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Lima I, Silva A, Sousa F, Ferreira W, Freire R, de Oliveira C, de Sousa J. Measuring the viscoelastic relaxation function of cells with a time-dependent interpretation of the Hertz-Sneddon indentation model. Heliyon 2024; 10:e30623. [PMID: 38770291 PMCID: PMC11103437 DOI: 10.1016/j.heliyon.2024.e30623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 04/15/2024] [Accepted: 04/30/2024] [Indexed: 05/22/2024] Open
Abstract
The Hertz-Sneddon elastic indentation model is widely adopted in the biomechanical investigation of living cells and other soft materials using atomic force microscopy despite the explicit viscoelastic nature of these materials. In this work, we demonstrate that an exact analytical viscoelastic force model for power-law materials, can be interpreted as a time-dependent Hertz-Sneddon-like model. Characterizing fibroblasts (L929) and osteoblasts (OFCOLII) demonstrates the model's accuracy. Our results show that the difference between Young's modulus E Y obtained by fitting force curves with the Hertz-Sneddon model and the effective Young's modulus derived from the viscoelastic force model is less than 3%, even when cells are probed at large forces where nonlinear deformation effects become significant. We also propose a measurement protocol that involves probing samples at different indentation speeds and forces, enabling the construction of the average viscoelastic relaxation function of samples by conveniently fitting the force curves with the Hertz-Sneddon model.
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Affiliation(s)
- I.V.M. Lima
- Departamento de Física, Universidade Federal do Ceará, Fortaleza, 60440-900, Ceará, Brazil
| | - A.V.S. Silva
- Departamento de Física, Universidade Federal do Ceará, Fortaleza, 60440-900, Ceará, Brazil
- Instituto Federal do Rio Grande do Norte, Pau dos Ferros, 59900-000, Rio Grande do Norte, Brazil
| | - F.D. Sousa
- Núcleo de Biologia Experimental, Universidade de Fortaleza, Fortaleza, 60811-905, Ceará, Brazil
| | - W.P. Ferreira
- Departamento de Física, Universidade Federal do Ceará, Fortaleza, 60440-900, Ceará, Brazil
| | - R.S. Freire
- Central Analítica, Universidade Federal do Ceará, Fortaleza, 60440-900, Ceará, Brazil
| | - C.L.N. de Oliveira
- Departamento de Física, Universidade Federal do Ceará, Fortaleza, 60440-900, Ceará, Brazil
| | - J.S. de Sousa
- Departamento de Física, Universidade Federal do Ceará, Fortaleza, 60440-900, Ceará, Brazil
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2
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Li M. Harnessing atomic force microscopy-based single-cell analysis to advance physical oncology. Microsc Res Tech 2024; 87:631-659. [PMID: 38053519 DOI: 10.1002/jemt.24467] [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: 08/22/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 12/07/2023]
Abstract
Single-cell analysis is an emerging and promising frontier in the field of life sciences, which is expected to facilitate the exploration of fundamental laws of physiological and pathological processes. Single-cell analysis allows experimental access to cell-to-cell heterogeneity to reveal the distinctive behaviors of individual cells, offering novel opportunities to dissect the complexity of severe human diseases such as cancers. Among the single-cell analysis tools, atomic force microscopy (AFM) is a powerful and versatile one which is able to nondestructively image the fine topographies and quantitatively measure multiple mechanical properties of single living cancer cells in their native states under aqueous conditions with unprecedented spatiotemporal resolution. Over the past few decades, AFM has been widely utilized to detect the structural and mechanical behaviors of individual cancer cells during the process of tumor formation, invasion, and metastasis, yielding numerous unique insights into tumor pathogenesis from the biomechanical perspective and contributing much to the field of cancer mechanobiology. Here, the achievements of AFM-based analysis of single cancer cells to advance physical oncology are comprehensively summarized, and challenges and future perspectives are also discussed. RESEARCH HIGHLIGHTS: Achievements of AFM in characterizing the structural and mechanical behaviors of single cancer cells are summarized, and future directions are discussed. AFM is not only capable of visualizing cellular fine structures, but can also measure multiple cellular mechanical properties as well as cell-generated mechanical forces. There is still plenty of room for harnessing AFM-based single-cell analysis to advance physical oncology.
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Affiliation(s)
- Mi Li
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, China
- University of Chinese Academy of Sciences, Beijing, China
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3
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Rodríguez-Cruz C, Molaei M, Thirumalaiswamy A, Feitosa K, Manoharan VN, Sivarajan S, Reich DH, Riggleman RA, Crocker JC. Experimental observations of fractal landscape dynamics in a dense emulsion. SOFT MATTER 2023; 19:6805-6813. [PMID: 37650227 DOI: 10.1039/d3sm00852e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Many soft and biological materials display so-called 'soft glassy' dynamics; their constituents undergo anomalous random motions and complex cooperative rearrangements. A recent simulation model of one soft glassy material, a coarsening foam, suggested that the random motions of its bubbles are due to the system configuration moving over a fractal energy landscape in high-dimensional space. Here we show that the salient geometrical features of such high-dimensional fractal landscapes can be explored and reliably quantified, using empirical trajectory data from many degrees of freedom, in a model-free manner. For a mayonnaise-like dense emulsion, analysis of the observed trajectories of oil droplets quantitatively reproduces the high-dimensional fractal geometry of the configuration path and its associated local energy minima generated using a computational model. That geometry in turn drives the droplets' complex random motion observed in real space. Our results indicate that experimental studies can elucidate whether the similar dynamics in different soft and biological materials may also be due to fractal landscape dynamics.
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Affiliation(s)
- Clary Rodríguez-Cruz
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA.
| | - Mehdi Molaei
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA.
| | - Amruthesh Thirumalaiswamy
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA.
| | - Klebert Feitosa
- Department of Physics and Astronomy, James Madison University, Harrisonburg, Virginia, USA
| | - Vinothan N Manoharan
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts, USA
| | - Shankar Sivarajan
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland, USA
| | - Daniel H Reich
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland, USA
| | - Robert A Riggleman
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA.
| | - John C Crocker
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA.
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4
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Pontes B, Mendes FA. Mechanical Properties of Glioblastoma: Perspectives for YAP/TAZ Signaling Pathway and Beyond. Diseases 2023; 11:86. [PMID: 37366874 DOI: 10.3390/diseases11020086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 06/06/2023] [Accepted: 06/12/2023] [Indexed: 06/28/2023] Open
Abstract
Glioblastoma is a highly aggressive brain tumor with a poor prognosis. Recent studies have suggested that mechanobiology, the study of how physical forces influence cellular behavior, plays an important role in glioblastoma progression. Several signaling pathways, molecules, and effectors, such as focal adhesions, stretch-activated ion channels, or membrane tension variations, have been studied in this regard. Also investigated are YAP/TAZ, downstream effectors of the Hippo pathway, which is a key regulator of cell proliferation and differentiation. In glioblastoma, YAP/TAZ have been shown to promote tumor growth and invasion by regulating genes involved in cell adhesion, migration, and extracellular matrix remodeling. YAP/TAZ can be activated by mechanical cues such as cell stiffness, matrix rigidity, and cell shape changes, which are all altered in the tumor microenvironment. Furthermore, YAP/TAZ have been shown to crosstalk with other signaling pathways, such as AKT, mTOR, and WNT, which are dysregulated in glioblastoma. Thus, understanding the role of mechanobiology and YAP/TAZ in glioblastoma progression could provide new insights into the development of novel therapeutic strategies. Targeting YAP/TAZ and mechanotransduction pathways in glioblastoma may offer a promising approach to treating this deadly disease.
