1
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Sreepadmanabh M, Arun AB, Bhattacharjee T. Design approaches for 3D cell culture and 3D bioprinting platforms. BIOPHYSICS REVIEWS 2024; 5:021304. [PMID: 38765221 PMCID: PMC11101206 DOI: 10.1063/5.0188268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 04/01/2024] [Indexed: 05/21/2024]
Abstract
The natural habitat of most cells consists of complex and disordered 3D microenvironments with spatiotemporally dynamic material properties. However, prevalent methods of in vitro culture study cells under poorly biomimetic 2D confinement or homogeneous conditions that often neglect critical topographical cues and mechanical stimuli. It has also become increasingly apparent that cells in a 3D conformation exhibit dramatically altered morphological and phenotypical states. In response, efforts toward designing biomaterial platforms for 3D cell culture have taken centerstage over the past few decades. Herein, we present a broad overview of biomaterials for 3D cell culture and 3D bioprinting, spanning both monolithic and granular systems. We first critically evaluate conventional monolithic hydrogel networks, with an emphasis on specific experimental requirements. Building on this, we document the recent emergence of microgel-based 3D growth media as a promising biomaterial platform enabling interrogation of cells within porous and granular scaffolds. We also explore how jammed microgel systems have been leveraged to spatially design and manipulate cellular structures using 3D bioprinting. The advent of these techniques heralds an unprecedented ability to experimentally model complex physiological niches, with important implications for tissue bioengineering and biomedical applications.
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Affiliation(s)
- M Sreepadmanabh
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, Karnataka, India
| | - Ashitha B. Arun
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, Karnataka, India
| | - Tapomoy Bhattacharjee
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, Karnataka, India
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2
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Keogh RR, Kozhukhov T, Thijssen K, Shendruk TN. Active Darcy's Law. PHYSICAL REVIEW LETTERS 2024; 132:188301. [PMID: 38759204 DOI: 10.1103/physrevlett.132.188301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 03/11/2024] [Indexed: 05/19/2024]
Abstract
While bacterial swarms can exhibit active turbulence in vacant spaces, they naturally inhabit crowded environments. We numerically show that driving disorderly active fluids through porous media enhances Darcy's law. While purely active flows average to zero flux, hybrid active/driven flows display greater drift than purely pressure-driven flows. This enhancement is nonmonotonic with activity, leading to an optimal activity to maximize flow rate. We incorporate the active contribution into an active Darcy's law, which may serve to help understand anomalous transport of swarming in porous media.
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Affiliation(s)
- Ryan R Keogh
- School of Physics and Astronomy, The University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, United Kingdom
| | - Timofey Kozhukhov
- School of Physics and Astronomy, The University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, United Kingdom
| | - Kristian Thijssen
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen, Denmark
| | - Tyler N Shendruk
- School of Physics and Astronomy, The University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, United Kingdom
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3
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Jin C, Sengupta A. Microbes in porous environments: from active interactions to emergent feedback. Biophys Rev 2024; 16:173-188. [PMID: 38737203 PMCID: PMC11078916 DOI: 10.1007/s12551-024-01185-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/27/2024] [Indexed: 05/14/2024] Open
Abstract
Microbes thrive in diverse porous environments-from soil and riverbeds to human lungs and cancer tissues-spanning multiple scales and conditions. Short- to long-term fluctuations in local factors induce spatio-temporal heterogeneities, often leading to physiologically stressful settings. How microbes respond and adapt to such biophysical constraints is an active field of research where considerable insight has been gained over the last decades. With a focus on bacteria, here we review recent advances in self-organization and dispersal in inorganic and organic porous settings, highlighting the role of active interactions and feedback that mediates microbial survival and fitness. We discuss open questions and opportunities for using integrative approaches to advance our understanding of the biophysical strategies which microbes employ at various scales to make porous settings habitable.
