1
|
Azadbakht A, Weikl TR, Kraft DJ. Nonadditivity in Many-Body Interactions between Membrane-Deforming Spheres Increases Disorder. ACS NANO 2024. [PMID: 39145618 DOI: 10.1021/acsnano.4c05222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/16/2024]
Abstract
Membrane-induced interactions play an important role in organizing membrane proteins. Measurements of the interactions between two and three membrane deforming objects have revealed their nonadditive nature. They are thought to lead to complex many-body effects, however, experimental evidence is lacking. We here present an experimental method to measure many-body effects in membrane-mediated interactions using colloidal spheres placed between a deflated giant unilamellar vesicles and a planar substrate. The confined colloidal particles cause a large deformation of the membrane while not being physicochemically attached to it and interact through it. Two particles attract with a maximum force of 0.2 pN. For three particles, compact equilateral triangles were preferred over linear arrangements. We use numerical energy minimization to establish that the attraction stems from a reduction in the membrane-deformation energy caused by the particles. Confining up to 36 particles, we find a preference for hexagonally close packed clusters. However, with increasing number of particles the order of the confined particles decreases, at the same time, diffusivity of the particles increases. Our experiments show that the nonadditive nature of membrane-mediated interactions affects the interactions and arrangements and ultimately leads to spherical aggregates with liquid-like order of potential importance for cellular processes.
Collapse
Affiliation(s)
- Ali Azadbakht
- Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands
| | - Thomas R Weikl
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Daniela J Kraft
- Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands
| |
Collapse
|
2
|
Fessler F, Wittmann M, Simmchen J, Stocco A. Autonomous engulfment of active colloids by giant lipid vesicles. SOFT MATTER 2024. [PMID: 38938147 DOI: 10.1039/d4sm00337c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
Our ability to design artificial micro/nanomachines able to perform sophisticated tasks crucially depends on our understanding of their interaction with biosystems and their compatibility with the biological environment. Here, we design Janus colloids fuelled only by glucose and light, which can autonomously interact with cell-like compartments and trigger endocytosis. We evidence the crucial role played by the far-field hydrodynamic interaction arising from the puller/pusher swimming mode and adhesion. We show that a large contact time between the active particle and the lipid membrane is required to observe the engulfment of a particle inside a floppy giant lipid vesicle. Active Janus colloids showing relatively small velocities and a puller type swimming mode are able to target giant vesicles, deform their membranes and subsequently get stably engulfed. An instability arising from the unbound membrane segment is responsible for the transition between partial and complete stable engulfment. These experiments shed light on the physical criteria required for autonomous active particle engulfment in giant vesicles, which can serve as general principles in disciplines ranging from drug delivery and microbial infection to nanomedicine.
Collapse
Affiliation(s)
- Florent Fessler
- Institut Charles Sadron, CNRS UPR-22, 23 rue du Loess, Strasbourg, France.
| | - Martin Wittmann
- Physical Chemistry, TU Dresden, Zellescher Weg 19, 01069 Dresden, Germany
| | - Juliane Simmchen
- Pure and Applied Chemistry, University of Strathclyde, Cathedral Street, Glasgow, UK
| | - Antonio Stocco
- Institut Charles Sadron, CNRS UPR-22, 23 rue du Loess, Strasbourg, France.
| |
Collapse
|
3
|
Jambon-Puillet E, Testa A, Lorenz C, Style RW, Rebane AA, Dufresne ER. Phase-separated droplets swim to their dissolution. Nat Commun 2024; 15:3919. [PMID: 38724503 PMCID: PMC11082165 DOI: 10.1038/s41467-024-47889-y] [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: 10/30/2023] [Accepted: 04/15/2024] [Indexed: 05/12/2024] Open
Abstract
Biological macromolecules can condense into liquid domains. In cells, these condensates form membraneless organelles that can organize chemical reactions. However, little is known about the physical consequences of chemical activity in and around condensates. Working with model bovine serum albumin (BSA) condensates, we show that droplets swim along chemical gradients. Active BSA droplets loaded with urease swim toward each other. Passive BSA droplets show diverse responses to externally applied gradients of the enzyme's substrate and products. In all these cases, droplets swim toward solvent conditions that favor their dissolution. We call this behavior "dialytaxis", and expect it to be generic, as conditions which favor dissolution typically reduce interfacial tension, whose gradients are well-known to drive droplet motion through the Marangoni effect. These results could potentially suggest alternative physical mechanisms for active transport in living cells, and may enable the design of fluid micro-robots.
Collapse
Affiliation(s)
- Etienne Jambon-Puillet
- Department of Materials, ETH Zürich, Zürich, Switzerland
- LadHyX, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France
| | - Andrea Testa
- Department of Materials, ETH Zürich, Zürich, Switzerland
| | - Charlotta Lorenz
- Department of Materials, ETH Zürich, Zürich, Switzerland
- Department of Materials Science and Engineering, Department of Physics, Cornell University, Ithaca, NY, USA
| | - Robert W Style
- Department of Materials, ETH Zürich, Zürich, Switzerland
| | - Aleksander A Rebane
- Department of Materials, ETH Zürich, Zürich, Switzerland
- Life Molecules and Materials Lab, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Eric R Dufresne
- Department of Materials, ETH Zürich, Zürich, Switzerland.
