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Sheikh S, Lonetti B, Touche I, Mohammadi A, Li Z, Abbas M. Brownian motion of soft particles near a fluctuating lipid bilayer. J Chem Phys 2023; 159:244903. [PMID: 38149741 DOI: 10.1063/5.0182499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 11/12/2023] [Indexed: 12/28/2023] Open
Abstract
The dynamics of a soft particle suspended in a viscous fluid can be changed by the presence of an elastic boundary. Understanding the mechanisms and dynamics of soft-soft surface interactions can provide valuable insights into many important research fields, including biomedical engineering, soft robotics development, and materials science. This work investigates the anomalous transport properties of a soft nanoparticle near a visco-elastic interface, where the particle consists of a polymer assembly in the form of a micelle and the interface is represented by a lipid bilayer membrane. Mesoscopic simulations using a dissipative particle dynamics model are performed to examine the impact of micelle's proximity to the membrane on its Brownian motion. Two different sizes are considered, which correspond to ≈10-20nm in physical units. The wavelengths typically seen by the largest micelle fall within the range of wavenumbers where the Helfrich model captures fairly well the bilayer mechanical properties. Several independent simulations allowed us to compute the micelle trajectories during an observation time smaller than the diffusive time scale (whose order of magnitude is similar to the membrane relaxation time of the largest wavelengths), this time scale being hardly accessible by experiments. From the probability density function of the micelle normal position with respect to the membrane, it is observed that the position remains close to the starting position during ≈0.05τd (where τd corresponds to the diffusion time), which allowed us to compare the negative excess of mean-square displacement (MSD) to existing theories. In that time range, the MSD exhibits different behaviors along parallel and perpendicular directions. When the micelle is sufficiently close to the bilayer (its initial distance from the bilayer equals approximately twice its gyration radius), the micelle motion becomes quickly subdiffusive in the normal direction. Moreover, the temporal evolution of the micelle MSD excess in the perpendicular direction follows that of a nanoparticle near an elastic membrane. However, in the parallel direction, the MSD excess is rather similar to that of a nanoparticle near a liquid interface.
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Affiliation(s)
- S Sheikh
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - B Lonetti
- IMRCP, UMR5623 CNRS, Université de Toulouse, Toulouse, France
- FR FERMAT, Université de Toulouse, CNRS, INPT, INSA, UPS, Toulouse, France
| | - I Touche
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - A Mohammadi
- Department of Mechanical Engineering, Clemson University, Clemson, South Carolina 29634, USA
| | - Z Li
- Department of Mechanical Engineering, Clemson University, Clemson, South Carolina 29634, USA
| | - M Abbas
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
- FR FERMAT, Université de Toulouse, CNRS, INPT, INSA, UPS, Toulouse, France
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2
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Jünger F, Rohrbach A. Making Hidden Cell Particle Interactions Visible by Thermal Noise Frequency Decomposition. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2207032. [PMID: 37337392 DOI: 10.1002/smll.202207032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 02/15/2023] [Indexed: 06/21/2023]
Abstract
Thermal noise drives cellular structures, bacteria, and viruses on different temporal and spatial scales. Their weak interactions with their environment can change on subsecond scales. However, particle interactions can be hidden or invisible-even when measured with thermal noise sensitivity, leading to misconceptions about their binding behavior. Here, it is demonstrated how invisible particle interactions at the cell periphery become visible by MHz interferometric thermal noise tracking and frequency decomposition at a spectral update rate of only 0.5 s. The particle fluctuations are analyzed in radial and lateral directions by a viscoelastic modulus G(ω,tex ) over the experiment time tex , revealing a surprisingly similar, frequency dependent response for different cell types. This response behavior can be explained by a mathematical model for molecular scale elasticity and damping. The method to reveal hidden interactions is tested at two examples: the stiffening of macrophage filopodia tips within 2 s with particle contact invisible by the fluctuation width. Second, the extent and stiffness of the soft cell glycocalyx is measured, which can be sensed by a particle only on microsecond-timescales, but which remains invisible on time-average. This concept study shows how to uncover hidden cellular interactions, if particle motions are measured at high-speed.