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Affiliation(s)
- Chenyu Jin
- Physics of Living Matter Group, Department of Physics and Materials Science, University of Luxembourg, 162 A, Avenue de la Faïencerie, Luxembourg City, L-1511 Luxembourg
| | - Anupam Sengupta
- Physics of Living Matter Group, Department of Physics and Materials Science, University of Luxembourg, 162 A, Avenue de la Faïencerie, Luxembourg City, L-1511 Luxembourg
- Institute for Advanced Studies, University of Luxembourg, 2 Avenue de l’Université, Esch-sur-Alzette, L-4365 Luxembourg
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4
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Turci F, Jack RL, Wilding NB. Partial and complete wetting of droplets of active Brownian particles. SOFT MATTER 2024; 20:2060-2074. [PMID: 38345308 DOI: 10.1039/d3sm01493b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
We study wetting droplets formed of active Brownian particles in contact with a repulsive potential barrier, in a wedge geometry. Our numerical results demonstrate a transition between partially wet and completely wet states, as a function of the barrier height, analogous to the corresponding surface phase transition in passive fluids. We analyse partially wet configurations characterised by a nonzero contact angle θ between the droplet surface and the barrier including the average density profile and its fluctuations. These findings are compared with two equilibrium systems: a Lennard-Jones fluid and a simple contour model for a liquid-vapour interface. We locate the wetting transition where cos(θ) = 1, and the neutral state where cos(θ) = 0. We discuss the implications of these results for possible definitions of surface tensions in active fluids.
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Affiliation(s)
- Francesco Turci
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK.
| | - Robert L Jack
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Nigel B Wilding
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK.
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5
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Crawford AJ, Gomez-Cruz C, Russo GC, Huang W, Bhorkar I, Roy T, Muñoz-Barrutia A, Wirtz D, Garcia-Gonzalez D. Tumor proliferation and invasion are intrinsically coupled and unraveled through tunable spheroid and physics-based models. Acta Biomater 2024; 175:170-185. [PMID: 38160858 DOI: 10.1016/j.actbio.2023.12.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/13/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024]
Abstract
Proliferation and invasion are two key drivers of tumor growth that are traditionally considered independent multicellular processes. However, these processes are intrinsically coupled through a maximum carrying capacity, i.e., the maximum spatial cell concentration supported by the tumor volume, total cell count, nutrient access, and mechanical properties of the tissue stroma. We explored this coupling of proliferation and invasion through in vitro and in silico methods where we modulated the mechanical properties of the tumor and the surrounding extracellular matrix. E-cadherin expression and stromal collagen concentration were manipulated in a tunable breast cancer spheroid to determine the overall impacts of these tumor variables on net tumor proliferation and continuum invasion. We integrated these results into a mixed-constitutive formulation to computationally delineate the influences of cellular and extracellular adhesion, stiffness, and mechanical properties of the extracellular matrix on net proliferation and continuum invasion. This framework integrates biological in vitro data into concise computational models of invasion and proliferation to provide more detailed physical insights into the coupling of these key tumor processes and tumor growth. STATEMENT OF SIGNIFICANCE: Tumor growth involves expansion into the collagen-rich stroma through intrinsic coupling of proliferation and invasion within the tumor continuum. These processes are regulated by a maximum carrying capacity that is determined by the total cell count, tumor volume, nutrient access, and mechanical properties of the surrounding stroma. The influences of biomechanical parameters (i.e., stiffness, cell elongation, net proliferation rate and cell-ECM friction) on tumor proliferation or invasion cannot be unraveled using experimental methods alone. By pairing a tunable spheroid system with computational modeling, we delineated the interdependencies of each system parameter on tumor proliferation and continuum invasion, and established a concise computational framework for studying tumor mechanobiology.
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Affiliation(s)
- Ashleigh J Crawford
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, 3400N Charles St, Baltimore, MD 21218, USA; Johns Hopkins Physical Sciences-Oncology Center and Institute for NanoBioTechnology, Johns Hopkins University, 3400N Charles St, Baltimore, Maryland 21218, USA
| | - Clara Gomez-Cruz
- Department of Continuum Mechanics and Structural Analysis, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganes, Madrid, Spain; Departamento de Bioingenieria, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganes, Madrid, Spain
| | - Gabriella C Russo
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, 3400N Charles St, Baltimore, MD 21218, USA; Johns Hopkins Physical Sciences-Oncology Center and Institute for NanoBioTechnology, Johns Hopkins University, 3400N Charles St, Baltimore, Maryland 21218, USA
| | - Wilson Huang
- Johns Hopkins Physical Sciences-Oncology Center and Institute for NanoBioTechnology, Johns Hopkins University, 3400N Charles St, Baltimore, Maryland 21218, USA; Department of Biology, Johns Hopkins University, 3400N Charles St, Baltimore, Maryland 21218, USA
| | - Isha Bhorkar
- Johns Hopkins Physical Sciences-Oncology Center and Institute for NanoBioTechnology, Johns Hopkins University, 3400N Charles St, Baltimore, Maryland 21218, USA; Department of Biomedical Engineering, Johns Hopkins University, 3400N Charles St, Baltimore, Maryland 21218, USA
| | - Triya Roy
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, 3400N Charles St, Baltimore, MD 21218, USA; Johns Hopkins Physical Sciences-Oncology Center and Institute for NanoBioTechnology, Johns Hopkins University, 3400N Charles St, Baltimore, Maryland 21218, USA
| | - Arrate Muñoz-Barrutia
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, 3400N Charles St, Baltimore, MD 21218, USA; Departamento de Bioingenieria, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganes, Madrid, Spain; Area de Ingenieria Biomedica, Instituto de Investigacion Sanitaria Gregorio Maranon, Calle del Doctor Esquerdo 46, Madrid' ES 28007, Spain
| | - Denis Wirtz
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, 3400N Charles St, Baltimore, MD 21218, USA; Johns Hopkins Physical Sciences-Oncology Center and Institute for NanoBioTechnology, Johns Hopkins University, 3400N Charles St, Baltimore, Maryland 21218, USA; Department of Biomedical Engineering, Johns Hopkins University, 3400N Charles St, Baltimore, Maryland 21218, USA; Departments of Pathology and Oncology and Sydney Kimmel Comprehensive Cancer Center, The Johns Hopkins School of Medicine, 1800 Orleans St, Baltimore, MD 21215, USA.
