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Mierke CT. Magnetic tweezers in cell mechanics. Methods Enzymol 2024; 694:321-354. [PMID: 38492957 DOI: 10.1016/bs.mie.2023.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2024]
Abstract
The chapter provides an overview of the applications of magnetic tweezers in living cells. It discusses the advantages and disadvantages of magnetic tweezers technology with a focus on individual magnetic tweezers configurations, such as electromagnetic tweezers. Solutions to the disadvantages identified are also outlined. The specific role of magnetic tweezers in the field of mechanobiology, such as mechanosensitivity, mechano-allostery and mechanotransduction are also emphasized. The specific usage of magnetic tweezers in mechanically probing cells via specific cell surface receptors, such as mechanosensitive channels is discussed and why mechanical probing has revealed the opening and closing of the channels. Finally, the future direction of magnetic tweezers is presented.
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Affiliation(s)
- Claudia Tanja Mierke
- Faculty of Physics and Earth System Sciences, Peter Debye Institute for Soft Matter Physics, Biological Physics Division, Leipzig University, Leipzig, Germany.
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2
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Dulin D. An Introduction to Magnetic Tweezers. Methods Mol Biol 2024; 2694:375-401. [PMID: 37824014 DOI: 10.1007/978-1-0716-3377-9_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Magnetic tweezers are a single-molecule force and torque spectroscopy technique that enable the mechanical interrogation in vitro of biomolecules, such as nucleic acids and proteins. They use a magnetic field originating from either permanent magnets or electromagnets to attract a magnetic particle, thus stretching the tethering biomolecule. They nicely complement other force spectroscopy techniques such as optical tweezers and atomic force microscopy (AFM) as they operate as a very stable force clamp, enabling long-duration experiments over a very broad range of forces spanning from 10 fN to 1 nN, with 1-10 milliseconds time and sub-nanometer spatial resolution. Their simplicity, robustness, and versatility have made magnetic tweezers a key technique within the field of single-molecule biophysics, being broadly applied to study the mechanical properties of, e.g., nucleic acids, genome processing molecular motors, protein folding, and nucleoprotein filaments. Furthermore, magnetic tweezers allow for high-throughput single-molecule measurements by tracking hundreds of biomolecules simultaneously both in real-time and at high spatiotemporal resolution. Magnetic tweezers naturally combine with surface-based fluorescence spectroscopy techniques, such as total internal reflection fluorescence microscopy, enabling correlative fluorescence and force/torque spectroscopy on biomolecules. This chapter presents an introduction to magnetic tweezers including a description of the hardware, the theory behind force calibration, its spatiotemporal resolution, combining it with other techniques, and a (non-exhaustive) overview of biological applications.
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Affiliation(s)
- David Dulin
- LaserLaB Amsterdam and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
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Scott S, Weiss M, Selhuber-Unkel C, Barooji YF, Sabri A, Erler JT, Metzler R, Oddershede LB. Extracting, quantifying, and comparing dynamical and biomechanical properties of living matter through single particle tracking. Phys Chem Chem Phys 2023; 25:1513-1537. [PMID: 36546878 DOI: 10.1039/d2cp01384c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A panoply of new tools for tracking single particles and molecules has led to an explosion of experimental data, leading to novel insights into physical properties of living matter governing cellular development and function, health and disease. In this Perspective, we present tools to investigate the dynamics and mechanics of living systems from the molecular to cellular scale via single-particle techniques. In particular, we focus on methods to measure, interpret, and analyse complex data sets that are associated with forces, materials properties, transport, and emergent organisation phenomena within biological and soft-matter systems. Current approaches, challenges, and existing solutions in the associated fields are outlined in order to support the growing community of researchers at the interface of physics and the life sciences. Each section focuses not only on the general physical principles and the potential for understanding living matter, but also on details of practical data extraction and analysis, discussing limitations, interpretation, and comparison across different experimental realisations and theoretical frameworks. Particularly relevant results are introduced as examples. While this Perspective describes living matter from a physical perspective, highlighting experimental and theoretical physics techniques relevant for such systems, it is also meant to serve as a solid starting point for researchers in the life sciences interested in the implementation of biophysical methods.
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Affiliation(s)
- Shane Scott
- Institute of Physiology, Kiel University, Hermann-Rodewald-Straße 5, 24118 Kiel, Germany
| | - Matthias Weiss
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, D-95447 Bayreuth, Germany
| | - Christine Selhuber-Unkel
- Institute for Molecular Systems Engineering, Heidelberg University, D-69120 Heidelberg, Germany.,Max Planck School Matter to Life, Jahnstraße 29, D-69120 Heidelberg, Germany
| | - Younes F Barooji
- Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
| | - Adal Sabri
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, D-95447 Bayreuth, Germany
| | - Janine T Erler
- BRIC, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark.