- Department of Materials Science and Engineering, Department of Physics, Cornell University, Ithaca, NY, USA.
| |
Collapse
|
4
|
van der Ham S, Agudo-Canalejo J, Vutukuri HR. Role of Shape in Particle-Lipid Membrane Interactions: From Surfing to Full Engulfment. ACS NANO 2024; 18:10407-10416. [PMID: 38513125 PMCID: PMC11025115 DOI: 10.1021/acsnano.3c11106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 03/08/2024] [Accepted: 03/13/2024] [Indexed: 03/23/2024]
Abstract
Understanding and manipulating the interactions between foreign bodies and cell membranes during endo- and phagocytosis is of paramount importance, not only for the fate of living cells but also for numerous biomedical applications. This study aims to elucidate the role of variables such as anisotropic particle shape, curvature, orientation, membrane tension, and adhesive strength in this essential process using a minimal experimental biomimetic system comprising giant unilamellar vesicles and rod-like particles with different curvatures and aspect ratios. We find that the particle wrapping process is dictated by the balance between the elastic free energy penalty and adhesion free energy gain, leading to two distinct engulfment pathways, tip-first and side-first, emphasizing the significance of the particle orientation in determining the pathway. Moreover, our experimental results are consistent with theoretical predictions in a state diagram, showcasing how to control the wrapping pathway from surfing to partial to complete wrapping by the interplay between membrane tension and adhesive strength. At moderate particle concentrations, we observed the formation of rod clusters, which exhibited cooperative and sequential wrapping. Our study contributes to a comprehensive understanding of the mechanistic intricacies of endocytosis by highlighting how the interplay between the anisotropic particle shape, curvature, orientation, membrane tension, and adhesive strength can influence the engulfment pathway.
Collapse
Affiliation(s)
- Stijn van der Ham
- Active
Soft Matter and Bio-inspired Materials Lab, Faculty of Science and
Technology, MESA+ Institute, University
of Twente, 7500 AE Enschede, The Netherlands
| | - Jaime Agudo-Canalejo
- Department
of Living Matter Physics, Max Planck Institute
for Dynamics and Self-Organization, Göttingen, D-37077, Germany
- Department
of Physics and Astronomy, University College
London, London WC1E 6BT, United Kingdom
| | - Hanumantha Rao Vutukuri
- Active
Soft Matter and Bio-inspired Materials Lab, Faculty of Science and
Technology, MESA+ Institute, University
of Twente, 7500 AE Enschede, The Netherlands
| |
Collapse
|
5
|
Azadbakht A, Meadowcroft B, Májek J, Šarić A, Kraft DJ. Nonadditivity in interactions between three membrane-wrapped colloidal spheres. Biophys J 2024; 123:307-316. [PMID: 38158654 PMCID: PMC10870171 DOI: 10.1016/j.bpj.2023.12.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 10/27/2023] [Accepted: 12/22/2023] [Indexed: 01/03/2024] Open
Abstract
Many cell functions require a concerted effort from multiple membrane proteins, for example, for signaling, cell division, and endocytosis. One contribution to their successful self-organization stems from the membrane deformations that these proteins induce. While the pairwise interaction potential of two membrane-deforming spheres has recently been measured, membrane-deformation-induced interactions have been predicted to be nonadditive, and hence their collective behavior cannot be deduced from this measurement. We here employ a colloidal model system consisting of adhesive spheres and giant unilamellar vesicles to test these predictions by measuring the interaction potential of the simplest case of three membrane-deforming, spherical particles. We quantify their interactions and arrangements and, for the first time, experimentally confirm and quantify the nonadditive nature of membrane-deformation-induced interactions. We furthermore conclude that there exist two favorable configurations on the membrane: (1) a linear and (2) a triangular arrangement of the three spheres. Using Monte Carlo simulations, we corroborate the experimentally observed energy minima and identify a lowering of the membrane deformation as the cause for the observed configurations. The high symmetry of the preferred arrangements for three particles suggests that arrangements of many membrane-deforming objects might follow simple rules.
Collapse
Affiliation(s)
- Ali Azadbakht
- Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, the Netherlands
| | - Billie Meadowcroft
- Institute of Science and Technology Austria, Klosterneuburg, Austria; Department of Physics and Astronomy, Institute for the Physics of Living Systems, University College London, London, United Kingdom
| | - Juraj Májek
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Anđela Šarić
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Daniela J Kraft
- Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, the Netherlands.