| | - Daniel Garcia-Gonzalez
- Department of Continuum Mechanics and Structural Analysis, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganes, Madrid, Spain.
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6
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Loewe B, Kozhukhov T, Shendruk TN. Anisotropic run-and-tumble-turn dynamics. SOFT MATTER 2024; 20:1133-1150. [PMID: 38226730 PMCID: PMC10828927 DOI: 10.1039/d3sm00589e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 12/12/2023] [Indexed: 01/17/2024]
Abstract
Run-and-tumble processes successfully model several living systems. While studies have typically focused on particles with isotropic tumbles, recent examples exhibit "tumble-turns", in which particles undergo 90° tumbles and so possess explicitly anisotropic dynamics. We study the consequences of such tumble-turn anisotropicity at both short and long-time scales. We model run-and-tumble-turn particles as self-propelled particles subjected to an angular potential that favors directions of movement parallel to Cartesian axes. Using agent-based simulations, we study the effects of the interplay between rotational diffusion and an aligning potential on the particles' trajectories, which leads to the right-angled turns. We demonstrate that the long-time effect is to alter the tumble-turn time, which governs the long-time dynamics. In particular, when normalized by this timescale, trajectories become independent of the underlying details of the potential. As such, we develop a simplified continuum theory, which quantitatively agrees with agent-based simulations. We find that the purely diffusive hydrodynamic limit still exhibits anisotropic features at intermediate times and conclude that the transition to diffusive dynamics precedes the transition to isotropic dynamics. By considering short-range repulsive and alignment particle-particle interactions, we show how the anisotropic features of a single particle are inherited by the global order of the system. We hope this work will shed light on how active systems can extend local anisotropic properties to macroscopic scales, which might be important in biological processes occurring in anisotropic environments.
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Affiliation(s)
- Benjamin Loewe
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK.
| | - Timofey Kozhukhov
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK.
| | - Tyler N Shendruk
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK.
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7
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Phan TV, Mattingly HH, Vo L, Marvin JS, Looger LL, Emonet T. Direct measurement of dynamic attractant gradients reveals breakdown of the Patlak-Keller-Segel chemotaxis model. Proc Natl Acad Sci U S A 2024; 121:e2309251121. [PMID: 38194458 PMCID: PMC10801886 DOI: 10.1073/pnas.2309251121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 12/07/2023] [Indexed: 01/11/2024] Open
Abstract
Chemotactic bacteria not only navigate chemical gradients, but also shape their environments by consuming and secreting attractants. Investigating how these processes influence the dynamics of bacterial populations has been challenging because of a lack of experimental methods for measuring spatial profiles of chemoattractants in real time. Here, we use a fluorescent sensor for aspartate to directly measure bacterially generated chemoattractant gradients during collective migration. Our measurements show that the standard Patlak-Keller-Segel model for collective chemotactic bacterial migration breaks down at high cell densities. To address this, we propose modifications to the model that consider the impact of cell density on bacterial chemotaxis and attractant consumption. With these changes, the model explains our experimental data across all cell densities, offering insight into chemotactic dynamics. Our findings highlight the significance of considering cell density effects on bacterial behavior, and the potential for fluorescent metabolite sensors to shed light on the complex emergent dynamics of bacterial communities.