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Affiliation(s)
- Felix Jünger
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany
| | - Alexander Rohrbach
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signaling Studies, University of Freiburg, Schänzlestr. 18, 79104, Freiburg, Germany
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3
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Mendonca T, Lis-Slimak K, Matheson AB, Smith MG, Anane-Adjei AB, Ashworth JC, Cavanagh R, Paterson L, Dalgarno PA, Alexander C, Tassieri M, Merry CLR, Wright AJ. OptoRheo: Simultaneous in situ micro-mechanical sensing and imaging of live 3D biological systems. Commun Biol 2023; 6:463. [PMID: 37117487 PMCID: PMC10147656 DOI: 10.1038/s42003-023-04780-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 03/30/2023] [Indexed: 04/30/2023] Open
Abstract
Biomechanical cues from the extracellular matrix (ECM) are essential for directing many cellular processes, from normal development and repair, to disease progression. To better understand cell-matrix interactions, we have developed a new instrument named 'OptoRheo' that combines light sheet fluorescence microscopy with particle tracking microrheology. OptoRheo lets us image cells in 3D as they proliferate over several days while simultaneously sensing the mechanical properties of the surrounding extracellular and pericellular matrix at a sub-cellular length scale. OptoRheo can be used in two operational modalities (with and without an optical trap) to extend the dynamic range of microrheology measurements. We corroborated this by characterising the ECM surrounding live breast cancer cells in two distinct culture systems, cell clusters in 3D hydrogels and spheroids in suspension culture. This cutting-edge instrument will transform the exploration of drug transport through complex cell culture matrices and optimise the design of the next-generation of disease models.
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Affiliation(s)
- Tania Mendonca
- Optics and Photonics Research Group, Faculty of Engineering, University of Nottingham, Nottingham, UK.
| | - Katarzyna Lis-Slimak
- Nottingham Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, UK
| | - Andrew B Matheson
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, UK
| | - Matthew G Smith
- Division of Biomedical Engineering, James Watt School of Engineering, University of Glasgow, Glasgow, UK
| | | | - Jennifer C Ashworth
- Nottingham Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, UK
- School of Veterinary Medicine & Science, University of Nottingham, Sutton Bonington Campus, Leicestershire, UK
| | - Robert Cavanagh
- School of Pharmacy, University of Nottingham, Nottingham, UK
| | - Lynn Paterson
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, UK
| | - Paul A Dalgarno
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, UK
| | | | - Manlio Tassieri
- Division of Biomedical Engineering, James Watt School of Engineering, University of Glasgow, Glasgow, UK
| | - Catherine L R Merry
- Nottingham Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, UK
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Amanda J Wright
- Optics and Photonics Research Group, Faculty of Engineering, University of Nottingham, Nottingham, UK
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4
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Ayala YA, Omidvar R, Römer W, Rohrbach A. Thermal fluctuations of the lipid membrane determine particle uptake into Giant Unilamellar Vesicles. Nat Commun 2023; 14:65. [PMID: 36599837 PMCID: PMC9813155 DOI: 10.1038/s41467-022-35302-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 11/25/2022] [Indexed: 01/06/2023] Open
Abstract
Phagocytic particle uptake is crucial for the fate of both living cells and pathogens. Invading particles have to overcome fluctuating lipid membranes as the first physical barrier. However, the energy and the role of the fluctuation-based particle-membrane interactions during particle uptake are not understood. We tackle this problem by indenting the membrane of differently composed Giant Unilamellar Vesicles (GUVs) with optically trapped particles until particle uptake. By continuous 1 MHz tracking and autocorrelating the particle's positions within 30µs delays for different indentations, the fluctuations' amplitude, the damping, the mean forces, and the energy profiles were obtained. Remarkably, the uptake energy into a GUV becomes predictable since it increases for smaller fluctuation amplitudes and longer relaxation time. Our observations could be explained by a mathematical model based on continuous suppression of fluctuation modes. Hence, the reduced particle uptake energy for protein-ligand interactions LecA-Gb3 or Biotin-Streptavidin results also from pronounced, low-friction membrane fluctuations.