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Affiliation(s)
- Bruno Pontes
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil
- Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil
| | - Fabio A Mendes
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil
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5
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Akcay G, Luttge R. Microenvironments Matter: Advances in Brain-on-Chip. BIOSENSORS 2023; 13:551. [PMID: 37232912 PMCID: PMC10216565 DOI: 10.3390/bios13050551] [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: 03/23/2023] [Revised: 05/04/2023] [Accepted: 05/12/2023] [Indexed: 05/27/2023]
Abstract
To highlight the particular needs with respect to modeling the unique and complex organization of the human brain structure, we reviewed the state-of-the-art in devising brain models with engineered instructive microenvironments. To acquire a better perspective on the brain's working mechanisms, we first summarize the importance of regional stiffness gradients in brain tissue, varying per layer and the cellular diversities of the layers. Through this, one can acquire an understanding of the essential parameters in emulating the brain in vitro. In addition to the brain's organizational architecture, we addressed also how the mechanical properties have an impact on neuronal cell responses. In this respect, advanced in vitro platforms emerged and profoundly changed the methods of brain modeling efforts from the past, mainly focusing on animal or cell line research. The main challenges in imitating features of the brain in a dish are with regard to composition and functionality. In neurobiological research, there are now methods that aim to cope with such challenges by the self-assembly of human-derived pluripotent stem cells (hPSCs), i.e., brainoids. Alternatively, these brainoids can be used stand-alone or in conjunction with Brain-on-Chip (BoC) platform technology, 3D-printed gels, and other types of engineered guidance features. Currently, advanced in vitro methods have made a giant leap forward regarding cost-effectiveness, ease-of-use, and availability. We bring these recent developments together into one review. We believe our conclusions will give a novel perspective towards advancing instructive microenvironments for BoCs and the understanding of the brain's cellular functions either in modeling healthy or diseased states of the brain.
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Affiliation(s)
- Gulden Akcay
- Neuro-Nanoscale Engineering, Department of Mechanical Engineering/Microsystems, Institute of Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands;
| | - Regina Luttge
- Neuro-Nanoscale Engineering, Department of Mechanical Engineering/Microsystems, Institute of Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands;
- Eindhoven Artificial Intelligence Systems Institute, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
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6
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Hoque MA, Mahmood N, Ali KM, Sefat E, Huang Y, Petersen E, Harrington S, Fang X, Gluck JM. Development of a Pneumatic-Driven Fiber-Shaped Robot Scaffold for Use as a Complex 3D Dynamic Culture System. Biomimetics (Basel) 2023; 8:biomimetics8020170. [PMID: 37092422 PMCID: PMC10123682 DOI: 10.3390/biomimetics8020170] [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: 03/21/2023] [Revised: 04/15/2023] [Accepted: 04/17/2023] [Indexed: 04/25/2023] Open
Abstract
Cells can sense and respond to different kinds of continuous mechanical strain in the human body. Mechanical stimulation needs to be included within the in vitro culture system to better mimic the existing complexity of in vivo biological systems. Existing commercial dynamic culture systems are generally two-dimensional (2D) which fail to mimic the three-dimensional (3D) native microenvironment. In this study, a pneumatically driven fiber robot has been developed as a platform for 3D dynamic cell culture. The fiber robot can generate tunable contractions upon stimulation. The surface of the fiber robot is formed by a braiding structure, which provides promising surface contact and adequate space for cell culture. An in-house dynamic stimulation using the fiber robot was set up to maintain NIH3T3 cells in a controlled environment. The biocompatibility of the developed dynamic culture systems was analyzed using LIVE/DEAD™ and alamarBlue™ assays. The results showed that the dynamic culture system was able to support cell proliferation with minimal cytotoxicity similar to static cultures. However, we observed a decrease in cell viability in the case of a high strain rate in dynamic cultures. Differences in cell arrangement and proliferation were observed between braided sleeves made of different materials (nylon and ultra-high molecular weight polyethylene). In summary, a simple and cost-effective 3D dynamic culture system has been proposed, which can be easily implemented to study complex biological phenomena in vitro.
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Affiliation(s)
- Muh Amdadul Hoque
- Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27606, USA
| | - Nasif Mahmood
- Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27606, USA
| | - Kiran M Ali
- Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27606, USA
| | - Eelya Sefat
- Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27606, USA
| | - Yihan Huang
- Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27606, USA
| | - Emily Petersen
- Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27606, USA
| | - Shane Harrington
- Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27606, USA
| | - Xiaomeng Fang
- Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27606, USA
| | - Jessica M Gluck
- Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27606, USA
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7
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Liang M, Tang Q, Zhong J, Ai Y. Machine learning empowered multi-stress level electromechanical phenotyping for high-dimensional single cell analysis. Biosens Bioelectron 2023; 225:115086. [PMID: 36696849 DOI: 10.1016/j.bios.2023.115086] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 11/17/2022] [Accepted: 01/16/2023] [Indexed: 01/20/2023]
Abstract
Microfluidics provides a powerful platform for biological analysis by harnessing the ability to precisely manipulate fluids and microparticles with integrated microsensors. Here, we introduce an imaging and impedance cell analyzer (IM2Cell), which implements single cell level impedance analysis and hydrodynamic mechanical phenotyping simultaneously. For the first time, IM2Cell demonstrates the capability of multi-stress level mechanical phenotyping. Specifically, IM2Cell is capable of characterizing cell diameter, three deformability responses, and four electrical properties. It presents high-dimensional information to give insight into subcellular components such as cell membrane, cytoplasm, cytoskeleton, and nucleus. In this work, we first validate imaging and impedance-based cell analyses separately. Then, the two techniques are combined to obtain both imaging and impedance data analyzed by machine learning method, exhibiting an improved prediction accuracy from 83.1% to 95.4% between fixed and living MDA-MB-231 breast cancer cells. Next, IM2Cell demonstrates 91.2% classification accuracy in a mixture of unlabeled MCF-10A, MCF-7, and MDA-MB-231 cell lines. Finally, an application demonstrates the potential of IM2Cell for the deformability studies of peripheral blood mononuclear cells (PBMCs) subpopulations without cumbersome isolation or labeling steps.
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Affiliation(s)
- Minhui Liang
- Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
| | - Qiang Tang
- Jiangsu Provincal Engineering Research Center for Biomedical Materials and Advanced Medical Devices, Faculty of Mechanical and Material Engineering, Huaiyin Institute of Technology, Huaian, 223003, China
| | - Jianwei Zhong
- Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
| | - Ye Ai
- Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore.
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8
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Xue S, Xu Q, Xu Z, Zhang X, Zhang H, Zhang X, He F, Chen Y, Xue Y, Hao P. Manipulation of Particle/Cell Based on Compressibility in a Divergent Microchannel by Surface Acoustic Wave. Anal Chem 2023; 95:4282-4290. [PMID: 36815437 DOI: 10.1021/acs.analchem.2c03841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The mechanical properties (compressibility or deformability) of cells are closely related to their death, migration, and differentiation. Accurate separation and manipulation of bioparticles based on these mechanical properties are still a challenging in the field of acoustofluidics. In this work, based on surface acoustic waves (SAW) and divergent microchannels, we developed a new method for separating and detecting particles or cells with different compressibility. The difference in acoustic radiation force (Fr) caused by compressibility are gradually amplified and accumulated by decreasing the flow velocity, and they are finally reflected in the particle migration distance. During the transverse migration process, the alternating dominance of the acoustic radiation force and the Stokes resistance force (Fs) drives the particles to create three typical migration patterns: intermittent migration, compound migration, and near-wall migration. In the present tilted SAW device, a 91% separation success rate of ∼10 μm polystyrene (PS) and polydimethylsiloxane (PDMS) particles can be achieved by optimizing the acoustic field input power and the fluid velocity. The application potential of the present divergent microchannel is validated by separating the myelogenous leukemia cell K562 and the natural killer cell NK92 that have similar densities and sizes (∼15 μm) but different compressibility. The results of this work are expected to provide valuable insights into the acoustofluidics separation and detection of the cells that are with different compressibility.