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Affiliation(s)
- Trung V. Phan
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT06511
- Quantitative Biology Institute, Yale University, New Haven, CT06511
| | | | - Lam Vo
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT06511
- Quantitative Biology Institute, Yale University, New Haven, CT06511
| | - Jonathan S. Marvin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA20147
| | - Loren L. Looger
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA20147
- HHMI, University of California, San Diego, CA92093
- Department of Neurosciences, University of California, San Diego, CA92093
| | - Thierry Emonet
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT06511
- Quantitative Biology Institute, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
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8
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Ridgway WJM, Dalwadi MP, Pearce P, Chapman SJ. Motility-Induced Phase Separation Mediated by Bacterial Quorum Sensing. PHYSICAL REVIEW LETTERS 2023; 131:228302. [PMID: 38101339 DOI: 10.1103/physrevlett.131.228302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 10/09/2023] [Indexed: 12/17/2023]
Abstract
We study motility-induced phase separation (MIPS) in living active matter, in which cells interact through chemical signaling, or quorum sensing. In contrast to previous theories of MIPS, our multiscale continuum model accounts explicitly for genetic regulation of signal production and motility. Through analysis and simulations, we derive a new criterion for the onset of MIPS that depends on features of the genetic network. Furthermore, we identify and characterize a new type of oscillatory instability that occurs when gene regulation inside cells promotes motility in higher signal concentrations.
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Affiliation(s)
- Wesley J M Ridgway
- Mathematical Institute, University of Oxford, Oxford OX2 6GG, United Kingdom
| | - Mohit P Dalwadi
- Mathematical Institute, University of Oxford, Oxford OX2 6GG, United Kingdom
- Department of Mathematics, University College London, London WC1H 0AY, United Kingdom
- Institute for the Physics of Living Systems, University College London, London, United Kingdom
| | - Philip Pearce
- Department of Mathematics, University College London, London WC1H 0AY, United Kingdom
- Institute for the Physics of Living Systems, University College London, London, United Kingdom
| | - S Jonathan Chapman
- Mathematical Institute, University of Oxford, Oxford OX2 6GG, United Kingdom
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9
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Saintillan D. Dispersion of run-and-tumble microswimmers through disordered media. Phys Rev E 2023; 108:064608. [PMID: 38243487 DOI: 10.1103/physreve.108.064608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 11/20/2023] [Indexed: 01/21/2024]
Abstract
Understanding the transport properties of microorganisms and self-propelled particles in porous media has important implications for human health as well as microbial ecology. In free space, most microswimmers perform diffusive random walks as a result of the interplay of self-propulsion and orientation decorrelation mechanisms such as run-and-tumble dynamics or rotational diffusion. In an unstructured porous medium, collisions with the microstructure result in a decrease in the effective spatial diffusivity of the particles from its free-space value. Here, we analyze this problem for a simple model system consisting of noninteracting point particles performing run-and-tumble dynamics through a two-dimensional disordered medium composed of a random distribution of circular obstacles, in the absence of Brownian diffusion or hydrodynamic interactions. The particles are assumed to collide with the obstacles as hard spheres and subsequently slide on the obstacle surface with no frictional resistance while maintaining their orientation, until they either escape or tumble. We show that the variations in the long-time diffusivity can be described by a universal dimensionless hindrance function f(ϕ,Pe) of the obstacle area fraction ϕ and Péclet number Pe, or ratio of the swimmer run length to the obstacle size. We analytically derive an asymptotic expression for the hindrance function valid for dilute media (Peϕ≪1), and its extension to denser media is obtained using stochastic simulations. As we explain, the model is also easily generalized to describe dispersion in three dimensions.
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Affiliation(s)
- David Saintillan
- Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
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10
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Stillman NR, Mayor R. Generative models of morphogenesis in developmental biology. Semin Cell Dev Biol 2023; 147:83-90. [PMID: 36754751 PMCID: PMC10615838 DOI: 10.1016/j.semcdb.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/02/2023] [Accepted: 02/02/2023] [Indexed: 02/08/2023]
Abstract
Understanding the mechanism by which cells coordinate their differentiation and migration is critical to our understanding of many fundamental processes such as wound healing, disease progression, and developmental biology. Mathematical models have been an essential tool for testing and developing our understanding, such as models of cells as soft spherical particles, reaction-diffusion systems that couple cell movement to environmental factors, and multi-scale multi-physics simulations that combine bottom-up rule-based models with continuum laws. However, mathematical models can often be loosely related to data or have so many parameters that model behaviour is weakly constrained. Recent methods in machine learning introduce new means by which models can be derived and deployed. In this review, we discuss examples of mathematical models of aspects of developmental biology, such as cell migration, and how these models can be combined with these recent machine learning methods.