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Affiliation(s)
- Yareni A Ayala
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering - IMTEK, University of Freiburg, Georges-Köhler-Allee 102, 79110, Freiburg, Germany
| | - Ramin Omidvar
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany
| | - Winfried Römer
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany.,Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Albertstraße 19, 79104, Freiburg, Germany
| | - Alexander Rohrbach
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering - IMTEK, University of Freiburg, Georges-Köhler-Allee 102, 79110, Freiburg, Germany. .,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany.
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Optical Tweezers with Integrated Multiplane Microscopy (OpTIMuM): a new tool for 3D microrheology. Sci Rep 2021; 11:5614. [PMID: 33692443 PMCID: PMC7946888 DOI: 10.1038/s41598-021-85013-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 02/05/2021] [Indexed: 11/09/2022] Open
Abstract
We introduce a novel 3D microrheology system that combines for the first time Optical Tweezers with Integrated Multiplane Microscopy (OpTIMuM). The system allows the 3D tracking of an optically trapped bead, with ~ 20 nm accuracy along the optical axis. This is achieved without the need for a high precision z-stage, separate calibration sample, nor a priori knowledge of either the bead size or the optical properties of the suspending medium. Instead, we have developed a simple yet effective in situ spatial calibration method using image sharpness and exploiting the fact we image at multiple planes simultaneously. These features make OpTIMuM an ideal system for microrheology measurements, and we corroborate the effectiveness of this novel microrheology tool by measuring the viscosity of water in three dimensions, simultaneously.
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6
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Vaippully R, Ramanujan V, Gopalakrishnan M, Bajpai S, Roy B. Detection of sub-degree angular fluctuations of the local cell membrane slope using optical tweezers. SOFT MATTER 2020; 16:7606-7612. [PMID: 32724976 DOI: 10.1039/d0sm00566e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Normal thermal fluctuations of the cell membrane have been studied extensively using high resolution microscopy and focused light, particularly at the peripheral regions of a cell. We use a single probe particle attached non-specifically to the cell-membrane to determine that the power spectral density is proportional to (frequency)-5/3 in the range of 5 Hz to 1 kHz. We also use a new technique to simultaneously ascertain the slope fluctuations of the membrane by relying upon the determination of pitch motion of the birefringent probe particle trapped in linearly polarized optical tweezers. In the process, we also develop the technique to identify pitch rotation to a high resolution using optical tweezers. We find that the power spectrum of slope fluctuations is proportional to (frequency)-1, which we also explain theoretically. We find that we can extract parameters like bending rigidity directly from the coefficient of the power spectrum particularly at high frequencies, instead of being convoluted with other parameters, thereby improving the accuracy of estimation. We anticipate this technique for determination of the pitch angle in spherical particles to high resolution as a starting point for many interesting studies using the optical tweezers.
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Affiliation(s)
- Rahul Vaippully
- Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India.
| | - Vaibavi Ramanujan
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Manoj Gopalakrishnan
- Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India.
| | - Saumendra Bajpai
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Basudev Roy
- Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India.
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7
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Xu Z, Gao L, Chen P, Yan LT. Diffusive transport of nanoscale objects through cell membranes: a computational perspective. SOFT MATTER 2020; 16:3869-3881. [PMID: 32236197 DOI: 10.1039/c9sm02338k] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Diffusion is an essential and fundamental means of transport of substances on cell membranes, and the dynamics of biomembranes plays a crucial role in the regulation of numerous cellular processes. The understanding of the complex mechanisms and the nature of particle diffusion have a bearing on establishing guidelines for the design of efficient transport materials and unique therapeutic approaches. Herein, this review article highlights the most recent advances in investigating diffusion dynamics of nanoscale objects on biological membranes, focusing on the approaches of tailored computer simulations and theoretical analysis. Due to the presence of the complicated and heterogeneous environment on native cell membranes, the diffusive transport behaviors of nanoparticles exhibit unique and variable characteristics. The general aspects and basic theories of normal diffusion and anomalous diffusion have been introduced. In addition, the influence of a series of external and internal factors on the diffusion behaviors is discussed, including particle size, membrane curvature, particle-membrane interactions or particle-inclusion, and the crowding degree of membranes. Finally, we seek to identify open problems in the existing experimental, simulation, and theoretical research studies, and to propose challenges for future development.