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Affiliation(s)
- Sen Xue
- Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Qingmei Xu
- School of Integrated Circuits, Peking University, Beijing 100871, China
| | - Zhike Xu
- Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Xuanhe Zhang
- Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Haixiang Zhang
- Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Xiwen Zhang
- Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Feng He
- Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Yiqing Chen
- Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Yu Xue
- School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Pengfei Hao
- Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
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9
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Weber A, Benitez R, Toca‐Herrera JL. Measuring biological materials mechanics with atomic force microscopy - Determination of viscoelastic cell properties from stress relaxation experiments. Microsc Res Tech 2022; 85:3284-3295. [PMID: 35736395 PMCID: PMC9796732 DOI: 10.1002/jemt.24184] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 01/07/2023]
Abstract
Cells are complex, viscoelastic bodies. Their mechanical properties are defined by the arrangement of semiflexible cytoskeletal fibers, their crosslinking, and the active remodeling of the cytoskeletal network. Atomic force microscopy (AFM) is an often-used technique for the study of cell mechanics, enabling time- and frequency-dependent measurements with nanometer resolution. Cells exhibit time-dependent deformation when stress is applied. In this work, we have investigated the stress relaxation of HeLa cells when subjected to a constant strain. We have varied the applied force (1, 2, 4, and 8 nN) and pause time (1, 10, and 60 s) to check for common assumptions for the use of models of linear viscoelasticity. Then, we have applied three models (standard linear solid, five element Maxwell, power law rheology) to study their suitability to fit the datasets. We show that the five element Maxwell model captures the stress relaxation response the best while still retaining a low number of free variables. This work serves as an introduction and guide when performing stress relaxation experiments on soft matter using AFM. RESEARCH HIGHLIGHTS: Cells exhibit linear viscoelastic properties when subjected to stress relaxation measurements at the studied different forces and times. The stress relaxation is best described by a five element Maxwell model. All three used models capture a softening and fluidization of cells when disrupting actin filaments.
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Affiliation(s)
- Andreas Weber
- Institute of Biophysics, Department of NanobiotechnologyUniversity of Natural Resources and Life Sciences Vienna (BOKU)ViennaAustria
| | - Rafael Benitez
- Departamento de Matemáticas para la Economía y la EmpresaFacultad de Economía, Universidad de ValenciaValenciaSpain
| | - José L. Toca‐Herrera
- Institute of Biophysics, Department of NanobiotechnologyUniversity of Natural Resources and Life Sciences Vienna (BOKU)ViennaAustria
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10
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Li Y, Wong IY, Guo M. Reciprocity of Cell Mechanics with Extracellular Stimuli: Emerging Opportunities for Translational Medicine. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2107305. [PMID: 35319155 PMCID: PMC9463119 DOI: 10.1002/smll.202107305] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 02/20/2022] [Indexed: 06/14/2023]
Abstract
Human cells encounter dynamic mechanical cues in healthy and diseased tissues, which regulate their molecular and biophysical phenotype, including intracellular mechanics as well as force generation. Recent developments in bio/nanomaterials and microfluidics permit exquisitely sensitive measurements of cell mechanics, as well as spatiotemporal control over external mechanical stimuli to regulate cell behavior. In this review, the mechanobiology of cells interacting bidirectionally with their surrounding microenvironment, and the potential relevance for translational medicine are considered. Key fundamental concepts underlying the mechanics of living cells as well as the extracelluar matrix are first introduced. Then the authors consider case studies based on 1) microfluidic measurements of nonadherent cell deformability, 2) cell migration on micro/nano-topographies, 3) traction measurements of cells in three-dimensional (3D) matrix, 4) mechanical programming of organoid morphogenesis, as well as 5) active mechanical stimuli for potential therapeutics. These examples highlight the promise of disease diagnosis using mechanical measurements, a systems-level understanding linking molecular with biophysical phenotype, as well as therapies based on mechanical perturbations. This review concludes with a critical discussion of these emerging technologies and future directions at the interface of engineering, biology, and medicine.
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Affiliation(s)
- Yiwei Li
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, China
| | - Ian Y Wong
- School of Engineering, Center for Biomedical Engineering, Joint Program in Cancer Biology, Brown University, 184 Hope St Box D, Providence, RI, 02912, USA
| | - Ming Guo
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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11
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Microfabricated Stretching Devices for Studying the Effects of Tensile Stress on Cells and Tissues. BIOCHIP JOURNAL 2022. [DOI: 10.1007/s13206-022-00073-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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12
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Xu D, Zhang N, Wang S, Yu Y, Zhang P, Li Y, Yang H. A Novel In Vitro Platform Development in the Lab for Modeling Blast Injury to Microglia. Front Bioeng Biotechnol 2022; 10:883545. [PMID: 35903797 PMCID: PMC9315251 DOI: 10.3389/fbioe.2022.883545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 06/10/2022] [Indexed: 11/23/2022] Open
Abstract
Traumatic brain injury (TBI), which is mainly caused by impact, often results in chronic neurological abnormalities. Since the pathological changes in vivo during primary biomechanical injury are quite complicated, the in-depth understanding of the pathophysiology and mechanism of TBI depends on the establishment of an effective experimental in vitro model. Usually, a bomb explosive blast was employed to establish the in vitro model, while the process is complex and unsuitable in the lab. Based on water-hammer, we have developed a device system to provide a single dynamic compression stress on living cells. A series of amplitude (∼5.3, ∼9.8, ∼13.5 MPa) were generated to explore the effects of dynamic compression loading on primary microglia within 48 h. Apoptosis experiments indicated that primary microglia had strong tolerance to blast waves. In addition, the generation of intercellular reactive oxygen species and secretory nitric oxide was getting strongly enhanced and recovered within 48 h. In addition, there is a notable release of pro-inflammatory cytokine by microglia. Our work provides a reproducible and peaceable method of loading single dynamic compression forces to cells in vitro. Microglia showed an acute inflammatory response to dynamic loadings, while no significant cell death was observed. This insight delivers a new technological approach that could open new areas to a better understanding of the mechanism of cell blast injuries.
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Affiliation(s)
- Dasen Xu
- School of Aeronautics, Northwestern Polytechnical University, Xi’an, China
- Center of Special Environmental Biomechanics and Biomedical Engineering, Northwestern Polytechnical University, Xi’an, China
| | - Nu Zhang
- Center of Special Environmental Biomechanics and Biomedical Engineering, Northwestern Polytechnical University, Xi’an, China
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, China
| | - Sijie Wang
- Center of Special Environmental Biomechanics and Biomedical Engineering, Northwestern Polytechnical University, Xi’an, China
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, China
| | - Yawei Yu
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, China
| | - Pan Zhang
- Center of Special Environmental Biomechanics and Biomedical Engineering, Northwestern Polytechnical University, Xi’an, China
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, China
| | - Yulong Li
- School of Aeronautics, Northwestern Polytechnical University, Xi’an, China
- Center of Special Environmental Biomechanics and Biomedical Engineering, Northwestern Polytechnical University, Xi’an, China
- *Correspondence: Yulong Li, ; Hui Yang,
| | - Hui Yang
- Center of Special Environmental Biomechanics and Biomedical Engineering, Northwestern Polytechnical University, Xi’an, China
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, China
- *Correspondence: Yulong Li, ; Hui Yang,
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13
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Beppi C, Penner M, Straumann D, Bögli SY. A non-invasive biomechanical model of mild TBI in larval zebrafish. PLoS One 2022; 17:e0268901. [PMID: 35622781 PMCID: PMC9140253 DOI: 10.1371/journal.pone.0268901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 05/05/2022] [Indexed: 11/18/2022] Open
Abstract
A mild traumatic brain injury is a neurological dysfunction caused by biomechanical forces transmitted to the brain in physical impacts. The current understanding of the neuropathological cascade resulting in the manifested clinical signs and symptoms is limited due to the absence of sensitive brain imaging methods. Zebrafish are established models for the reproduction and study of neurobiological pathologies. However, all available models mostly recreate moderate-to-severe focal injuries in adult zebrafish. The present work has induced a mild brain trauma in larval zebrafish through a non-invasive biomechanical approach. A custom-made apparatus with a commercially available motor was employed to expose larvae to rapidly decelerating linear movements. The neurophysiological changes following concussion were assessed through behavioural quantifications of startle reflex locomotor distance and habituation metrics. Here we show that the injury was followed, within five minutes, by a transient anxiety state and CNS dysfunction manifested by increased startle responsivity with impaired startle habituation, putatively mirroring the human clinical sign of hypersensitivity to noise. Within a day after the injury, chronic effects arose, as evidenced by an overall reduced responsivity to sensory stimulation (lower amplitude and distance travelled along successive stimuli), reflecting the human post-concussive symptomatology. This study represents a step forward towards the establishment of a parsimonious (simple, less ethically concerning, yet sensitive) animal model of mild TBI. Our behavioural findings mimic aspects of acute and chronic effects of human concussion, which warrant further study at molecular, cellular and circuit levels. While our model opens wide avenues for studying the underlying cellular and molecular pathomechanisms, it also enables high-throughput testing of therapeutic interventions to accelerate post-concussive recovery.