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Affiliation(s)
- Namid R Stillman
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | - Roberto Mayor
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK; Center for Integrative Biology, Faculty of Sciences, Universidad Mayor; Santiago, Chile Santiago, Chile..
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11
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Martínez-Calvo A, Wingreen NS, Datta SS. Pattern formation by bacteria-phage interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.19.558479. [PMID: 37786699 PMCID: PMC10541591 DOI: 10.1101/2023.09.19.558479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
The interactions between bacteria and phages-viruses that infect bacteria-play critical roles in agriculture, ecology, and medicine; however, how these interactions influence the spatial organization of both bacteria and phages remain largely unexplored. Here, we address this gap in knowledge by developing a theoretical model of motile, proliferating bacteria that aggregate via motility-induced phase separation (MIPS) and encounter phage that infect and lyse the cells. We find that the non-reciprocal predator-prey interactions between phage and bacteria strongly alter spatial organization, in some cases giving rise to a rich array of finite-scale stationary and dynamic patterns in which bacteria and phage coexist. We establish principles describing the onset and characteristics of these diverse behaviors, thereby helping to provide a biophysical basis for understanding pattern formation in bacteria-phage systems, as well as in a broader range of active and living systems with similar predator-prey or other non-reciprocal interactions.
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12
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Paz A, Holt KJ, Clarke A, Aviles A, Abraham B, Keene AC, Duboué ER, Fily Y, Kowalko JE. Changes in local interaction rules during ontogeny underlie the evolution of collective behavior. iScience 2023; 26:107431. [PMID: 37636065 PMCID: PMC10448030 DOI: 10.1016/j.isci.2023.107431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/17/2023] [Accepted: 07/17/2023] [Indexed: 08/29/2023] Open
Abstract
Collective motion emerges from individual interactions which produce group-wide patterns in behavior. While adaptive changes to collective motion are observed across animal species, how local interactions change when these collective behaviors evolve is poorly understood. Here, we use the Mexican tetra, Astyanax mexicanus, which exists as a schooling surface form and a non-schooling cave form, to study differences in how fish alter their swimming in response to neighbors across ontogeny and between evolutionarily diverged populations. We find that surface fish undergo a transition to schooling mediated by changes in the way fish modulate speed and turning relative to neighbors. This transition begins with the tendency to align to neighbors emerging by 28 days post-fertilization and ends with the emergence of robust attraction by 70 days post-fertilization. Cavefish exhibit neither alignment nor attraction at any stage of development. These results reveal how evolution alters local interactions to produce striking differences in collective behavior.
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Affiliation(s)
- Alexandra Paz
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Karla J. Holt
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Anik Clarke
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Ari Aviles
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Briana Abraham
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Alex C. Keene
- Department of Biology, Texas A&M, College Station, TX 77840, USA
| | - Erik R. Duboué
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Yaouen Fily
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Johanna E. Kowalko
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, USA
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13
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Zhao H, Košmrlj A, Datta SS. Chemotactic Motility-Induced Phase Separation. PHYSICAL REVIEW LETTERS 2023; 131:118301. [PMID: 37774273 DOI: 10.1103/physrevlett.131.118301] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 06/08/2023] [Accepted: 08/16/2023] [Indexed: 10/01/2023]
Abstract
Collectives of actively moving particles can spontaneously separate into dilute and dense phases-a fascinating phenomenon known as motility-induced phase separation (MIPS). MIPS is well-studied for randomly moving particles with no directional bias. However, many forms of active matter exhibit collective chemotaxis, directed motion along a chemical gradient that the constituent particles can generate themselves. Here, using theory and simulations, we demonstrate that collective chemotaxis strongly competes with MIPS-in some cases, arresting or completely suppressing phase separation, or in other cases, generating fundamentally new dynamic instabilities. We establish principles describing this competition, thereby helping to reveal and clarify the rich physics underlying active matter systems that perform chemotaxis, ranging from cells to robots.