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Affiliation(s)
- Ziyang Xu
- Key Laboratory of Advanced Materials (MOE), Department of Chemical Engineering, Tsinghua University, Beijing 100084, P. R. China.
| | - Lijuan Gao
- Key Laboratory of Advanced Materials (MOE), Department of Chemical Engineering, Tsinghua University, Beijing 100084, P. R. China.
| | - Pengyu Chen
- Key Laboratory of Advanced Materials (MOE), Department of Chemical Engineering, Tsinghua University, Beijing 100084, P. R. China.
| | - Li-Tang Yan
- Key Laboratory of Advanced Materials (MOE), Department of Chemical Engineering, Tsinghua University, Beijing 100084, P. R. China.
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8
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Rohrbach A, Meyer T, Stelzer EHK, Kress H. Measuring Stepwise Binding of Thermally Fluctuating Particles to Cell Membranes without Fluorescence. Biophys J 2020; 118:1850-1860. [PMID: 32229315 DOI: 10.1016/j.bpj.2020.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 02/28/2020] [Accepted: 03/03/2020] [Indexed: 01/07/2023] Open
Abstract
Thermal motions enable a particle to probe the optimal interaction state when binding to a cell membrane. However, especially on the scale of microseconds and nanometers, position and orientation fluctuations are difficult to observe with common measurement technologies. Here, we show that it is possible to detect single binding events of immunoglobulin-G-coated polystyrene beads, which are held in an optical trap near the cell membrane of a macrophage. Changes in the spatial and temporal thermal fluctuations of the particle were measured interferometrically, and no fluorophore labeling was required. We demonstrate both by Brownian dynamic simulations and by experiments that sequential stepwise increases in the force constant of the bond between a bead and a cell of typically 20 pN/μm are clearly detectable. In addition, this technique provides estimates about binding rates and diffusion constants of membrane receptors. The simple approach of thermal noise tracking points out new strategies in understanding interactions between cells and particles, which are relevant for a large variety of processes, including phagocytosis, drug delivery, and the effects of small microplastics and particulates on cells.
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Affiliation(s)
- Alexander Rohrbach
- Laboratory for Bio- and Nano-Photonics, University of Freiburg, Department of Microsystems Engineering, Freiburg, Germany; Centre for integrative Biological Signalling Studies, Freiburg, Germany.
| | - Tim Meyer
- Laboratory for Bio- and Nano-Photonics, University of Freiburg, Department of Microsystems Engineering, Freiburg, Germany
| | - Ernst H K Stelzer
- Laboratory for Physical Biology, Buchmann Institute for Molecular Life Sciences, University of Frankfurt, Frankfurt Main, Germany
| | - Holger Kress
- Department of Physics, University of Bayreuth, Bayreuth, Germany.