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Affiliation(s)
- Carolina Beppi
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
- Clinical Neuroscience Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland
- Swiss Concussion Center, Schulthess Clinic, Zurich, Switzerland
- * E-mail:
| | - Marco Penner
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Dominik Straumann
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
- Clinical Neuroscience Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland
- Swiss Concussion Center, Schulthess Clinic, Zurich, Switzerland
| | - Stefan Yu Bögli
- Department of Neurology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
- Clinical Neuroscience Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland
- Swiss Concussion Center, Schulthess Clinic, Zurich, Switzerland
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14
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Che YJ, Guo JB, Hao YF, Luo ZP. Regenerating and repairing degenerative intervertebral discs by regulating the micro/nano environment of degenerative bony endplates based on low-tension mechanics. BMC Musculoskelet Disord 2022; 23:462. [PMID: 35578221 PMCID: PMC9112526 DOI: 10.1186/s12891-022-05422-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 05/05/2022] [Indexed: 11/10/2022] Open
Abstract
Background Conservative treatment is the recommended first-line treatment for degenerative disc diseases. Traction therapy has historically been one of the most common clinical methods to address this, but the clinical effect remains controversial. Methods Forty-two six-month-old male Sprague-Dawley rats were randomly divided into six groups: the model group (Group A, four coccyx vertebrae (Co7-Co10) were fixed with customized external fixators, and the vertebral disc degeneration model was constructed by axial compression of the target segment Co8 - Co9 for 4 weeks), the experimental control group (Group B, after successful modeling, the external fixation device was removed and self-rehabilitation was performed) and four intervention groups (Groups C to F): Groups C and E: Co8 - Co9 vertebrae compressed for 4 weeks followed by two or 4 weeks of high tension traction (HTT), respectively, and Groups D and F: vertebrae compressed for 4 weeks followed by two or 4 weeks of low-tension traction (LTT), respectively. Imaging tests (X-ray and MRI) were performed to assess disc height and T2 signal intensity at each time point. After the experiment, the animals were euthanized, and the caudal vertebrae were collected for analysis of intervertebral disc histopathology, proteoglycan content, and micronanostructure of the annulus fibrosus, nucleus pulposus and bony endplate. Results Signs of tissue regeneration were apparent in all four intervention groups. After two to 4 weeks of intervention (HTT and LTT), the morphology of pores in the bony endplate, their number, and diameter had recovered significantly compared with those in Group A. The LTT group was superior to the HTT group, and the 4w in situ group was significantly superior to the 2w group. Meanwhile, the histological scores of discs, the mean fibril diameter and modulus of annulus fibrosus were significantly improved compared with the control groups, and the LTT group was superior to HTT group. Conclusions Low-tension traction better promotes active reconstruction of bony endplates and improves the elastic modulus and micro/nanostructure of the disc. Thus, it further promotes the regeneration and repair of intervertebral discs.
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Affiliation(s)
- Yan-Jun Che
- Orthopedics and Sports Medicine Center, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, 215008, Jiangsu Province, China.
| | - Jiang-Bo Guo
- Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital of SooChow University, 708 Renmin Rd, SuZhou, Jiangsu, 215007, People's Republic of China
| | - Yue Feng Hao
- Orthopedics and Sports Medicine Center, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, 215008, Jiangsu Province, China
| | - Zong-Ping Luo
- Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital of SooChow University, 708 Renmin Rd, SuZhou, Jiangsu, 215007, People's Republic of China
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15
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Bajpai S, Chelakkot R, Prabhakar R, Inamdar MM. Role of Delta-Notch signalling molecules on cell-cell adhesion in determining heterogeneous chemical and cell morphological patterning. SOFT MATTER 2022; 18:3505-3520. [PMID: 35438097 DOI: 10.1039/d2sm00064d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cell mechanics and motility are responsible for collective motion of cells that result in overall deformation of epithelial tissues. On the other hand, contact-dependent cell-cell signalling is responsible for generating a large variety of intricate, self-organized, spatial patterns of the signalling molecules. Moreover, it is becoming increasingly clear that the combined mechanochemical patterns of cell shape/size and signalling molecules in the tissues, for example, in cancerous and sensory epithelium, are governed by mechanochemical coupling between chemical signalling and cell mechanics. However, a clear quantitative picture of how these two aspects of tissue dynamics, i.e., signalling and mechanics, lead to pattern and form is still emerging. Although, a number of recent experiments demonstrate that cell mechanics, cell motility, and cell-cell signalling are tightly coupled in many morphogenetic processes, relatively few modeling efforts have focused on an integrated approach. We extend the vertex model of an epithelial monolayer to account for contact-dependent signalling between adjacent cells and between non-adjacent neighbors through long protrusional contacts with a feedback mechanism wherein the adhesive strength between adjacent cells is controlled by the expression of the signalling molecules in those cells. Local changes in cell-cell adhesion lead to changes in cell shape and size, which in turn drives changes in the levels of signalling molecules. Our simulations show that even this elementary two-way coupling of chemical signalling and cell mechanics is capable of giving rise to a rich variety of mechanochemical patterns in epithelial tissues. In particular, under certain parametric conditions, bimodal distributions in cell size and shape are obtained, which resemble experimental observations in cancerous and sensory tissues.
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Affiliation(s)
- Supriya Bajpai
- IITB-Monash Research Academy, Mumbai 400076, India.
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia.
- Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India.
| | - Raghunath Chelakkot
- Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, India.
| | - Ranganathan Prabhakar
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia.
| | - Mandar M Inamdar
- Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India.
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16
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Jakka VVSV, Bursa J. Impact of physiological loads of arterial wall on nucleus deformation in endothelial cells: A computational study. Comput Biol Med 2022; 143:105266. [PMID: 35092882 DOI: 10.1016/j.compbiomed.2022.105266] [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: 11/24/2021] [Revised: 01/17/2022] [Accepted: 01/22/2022] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Computational modeling can enhance the understanding of cell mechanics. To achieve this, finite element models of endothelial cells were proposed with shapes mimicking their natural state inside the endothelium within the cardiovascular system. Implementing the recently proposed bendo-tensegrity concept, these models consider flexural (buckling) as well as tensional/compressional behavior of microtubules and also incorporate the waviness of intermediate filaments. MATERIALS AND METHODS Four different models were created (flat and domed hexagons, both regular and elongated in the direction of blood flow) and loaded by biaxial deformation, blood pressure, and shear load from blood flow - natural physiological conditions of the arterial endothelium - aiming to investigate the "in situ" mechanical response of the cell. RESULTS The impact of individual components of loads on the nucleus deformation (more specifically on the first principal strain) potentially influencing mechanotransduction was investigated and the role of the cytoskeleton and its constituents in the mechanical response of the endothelial cell was assessed. The results show (i) the impact of pulsating blood pressure on cyclic deformations of the nucleus, which increase substantially with decreasing axial pre-stretch of the cell, (ii) the importance of relatively low shear stresses in the cell response and nucleus deformation. CONCLUSION Not only the pulsatile blood pressure but also the wall shear stress may induce significant deformation of the nucleus and thus trigger remodelation processes in endothelial cells.