| |
Collapse
|
6
|
Sharma V, Fessler F, Thalmann F, Marques CM, Stocco A. Rotational and translational drags of a Janus particle close to a wall and a lipid membrane. J Colloid Interface Sci 2023; 652:2159-2166. [PMID: 37713952 DOI: 10.1016/j.jcis.2023.09.026] [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: 04/20/2023] [Revised: 09/01/2023] [Accepted: 09/04/2023] [Indexed: 09/17/2023]
Abstract
HYPOTHESIS Measuring rotational and translational Brownian motion of single spherical particles reveals dissipations due to the interaction between the particle and the environment. EXPERIMENTS In this article, we show experiments where the in-plane translational and the two rotational drag coefficients of a single spherical Brownian particle can be measured. These particle drags are functions of the particle size and of the particle-wall distance, and of the viscous dissipations at play. We measure drag coefficients for Janus particles close to a solid wall and close to a lipid bilayer membrane. FINDINGS For a particle close to a wall, we show that according to hydrodynamic models, particle-wall distance and particle size can be determined. For a particle partially wrapped by lipid membranes, in absence of strong binding interactions, translational and rotational drags are significantly larger than the ones of non-wrapped particles. Beside the effect of the membrane viscosity, we show that dissipations in the deformed membrane cap region strongly contribute to the drag coefficients.
Collapse
Affiliation(s)
- Vaibhav Sharma
- Institut Charles Sadron, CNRS UPR22-University of Strasbourg, 23 rue du Loess, Strasbourg 67034, France
| | - Florent Fessler
- Institut Charles Sadron, CNRS UPR22-University of Strasbourg, 23 rue du Loess, Strasbourg 67034, France
| | - Fabrice Thalmann
- Institut Charles Sadron, CNRS UPR22-University of Strasbourg, 23 rue du Loess, Strasbourg 67034, France
| | - Carlos M Marques
- ENS Lyon, CNRS, Université Lyon 1, Laboratoire de Chimie UMR 5182, F-69342 Lyon, France
| | - Antonio Stocco
- Institut Charles Sadron, CNRS UPR22-University of Strasbourg, 23 rue du Loess, Strasbourg 67034, France.
| |
Collapse
|
7
|
Lu T, Javed S, Bonfio C, Spruijt E. Interfacing Coacervates with Membranes: From Artificial Organelles and Hybrid Protocells to Intracellular Delivery. SMALL METHODS 2023; 7:e2300294. [PMID: 37354057 DOI: 10.1002/smtd.202300294] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/30/2023] [Indexed: 06/26/2023]
Abstract
Compartmentalization is crucial for the functioning of cells. Membranes enclose and protect the cell, regulate the transport of molecules entering and exiting the cell, and organize cellular machinery in subcompartments. In addition, membraneless condensates, or coacervates, offer dynamic compartments that act as biomolecular storage centers, organizational hubs, or reaction crucibles. Emerging evidence shows that phase-separated membraneless bodies in the cell are involved in a wide range of functional interactions with cellular membranes, leading to transmembrane signaling, membrane remodeling, intracellular transport, and vesicle formation. Such functional and dynamic interplay between phase-separated droplets and membranes also offers many potential benefits to artificial cells, as shown by recent studies involving coacervates and liposomes. Depending on the relative sizes and interaction strength between coacervates and membranes, coacervates can serve as artificial membraneless organelles inside liposomes, as templates for membrane assembly and hybrid artificial cell formation, as membrane remodelers for tubulation and possibly division, and finally, as cargo containers for transport and delivery of biomolecules across membranes by endocytosis or direct membrane crossing. Here, recent experimental examples of each of these functions are reviewed and the underlying physicochemical principles and possible future applications are discussed.
Collapse
Affiliation(s)
- Tiemei Lu
- Institute for Molecules and Materials, Radboud University, Nijmegen, 6525 AJ, The Netherlands
| | - Sadaf Javed
- Institute for Molecules and Materials, Radboud University, Nijmegen, 6525 AJ, The Netherlands
| | - Claudia Bonfio
- Institut de Science et d'Ingénierie Supramoléculaires (ISIS), CNRS UMR 7006, Université de Strasbourg, Strasbourg, 67083, France
| | - Evan Spruijt
- Institute for Molecules and Materials, Radboud University, Nijmegen, 6525 AJ, The Netherlands
| |
Collapse
|
8
|
Testa A, Spanke HT, Jambon-Puillet E, Yasir M, Feng Y, Küffner AM, Arosio P, Dufresne ER, Style RW, Rebane AA. Surface Passivation Method for the Super-repellence of Aqueous Macromolecular Condensates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:14626-14637. [PMID: 37797324 PMCID: PMC10586374 DOI: 10.1021/acs.langmuir.3c01886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/21/2023] [Indexed: 10/07/2023]
Abstract
Solutions of macromolecules can undergo liquid-liquid phase separation to form droplets with ultralow surface tension. Droplets with such low surface tension wet and spread over common surfaces such as test tubes and microscope slides, complicating in vitro experiments. The development of a universal super-repellent surface for macromolecular droplets has remained elusive because their ultralow surface tension requires low surface energies. Furthermore, the nonwetting of droplets containing proteins poses additional challenges because the surface must remain inert to a wide range of chemistries presented by the various amino acid side chains at the droplet surface. Here, we present a method to coat microscope slides with a thin transparent hydrogel that exhibits complete dewetting (contact angles θ ≈ 180°) and minimal pinning of phase-separated droplets in aqueous solution. The hydrogel is based on a swollen matrix of chemically cross-linked polyethylene glycol diacrylate of molecular weight 12 kDa (PEGDA), and can be prepared with basic chemistry laboratory equipment. The PEGDA hydrogel is a powerful tool for in vitro studies of weak interactions, dynamics, and the internal organization of phase-separated droplets in aqueous solutions.