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9
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Daddi-Moussa-Ider A, Kurzthaler C, Hoell C, Zöttl A, Mirzakhanloo M, Alam MR, Menzel AM, Löwen H, Gekle S. Frequency-dependent higher-order Stokes singularities near a planar elastic boundary: Implications for the hydrodynamics of an active microswimmer near an elastic interface. Phys Rev E 2019; 100:032610. [PMID: 31639990 DOI: 10.1103/physreve.100.032610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Indexed: 06/10/2023]
Abstract
The emerging field of self-driven active particles in fluid environments has recently created significant interest in the biophysics and bioengineering communities owing to their promising future for biomedical and technological applications. These microswimmers move autonomously through aqueous media, where under realistic situations they encounter a plethora of external stimuli and confining surfaces with peculiar elastic properties. Based on a far-field hydrodynamic model, we present an analytical theory to describe the physical interaction and hydrodynamic couplings between a self-propelled active microswimmer and an elastic interface that features resistance toward shear and bending. We model the active agent as a superposition of higher-order Stokes singularities and elucidate the associated translational and rotational velocities induced by the nearby elastic boundary. Our results show that the velocities can be decomposed in shear and bending related contributions which approach the velocities of active agents close to a no-slip rigid wall in the steady limit. The transient dynamics predict that contributions to the velocities of the microswimmer due to bending resistance are generally more pronounced than those due to shear resistance. Bending can enhance (suppress) the velocities resulting from higher-order singularities whereas the shear related contribution decreases (increases) the velocities. Most prominently, we find that near an elastic interface of only energetic resistance toward shear deformation, such as that of an elastic capsule designed for drug delivery, a swimming bacterium undergoes rotation of the same sense as observed near a no-slip wall. In contrast to that, near an interface of only energetic resistance toward bending, such as that of a fluid vesicle or liposome, we find a reversed sense of rotation. Our results provide insight into the control and guidance of artificial and synthetic self-propelling active microswimmers near elastic confinements.
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Affiliation(s)
- Abdallah Daddi-Moussa-Ider
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Christina Kurzthaler
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Christian Hoell
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Andreas Zöttl
- Institute for Theoretical Physics, Technische Universität Wien, Wiedner Hauptstraße 8-10, 1040 Wien, Austria
| | - Mehdi Mirzakhanloo
- Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA
| | - Mohammad-Reza Alam
- Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA
| | - Andreas M Menzel
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Hartmut Löwen
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Stephan Gekle
- Biofluid Simulation and Modeling, Theoretische Physik VI, Universität Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany
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10
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Zhang S, Gibson LJ, Stilgoe AB, Nieminen TA, Rubinsztein-Dunlop H. Measuring local properties inside a cell-mimicking structure using rotating optical tweezers. JOURNAL OF BIOPHOTONICS 2019; 12:e201900022. [PMID: 30779305 DOI: 10.1002/jbio.201900022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 02/13/2019] [Accepted: 02/14/2019] [Indexed: 05/06/2023]
Abstract
Exploring the rheological properties of intracellular materials is essential for understanding cellular and subcellular processes. Optical traps have been widely used for physical manipulation of micro and nano objects within fluids enabling studies of biological systems. However, experiments remain challenging as it is unclear how the probe particle's mobility is influenced by the nearby membranes and organelles. We use liposomes (unilamellar lipid vesicles) as a simple biomimetic model of living cells, together with a trapped particle rotated by optical tweezers to study mechanical and rheological properties inside a liposome both theoretically and experimentally. Here, we demonstrate that this system has the capacity to predict the hydrodynamic interaction between three-dimensional spatial membranes and internal probe particles within submicron distances, and it has the potential to aid in the design of high resolution optical micro/nanorheology techniques to be used inside living cells.