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Affiliation(s)
- Veera Venkata Satya Varaprasad Jakka
- Institute of Solid Mechanics, Mechatronics and Biomechanics (ISMMB), Faculty of Mechanical Engineering (FME), Brno University of Technology (BUT), Technicka 2896/2, 61669, Brno, Czech Republic.
| | - Jiri Bursa
- Institute of Solid Mechanics, Mechatronics and Biomechanics (ISMMB), Faculty of Mechanical Engineering (FME), Brno University of Technology (BUT), Technicka 2896/2, 61669, Brno, Czech Republic
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17
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Green BJ, Marazzini M, Hershey B, Fardin A, Li Q, Wang Z, Giangreco G, Pisati F, Marchesi S, Disanza A, Frittoli E, Martini E, Magni S, Beznoussenko GV, Vernieri C, Lobefaro R, Parazzoli D, Maiuri P, Havas K, Labib M, Sigismund S, Fiore PPD, Gunby RH, Kelley SO, Scita G. PillarX: A Microfluidic Device to Profile Circulating Tumor Cell Clusters Based on Geometry, Deformability, and Epithelial State. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2106097. [PMID: 35344274 DOI: 10.1002/smll.202106097] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 03/07/2022] [Indexed: 06/14/2023]
Abstract
Circulating tumor cell (CTC) clusters are associated with increased metastatic potential and worse patient prognosis, but are rare, difficult to count, and poorly characterized biophysically. The PillarX device described here is a bimodular microfluidic device (Pillar-device and an X-magnetic device) to profile single CTCs and clusters from whole blood based on their size, deformability, and epithelial marker expression. Larger, less deformable clusters and large single cells are captured in the Pillar-device and sorted according to pillar gap sizes. Smaller, deformable clusters and single cells are subsequently captured in the X-device and separated based on epithelial marker expression using functionalized magnetic nanoparticles. Clusters of established and primary breast cancer cells with variable degrees of cohesion driven by different cell-cell adhesion protein expression are profiled in the device. Cohesive clusters exhibit a lower deformability as they travel through the pillar array, relative to less cohesive clusters, and have greater collective invasive behavior. The ability of the PillarX device to capture clusters is validated in mouse models and patients of metastatic breast cancer. Thus, this device effectively enumerates and profiles CTC clusters based on their unique geometrical, physical, and biochemical properties, and could form the basis of a novel prognostic clinical tool.
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Affiliation(s)
- Brenda J Green
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | - Margherita Marazzini
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | - Ben Hershey
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | - Amir Fardin
- IEO, Istituto Europeo di Oncologia IRCCS, Via Ripamonti 435, Milan, 20141, Italy
| | - Qingsen Li
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | - Zongjie Wang
- Institute for Biomaterials and Biomedical Engineering, University of Toronto, 144 College St, Toronto, Ontario, M5S 3M2, Canada
| | - Giovanni Giangreco
- IEO, Istituto Europeo di Oncologia IRCCS, Via Ripamonti 435, Milan, 20141, Italy
- Tumour Cell Biology Laboratory, The Francis Crick Institute, 1 Midland Rd, London, NW1 1AT, UK
| | - Federica Pisati
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | - Stefano Marchesi
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | - Andrea Disanza
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | - Emanuela Frittoli
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | - Emanuele Martini
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | - Serena Magni
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | | | - Claudio Vernieri
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
- Fondazione IRCCS Istituto Nazionale dei Tumori, Via G. Venezian 1, Milan, 20133, Italy
| | - Riccardo Lobefaro
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
- Fondazione IRCCS Istituto Nazionale dei Tumori, Via G. Venezian 1, Milan, 20133, Italy
| | - Dario Parazzoli
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | - Paolo Maiuri
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | - Kristina Havas
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
| | - Mahmoud Labib
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Sara Sigismund
- IEO, Istituto Europeo di Oncologia IRCCS, Via Ripamonti 435, Milan, 20141, Italy
- Department of Oncology and Haemato-Oncology, Università degli Studi di Milano, Via Festa del Perdono, 7, Milan, 20122, Italy
| | - Pier Paolo Di Fiore
- IEO, Istituto Europeo di Oncologia IRCCS, Via Ripamonti 435, Milan, 20141, Italy
- Department of Oncology and Haemato-Oncology, Università degli Studi di Milano, Via Festa del Perdono, 7, Milan, 20122, Italy
| | - Rosalind H Gunby
- IEO, Istituto Europeo di Oncologia IRCCS, Via Ripamonti 435, Milan, 20141, Italy
| | - Shana O Kelley
- Institute for Biomaterials and Biomedical Engineering, University of Toronto, 144 College St, Toronto, Ontario, M5S 3M2, Canada
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Giorgio Scita
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, Milan, 20139, Italy
- Department of Oncology and Haemato-Oncology, Università degli Studi di Milano, Via Festa del Perdono, 7, Milan, 20122, Italy
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18
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Molaei M, Kandy SK, Graber ZT, Baumgart T, Radhakrishnan R, Crocker JC. Probing lipid membrane bending mechanics using gold nanorod tracking. PHYSICAL REVIEW RESEARCH 2022; 4:L012027. [PMID: 35373142 PMCID: PMC8975244 DOI: 10.1103/physrevresearch.4.l012027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Lipid bilayer membranes undergo rapid bending undulations with wavelengths from tens of nanometers to tens of microns due to thermal fluctuations. Here, we probe such undulations and the membranes' mechanics by measuring the time-varying orientation of single gold nanorods (GNRs) adhered to the membrane, using high-speed dark field microscopy. In a lipid vesicle, such measurements allow the determination of the membrane's viscosity, bending rigidity, and tension as well as the friction coefficient for sliding of the monolayers over one another. The in-plane rotation of the GNR is hindered by undulations in a tension dependent manner, consistent with simulations. The motion of single GNRs adhered to the plasma membrane of living cultured cells similarly reveals the membrane's complex physics and coupling to the cell's actomyosin cortex.
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Affiliation(s)
- Mehdi Molaei
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Sreeja Kutti Kandy
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Zachary T. Graber
- Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Tobias Baumgart
- Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Ravi Radhakrishnan
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - John C. Crocker
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Corresponding author:
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19
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Kulkarni T, Mukhopadhyay D, Bhattacharya S. Dynamic alteration of poroelastic attributes as determinant membrane nanorheology for endocytosis of organ specific targeted gold nanoparticles. J Nanobiotechnology 2022; 20:74. [PMID: 35135558 PMCID: PMC8822666 DOI: 10.1186/s12951-022-01276-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/20/2022] [Indexed: 01/21/2023] Open
Abstract
Background Efficacy of targeted drug delivery using nanoparticles relies on several factors including the uptake mechanisms such as phagocytosis, macropinocytosis, micropinocytosis and receptor mediated endocytosis. These mechanisms have been studied with respect to the alteration in signaling mechanisms, cellular morphology, and linear nanomechanical properties (NMPs). Commonly employed classical contact mechanics models to address cellular NMPs fail to address mesh like structure consisting of bilayer lipids and proteins of cell membrane. To overcome this technical challenge, we employed poroelastic model which accounts for the biphasic nature of cells including their porous behavior exhibiting both solid like (fluid storage) and liquid like (fluid dissipate) behavior. Results In this study, we employed atomic force microscopy to monitor the influence of surface engineering of gold nanoparticles (GNPs) to the alteration of nonlinear NMPs such as drained Poisson’s ratio, effective shear stress, diffusion constant and pore dimensions of cell membranes during their uptake. Herein, we used pancreatic cancer (PDAC) cell lines including Panc1, AsPC-1 and endothelial cell (HUVECs) to understand the receptor-dependent and -independent endocytosis of two different GNPs derived using plectin-1 targeting peptide (PTP-GNP) and corresponding scrambled peptide (sPEP-GNP). Compared to untreated cells, in case of receptor dependent endocytosis of PTP-GNPs diffusion coefficient altered ~ 1264-fold and ~ 1530-fold and pore size altered ~ 320-fold and ~ 260-fold in Panc1 and AsPC-1 cells, respectively. Whereas for receptor independent mechanisms, we observed modest alteration in diffusion coefficient and pore size, in these cells compared to untreated cells. Effective shear stress corresponding to 7.38 ± 0.15 kPa and 20.49 ± 0.39 kPa in PTP-GNP treatment in Panc1 and AsPC-1, respectively was significantly more than that for sPEP-GNP. These results demonstrate that with temporal recruitment of plectin-1 during receptor mediated endocytosis affects the poroelastic attributes of the membrane. Conclusion This study confirms that nonlinear NMPs of cell membrane are directly associated with the uptake mechanism of nanoparticles and can provide promising insights of the nature of endocytosis mechanism involved for organ specific drug delivery using nanoparticles. Hence, nanomechanical analysis of cell membrane using this noninvasive, label-free and live-cell analytical tool can therefore be instrumental to evaluate therapeutic benefit of nanoformulations. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s12951-022-01276-1.
