspects of active colloids can make more informed decisions and maximize their creativity.
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Affiliation(s)
- Wei Wang
- School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, China.
| | - Xianglong Lv
- School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, China.
| | - Jeffrey L Moran
- Department of Mechanical Engineering, George Mason University, Fairfax, USA
| | - Shifang Duan
- School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, China.
| | - Chao Zhou
- School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, China.
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28
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Fily Y, Subramanian P, Schneider TM, Chelakkot R, Gopinath A. Buckling instabilities and spatio-temporal dynamics of active elastic filaments. J R Soc Interface 2020; 17:20190794. [PMID: 32316880 DOI: 10.1098/rsif.2019.0794] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Biological filaments driven by molecular motors tend to experience tangential propulsive forces also known as active follower forces. When such a filament encounters an obstacle, it deforms, which reorients its follower forces and alters its entire motion. If the filament pushes a cargo, the friction on the cargo can be enough to deform the filament, thus affecting the transport properties of the cargo. Motivated by cytoskeletal filament motility assays, we study the dynamic buckling instabilities of a two-dimensional slender elastic filament driven through a dissipative medium by tangential propulsive forces in the presence of obstacles or cargo. We observe two distinct instabilities. When the filament's head is pinned or experiences significant translational but little rotational drag from its cargo, it buckles into a steadily rotating coiled state. When it is clamped or experiences both significant translational and rotational drag from its cargo, it buckles into a periodically beating, overall translating state. Using minimal analytically tractable models, linear stability theory and fully nonlinear computations, we study the onset of each buckling instability, characterize each buckled state, and map out the phase diagram of the system. Finally, we use particle-based Brownian dynamics simulations to show our main results are robust to moderate noise and steric repulsion. Overall, our results provide a unified framework to understand the dynamics of tangentially propelled filaments and filament-cargo assemblies.
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Affiliation(s)
- Yaouen Fily
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL, USA
| | | | - Tobias M Schneider
- Emergent Complexity in Physical Systems Laboratory (ECPS), Ecole Polytechnique Federale de Lausanne, CH 1015 Lausanne, Switzerland
| | | | - Arvind Gopinath
- Department of Bioengineering, University of California Merced, Merced, CA, USA
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29
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Chen X, Zhou C, Peng Y, Wang Q, Wang W. Temporal Light Modulation of Photochemically Active, Oscillating Micromotors: Dark Pulses, Mode Switching, and Controlled Clustering. ACS APPLIED MATERIALS & INTERFACES 2020; 12:11843-11851. [PMID: 32092253 DOI: 10.1021/acsami.9b22342] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Photochemically powered micromotors are prototype microrobots, and spatiotemporal control is pivotal for a wide range of potential applications. Although their spatial navigation has been extensively studied, temporal control of photoactive micromotors remains much less explored. Using Ag-based oscillating micromotors as a model system, a strategy is presented for the controlled modulation of their individual and collective dynamics via periodically switching illumination on and off. In particular, such temporal light modulation drives individual oscillating micromotors into a total of six regimes of distinct dynamics, as the light-toggling frequencies vary from 0 to 103 Hz. On an ensemble level, toggling light at 5 Hz gives rise to controlled, reversible clustering of oscillating micromotors and self-assembly of tracer microspheres into colloidal crystals. A qualitative mechanism based on Ag-catalyzed decomposition of H2O2 is given to account for some, but not all, of the above observations. This study might potentially inspire more sophisticated temporal control of micromotors and the development of smart, biomimetic materials that respond to environmental stimuli that not only change in space but also in time.