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Affiliation(s)
- Shu Zhang
- Department of Physics, School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, Australia
| | - Lachlan J Gibson
- Department of Physics, School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, Australia
| | - Alexander B Stilgoe
- Department of Physics, School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, Australia
| | - Timo A Nieminen
- Department of Physics, School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, Australia
| | - Halina Rubinsztein-Dunlop
- Department of Physics, School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, Australia
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11
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Jünger F, Rohrbach A. Strong cytoskeleton activity on millisecond timescales upon particle binding revealed by ROCS microscopy. Cytoskeleton (Hoboken) 2018; 75:410-424. [PMID: 30019494 DOI: 10.1002/cm.21478] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 07/05/2018] [Accepted: 07/10/2018] [Indexed: 01/09/2023]
Abstract
Cells change their shape within seconds, cellular protrusions even on subsecond timescales enabling various responses to stimuli of approaching bacteria, viruses or pharmaceutical drugs. Typical response patterns are governed by a complex reorganization of the actin cortex, where single filaments and molecules act on even faster timescales. These dynamics have remained mostly invisible due to a superposition of slow and fast motions, but also due to a lack of adequate imaging technology. Whereas fluorescence techniques require too long integration times, novel coherent techniques such as ROCS microscopy can achieve sufficiently high spatiotemporal resolution. ROCS uses rotating back-scattered laser light from cellular structures and generates a consistently high image contrast at 150 nm resolution and frame rates of 100 Hz-without fluorescence or bleaching. Here, we present an extension of ROCS microscopy that exploits the principles of dynamic light scattering for precise localization, visualization and quantification of the cytoskeleton activity of mouse macrophages. The locally observed structural reorganization processes, encoded by dynamic speckle patterns, occur upon distinct mechanical stimuli, such as soft contacts with optically trapped beads. We find that a substantial amount of the near-membrane cytoskeleton activity takes place on millisecond timescales, which is much faster than reported ever before.
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Affiliation(s)
- Felix Jünger
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Alexander Rohrbach
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, Freiburg, Germany
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12
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Kashekodi AB, Meinert T, Michiels R, Rohrbach A. Miniature scanning light-sheet illumination implemented in a conventional microscope. BIOMEDICAL OPTICS EXPRESS 2018; 9:4263-4274. [PMID: 30615716 PMCID: PMC6157761 DOI: 10.1364/boe.9.004263] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 08/02/2018] [Indexed: 05/02/2023]
Abstract
Living cells are highly dynamic systems responding to a large variety of biochemical and mechanical stimuli over minutes, which are well controlled by e.g. optical tweezers. However, live cell investigation through fluorescence microscopy is usually limited not only by the spatial and temporal imaging resolution but also by fluorophore bleaching. Therefore, we designed a miniature light-sheet illumination system that is implemented in a conventional inverted microscope equipped with optical tweezers and interferometric tracking to capture 3D images of living macrophages at reduced bleaching. The horizontal light-sheet is generated with a 0.12 mm small cantilevered mirror placed at 45° to the detection axis. The objective launched illumination beam is reflected by the micro-mirror and illuminates the sample perpendicular to the detection axis. Lateral and axial scanning of both Gaussian and Bessel beams, together with an electrically tunable lens for fast focusing, enables rapid 3D image capture without moving the sample or the objective lens. Using scanned Bessel beams and line-confocal detection, an average axial resolution of 0.8 µm together with a 10-15 fold improved image contrast is achieved.
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13
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Daddi-Moussa-Ider A, Lisicki M, Gekle S, Menzel AM, Löwen H. Hydrodynamic coupling and rotational mobilities near planar elastic membranes. J Chem Phys 2018; 149:014901. [DOI: 10.1063/1.5032304] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Abdallah Daddi-Moussa-Ider
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
- Biofluid Simulation and Modeling, Theoretische Physik, Universität Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany
| | - Maciej Lisicki
- Department of Applied Mathematics and Theoretical Physics, Wilberforce Rd, Cambridge CB3 0WA, United Kingdom
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Stephan Gekle
- Biofluid Simulation and Modeling, Theoretische Physik, Universität Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany
| | - Andreas M. Menzel
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Hartmut Löwen
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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Daddi-Moussa-Ider A, Gekle S. Brownian motion near an elastic cell membrane: A theoretical study. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2018; 41:19. [PMID: 29404712 DOI: 10.1140/epje/i2018-11627-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 01/18/2018] [Indexed: 06/07/2023]
Abstract
Elastic confinements are an important component of many biological systems and dictate the transport properties of suspended particles under flow. In this paper, we review the Brownian motion of a particle moving in the vicinity of a living cell whose membrane is endowed with a resistance towards shear and bending. The analytical calculations proceed through the computation of the frequency-dependent mobility functions and the application of the fluctuation-dissipation theorem. Elastic interfaces endow the system with memory effects that lead to a long-lived anomalous subdiffusive regime of nearby particles. In the steady limit, the diffusional behavior approaches that near a no-slip hard wall. The analytical predictions are validated and supplemented with boundary-integral simulations.