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Affiliation(s)
- Tanmay Kulkarni
- Department of Biochemistry and Molecular Biology, Mayo College of Medicine and Science, Griffin 413, Mayo Clinic Florida, 4500 San Pablo Road S, Jacksonville, FL, 32224, USA
| | - Debabrata Mukhopadhyay
- Department of Biochemistry and Molecular Biology, Mayo College of Medicine and Science, Griffin 413, Mayo Clinic Florida, 4500 San Pablo Road S, Jacksonville, FL, 32224, USA.,Department of Physiology and Biomedical Engineering, Mayo College of Medicine and Science, Jacksonville, FL, USA
| | - Santanu Bhattacharya
- Department of Biochemistry and Molecular Biology, Mayo College of Medicine and Science, Griffin 413, Mayo Clinic Florida, 4500 San Pablo Road S, Jacksonville, FL, 32224, USA. .,Department of Physiology and Biomedical Engineering, Mayo College of Medicine and Science, Jacksonville, FL, USA.
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20
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Beeghly GF, Amofa KY, Fischbach C, Kumar S. Regulation of Tumor Invasion by the Physical Microenvironment: Lessons from Breast and Brain Cancer. Annu Rev Biomed Eng 2022; 24:29-59. [PMID: 35119915 DOI: 10.1146/annurev-bioeng-110220-115419] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The success of anticancer therapies is often limited by heterogeneity within and between tumors. While much attention has been devoted to understanding the intrinsic molecular diversity of tumor cells, the surrounding tissue microenvironment is also highly complex and coevolves with tumor cells to drive clinical outcomes. Here, we propose that diverse types of solid tumors share common physical motifs that change in time and space, serving as universal regulators of malignancy. We use breast cancer and glioblastoma as instructive examples and highlight how invasion in both diseases is driven by the appropriation of structural guidance cues, contact-dependent heterotypic interactions with stromal cells, and elevated interstitial fluid pressure and flow. We discuss how engineering strategies show increasing value for measuring and modeling these physical properties for mechanistic studies. Moreover, engineered systems offer great promise for developing and testing novel therapies that improve patient prognosis by normalizing the physical tumor microenvironment. Expected final online publication date for the Annual Review of Biomedical Engineering, Volume 24 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Garrett F Beeghly
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA;
| | - Kwasi Y Amofa
- University of California, Berkeley-University of California, San Francisco Graduate Program in Bioengineering, Berkeley, California, USA; .,Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA
| | - Claudia Fischbach
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA; .,Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York, USA
| | - Sanjay Kumar
- University of California, Berkeley-University of California, San Francisco Graduate Program in Bioengineering, Berkeley, California, USA; .,Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA.,Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California, USA.,Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA
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21
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Yan G, Monnier S, Mouelhi M, Dehoux T. Probing molecular crowding in compressed tissues with Brillouin light scattering. Proc Natl Acad Sci U S A 2022; 119:e2113614119. [PMID: 35046032 PMCID: PMC8795543 DOI: 10.1073/pnas.2113614119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/13/2021] [Indexed: 12/11/2022] Open
Abstract
Volume regulation is key in maintaining important tissue functions, such as growth or healing. This is achieved by modulation of active contractility as well as water efflux that changes molecular crowding within individual cells. Local sensors have been developed to monitor stresses or forces in model tissues, but these approaches do not capture the contribution of liquid flows to volume regulation. Here, we use a tool based on Brillouin light scattering (BLS) that uses the interaction of a laser light with inherent picosecond timescale density fluctuations in the sample. To investigate volume variations, we induced osmotic perturbations with a polysaccharide osmolyte, Dextran (Dx), and compress cells locally within multicellular spheroids (MCSs). During osmotic compressions, we observe an increase in the BLS frequency shift that reflects local variations in the compressibility. To elucidate these data, we propose a model based on a mixing law that describes the increase of molecular crowding upon reduction of the intracellular fluids. Comparison with the data suggests a nonlinear increase of the compressibility due to the dense crowding that induces hydrodynamic interactions between the cellular polymers.
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Affiliation(s)
- Guqi Yan
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
| | - Sylvain Monnier
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
| | - Malèke Mouelhi
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
| | - Thomas Dehoux
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
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22
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Shi Y, Sivarajan S, Xiang KM, Kostecki GM, Tung L, Crocker JC, Reich DH. Pervasive cytoquakes in the actomyosin cortex across cell types and substrate stiffness. Integr Biol (Camb) 2021; 13:246-257. [PMID: 34875067 DOI: 10.1093/intbio/zyab017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 10/25/2021] [Accepted: 11/02/2021] [Indexed: 11/14/2022]
Abstract
The actomyosin cytoskeleton enables cells to resist deformation, crawl, change their shape and sense their surroundings. Despite decades of study, how its molecular constituents can assemble together to form a network with the observed mechanics of cells remains poorly understood. Recently, it has been shown that the actomyosin cortex of quiescent cells can undergo frequent, abrupt reconfigurations and displacements, called cytoquakes. Notably, such fluctuations are not predicted by current physical models of actomyosin networks, and their prevalence across cell types and mechanical environments has not previously been studied. Using micropost array detectors, we have performed high-resolution measurements of the dynamic mechanical fluctuations of cells' actomyosin cortex and stress fiber networks. This reveals cortical dynamics dominated by cytoquakes-intermittent events with a fat-tailed distribution of displacements, sometimes spanning microposts separated by 4 μm, in all cell types studied. These included 3T3 fibroblasts, where cytoquakes persisted over substrate stiffnesses spanning the tissue-relevant range of 4.3 kPa-17 kPa, and primary neonatal rat cardiac fibroblasts and myofibroblasts, human embryonic kidney cells and human bone osteosarcoma epithelial (U2OS) cells, where cytoquakes were observed on substrates in the same stiffness range. Overall, these findings suggest that the cortex self-organizes into a marginally stable mechanical state whose physics may contribute to cell mechanical properties, active behavior and mechanosensing.
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Affiliation(s)
- Yu Shi
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Shankar Sivarajan
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Katherine M Xiang
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Geran M Kostecki
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Leslie Tung
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - John C Crocker
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Daniel H Reich
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
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23
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Bakalis E, Gavriil V, Cefalas AC, Kollia Z, Zerbetto F, Sarantopoulou E. Viscoelasticity and Noise Properties Reveal the Formation of Biomemory in Cells. J Phys Chem B 2021; 125:10883-10892. [PMID: 34546052 PMCID: PMC8503882 DOI: 10.1021/acs.jpcb.1c01752] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
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Living cells are
neither perfectly elastic nor liquid and return
a viscoelastic response to external stimuli. Nanoindentation provides
force–distance curves, allowing the investigation of cell mechanical
properties, and yet, these curves can differ from point to point on
the cell surface, revealing its inhomogeneous character. In the present
work, we propose a mathematical method to estimate both viscoelastic
and noise properties of cells as these are depicted on the values
of the scaling exponents of relaxation function and power spectral
density, respectively. The method uses as input the time derivative
of the response force in a nanoindentation experiment. Generalized
moments method and/or rescaled range analysis is used to study the
resulting time series depending on their nonstationary or stationary
nature. We conducted experiments in living Ulocladium
chartarum spores. We found that spores in the approaching
phase present a viscoelastic behavior with the corresponding scaling
exponent in the range 0.25–0.52 and in the retracting phase
present a liquid-like behavior with exponents in the range 0.67–0.85.
This substantial difference of the scaling exponents in the two phases
suggests the formation of biomemory as a response of the spores to
the indenting AFM mechanical stimulus. The retracting phase may be
described as a process driven by bluish noises, while the approaching
one is driven by persistent noise.