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Affiliation(s)
- Xi Chen
- Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, China
| | - Chao Zhou
- Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, China
| | - Yixin Peng
- Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, China
| | - Qizhang Wang
- Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, China
| | - Wei Wang
- Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, China
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30
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Saad S, Natale G. Diffusiophoresis of active colloids in viscoelastic media. SOFT MATTER 2019; 15:9909-9919. [PMID: 31748761 DOI: 10.1039/c9sm01801h] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Self-diffusiophoresis of synthetic Janus (Si/Pt) microspheres in the presence of hydrogen peroxide in complex environments is here investigated. We aim to address the single particle dynamics of these active colloids in different viscoelastic fluids. Experimentally, the Janus colloids were dispersed in a dilute polyvinylpyrrolidone (PVP) solution and in a polyacrylamide (PAM) solution in semi-dilute and semi-dilute entangled regime to analyze their Brownian and active motion. These two systems were chosen to probe different relaxation times from relatively short (∼5 ms) for PVP to large (∼14.5 s) for PAM but always smaller than the rotary Brownian motion time scale. Within this regime, we investigate the coupling between the self-propulsion velocity and the medium rheology. Janus particles are found to get physically confined by polymeric entanglements but surprisingly they are able to escape the physical cage in a time scale much shorter than the relaxation time of the polymer solution. This is particularly relevant for application of self-propelling particles in biomedicine, water and soil remediation where complex environments are naturally present.
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Affiliation(s)
- Shabab Saad
- Department of Chemical & Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
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31
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Zhang L, Xiao Z, Chen X, Chen J, Wang W. Confined 1D Propulsion of Metallodielectric Janus Micromotors on Microelectrodes under Alternating Current Electric Fields. ACS NANO 2019; 13:8842-8853. [PMID: 31265246 DOI: 10.1021/acsnano.9b02100] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
There is mounting interest in synthetic microswimmers ("micromotors") as microrobots as well as a model system for the study of active matters, and spatial navigation is critical for their success. Current navigational technologies mostly rely on magnetic steering or guiding with physical boundaries, yet limitations with these strategies are plenty. Inspired by an earlier work with magnetic domains on a garnet film as predefined tracks, we present an interdigitated microelectrodes (IDE) system where, upon the application of AC electric fields, metallodielectric (e.g., SiO2-Ti) Janus particles are hydrodynamically confined and electrokinetically propelled in one dimension along the electrode center lines with tunable speeds. In addition, comoving micromotors moved in single files, while those moving in opposite directions primarily reoriented and moved past each other. At high particle densities, turbulence-like aggregates formed as many-body interactions became complicated. Furthermore, a micromotor made U-turns when approaching an electrode closure, while it gradually slowed down at the electrode opening and was collected in large piles. Labyrinth patterns made of serpentine chains of Janus particles emerged by modifying the electrode configuration. Most of these observations can be qualitatively understood by a combination of electroosmotic flows pointing inward to the electrodes, and asymmetric electrical polarization of the Janus particles under an AC electric field. Emerging from these observations is a strategy that not only powers and confines micromotors on prefabricated tracks in a contactless, on-demand manner, but is also capable of concentrating active particles at predefined locations. These features could prove useful for designing tunable tracks that steer synthetic microrobots, as well as to enable the study of single file diffusion, active turbulence, and other collective behaviors of active matters.