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Affiliation(s)
- Abdallah Daddi-Moussa-Ider
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany.
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, 95440, Bayreuth, Germany.
| | - Stephan Gekle
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, 95440, Bayreuth, Germany
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Daddi-Moussa-Ider A, Lisicki M, Gekle S. Hydrodynamic mobility of a solid particle near a spherical elastic membrane. II. Asymmetric motion. Phys Rev E 2017; 95:053117. [PMID: 28618646 DOI: 10.1103/physreve.95.053117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Indexed: 06/07/2023]
Abstract
In this paper, we derive analytical expressions for the leading-order hydrodynamic mobility of a small solid particle undergoing motion tangential to a nearby large spherical capsule whose membrane possesses resistance toward shearing and bending. Together with the results obtained in the first part [Daddi-Moussa-Ider and Gekle, Phys. Rev. E 95, 013108 (2017)2470-004510.1103/PhysRevE.95.013108], where the axisymmetric motion perpendicular to the capsule membrane is considered, the solution of the general mobility problem is thus determined. We find that shearing resistance induces a low-frequency peak in the particle self-mobility, resulting from the membrane normal displacement in the same way, although less pronounced, to what has been observed for the axisymmetric motion. In the zero-frequency limit, the self-mobility correction near a hard sphere is recovered only if the membrane has a nonvanishing resistance toward shearing. We further compute the in-plane mean-square displacement of a nearby diffusing particle, finding that the membrane induces a long-lasting subdiffusive regime. Considering capsule motion, we find that the correction to the pair-mobility function is solely determined by membrane shearing properties. Our analytical calculations are compared and validated with fully resolved boundary integral simulations where a very good agreement is obtained.
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Affiliation(s)
- Abdallah Daddi-Moussa-Ider
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany
| | - Maciej Lisicki
- Department of Applied Mathematics and Theoretical Physics, Wilberforce Rd, Cambridge CB3 0WA, United Kingdom
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Stephan Gekle
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany
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Daddi-Moussa-Ider A, Gekle S. Hydrodynamic interaction between particles near elastic interfaces. J Chem Phys 2017; 145:014905. [PMID: 27394123 DOI: 10.1063/1.4955099] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present an analytical calculation of the hydrodynamic interaction between two spherical particles near an elastic interface such as a cell membrane. The theory predicts the frequency dependent self- and pair-mobilities accounting for the finite particle size up to the 5th order in the ratio between particle diameter and wall distance as well as between diameter and interparticle distance. We find that particle motion towards a membrane with pure bending resistance always leads to mutual repulsion similar as in the well-known case of a hard-wall. In the vicinity of a membrane with shearing resistance, however, we observe an attractive interaction in a certain parameter range which is in contrast to the behavior near a hard wall. This attraction might facilitate surface chemical reactions. Furthermore, we show that there exists a frequency range in which the pair-mobility for perpendicular motion exceeds its bulk value, leading to short-lived superdiffusive behavior. Using the analytical particle mobilities we compute collective and relative diffusion coefficients. The appropriateness of the approximations in our analytical results is demonstrated by corresponding boundary integral simulations which are in excellent agreement with the theoretical predictions.
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Affiliation(s)
- Abdallah Daddi-Moussa-Ider
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany
| | - Stephan Gekle
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany
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Abstract
Thirty years after their invention by Arthur Ashkin and colleagues at Bell Labs in 1986 [1], optical tweezers (or traps) have become a versatile tool to address numerous biological problems. Put simply, an optical trap is a highly focused laser beam that is capable of holding and applying forces to micron-sized dielectric objects. However, their development over the last few decades has converted these tools from boutique instruments into highly versatile instruments of molecular biophysics. This introductory chapter intends to give a brief overview of the field, highlight some important scientific achievements, and demonstrate why optical traps have become a powerful tool in the biological sciences. We introduce a typical optical setup, describe the basic theoretical concepts of how trapping forces arise, and present the quantitative position and force measurement techniques that are most widely used today.