Collapse
Affiliation(s)
- Andrea Testa
- Department
of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | | | - Etienne Jambon-Puillet
- Department
of Materials, ETH Zürich, 8093 Zürich, Switzerland
- LadHyX,
CNRS, Ecole Polytechnique, Institut Polytechnique
de Paris, Palaiseau 91120, France
| | - Mohammad Yasir
- Department
of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Yanxia Feng
- Department
of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Andreas M. Küffner
- Department
of Chemistry and Applied Biosciences, Institute
for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Paolo Arosio
- Department
of Chemistry and Applied Biosciences, Institute
for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland
| | | | - Robert W. Style
- Department
of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Aleksander A. Rebane
- Department
of Materials, ETH Zürich, 8093 Zürich, Switzerland
- Life
Molecules and Materials Laboratory, Programs in Chemistry and in Physics, New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| |
Collapse
|
9
|
Azadbakht A, Meadowcroft B, Varkevisser T, Šarić A, Kraft DJ. Wrapping Pathways of Anisotropic Dumbbell Particles by Giant Unilamellar Vesicles. NANO LETTERS 2023; 23:4267-4273. [PMID: 37141427 DOI: 10.1021/acs.nanolett.3c00375] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Endocytosis is a key cellular process involved in the uptake of nutrients, pathogens, or the therapy of diseases. Most studies have focused on spherical objects, whereas biologically relevant shapes can be highly anisotropic. In this letter, we use an experimental model system based on Giant Unilamellar Vesicles (GUVs) and dumbbell-shaped colloidal particles to mimic and investigate the first stage of the passive endocytic process: engulfment of an anisotropic object by the membrane. Our model has specific ligand-receptor interactions realized by mobile receptors on the vesicles and immobile ligands on the particles. Through a series of experiments, theory, and molecular dynamics simulations, we quantify the wrapping process of anisotropic dumbbells by GUVs and identify distinct stages of the wrapping pathway. We find that the strong curvature variation in the neck of the dumbbell as well as membrane tension are crucial in determining both the speed of wrapping and the final states.
Collapse
Affiliation(s)
- Ali Azadbakht
- Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands
| | - Billie Meadowcroft
- Department of Physics and Astronomy, Institute for the Physics of Living Systems, University College London, London WC1E 6BT, United Kingdom
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Thijs Varkevisser
- Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
| | - Anđela Šarić
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Daniela J Kraft
- Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands
| |
Collapse
|
10
|
Xiao K, Ma R, Wu CX. Wrapping dynamics and critical conditions for active nonspherical nanoparticle uptake. Phys Rev E 2023; 107:054401. [PMID: 37329073 DOI: 10.1103/physreve.107.054401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 04/17/2023] [Indexed: 06/18/2023]
Abstract
The cellular uptake of self-propelled nonspherical nanoparticles (NPs) or viruses by cell membrane is crucial in many biological processes, but its universal dynamics have yet to be elucidated. In this study, using the Onsager variational principle, we obtain a general wrapping equation for nonspherical self-propelled nanoparticles. Two analytical critical conditions are theoretically found, indicating a continuous full uptake for prolate particles and a snapthrough full uptake for oblate particles. They precisely capture the full uptake critical boundaries in the phase diagrams numerically constructed in terms of active force, aspect ratio, adhesion energy density, and membrane tension. It is found that enhancing activity (active force), reducing effective dynamic viscosity, increasing adhesion energy density, and decreasing membrane tension can significantly improve the wrapping efficiency of the self-propelled nonspherical nanoparticles. These results give a panoramic view of the uptake dynamics of active nonspherical nanoparticles, and may offer instructions for designing an effective active NP-based vehicle for controlled drug delivery.
Collapse
Affiliation(s)
- Ke Xiao
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325016, People's Republic of China and Department of Physics, College of Physical Science and Technology, Xiamen University, Xiamen 361005, People's Republic of China
| | - Rui Ma
- Fujian Provincial Key Lab for Soft Functional Materials Research, Research Institute for Biomimetics and Soft Matter, Department of Physics, College of Physical Science and Technology, Xiamen University, Xiamen 361005, People's Republic of China
| | - Chen-Xu Wu
- Fujian Provincial Key Lab for Soft Functional Materials Research, Research Institute for Biomimetics and Soft Matter, Department of Physics, College of Physical Science and Technology, Xiamen University, Xiamen 361005, People's Republic of China
| |
Collapse
|
11
|
Fessler F, Sharma V, Muller P, Stocco A. Entry of microparticles into giant lipid vesicles by optical tweezers. Phys Rev E 2023; 107:L052601. [PMID: 37328973 DOI: 10.1103/physreve.107.l052601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 04/20/2023] [Indexed: 06/18/2023]
Abstract
Entry of micro- or nanosized objects into cells or vesicles made of lipid membranes occurs in many processes such as entry of viruses into host cells, microplastics pollution, drug delivery, or biomedical imaging. Here we investigate the microparticle crossing of lipid membranes in giant unilamellar vesicles in the absence of strong binding interactions (e.g., streptavidin-biotin binding). In these conditions, we observe that organic and inorganic particles can always penetrate inside the vesicles provided an external piconewton force is applied and for relatively low membrane tensions. In the limit of vanishing adhesion, we identify the role of the membrane area reservoir and show that a force minimum exists when the particle size is comparable to the bendocapillary length.