| | - Ralf Metzler
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Str. 24/25, D-14476 Potsdam, Germany.,Asia Pacific Center for Theoretical Physics, Pohang 37673, Republic of Korea
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Shi L, Zhong X, Wu T, Bian Q, Liu X, Miao H, Deng Y, Yin B, Zhou T. The electrodynamics of rod‐like microparticles based on optically induced dielectrophoresis. Electrophoresis 2022; 43:2175-2183. [DOI: 10.1002/elps.202200102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 09/03/2022] [Accepted: 09/06/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Liuyong Shi
- Mechanical and Electrical Engineering College Hainan University Haikou P. R. China
| | - Xiangtao Zhong
- Mechanical and Electrical Engineering College Hainan University Haikou P. R. China
| | - Tao Wu
- Mechanical and Electrical Engineering College Hainan University Haikou P. R. China
| | - Qin Bian
- Mechanical and Electrical Engineering College Hainan University Haikou P. R. China
| | - Xiaomei Liu
- Mechanical and Electrical Engineering College Hainan University Haikou P. R. China
| | - Huaqing Miao
- Shenzhen Academy of Metrology & Quality Inspection Shenzhen P. R. China
| | - Yongbo Deng
- Changchun Institute of Optics Fine Mechanics and Physics (CIOMP) Chinese Academy of Science Changchun P. R. China
| | - Binfeng Yin
- School of Mechanical Engineering Yangzhou University Yangzhou P. R. China
| | - Teng Zhou
- Mechanical and Electrical Engineering College Hainan University Haikou P. R. China
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Berghoff K, Gross W, Eisentraut M, Kress H. Using blinking optical tweezers to study cell rheology during initial cell-particle contact. Biophys J 2021; 120:3527-3537. [PMID: 34181902 PMCID: PMC8391049 DOI: 10.1016/j.bpj.2021.04.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 04/21/2021] [Accepted: 04/26/2021] [Indexed: 01/01/2023] Open
Abstract
Phagocytosis is an important part of innate immunity and describes the engulfment of bacteria and other extracellular objects on the micrometer scale. The protrusion of the cell membrane around the bacteria during this process is driven by a reorganization of the actin cortex. The process has been studied on the molecular level to great extent during the past decades. However, a deep, fundamental understanding of the mechanics of the process is still lacking, in particular because of a lack of techniques that give access to binding dynamics below the optical resolution limit and cellular viscoelasticity at the same time. In this work, we propose a technique to characterize the mechanical properties of cells in a highly localized manner and apply it to investigate the early stages of phagocytosis. The technique can simultaneously resolve the contact region between a cell and an external object (in our application, a phagocytic target) even below the optical resolution limit. We used immunoglobulin-G-coated microparticles with a size of 2 μm as a model system and attached the particles to the macrophages with holographic optical tweezers. By switching the trap on and off, we were able to measure the rheological properties of the cells in a time-resolved manner during the first few minutes after attachment. The measured viscoelastic cellular response is consistent with power law rheology. The contact radius between particle and cell increased on a timescale of ∼30 s and converged after a few minutes. Although the binding dynamics are not affected by cytochalasin D, we observed an increase of the cellular compliance and a significant fluidization of the cortex after addition of cytochalasin D treatment. Furthermore, we report upper boundaries for the length- and timescale, at which cortical actin has been hypothesized to depolymerize during early phagocytosis.
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Affiliation(s)
- Konrad Berghoff
- Department of Physics, University of Bayreuth, Bayreuth, Germany
| | - Wolfgang Gross
- Department of Physics, University of Bayreuth, Bayreuth, Germany
| | | | - Holger Kress
- Department of Physics, University of Bayreuth, Bayreuth, Germany.
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Huang Z, Wu Z, Zhou T, Shi L, Liu Z, Huang J. Multi-particle interaction in AC electric field driven by dielectrophoresis force. Electrophoresis 2021; 42:2189-2196. [PMID: 34117650 DOI: 10.1002/elps.202100094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 11/11/2022]
Abstract
When the dielectrophoresis technology is used to manipulate micron-sized particles, the interaction between particles should not be ignored because of the particle-particle interaction. Especially, when multiple particles (number of particles is above 2) are simultaneously manipulated, the interaction between neighboring particles will affect the results of the manipulation. This research investigates the interaction of particles caused dielectrophoresis effect by the Arbitrary Lagrangian-Eulerian (ALE) method based on the hypothesis of the thin layer of the electric double layer at the microscale. The mathematics model can be solved simultaneously by the finite element method for the AC electric field, the flow field around the suspended particles and the particle mechanics at the micrometer scale. In this study, the particle conductivity and the direction of the electric field are investigated, we find that particle conductivity and electric field direction pose an impact on particle movement, and the research reveal the law of microparticle dielectrophoresis movement, which could offer theoretical and technology support to profoundly understand the precise manipulation of particles in microfluidic chips by the dielectrophoresis effect.