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Daddi-Moussa-Ider A, Gekle S. Hydrodynamic mobility of a solid particle near a spherical elastic membrane: Axisymmetric motion. Phys Rev E 2017; 95:013108. [PMID: 28208420 DOI: 10.1103/physreve.95.013108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Indexed: 06/06/2023]
Abstract
We use the image solution technique to compute the leading order frequency-dependent self-mobility function of a small solid particle moving perpendicular to the surface of a spherical capsule whose membrane possesses shearing and bending rigidities. Comparing our results with those obtained earlier for an infinitely extended planar elastic membrane, we find that membrane curvature leads to the appearance of a prominent additional peak in the mobility. This peak is attributed to the fact that the shear resistance of the curved membrane involves a contribution from surface-normal displacements, which is not the case for planar membranes. In the vanishing frequency limit, the particle self-mobility near a no-slip hard sphere is recovered only when the membrane possesses a nonvanishing resistance toward shearing. We further investigate capsule motion, finding that the pair-mobility function is solely determined by membrane shearing properties. Our analytical predictions are validated by fully resolved boundary integral simulations where a very good agreement is obtained.
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Affiliation(s)
- Abdallah Daddi-Moussa-Ider
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany
| | - Stephan Gekle
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany
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Tränkle B, Ruh D, Rohrbach A. Interaction dynamics of two diffusing particles: contact times and influence of nearby surfaces. SOFT MATTER 2016; 12:2729-2736. [PMID: 26931403 DOI: 10.1039/c5sm03085d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Interactions of diffusing particles are governed by hydrodynamics on different length and timescales. The local hydrodynamics can be influenced substantially by simple interfaces. Here, we investigate the interaction dynamics of two micron-sized spheres close to plane interfaces to mimic more complex biological systems or microfluidic environments. Using scanned line optical tweezers and fast 3D interferometric particle tracking, we are able to track the motion of each bead with precisions of a few nanometers and at a rate of 10 kilohertz. From the recorded trajectories, all spatial and temporal information is accessible. This way, we measure diffusion coefficients for two coupling particles at varying distances h to one or two glass interfaces. We analyze their coupling strength and length by cross-correlation analysis relative to h and find a significant decrease in the coupling length when a second particle diffuses nearby. By analysing the times the particles are in close contact, we find that the influence of nearby surfaces and interaction potentials reduce the diffusivity strongly, although we found that the diffusivity hardly affects the contact times and the binding probability between the particles. All experimental results are compared to a theoretical model, which is based on the number of possible diffusion paths following the Catalan numbers and a diffusion probability, which is biased by the spheres' surface potential. The theoretical and experimental results agree very well and therefore enable a better understanding of hydrodynamically coupled interaction processes.
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Affiliation(s)
- B Tränkle
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110 Freiburg, Germany.
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Daddi-Moussa-Ider A, Guckenberger A, Gekle S. Long-lived anomalous thermal diffusion induced by elastic cell membranes on nearby particles. Phys Rev E 2016; 93:012612. [PMID: 26871127 DOI: 10.1103/physreve.93.012612] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Indexed: 01/28/2023]
Abstract
The physical approach of a small particle (virus, medical drug) to the cell membrane represents the crucial first step before active internalization and is governed by thermal diffusion. Using a fully analytical theory we show that the stretching and bending of the elastic membrane by the approaching particle induces a memory in the system, which leads to anomalous diffusion, even though the particle is immersed in a purely Newtonian liquid. For typical cell membranes the transient subdiffusive regime extends beyond 10 ms and can enhance residence times and possibly binding rates up to 50%. Our analytical predictions are validated by numerical simulations.
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Affiliation(s)
- Abdallah Daddi-Moussa-Ider
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany
| | - Achim Guckenberger
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany
| | - Stephan Gekle
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany
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