Collapse
Affiliation(s)
- Florent Fessler
- Institut Charles Sadron, UPR No. 22, CNRS, 23 Rue du Loess, 67200 Strasbourg, France
| | - Vaibhav Sharma
- Institut Charles Sadron, UPR No. 22, CNRS, 23 Rue du Loess, 67200 Strasbourg, France
| | - Pierre Muller
- Institut Charles Sadron, UPR No. 22, CNRS, 23 Rue du Loess, 67200 Strasbourg, France
| | - Antonio Stocco
- Institut Charles Sadron, UPR No. 22, CNRS, 23 Rue du Loess, 67200 Strasbourg, France
| |
Collapse
|
12
|
Eisentraut M, Sabri A, Kress H. The spatial resolution limit of phagocytosis. Biophys J 2023; 122:868-879. [PMID: 36703557 PMCID: PMC10027436 DOI: 10.1016/j.bpj.2023.01.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/05/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023] Open
Abstract
Antibody-opsonized bacteria interact with Fc receptors in macrophages and trigger signaling cascades, which induce phagocytosis. The signaling pathways ultimately lead to actin polymerization that induces the protrusion of the membrane around the bacterium until it is completely engulfed. Although many proteins involved in the phagocytic cup formation have already been identified, it is still unclear how far the initial stimulus created by the bacterium-cell contact propagates in the cell. We hypothesize that this spreading distance is closely related to the spatial resolution limit of phagocytosis, the smallest distance in which two stimuli can be differentiated. Here, we probe this resolution limit by using holographic optical tweezers to attach pairs of immunoglobulin G-coated polystyrene microparticles (as models for opsonized bacteria) to murine macrophages in distances ranging from zero to several micrometers. By using 2-μm-sized particles, we found that the particles can be internalized jointly into one phagosome if they are attached to the cell very close together, but that they are taken up separately if they are attached far from each other. To explain this, we developed a model of the signaling process, which predicts the probabilities for separate uptake for different particle sizes and distances using cellular parameters including the average receptor distance. We tested the model by measuring the separate uptake probabilities for particles with a diameter of 1 to 3 μm and for cells with reduced numbers of Fcγ receptors and found very good agreement. Our model shows that the phagocytic uptake behavior can be explained by assuming an effective phagocytic signaling range of about 500 nm. Interestingly, this value corresponds to the lower size limit of phagocytosis. Our work provides quantitative access to spatial parameters of cellular signaling during phagocytosis and thereby contributes to a more quantitative understanding of cellular information processing.
Collapse
Affiliation(s)
| | - Adal Sabri
- Biological Physics, University of Bayreuth, Bayreuth, Germany
| | - Holger Kress
- Biological Physics, University of Bayreuth, Bayreuth, Germany.
| |
Collapse
|
13
|
Sadhu RK, Barger SR, Penič S, Iglič A, Krendel M, Gauthier NC, Gov NS. A theoretical model of efficient phagocytosis driven by curved membrane proteins and active cytoskeleton forces. SOFT MATTER 2022; 19:31-43. [PMID: 36472164 PMCID: PMC10078962 DOI: 10.1039/d2sm01152b] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Phagocytosis is the process of engulfment and internalization of comparatively large particles by cells, and plays a central role in the functioning of our immune system. We study the process of phagocytosis by considering a simplified coarse grained model of a three-dimensional vesicle, having a uniform adhesion interaction with a rigid particle, and containing curved membrane-bound protein complexes or curved membrane nano-domains, which in turn recruit active cytoskeletal forces. Complete engulfment is achieved when the bending energy cost of the vesicle is balanced by the gain in the adhesion energy. The presence of curved (convex) proteins reduces the bending energy cost by self-organizing with a higher density at the highly curved leading edge of the engulfing membrane, which forms the circular rim of the phagocytic cup that wraps around the particle. This allows the engulfment to occur at much smaller adhesion strength. When the curved membrane-bound protein complexes locally recruit actin polymerization machinery, which leads to outward forces being exerted on the membrane, we found that engulfment is achieved more quickly and at a lower protein density. We consider spherical and non-spherical particles and found that non-spherical particles are more difficult to engulf in comparison to the spherical particles of the same surface area. For non-spherical particles, the engulfment time crucially depends on the initial orientation of the particles with respect to the vesicle. Our model offers a mechanism for the spontaneous self-organization of the actin cytoskeleton at the phagocytic cup, in good agreement with recent high-resolution experimental observations.