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Affiliation(s)
- Evangelos Bakalis
- Dipartimento di Chimica "G. Ciamician", Universita di Bologna, V. F. Selmi 2, Bologna 40126, Italy
| | - Vassilios Gavriil
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens 11635, Greece
| | - Alkiviadis-Constantinos Cefalas
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens 11635, Greece
| | - Zoe Kollia
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens 11635, Greece
| | - Francesco Zerbetto
- Dipartimento di Chimica "G. Ciamician", Universita di Bologna, V. F. Selmi 2, Bologna 40126, Italy
| | - Evangelia Sarantopoulou
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens 11635, Greece
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24
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Numerical Modelling of Multicellular Spheroid Compression: Viscoelastic Fluid vs. Viscoelastic Solid. MATHEMATICS 2021. [DOI: 10.3390/math9182333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Parallel-plate compression of multicellular spheroids (MCSs) is a promising and popular technique to quantify the viscoelastic properties of living tissues. This work presents two different approaches to the simulation of the MCS compression based on viscoelastic solid and viscoelastic fluid models. The first one is the standard linear solid model implemented in ABAQUS/CAE. The second one is the new model for 3D viscoelastic free surface fluid flow, which combines the Oldroyd-B incompressible fluid model and the incompressible neo-Hookean solid model via incorporation of an additional elastic tensor and a dynamic equation for it. The simulation results indicate that either approach can be applied to model the MCS compression with reasonable accuracy. Future application of the viscoelastic free surface fluid model is the MCSs fusion highly-demanded in bioprinting.
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25
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Li Y, Tang W, Guo M. The Cell as Matter: Connecting Molecular Biology to Cellular Functions. MATTER 2021; 4:1863-1891. [PMID: 35495565 PMCID: PMC9053450 DOI: 10.1016/j.matt.2021.03.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Viewing cell as matter to understand the intracellular biomolecular processes and multicellular tissue behavior represents an emerging research area at the interface of physics and biology. Cellular material displays various physical and mechanical properties, which can strongly affect both intracellular and multicellular biological events. This review provides a summary of how cells, as matter, connect molecular biology to cellular and multicellular scale functions. As an impact in molecular biology, we review recent progresses in utilizing cellular material properties to direct cell fate decisions in the communities of immune cells, neurons, stem cells, and cancer cells. Finally, we provide an outlook on how to integrate cellular material properties in developing biophysical methods for engineered living systems, regenerative medicine, and disease treatments.
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Affiliation(s)
- Yiwei Li
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Wenhui Tang
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ming Guo
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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26
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Moradi M, Nazockdast E. Cell nucleus as a microrheological probe to study the rheology of the cytoskeleton. Biophys J 2021; 120:1542-1564. [PMID: 33705756 DOI: 10.1016/j.bpj.2021.01.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/29/2020] [Accepted: 01/11/2021] [Indexed: 01/12/2023] Open
Abstract
Mechanical properties of the cell are important biomarkers for probing its architectural changes caused by cellular processes and/or pathologies. The development of microfluidic technologies has enabled measuring the cell's mechanical properties at high throughput so that mechanical phenotyping can be applied to large samples in reasonable timescales. These studies typically measure the stiffness of the cell as the only mechanical biomarker and do not disentangle the rheological contributions of different structural components of the cell, including the cell cortex, the interior cytoplasm and its immersed cytoskeletal structures, and the nucleus. Recent advancements in high-speed fluorescent imaging have enabled probing the deformations of the cell cortex while also tracking different intracellular components in rates applicable to microfluidic platforms. We present a, to our knowledge, novel method to decouple the mechanics of the cell cortex and the cytoplasm by analyzing the correlation between the cortical deformations that are induced by external microfluidic flows and the nucleus displacements, induced by those cortical deformations, i.e., we use the nucleus as a high-throughput microrheological probe to study the rheology of the cytoplasm, independent of the cell cortex mechanics. To demonstrate the applicability of this method, we consider a proof-of-concept model consisting of a rigid spherical nucleus centered in a spherical cell. We obtain analytical expressions for the time-dependent nucleus velocity as a function of the cell deformations when the interior cytoplasm is modeled as a viscous, viscoelastic, porous, and poroelastic material and demonstrate how the nucleus velocity can be used to characterize the linear rheology of the cytoplasm over a wide range of forces and timescales/frequencies.
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Affiliation(s)
- Moslem Moradi
- UNC Chapel Hill, Applied Physical Sciences, Chapel Hill, North Carolina
| | - Ehssan Nazockdast
- UNC Chapel Hill, Applied Physical Sciences, Chapel Hill, North Carolina.
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27
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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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28
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Silvani G, Romanov V, Cox CD, Martinac B. Biomechanical Characterization of Endothelial Cells Exposed to Shear Stress Using Acoustic Force Spectroscopy. Front Bioeng Biotechnol 2021; 9:612151. [PMID: 33614612 PMCID: PMC7891662 DOI: 10.3389/fbioe.2021.612151] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/07/2021] [Indexed: 01/27/2023] Open
Abstract
Characterizing mechanical properties of cells is important for understanding many cellular processes, such as cell movement, shape, and growth, as well as adaptation to changing environments. In this study, we explore the mechanical properties of endothelial cells that form the biological barrier lining blood vessels, whose dysfunction leads to development of many cardiovascular disorders. Stiffness of living endothelial cells was determined by Acoustic Force Spectroscopy (AFS), by pull parallel multiple functionalized microspheres located at the cell-cell periphery. The unique configuration of the acoustic microfluidic channel allowed us to develop a long-term dynamic culture protocol exposing cells to laminar flow for up to 48 h, with shear stresses in the physiological range (i.e., 6 dyn/cm2). Two different Endothelial cells lines, Human Aortic Endothelial Cells (HAECs) and Human Umbilical Vein Endothelial Cells (HUVECs), were investigated to show the potential of this tool to capture the change in cellular mechanical properties during maturation of a confluent endothelial monolayer. Immunofluorescence microscopy was exploited to follow actin filament rearrangement and junction formation over time. For both cell types we found that the application of shear-stress promotes the typical phenotype of a mature endothelium expressing a linear pattern of VE-cadherin at the cell-cell border and actin filament rearrangement along the perimeter of Endothelial cells. A staircase-like sequence of increasing force steps, ranging from 186 pN to 3.5 nN, was then applied in a single measurement revealing the force-dependent apparent stiffness of the membrane cortex in the kPa range. We also found that beads attached to cells cultured under dynamic conditions were harder to displace than cells cultured under static conditions, showing a stiffer membrane cortex at cell periphery. All together these results demonstrate that the AFS can identify changes in cell mechanics based on force measurements of adherent cells under conditions mimicking their native microenvironment, thus revealing the shear stress dependence of the mechanical properties of neighboring endothelial cells.
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Affiliation(s)
- Giulia Silvani
- Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
| | | | - Charles D. Cox
- Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
- St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
- St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
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29
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Gensbittel V, Kräter M, Harlepp S, Busnelli I, Guck J, Goetz JG. Mechanical Adaptability of Tumor Cells in Metastasis. Dev Cell 2020; 56:164-179. [PMID: 33238151 DOI: 10.1016/j.devcel.2020.10.011] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/18/2020] [Accepted: 10/16/2020] [Indexed: 12/12/2022]
Abstract
The most dangerous aspect of cancer lies in metastatic progression. Tumor cells will successfully form life-threatening metastases when they undergo sequential steps along a journey from the primary tumor to distant organs. From a biomechanics standpoint, growth, invasion, intravasation, circulation, arrest/adhesion, and extravasation of tumor cells demand particular cell-mechanical properties in order to survive and complete the metastatic cascade. With metastatic cells usually being softer than their non-malignant counterparts, high deformability for both the cell and its nucleus is thought to offer a significant advantage for metastatic potential. However, it is still unclear whether there is a finely tuned but fixed mechanical state that accommodates all mechanical features required for survival throughout the cascade or whether tumor cells need to dynamically refine their properties and intracellular components at each new step encountered. Here, we review the various mechanical requirements successful cancer cells might need to fulfill along their journey and speculate on the possibility that they dynamically adapt their properties accordingly. The mechanical signature of a successful cancer cell might actually be its ability to adapt to the successive microenvironmental constraints along the different steps of the journey.