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Affiliation(s)
- Hongbo Zhao
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Andrej Košmrlj
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA
- Princeton Materials Institute, Princeton University, Princeton, New Jersey 08544, USA
| | - Sujit S Datta
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
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14
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Nelson G, Strain A, Isu A, Rahnama A, Wakabayashi KI, Melvin AT, Kato N. Cells collectively migrate during ammonium chemotaxis in Chlamydomonas reinhardtii. Sci Rep 2023; 13:10781. [PMID: 37402785 DOI: 10.1038/s41598-023-36818-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 06/10/2023] [Indexed: 07/06/2023] Open
Abstract
The mechanisms governing chemotaxis in Chlamydomonas reinhardtii are largely unknown compared to those regulating phototaxis despite equal importance on the migratory response in the ciliated microalga. To study chemotaxis, we made a simple modification to a conventional Petri dish assay. Using the assay, a novel mechanism governing Chlamydomonas ammonium chemotaxis was revealed. First, we found that light exposure enhances the chemotactic response of wild-type Chlamydomonas strains, yet phototaxis-incompetent mutant strains, eye3-2 and ptx1, exhibit normal chemotaxis. This suggests that Chlamydomonas transduces the light signal pathway in chemotaxis differently from that in phototaxis. Second, we found that Chlamydomonas collectively migrate during chemotaxis but not phototaxis. Collective migration during chemotaxis is not clearly observed when the assay is conducted in the dark. Third, the Chlamydomonas strain CC-124 carrying agg1-, the AGGREGATE1 gene (AGG1) null mutation, exhibited a more robust collective migratory response than strains carrying the wild-type AGG1 gene. The expression of a recombinant AGG1 protein in the CC-124 strain suppressed this collective migration during chemotaxis. Altogether, these findings suggest a unique mechanism; ammonium chemotaxis in Chlamydomonas is mainly driven by collective cell migration. Furthermore, it is proposed that collective migration is enhanced by light and suppressed by the AGG1 protein.
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Affiliation(s)
- Gabela Nelson
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Alexis Strain
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Atsuko Isu
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Alireza Rahnama
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Ken-Ichi Wakabayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Adam T Melvin
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Naohiro Kato
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
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15
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Paz A, Holt KJ, Clarke A, Aviles A, Abraham B, Keene AC, Duboué ER, Fily Y, Kowalko JE. Changes in local interaction rules during ontogeny underlie the evolution of collective behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.28.534467. [PMID: 37034671 PMCID: PMC10081253 DOI: 10.1101/2023.03.28.534467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Collective motion emerges from individual interactions which produce groupwide patterns in behavior. While adaptive changes to collective motion are observed across animal species, how local interactions change when these collective behaviors evolve is poorly understood. Here, we use the Mexican tetra, A. mexicanus, which exists as a schooling surface form and a non-schooling cave form, to study differences in how fish alter their swimming in response to neighbors across ontogeny and between evolutionarily diverged populations. We find that surface fish undergo a transition to schooling during development that occurs through increases in inter-individual alignment and attraction mediated by changes in the way fish modulate speed and turning relative to neighbors. Cavefish, which have evolved loss of schooling, exhibit neither of these schooling-promoting interactions at any stage of development. These results reveal how evolution alters local interaction rules to produce striking differences in collective behavior.
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Affiliation(s)
- Alexandra Paz
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
| | - Karla J. Holt
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
| | - Anik Clarke
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
| | - Ari Aviles
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
| | - Briana Abraham
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
| | | | - Erik R. Duboué
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
| | - Yaouen Fily
- Wilkes Honors College, Florida Atlantic University, Jupiter FL
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16
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Ni C, Lu T. Individual-Based Modeling of Spatial Dynamics of Chemotactic Microbial Populations. ACS Synth Biol 2022; 11:3714-3723. [PMID: 36336839 PMCID: PMC10129442 DOI: 10.1021/acssynbio.2c00322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
One important direction of synthetic biology is to establish desired spatial structures from microbial populations. Underlying this structural development process are different driving factors, among which bacterial motility and chemotaxis serve as a major force. Here, we present an individual-based, biophysical computational framework for mechanistic and multiscale simulation of the spatiotemporal dynamics of motile and chemotactic microbial populations. The framework integrates cellular movement with spatial population growth, mechanical and chemical cellular interactions, and intracellular molecular kinetics. It is validated by a statistical comparison of single-cell chemotaxis simulations with reported experiments. The framework successfully captures colony range expansion of growing isogenic populations and also reveals chemotaxis-modulated, spatial patterns of a two-species amensal community. Partial differential equation-based models subsequently validate these simulation findings. This study provides a versatile computational tool to uncover the fundamentals of microbial spatial ecology as well as to facilitate the design of synthetic consortia for desired spatial patterns.