Collapse
Affiliation(s)
- Raj Kumar Sadhu
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Sarah R Barger
- Molecular, Cellular, Developmental Biology, Yale University, New Haven, USA
| | - Samo Penič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Aleš Iglič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Mira Krendel
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, USA
| | | | - Nir S Gov
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel.
| |
Collapse
|
14
|
Huang X, Hürlimann D, Spanke HT, Wu D, Skowicki M, Dinu IA, Dufresne ER, Palivan CG. Cell-Derived Vesicles with Increased Stability and On-Demand Functionality by Equipping Their Membrane with a Cross-Linkable Copolymer. Adv Healthc Mater 2022; 11:e2202100. [PMID: 36208079 DOI: 10.1002/adhm.202202100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Indexed: 01/28/2023]
Abstract
Cell-derived vesicles retain the cytoplasm and much of the native cell membrane composition. Therefore, they are attractive for investigations of membrane biophysics, drug delivery systems, and complex molecular factories. However, their fragility and aggregation limit their applications. Here, the mechanical properties and stability of giant plasma membrane vesicles (GPMVs) are enhanced by decorating them with a specifically designed diblock copolymer, cholesteryl-poly[2-aminoethyl methacrylate-b-poly(ethylene glycol) methyl ether acrylate]. When cross-linked, this polymer brush enhances the stability of the GPMVs. Furthermore, the pH-responsiveness of the copolymer layer allows for a controlled cargo loading/release, which may enable various bioapplications. Importantly, the cross-linked-copolymer GPMVs are not cytotoxic and preserve in vitro membrane integrity and functionality. This effective strategy to equip the cell-derived vesicles with stimuli-responsive cross-linkable copolymers is expected to open a new route to the stabilization of natural membrane systems and overcome barriers to biomedical applications.
Collapse
Affiliation(s)
- Xinan Huang
- Department of Chemistry, University of Basel, BPR1096, Mattenstrasse 24a, Basel, 4058, Switzerland
| | - Dimitri Hürlimann
- Department of Chemistry, University of Basel, BPR1096, Mattenstrasse 24a, Basel, 4058, Switzerland.,NCCR-Molecular Systems Engineering, BPR1095, Mattenstrasse 24a, Basel, 4058, Switzerland
| | - Hendrik T Spanke
- Laboratory for Soft and Living Materials, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, Zurich, 8093, Switzerland
| | - Dalin Wu
- Department of Chemistry, University of Basel, BPR1096, Mattenstrasse 24a, Basel, 4058, Switzerland
| | - Michal Skowicki
- Department of Chemistry, University of Basel, BPR1096, Mattenstrasse 24a, Basel, 4058, Switzerland.,NCCR-Molecular Systems Engineering, BPR1095, Mattenstrasse 24a, Basel, 4058, Switzerland
| | - Ionel Adrian Dinu
- Department of Chemistry, University of Basel, BPR1096, Mattenstrasse 24a, Basel, 4058, Switzerland.,NCCR-Molecular Systems Engineering, BPR1095, Mattenstrasse 24a, Basel, 4058, Switzerland
| | - Eric R Dufresne
- Laboratory for Soft and Living Materials, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, Zurich, 8093, Switzerland
| | - Cornelia G Palivan
- Department of Chemistry, University of Basel, BPR1096, Mattenstrasse 24a, Basel, 4058, Switzerland.,NCCR-Molecular Systems Engineering, BPR1095, Mattenstrasse 24a, Basel, 4058, Switzerland
| |
Collapse
|
15
|
Xiao K, Ma R, Wu CX. Force-induced wrapping phase transition in activated cellular uptake. Phys Rev E 2022; 106:044411. [PMID: 36397463 DOI: 10.1103/physreve.106.044411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Intracellular pathogens, including all viruses and many bacteria, enter a host cell through either passive endocytosis or active self-propulsion. Though the cellular uptake of passive particles via endocytic process has been studied extensively, little work has been done on the active entry of self-propelled pathogens, such as Listeria monocytogenes. Here, we present a theoretical model to investigate the adhesive wrapping of a self-propelled particle by a plasma membrane, and find a type of first-order wrapping transition from a small partial wrapping state to a large partial wrapping state triggered by the active force. The phase diagram displays more complex behaviors compared with the passive wrapping mediated merely by adhesion. We also find that a tubular protrusion can be formed if the active force exceeds a force barrier. These results may provide a useful guidance to the study of activity-driven cellular entry of active particles into cells.