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Affiliation(s)
- Liangliang Zhang
- School of Materials Science and Engineering , Harbin Institute of Technology (Shenzhen) , Shenzhen , Guangdong 518055 , China
| | - Zuyao Xiao
- School of Materials Science and Engineering , Harbin Institute of Technology (Shenzhen) , Shenzhen , Guangdong 518055 , China
| | - Xi Chen
- School of Materials Science and Engineering , Harbin Institute of Technology (Shenzhen) , Shenzhen , Guangdong 518055 , China
| | - Jingyuan Chen
- School of Materials Science and Engineering , Harbin Institute of Technology (Shenzhen) , Shenzhen , Guangdong 518055 , China
| | - Wei Wang
- School of Materials Science and Engineering , Harbin Institute of Technology (Shenzhen) , Shenzhen , Guangdong 518055 , China
- IBS Center for Soft and Living Matter , Institute of Basic Science , Ulsan 44919 , Republic of Korea
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Yang J, Arratia PE, Patteson AE, Gopinath A. Quenching active swarms: effects of light exposure on collective motility in swarming Serratia marcescens. J R Soc Interface 2019; 16:20180960. [PMID: 31311436 DOI: 10.1098/rsif.2018.0960] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Swarming colonies of the light-responsive bacteria Serratia marcescens grown on agar exhibit robust fluctuating large-scale flows that include arrayed vortices, jets and sinuous streamers. We study the immobilization and quenching of these collective flows when the moving swarm is exposed to intense wide-spectrum light with a substantial ultraviolet component. We map the emergent response of the swarm to light in terms of two parameters-light intensity and duration of exposure-and identify the conditions under which collective motility is impacted. For small exposure times and/or low intensities, we find collective motility to be negligibly affected. Increasing exposure times and/or intensity to higher values suppresses collective motility but only temporarily. Terminating exposure allows bacteria to recover and eventually reestablish collective flows similar to that seen in unexposed swarms. For long exposure times or at high intensities, exposed bacteria become paralysed and form aligned, jammed regions where macroscopic speeds reduce to zero. The effective size of the quenched region increases with time and saturates to approximately the extent of the illuminated region. Post-exposure, active bacteria dislodge immotile bacteria; initial dissolution rates are strongly dependent on duration of exposure. Based on our experimental observations, we propose a minimal Brownian dynamics model to examine the escape of exposed bacteria from the region of exposure. Our results complement studies on planktonic bacteria, inform models of patterning in gradated illumination and provide a starting point for the study of specific wavelengths on swarming bacteria.
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Affiliation(s)
- Junyi Yang
- Department of Bioengineering, University of California Merced, Merced, CA, USA
| | - Paulo E Arratia
- Department of Mechanical Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Arvind Gopinath
- Department of Bioengineering, University of California Merced, Merced, CA, USA
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Pagès JM, Ignés-Mullol J, Sagués F. Anomalous Diffusion of Motile Colloids Dispersed in Liquid Crystals. PHYSICAL REVIEW LETTERS 2019; 122:198001. [PMID: 31144957 DOI: 10.1103/physrevlett.122.198001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Indexed: 06/09/2023]
Abstract
We study the superdiffusion of driven colloidal particles dispersed in a nematic liquid crystal. While motion is ballistic in the driving direction, our experiments show that transversal fluctuations become superdiffusive depending on the topological defect pattern around the inclusions. The phenomenon can be reproduced with different driving methods and propulsion speeds, while it is strongly dependent on particle size and temperature. We propose a mechanism based on the geometry of the liquid crystal backflow around the inclusions to justify the persistence of thermal fluctuations and to explain the observed temperature and particle size dependence of the superdiffusive behavior based on material and geometrical parameters.
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Affiliation(s)
- Josep M Pagès
- Departament de Ciència de Materials i Química Física, and Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Catalonia, Spain
| | - Jordi Ignés-Mullol
- Departament de Ciència de Materials i Química Física, and Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Catalonia, Spain
| | - Francesc Sagués
- Departament de Ciència de Materials i Química Física, and Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Catalonia, Spain
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Chen X, Zhou C, Wang W. Colloidal Motors 101: A Beginner's Guide to Colloidal Motor Research. Chem Asian J 2019; 14:2388-2405. [DOI: 10.1002/asia.201900377] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/09/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Xi Chen
- School of Materials Science and EngineeringHarbin Institute of Technology (Shenzhen) G 908, HIT Campus, Xili University Town Shenzhen Guangdong China
| | - Chao Zhou
- School of Materials Science and EngineeringHarbin Institute of Technology (Shenzhen) G 908, HIT Campus, Xili University Town Shenzhen Guangdong China
| | - Wei Wang
- School of Materials Science and EngineeringHarbin Institute of Technology (Shenzhen) G 908, HIT Campus, Xili University Town Shenzhen Guangdong China
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Gordon V, Bakhtiari L, Kovach K. From molecules to multispecies ecosystems: the roles of structure in bacterial biofilms. Phys Biol 2019; 16:041001. [PMID: 30913545 DOI: 10.1088/1478-3975/ab1384] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Biofilms are communities of sessile microbes that are bound to each other by a matrix made of biopolymers and proteins. Spatial structure is present in biofilms on many lengthscales. These range from the nanometer scale of molecular motifs to the hundred-micron scale of multicellular aggregates. Spatial structure is a physical property that impacts the biology of biofilms in many ways. The molecular structure of matrix components controls their interaction with each other (thereby impacting biofilm mechanics) and with diffusing molecules such as antibiotics and immune factors (thereby impacting antibiotic tolerance and evasion of the immune system). The size and structure of multicellular aggregates, combined with microbial consumption of growth substrate, give rise to differentiated microenvironments with different patterns of metabolism and gene expression. Spatial association of more than one species can benefit one or both species, while distances between species can both determine and result from the transport of diffusible factors between species. Thus, a widespread theme in the biological importance of spatial structure in biofilms is the effect of structure on transport. We survey what is known about this and other effects of spatial structure in biofilms, from molecules up to multispecies ecosystems. We conclude with an overview of what experimental approaches have been developed to control spatial structure in biofilms and how these and other experiments can be complemented with computational work.