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Affiliation(s)
- Congjian Ni
- Center of Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Ting Lu
- Center of Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States.,Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States.,Department of Physics, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States.,Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States.,National Center for Supercomputing Applications, Urbana, Illinois 61801, United States
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17
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Abstract
The morphogenesis of two-dimensional bacterial colonies has been well studied. However, little is known about the colony morphologies of bacteria growing in three dimensions, despite the prevalence of three-dimensional environments (e.g., soil, inside hosts) as natural bacterial habitats. Using experiments on bacteria in granular hydrogel matrices, we find that dense multicellular colonies growing in three dimensions undergo a common morphological instability and roughen, adopting a characteristic broccoli-like morphology when they exceed a critical size. Analysis of a continuum “active fluid” model of the expanding colony reveals that this behavior originates from an interplay of competition for nutrients with growth-driven colony expansion, both of which vary spatially. These results shed light on the fundamental biophysical principles underlying growth in three dimensions. How do growing bacterial colonies get their shapes? While colony morphogenesis is well studied in two dimensions, many bacteria grow as large colonies in three-dimensional (3D) environments, such as gels and tissues in the body or subsurface soils and sediments. Here, we describe the morphodynamics of large colonies of bacteria growing in three dimensions. Using experiments in transparent 3D granular hydrogel matrices, we show that dense colonies of four different species of bacteria generically become morphologically unstable and roughen as they consume nutrients and grow beyond a critical size—eventually adopting a characteristic branched, broccoli-like morphology independent of variations in the cell type and environmental conditions. This behavior reflects a key difference between two-dimensional (2D) and 3D colonies; while a 2D colony may access the nutrients needed for growth from the third dimension, a 3D colony inevitably becomes nutrient limited in its interior, driving a transition to unstable growth at its surface. We elucidate the onset of the instability using linear stability analysis and numerical simulations of a continuum model that treats the colony as an “active fluid” whose dynamics are driven by nutrient-dependent cellular growth. We find that when all dimensions of the colony substantially exceed the nutrient penetration length, nutrient-limited growth drives a 3D morphological instability that recapitulates essential features of the experimental observations. Our work thus provides a framework to predict and control the organization of growing colonies—as well as other forms of growing active matter, such as tumors and engineered living materials—in 3D environments.
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18
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Pradeep S, Arratia PE. To biofilm or not to biofilm. eLife 2022; 11:80891. [PMID: 35861322 PMCID: PMC9302967 DOI: 10.7554/elife.80891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
A new model helps to predict under which conditions a species of bacteria will switch to a static lifestyle.
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Affiliation(s)
- Shravan Pradeep
- Department of Earth and Environmental Sciences, University of Pennsylvania, Philadelphia, United States
| | - Paulo E Arratia
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, United States
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19
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Collective behavior and nongenetic inheritance allow bacterial populations to adapt to changing environments. Proc Natl Acad Sci U S A 2022; 119:e2117377119. [PMID: 35727978 DOI: 10.1073/pnas.2117377119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Collective behaviors require coordination among a group of individuals. As a result, individuals that are too phenotypically different from the rest of the group can be left out, reducing heterogeneity, but increasing coordination. If individuals also reproduce, the offspring can have different phenotypes from their parent(s). This raises the question of how these two opposing processes-loss of diversity by collective behaviors and generation of it through growth and inheritance-dynamically shape the phenotypic composition of an isogenic population. We examine this question theoretically using collective migration of chemotactic bacteria as a model system, where cells of different swimming phenotypes are better suited to navigate in different environments. We find that the differential loss of phenotypes caused by collective migration is environment-dependent. With cell growth, this differential loss enables migrating populations to dynamically adapt their phenotype compositions to the environment, enhancing migration through multiple environments. Which phenotypes are produced upon cell division depends on the level of nongenetic inheritance, and higher inheritance leads to larger composition adaptation and faster migration at steady state. However, this comes at the cost of slower responses to new environments. Due to this trade-off, there is an optimal level of inheritance that maximizes migration speed through changing environments, which enables a diverse population to outperform a nondiverse one. Growing populations might generally leverage the selection-like effects provided by collective behaviors to dynamically shape their own phenotype compositions, without mutations.