Collapse
Affiliation(s)
- Ke Xiao
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325016, People's Republic of China and Department of Physics, College of Physical Science and Technology, Xiamen University, Xiamen 361005, People's Republic of China
| | - Rui Ma
- Fujian Provincial Key Lab for Soft Functional Materials Research, Research Institute for Biomimetics and Soft Matter, Department of Physics, College of Physical Science and Technology, Xiamen University, Xiamen 361005, People's Republic of China
| | - Chen-Xu Wu
- Fujian Provincial Key Lab for Soft Functional Materials Research, Research Institute for Biomimetics and Soft Matter, Department of Physics, College of Physical Science and Technology, Xiamen University, Xiamen 361005, People's Republic of China
| |
Collapse
|
16
|
Cao Y, Qiao Y, Cui S, Ge J. Origin of Metal Cluster Tuning Enzyme Activity at the Bio-Nano Interface. JACS AU 2022; 2:961-971. [PMID: 35557767 PMCID: PMC9088776 DOI: 10.1021/jacsau.2c00077] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 06/15/2023]
Abstract
Detailed understanding of how the bio-nano interface orchestrates the function of both biological components and nanomaterials remains ambiguous. Here, through a combination of experiments and molecular dynamics simulations, we investigated how the interface between Candida Antarctic lipase B and palladium (Pd) nanoparticles (NPs) tunes the structure, dynamics, and catalysis of the enzyme. Our simulations show that the metal binding to protein is a shape matching behavior and there is a transition from saturated binding to unsaturated binding along with the increase in the size of metal NPs. When we engineered the interface with the polymer, not only did the critical size of saturated binding of metal NPs become larger, but also the disturbance of the metal NPs to the enzyme function was reduced. In addition, we found that an enzyme-metal interface engineered with the polymer can boost bio-metal cascade reactions via substrate channeling. Understanding and control of the bio-nano interface at the molecular level enable us to rationally design bio-nanocomposites with prospective properties.
Collapse
Affiliation(s)
- Yufei Cao
- Key
Lab for Industrial Biocatalysis, Ministry of Education, Department
of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Yida Qiao
- Key
Lab for Industrial Biocatalysis, Ministry of Education, Department
of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Shitong Cui
- Key
Lab for Industrial Biocatalysis, Ministry of Education, Department
of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Jun Ge
- Key
Lab for Industrial Biocatalysis, Ministry of Education, Department
of Chemical Engineering, Tsinghua University, Beijing 100084, China
- Institute
of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Shenzhen 518055, China
- Institute
of Biomedical Health Technology and Engineering, Shenzhen Bay Laboratory, Shenzhen 518107, China
| |
Collapse
|
17
|
Driven Engulfment of Janus Particles by Giant Vesicles in and out of Thermal Equilibrium. NANOMATERIALS 2022; 12:nano12091434. [PMID: 35564144 PMCID: PMC9101053 DOI: 10.3390/nano12091434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/12/2022] [Accepted: 04/19/2022] [Indexed: 02/01/2023]
Abstract
The interaction between Janus colloids and giant lipid vesicles was experimentally investigated to elucidate the dynamics and mechanisms related to microparticle engulfment by lipid vesicles. Janus (Pt–SiO2 and Pt–MF, where MF is melamine formaldehyde) colloids do not spontaneously adhere to POPC or DOPC bilayers, but by applying external forces via centrifugation we were able to force the contact between the particles and the membranes, which may result in a partial engulfment state of the particle. Surface properties of the Janus colloids play a crucial role in the driven particle engulfment by vesicles. Engulfment of the silica and platinum regions of the Janus particles can be observed, whereas the polymer (MF) region does not show any affinity towards the lipid bilayer. By using fluorescence microscopy, we were able to monitor the particle orientation and measure the rotational dynamics of a single Janus particle engulfed by a vesicle. By adding hydrogen peroxide to the solution, particle self-propulsion was used to perform an active transport of a giant vesicle by a single active particle. Finally, we observe that partially engulfed particles experience a membrane curvature-induced force, which pushes the colloids towards the bottom where the membrane curvature is the lowest.
Collapse
|
18
|
Ewins EJ, Han K, Bharti B, Robinson T, Velev OD, Dimova R. Controlled adhesion, membrane pinning and vesicle transport by Janus particles. Chem Commun (Camb) 2022; 58:3055-3058. [PMID: 35166272 DOI: 10.1039/d1cc07026f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The interactions between biomembranes and particles are key to many applications, but the lack of controllable model systems to study them limits the progress in their research. Here, we describe how Janus polystyrene microparticles, half coated with iron, can be partially engulfed by artificial cells, namely giant vesicles, with the goals to control and investigate their adhesion and degree of encapsulation. The interaction between the Janus particles and these model cell membrane systems is mediated by electrostatic charge, offering a further mode of modulation in addition to the iron patches. The ferromagnetic particle coatings also enable manipulation and transport of the vesicles by magnetic fields.