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Affiliation(s)
- Zhiwei Huang
- Mechanical and Electrical Engineering College, Hainan University, Haikou, Hainan, P. R. China
| | - Zhihao Wu
- Mechanical and Electrical Engineering College, Hainan University, Haikou, Hainan, P. R. China
| | - Teng Zhou
- Mechanical and Electrical Engineering College, Hainan University, Haikou, Hainan, P. R. China
| | - Liuyong Shi
- Mechanical and Electrical Engineering College, Hainan University, Haikou, Hainan, P. R. China
| | - Zhenyu Liu
- Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) 130033, Chinese Academy of Science, Changchun, Jilin, P. R. China
| | - Jiaomei Huang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, P. R. China
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Moghram WI, Kruger A, Sander EA, Selby JC. Magnetic tweezers with magnetic flux density feedback control. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:034101. [PMID: 33820004 DOI: 10.1063/5.0039696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 02/16/2021] [Indexed: 06/12/2023]
Abstract
In this work, we present a single-pole magnetic tweezers (MT) device designed for integration with substrate deformation tracking microscopy and/or traction force microscopy experiments intended to explore extracellular matrix rheology and human epidermal keratinocyte mechanobiology. Assembled from commercially available off-the-shelf electronics hardware and software, the MT device is amenable to replication in the basic biology laboratory. In contrast to conventional solenoid current-controlled MT devices, operation of this instrument is based on real-time feedback control of the magnetic flux density emanating from the blunt end of the needle core using a cascade control scheme and a digital proportional-integral-derivative (PID) controller. Algorithms that compensate for a spatially non-uniform remnant magnetization of the needle core that develops during actuation are implemented into the feedback control scheme. Through optimization of PID gain scheduling, the MT device exhibits magnetization and demagnetization response times of less than 100 ms without overshoot over a wide range of magnetic flux density setpoints. Compared to current-based control, magnetic flux density-based control allows for more accurate and precise magnetic actuation forces by compensating for temperature increases within the needle core due to heat generated by the applied solenoid currents. Near field calibrations validate the ability of the MT device to actuate 4.5 μm-diameter superparamagnetic beads with forces up to 25 nN with maximum relative uncertainties of ±30% for beads positioned between 2.5 and 40 µm from the needle tip.
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Affiliation(s)
- Waddah I Moghram
- Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242, USA
| | - Anton Kruger
- Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa 52242, USA
| | - Edward A Sander
- Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242, USA
| | - John C Selby
- Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242, USA
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Aermes C, Hayn A, Fischer T, Mierke CT. Environmentally controlled magnetic nano-tweezer for living cells and extracellular matrices. Sci Rep 2020; 10:13453. [PMID: 32778758 PMCID: PMC7417586 DOI: 10.1038/s41598-020-70428-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 07/16/2020] [Indexed: 01/08/2023] Open
Abstract
The magnetic tweezer technique has become a versatile tool for unfolding or folding of individual molecules, mainly DNA. In addition to single molecule analysis, the magnetic tweezer can be used to analyze the mechanical properties of cells and extracellular matrices. We have established a magnetic tweezer that is capable of measuring the linear and non-linear viscoelastic behavior of a wide range of soft matter in precisely controlled environmental conditions, such as temperature, CO2 and humidity. The magnetic tweezer presented in this study is suitable to detect specific differences in the mechanical properties of different cell lines, such as human breast cancer cells and mouse embryonic fibroblasts, as well as collagen matrices of distinct concentrations in the presence and absence of fibronectin crosslinks. The precise calibration and control mechanism employed in the presented magnetic tweezer setup provides the ability to apply physiological force up to 5 nN on 4.5 µm superparamagnetic beads coated with fibronectin and coupled to the cells or collagen matrices. These measurements reveal specific local linear and non-linear viscoelastic behavior of the investigated samples. The viscoelastic response of cells and collagen matrices to the force application is best described by a weak power law behavior. Our results demonstrate that the stress stiffening response and the fluidization of cells is cell type specific and varies largely between differently invasive and aggressive cancer cells. Finally, we showed that the viscoelastic behavior of collagen matrices with and without fibronectin crosslinks measured by the magnetic tweezer can be related to the microstructure of these matrices.
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Affiliation(s)
- Christian Aermes
- Faculty of Physics and Earth Science, Peter Debye Institute of Soft Matter Physics, Biological Physics Division, University of Leipzig, Linnéstr. 5, 04103, Leipzig, Germany
| | - Alexander Hayn
- Faculty of Physics and Earth Science, Peter Debye Institute of Soft Matter Physics, Biological Physics Division, University of Leipzig, Linnéstr. 5, 04103, Leipzig, Germany
| | - Tony Fischer
- Faculty of Physics and Earth Science, Peter Debye Institute of Soft Matter Physics, Biological Physics Division, University of Leipzig, Linnéstr. 5, 04103, Leipzig, Germany
| | - Claudia Tanja Mierke
- Faculty of Physics and Earth Science, Peter Debye Institute of Soft Matter Physics, Biological Physics Division, University of Leipzig, Linnéstr. 5, 04103, Leipzig, Germany.
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