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20
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Moore-Ott JA, Chiu S, Amchin DB, Bhattacharjee T, Datta SS. A biophysical threshold for biofilm formation. eLife 2022; 11:76380. [PMID: 35642782 PMCID: PMC9302973 DOI: 10.7554/elife.76380] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 06/01/2022] [Indexed: 11/13/2022] Open
Abstract
Bacteria are ubiquitous in our daily lives, either as motile planktonic cells or as immobilized surface-attached biofilms. These different phenotypic states play key roles in agriculture, environment, industry, and medicine; hence, it is critically important to be able to predict the conditions under which bacteria transition from one state to the other. Unfortunately, these transitions depend on a dizzyingly complex array of factors that are determined by the intrinsic properties of the individual cells as well as those of their surrounding environments, and are thus challenging to describe. To address this issue, here, we develop a generally-applicable biophysical model of the interplay between motility-mediated dispersal and biofilm formation under positive quorum sensing control. Using this model, we establish a universal rule predicting how the onset and extent of biofilm formation depend collectively on cell concentration and motility, nutrient diffusion and consumption, chemotactic sensing, and autoinducer production. Our work thus provides a key step toward quantitatively predicting and controlling biofilm formation in diverse and complex settings.
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Affiliation(s)
- Jenna Anne Moore-Ott
- Department of Chemical and Biological Engineering, Princeton University, Princeton, United States
| | - Selena Chiu
- Department of Chemical and Biological Engineering, Princeton University, Princeton, United States
| | - Daniel B Amchin
- Department of Chemical and Biological Engineering, Princeton University, Princeton, United States
| | - Tapomoy Bhattacharjee
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, United States
| | - Sujit Sankar Datta
- Department of Chemical and Biological Engineering, Princeton University, Princeton, United States
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21
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Amchin DB, Ott JA, Bhattacharjee T, Datta SS. Influence of confinement on the spreading of bacterial populations. PLoS Comput Biol 2022; 18:e1010063. [PMID: 35533196 PMCID: PMC9119553 DOI: 10.1371/journal.pcbi.1010063] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 05/19/2022] [Accepted: 03/28/2022] [Indexed: 11/25/2022] Open
Abstract
The spreading of bacterial populations is central to processes in agriculture, the environment, and medicine. However, existing models of spreading typically focus on cells in unconfined settings—despite the fact that many bacteria inhabit complex and crowded environments, such as soils, sediments, and biological tissues/gels, in which solid obstacles confine the cells and thereby strongly regulate population spreading. Here, we develop an extended version of the classic Keller-Segel model of bacterial spreading via motility that also incorporates cellular growth and division, and explicitly considers the influence of confinement in promoting both cell-solid and cell-cell collisions. Numerical simulations of this extended model demonstrate how confinement fundamentally alters the dynamics and morphology of spreading bacterial populations, in good agreement with recent experimental results. In particular, with increasing confinement, we find that cell-cell collisions increasingly hinder the initial formation and the long-time propagation speed of chemotactic pulses. Moreover, also with increasing confinement, we find that cellular growth and division plays an increasingly dominant role in driving population spreading—eventually leading to a transition from chemotactic spreading to growth-driven spreading via a slower, jammed front. This work thus provides a theoretical foundation for further investigations of the influence of confinement on bacterial spreading. More broadly, these results help to provide a framework to predict and control the dynamics of bacterial populations in complex and crowded environments. The spreading of bacteria through their environments critically impacts our everyday lives; it can be harmful, underlying the progression of infections and spoilage of foods, or can be beneficial, enabling the delivery of therapeutics, sustaining plant growth, and remediating polluted terrain. In all these cases, bacteria typically inhabit crowded environments, such as soils, sediments, and biological tissues/gels, in which solid obstacles confine the cells and regulate their spreading. However, existing models of spreading typically focus on cells in unconfined settings, and thus are frequently not applicable to cells in more complex environments. Here, we address this gap in knowledge by extending the classic Keller-Segel model of bacterial spreading via motility to also incorporate cellular growth and division, and explicitly consider the influence of confinement. Through numerical simulations of this extended model, we show how confinement fundamentally alters the dynamics and morphology of spreading bacterial populations—in particular, driving a transition from chemotactic spreading of motile cells to growth-driven spreading via a slower, jammed front. These results provide a foundation for further investigations of the influence of confinement on bacterial spreading, both by yielding testable predictions for future experiments, and by providing guidelines to predict and control the dynamics of bacterial populations in complex and crowded environments.
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Affiliation(s)
- Daniel B. Amchin
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, United States of America
| | - Jenna A. Ott
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, United States of America
| | - Tapomoy Bhattacharjee
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey, United States of America
| | - Sujit S. Datta
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, United States of America
- * E-mail:
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