Collapse
Affiliation(s)
- Eleanor J Ewins
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany.
| | - Koohee Han
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Bhuvnesh Bharti
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Tom Robinson
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany.
| | - Orlin D Velev
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany.
| |
Collapse
|
19
|
Chen T, Zhang Y, Li X, Li C, Lu T, Xiao S, Liang H. Curvature-Mediated Pair Interactions of Soft Nanoparticles Adhered to a Cell Membrane. J Chem Theory Comput 2021; 17:7850-7861. [PMID: 34865469 DOI: 10.1021/acs.jctc.1c00897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The curvature-mediated interactions by cell membranes are crucial in many biological processes. We systematically studied the curvature-mediated wrapping of soft nanoparticles (NPs) by a tensionless membrane and the underlying pair interactions between NPs in determining it. We found that there are three types of wrapping pathways, namely, independence, cooperation, and tubulation. The particle size, adhesion strength, and softness are found to be strongly related with the wrapping mechanism. Reducing the adhesion strength transforms the wrapping pathway from cooperation to independence, while enhancing the NP softness requires a stronger adhesion to achieve the cooperative wrapping. This transformation of the wrapping pathway is controlled by the curvature-mediated interactions between NPs. For either soft or rigid NPs, the pair interactions are repulsive at short-ranged distances between NPs, while at long-ranged distances, a larger adhesion between NPs and a membrane is needed to generate attraction between NPs. Moreover, an enhancement of NP softness weakens the repulsion between NPs. These distinct behaviors of soft NPs are ascribed to the gentler deformation of the membrane at the face-to-face region between NPs due to the flattening and spreading of soft NPs along the membrane, requiring a reduced energy cost for soft NPs to approach each other. Our results provide a mechanistic understanding in detail about the membrane-mediated interactions between NPs and their interactions with cell membranes, which is helpful to understand the curvature-mediated assemblies of adhesive proteins or NPs on membranes, and offer novel possibilities for designing an effective NP-based vehicle for controlled drug delivery.
Collapse
Affiliation(s)
- Tongwei Chen
- Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Yunhan Zhang
- Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Xuejin Li
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou 310027, P. R. China
| | - Chengxu Li
- Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Teng Lu
- Computer Network Information Center of the Chinese Academy of Sciences, Beijing 100083, P. R. China
| | - Shiyan Xiao
- Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Haojun Liang
- Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| |
Collapse
|
20
|
Schneemilch M, Quirke N. Predicting nanoparticle uptake by biological membranes: theory and simulation. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.1996574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - N. Quirke
- Department of Chemistry, Imperial College, London, UK
| |
Collapse
|
21
|
Fleury JB, Baulin VA. Microplastics destabilize lipid membranes by mechanical stretching. Proc Natl Acad Sci U S A 2021; 118:e2104610118. [PMID: 34326264 PMCID: PMC8346836 DOI: 10.1073/pnas.2104610118] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Estimated millions of tons of plastic are dumped annually into oceans. Plastic has been produced only for 70 y, but the exponential rise of mass production leads to its widespread proliferation in all environments. As a consequence of their large abundance globally, microplastics are also found in many living organisms including humans. While the health impact of digested microplastics on living organisms is debatable, we reveal a physical mechanism of mechanical stretching of model cell lipid membranes induced by adsorbed micrometer-sized microplastic particles most commonly found in oceans. Combining experimental and theoretical approaches, we demonstrate that microplastic particles adsorbed on lipid membranes considerably increase membrane tension even at low particle concentrations. Each particle adsorbed at the membrane consumes surface area that is proportional to the contact area between particle and the membrane. Although lipid membranes are liquid and able to accommodate mechanical stress, the relaxation time is much slower than the rate of adsorption; thus, the cumulative effect from arriving microplastic particles to the membrane leads to the global reduction of the membrane area and increase of membrane tension. This, in turn, leads to a strong reduction of membrane lifetime. The effect of mechanical stretching of microplastics on living cells membranes was demonstrated by using the aspiration micropipette technique on red blood cells. The described mechanical stretching mechanism on lipid bilayers may provide better understanding of the impact of microplastic particles in living systems.
Collapse
Affiliation(s)
- Jean-Baptiste Fleury
- Experimental Physics, Universitat des Saarlandes, 66123 Saarbruecken, Germany;
- Center for Biophysics, Universitat des Saarlandes, 66123 Saarbruecken, Germany
| | - Vladimir A Baulin
- Departament Química Física i Inorgànica, Universitat Rovira i Virgili, 43007 Tarragona, Spain
| |
Collapse
|
22
|
Frey F, Idema T. More than just a barrier: using physical models to couple membrane shape to cell function. SOFT MATTER 2021; 17:3533-3549. [PMID: 33503097 DOI: 10.1039/d0sm01758b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The correct execution of many cellular processes, such as division and motility, requires the cell to adopt a specific shape. Physically, these shapes are determined by the interplay of the plasma membrane and internal cellular driving factors. While the plasma membrane defines the boundary of the cell, processes inside the cell can result in the generation of forces that deform the membrane. These processes include protein binding, the assembly of protein superstructures, and the growth and contraction of cytoskeletal networks. Due to the complexity of the cell, relating observed membrane deformations back to internal processes is a challenging problem. Here, we review cell shape changes in endocytosis, cell adhesion, cell migration and cell division and discuss how by modeling membrane deformations we can investigate the inner working principles of the cell.
Collapse
Affiliation(s)
- Felix Frey
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
| | | |
Collapse
|