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Affiliation(s)
- Vernita Gordon
- Department of Physics, University of Texas at Austin, Austin TX 78712, United States of America. Center for Nonlinear Dynamics, University of Texas at Austin, Austin TX 78712, United States of America. Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin TX 78712, United States of America. Author to whom any correspondence should be addressed
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36
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Leveraging collective effects in externally driven colloidal suspensions: experiments and simulations. Curr Opin Colloid Interface Sci 2019. [DOI: 10.1016/j.cocis.2018.10.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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37
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Du Y, Jiang H, Hou Z. Study of active Brownian particle diffusion in polymer solutions. SOFT MATTER 2019; 15:2020-2031. [PMID: 30724318 DOI: 10.1039/c8sm02292e] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The diffusion behavior of an active Brownian particle (ABP) in polymer solutions is studied using Langevin dynamics simulations. We find that the long time diffusion coefficient D can show a non-monotonic dependence on the particle size R if the active force Fa is large enough, wherein a bigger particle would diffuse faster than a smaller one which is quite counterintuitive. By analyzing the short time dynamics in comparison to the passive one, we find that such non-trivial dependence results from the competition between persistent motion of the ABP and the length-scale dependent effective viscosity that the particle experiences in the polymer solution. We have also introduced an effective viscosity ηeff experienced by the ABP phenomenologically. Such an active ηeff is found to be larger than a passive one and strongly depends on R and Fa. In addition, we find that the dependence of D on propelling force Fa presents a good power-law scaling at a fixed R and the scaling factor changes non-monotonically with R. Such results demonstrate that the active process plays rather subtle roles in the diffusion of nano-particles in complex solutions.
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Affiliation(s)
- Yunfei Du
- Department of Chemical Physics and Hefei National Laboratory for Physical Sciences at Microscales, iChEM, University of Science and Technology of China, Hefei, Anhui 230026, China.
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38
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Krinninger P, Schmidt M. Power functional theory for active Brownian particles: General formulation and power sum rules. J Chem Phys 2019; 150:074112. [DOI: 10.1063/1.5061764] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Philip Krinninger
- Theoretische Physik II, Physikalisches Institut, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - Matthias Schmidt
- Theoretische Physik II, Physikalisches Institut, Universität Bayreuth, D-95440 Bayreuth, Germany
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Xiao Z, Wei M, Wang W. A Review of Micromotors in Confinements: Pores, Channels, Grooves, Steps, Interfaces, Chains, and Swimming in the Bulk. ACS APPLIED MATERIALS & INTERFACES 2019; 11:6667-6684. [PMID: 30562451 DOI: 10.1021/acsami.8b13103] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
One of the recent frontiers of nanotechnology research involves machines that operate at nano- and microscales, also known as nano/micromotors. Their potential applications in biomedicine, environmental sciences and engineering, military and defense industries, self-assembly, and many other areas have fueled an intense interest in this topic over the last 15 years. Despite deepened understanding of their propulsion mechanisms, we are still in the early days of exploring the dynamics of micromotors in complex and more realistic environments. Confinements, as a typical example of complex environments, are extremely relevant to the applications of micromotors, which are expected to travel in mucus gels, blood vessels, reproductive and digestive tracts, microfluidic chips, and capillary tubes. In this review, we summarize and critically examine recent studies (mostly experimental ones) of micromotor dynamics in confinements in 3D (spheres and porous network, channels, grooves, steps, and obstacles), 2D (liquid-liquid, liquid-solid, and liquid-air interfaces), and 1D (chains). In addition, studies of micromotors moving in the bulk solution and the usefulness of acoustic levitation is discussed. At the end of this article, we summarize how confinements can affect micromotors and offer our insights on future research directions. This review article is relevant to readers who are interested in the interactions of materials with interfaces and structures at the microscale and helpful for the design of smart and multifunctional materials for various applications.
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Affiliation(s)
- Zuyao Xiao
- School of Materials Science and Engineering , Harbin Institute of Technology (Shenzhen) , Shenzhen , Guangdong 518055 , China
| | - Mengshi Wei
- School of Materials Science and Engineering , Harbin Institute of Technology (Shenzhen) , Shenzhen , Guangdong 518055 , China
| | - Wei Wang
- School of Materials Science and Engineering , Harbin Institute of Technology (Shenzhen) , Shenzhen , Guangdong 518055 , China
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40
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Mallory SA, Cacciuto A. Activity-Enhanced Self-Assembly of a Colloidal Kagome Lattice. J Am Chem Soc 2019; 141:2500-2507. [DOI: 10.1021/jacs.8b12165] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Stewart A. Mallory
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Angelo Cacciuto
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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41
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Yuan C, Chen A, Zhang B, Zhao N. Activity–crowding coupling effect on the diffusion dynamics of a self-propelled particle in polymer solutions. Phys Chem Chem Phys 2019; 21:24112-24125. [DOI: 10.1039/c9cp04498a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The anomalous diffusion dynamics of an active particle in polymer solutions is studied based on a Langevin Brownian dynamics simulation.
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Affiliation(s)
- Chengli Yuan
- College of Chemistry
- Sichuan University
- Chengdu 610064
- China
| | - Anpu Chen
- College of Chemistry
- Sichuan University
- Chengdu 610064
- China
| | - Bingjie Zhang
- College of Chemistry
- Sichuan University
- Chengdu 610064
- China
| | - Nanrong Zhao
- College of Chemistry
- Sichuan University
- Chengdu 610064
- China
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42
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Patteson AE, Gopinath A, Arratia PE. The propagation of active-passive interfaces in bacterial swarms. Nat Commun 2018; 9:5373. [PMID: 30560867 PMCID: PMC6299137 DOI: 10.1038/s41467-018-07781-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 11/20/2018] [Indexed: 11/08/2022] Open
Abstract
Propagating interfaces are ubiquitous in nature, underlying instabilities and pattern formation in biology and material science. Physical principles governing interface growth are well understood in passive settings; however, our understanding of interfaces in active systems is still in its infancy. Here, we study the evolution of an active-passive interface using a model active matter system, bacterial swarms. We use ultra-violet light exposure to create compact domains of passive bacteria within Serratia marcescens swarms, thereby creating interfaces separating motile and immotile cells. Post-exposure, the boundary re-shapes and erodes due to self-emergent collective flows. We demonstrate that the active-passive boundary acts as a diffuse interface with mechanical properties set by the flow. Intriguingly, interfacial velocity couples to local swarm speed and interface curvature, raising the possibility that an active analogue to classic Gibbs-Thomson-Stefan conditions may control this boundary propagation.
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Affiliation(s)
- Alison E Patteson
- Department of Mechanical Engineering & Applied Mechanics, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Physics Department, Syracuse University, Syracuse, NY, 13244, USA.
| | - Arvind Gopinath
- Department of Bioengineering, University of California, Merced, CA, 95340, USA
- Health Sciences Research Institute, University of California, Merced, CA, 95340, USA
| | - Paulo E Arratia
- Department of Mechanical Engineering & Applied Mechanics, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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43
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Tang EM, Underhill PT. Examination of the Statistical Effects Associated with Tracking Propulsive Particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:10694-10701. [PMID: 30109937 DOI: 10.1021/acs.langmuir.8b02331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Particle tracking of active colloidal particles can be used to compute mean-squared displacements that are fit to extract properties of the particles including the propulsive speed. Statistical errors in the mean-squared displacement leads to errors in the extracted properties especially for more weakly propelling particles. Brownian dynamics simulations in which the particle parameters are prescribed were used to examine the statistics of tracking self-propelling objects. It was found that the manner in which tracking data is analyzed has a profound impact on the precision and accuracy of measurements. To properly extract particle parameters, it was necessary to apply a nonlinear fit of the mean-squared displacement over a time region that includes transition behavior from ballistic to diffusive. The dependence of the statistics on the number of particles tracked and the length of movies was examined, showing how and why weakly propelling particles are difficult to analyze.
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Affiliation(s)
- Edmund M Tang
- Department of Chemical and Biological Engineering , Rensselaer Polytechnic Institute , 110 8th Street , Troy , New York 12180 , United States
| | - Patrick T Underhill
- Department of Chemical and Biological Engineering , Rensselaer Polytechnic Institute , 110 8th Street , Troy , New York 12180 , United States
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Holloway CR, Cupples G, Smith DJ, Green JEF, Clarke RJ, Dyson RJ. Influences of transversely isotropic rheology and translational diffusion on the stability of active suspensions. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180456. [PMID: 30225034 PMCID: PMC6124136 DOI: 10.1098/rsos.180456] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/03/2018] [Indexed: 06/08/2023]
Abstract
Suspensions of self-motile, elongated particles are a topic of significant current interest, exemplifying a form of 'active matter'. Examples include self-propelling bacteria, algae and sperm, and artificial swimmers. Ericksen's model of a transversely isotropic fluid (Ericksen 1960 Colloid Polym. Sci.173, 117-122 (doi:10.1007/bf01502416)) treats suspensions of non-motile particles as a continuum with an evolving preferred direction; this model describes fibrous materials as diverse as extracellular matrix, textile tufts and plant cell walls. Director-dependent effects are incorporated through a modified stress tensor with four viscosity-like parameters. By making fundamental connections with recent models for active suspensions, we propose a modification to Ericksen's model, mainly the inclusion of self-motility; this can be considered the simplest description of an oriented suspension including transversely isotropic effects. Motivated by the fact that transversely isotropic fluids exhibit modified flow stability, we conduct a linear stability analysis of two distinct cases, aligned and isotropic suspensions of elongated active particles. Novel aspects include the anisotropic rheology and translational diffusion. In general, anisotropic effects increase the instability of small perturbations, while translational diffusion stabilizes a range of wave-directions and, in some cases, a finite range of wavenumbers, thus emphasizing that both anisotropy and translational diffusion can have important effects in these systems.
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Affiliation(s)
- C. R. Holloway
- School of Mathematics, University of Birmingham, Birmingham B15 2TT, UK
| | - G. Cupples
- School of Mathematics, University of Birmingham, Birmingham B15 2TT, UK
| | - D. J. Smith
- School of Mathematics, University of Birmingham, Birmingham B15 2TT, UK
- Institute for Metabolism and Systems Research, University of Birmingham, Birmingham B15 2TT, UK
| | - J. E. F. Green
- School of Mathematical Sciences, University of Adelaide, Adelaide, Australia
| | - R. J. Clarke
- Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - R. J. Dyson
- School of Mathematics, University of Birmingham, Birmingham B15 2TT, UK
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45
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Lu SQ, Zhang BY, Zhang ZC, Shi Y, Zhang TH. Pair aligning improved motility of Quincke rollers. SOFT MATTER 2018; 14:5092-5097. [PMID: 29873655 DOI: 10.1039/c8sm00371h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Density-dependent speed is studied in a two-dimensional active colloid in which the colloidal particles are propelled by an external electric field via a Quincke rotation. Above the critcal electric field, dense dynamic clusters form spotaneously, in which the particles are highly aligned in velocity and move much faster than isolated units. Detailed observations on pair collision reveal that the alignment of velocity is induced by the long-ranged hydrodynamic interactions and the improvement of speed in the clusters arises from pair aligning in which two particles are closely paired and rotate synchronically. In the aligning state, the short-range in-plane dipole-dipole attraction enhances the rotation torque and gives rises to a larger rolling speed. The pair aligning becomes difficult and unstable at high electric field where the normal dipole-dipole repulsion becomes dominant. As a consequence, the dependence of speed on density becomes weak increasingly upon the increase of the electric field. This result offers an interpretation for the discrepancy between our and previous observations on Quincke rollers.
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Affiliation(s)
- Shi Qing Lu
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou, 215006, P. R. China.
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Affiliation(s)
| | - Chantal Valeriani
- Departamento de Física Aplicada I, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Angelo Cacciuto
- Department of Chemistry, Columbia University, New York, NY 10027, USA
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47
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Zhang J, Luijten E, Grzybowski BA, Granick S. Active colloids with collective mobility status and research opportunities. Chem Soc Rev 2018; 46:5551-5569. [PMID: 28762406 DOI: 10.1039/c7cs00461c] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The collective mobility of active matter (self-propelled objects that transduce energy into mechanical work to drive their motion, most commonly through fluids) constitutes a new frontier in science and achievable technology. This review surveys the current status of the research field, what kinds of new scientific problems can be tackled in the short term, and what long-term directions are envisioned. We focus on: (1) attempts to formulate design principles to tailor active particles; (2) attempts to design principles according to which active particles interact under circumstances where particle-particle interactions of traditional colloid science are augmented by a family of nonequilibrium effects discussed here; (3) attempts to design intended patterns of collective behavior and dynamic assembly; (4) speculative links to equilibrium thermodynamics. In each aspect, we assess achievements, limitations, and research opportunities.
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Affiliation(s)
- Jie Zhang
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801, USA
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48
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Wei M, Zhou C, Tang J, Wang W. Catalytic Micromotors Moving Near Polyelectrolyte-Modified Substrates: The Roles of Surface Charges, Morphology, and Released Ions. ACS APPLIED MATERIALS & INTERFACES 2018; 10:2249-2252. [PMID: 29300455 DOI: 10.1021/acsami.7b18399] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Synthetic microswimmers, or micromotors, are finding potential uses in a wide range of applications, most of which involve boundaries. However, subtle yet important effects beyond physical confinement on the motor dynamics remain less understood. In this letter, glass substrates were functionalized with positively and negatively charged polyelectrolytes, and the dynamics of micromotors moving close to the modified surfaces was examined. Using acoustic levitation and numerical simulation, we reveal how the speed of a chemically propelled micromotor slows down significantly near a polyelectrolyte-modified surface by the combined effects of surface charges, surface morphology, and ions released from the films.
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Affiliation(s)
- Mengshi Wei
- School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen) , Shenzhen 518055, China
| | - Chao Zhou
- School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen) , Shenzhen 518055, China
| | - Jinyao Tang
- Department of Chemistry, University of Hong Kong , Hong Kong SAR 999077, China
| | - Wei Wang
- School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen) , Shenzhen 518055, China
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49
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Fei W, Gu Y, Bishop KJ. Active colloidal particles at fluid-fluid interfaces. Curr Opin Colloid Interface Sci 2017. [DOI: 10.1016/j.cocis.2017.10.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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50
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The Evolution of Active Particles: Toward Externally Powered Self-Propelling and Self-Reconfiguring Particle Systems. Chem 2017. [DOI: 10.1016/j.chempr.2017.09.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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