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Affiliation(s)
- Valentin Gensbittel
- INSERM UMR_S1109, Tumor Biomechanics, Strasbourg, France; Université de Strasbourg, Strasbourg, France; Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
| | - Martin Kräter
- Max Planck Institute for the Science of Light & Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
| | - Sébastien Harlepp
- INSERM UMR_S1109, Tumor Biomechanics, Strasbourg, France; Université de Strasbourg, Strasbourg, France; Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
| | - Ignacio Busnelli
- INSERM UMR_S1109, Tumor Biomechanics, Strasbourg, France; Université de Strasbourg, Strasbourg, France; Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
| | - Jochen Guck
- Max Planck Institute for the Science of Light & Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany.
| | - Jacky G Goetz
- INSERM UMR_S1109, Tumor Biomechanics, Strasbourg, France; Université de Strasbourg, Strasbourg, France; Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France.
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30
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Kelkar M, Bohec P, Charras G. Mechanics of the cellular actin cortex: From signalling to shape change. Curr Opin Cell Biol 2020; 66:69-78. [DOI: 10.1016/j.ceb.2020.05.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/30/2020] [Accepted: 05/08/2020] [Indexed: 01/17/2023]
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31
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Stable mechanical environments created by a low-tension traction device is beneficial for the regeneration and repair of degenerated intervertebral discs. Spine J 2020; 20:1503-1516. [PMID: 32305426 DOI: 10.1016/j.spinee.2020.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND By blocking the cascade of reactions leading to intervertebral disc degeneration through immobilization-traction, a delay in intervertebral disc degeneration and its regeneration, to some extent, has been observed. However, the precise balance of regulation of the microenvironment of intervertebral disc biomechanics and coordination of the complex spatiotemporal reconstruction of the extracellular matrix have not yet been solved, and clinical results are far from successful. PURPOSE In the present study, a mechanical degeneration model was constructed to evaluate the possibility and effectiveness of disc regeneration or repair through low-tension traction of degenerated discs so as to provide basic biomechanical information for clinical optimization of the traction device and to establish traction parameters for prevention and treatment of disc degeneration. STUDY DESIGN A macro-, micro-, and nano-level structural analysis of degenerative discs of rat tail before and after controlled traction. METHODS Six-month-old male Sprague-Dawley rats were randomly divided into seven groups: Group A: control group (instrumented with Kirschner [K]-wires only); Group B: Model group (caudal vertebrae immobilized using a custom-made external device to fix four caudal vertebrae [Co7-Co10], while Co8-Co9 vertebrae underwent 4 weeks of compression to induce disc degeneration); Group C: experimental control group (devices removed after the 4 week compression described in Group B, and recovered by themselves for 4 weeks). The remaining four groups represented intervention groups (Groups D and F: Co8-Co9 vertebrae compressed for 4 weeks followed by 2 or 4 weeks of in situ traction, respectively; Groups E and G: vertebrae compressed for 4 weeks followed by 2 or 4 weeks of excessive traction, respectively). X-ray and magnetic resonance imaging were performed at each time point to measure disc height and T2 signal intensity. At the end of the experiment, the animals were euthanized and tail vertebrae harvested for analysis of intervertebral disc histopathology, proteoglycan content, elastic modulus of fibers of the annulus fibrosus (AF) and nucleus pulposus (NP), and microstructure of the bony end plate. RESULTS After 2 to 4 weeks of continuous traction (in situ and excessive traction), the Co8-Co9 intervertebral disc space of rats in Groups D to G increased significantly compared with Groups B and C (p < .05). In addition, signs of tissue regeneration were apparent in all four intervention groups (D-G). In addition, histologic scores of the intervention groups (D-G) were significantly lower than those in the model and experimental control groups (Groups B and C, respectively), although no significant difference was found between those four groups. Compared with the model group (Group B), total proteoglycan content of the NP in the intervention groups (D-G) increased significantly (p < .05). After 2 to 4 weeks of intervention (in situ and excessive traction), the morphology of pores in the bony end plate, their number, and the diameter had recovered significantly compared with those in Group B. The in situ traction group was superior to the excessive traction group, and 4 weeks in situ group significantly superior to the 2 weeks group. In all intervention groups, in both the inner and outer AF, mean fibril diameter decreased significantly (p < .05), although they remained larger in the excessive traction group than that in the in situ traction group. Consistent with trend in collagen fiber diameter, the outer AF was stiffer than the inner, and the modulus of the AF in each intervention group not significantly different from that of the control group (Group A) except Group C. However, within the NP, the variation in trend in diameter and modulus of collagen fibers was essentially inconsistent with that of the AF. CONCLUSIONS Degenerated discs exhibit greater reconstruction after low tension traction. It is clear that the intervertebral disc mechanical microenvironment depends to a greater extent on low-tension traction than high-tension traction.
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32
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Stamenović D, Smith ML. Tensional homeostasis at different length scales. SOFT MATTER 2020; 16:6946-6963. [PMID: 32696799 DOI: 10.1039/d0sm00763c] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Tensional homeostasis is a phenomenon of fundamental importance in mechanobiology. It refers to the ability of organs, tissues, and cells to respond to external disturbances by maintaining a homeostatic (set point) level of mechanical stress (tension). It is well documented that breakdown in tensional homeostasis is the hallmark of progression of diseases, including cancer and atherosclerosis. In this review, we surveyed quantitative studies of tensional homeostasis with the goal of providing characterization of this phenomenon across a broad range of length scales, from the organ level to the subcellular level. We considered both static and dynamics approaches that have been used in studies of this phenomenon. Results that we found in the literature and that we obtained from our own investigations suggest that tensional homeostasis is an emergent phenomenon driven by collective rheostatic mechanisms associated with focal adhesions, and by a collective action of cells in multicellular forms, whose impact on tensional homeostasis is cell type-dependent and cell microenvironment-dependent. Additionally, the finding that cadherins, adhesion molecules that are important for formation of cell-cell junctions, promote tensional homeostasis even in single cells, demonstrates their relevance as a signaling moiety.
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Affiliation(s)
- Dimitrije Stamenović
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215, USA.
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33
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Elitas M, Sengul E. Quantifying Heterogeneity According to Deformation of the U937 Monocytes and U937-Differentiated Macrophages Using 3D Carbon Dielectrophoresis in Microfluidics. MICROMACHINES 2020; 11:mi11060576. [PMID: 32521676 PMCID: PMC7345647 DOI: 10.3390/mi11060576] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/04/2020] [Accepted: 06/08/2020] [Indexed: 12/14/2022]
Abstract
A variety of force fields have thus far been demonstrated to investigate electromechanical properties of cells in a microfluidic platform which, however, are mostly based on fluid shear stress and may potentially cause irreversible cell damage. This work presents dielectric movement and deformation measurements of U937 monocytes and U937-differentiated macrophages in a low conductive medium inside a 3D carbon electrode array. Here, monocytes exhibited a crossover frequency around 150 kHz and presented maximum deformation index at 400 kHz and minimum deformation index at 1 MHz frequencies at 20 Vpeak-peak. Although macrophages were differentiated from monocytes, their crossover frequency was lower than 50 kHz at 10 Vpeak-peak. The change of the deformation index for macrophages was more constant and lower than the monocyte cells. Both dielectric mobility and deformation spectra revealed significant differences between the dielectric responses of U937 monocytes and U937-differentiated macrophages, which share the same origin. This method can be used for label-free, specific, and sensitive single-cell characterization. Besides, damage of the cells by aggressive shear forces can, hence, be eliminated and cells can be used for downstream analysis. Our results showed that dielectric mobility and deformation have a great potential as an electromechanical biomarker to reliably characterize and distinguish differentiated cell populations from their progenitors.
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Affiliation(s)
- Meltem Elitas
- Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul 34956, Turkey;
- Sabanci University Nanotechnology Research and Application Center, Istanbul 34956, Turkey
- Correspondence: ; Tel.: +90-538-810-2930
| | - Esra Sengul
- Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul 34956, Turkey;
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34
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Smith M, Chalklen T, Lindackers C, Calahorra Y, Howe C, Tamboli A, Bax DV, Barrett DJ, Cameron RE, Best SM, Kar-Narayan S. Poly-l-Lactic Acid Nanotubes as Soft Piezoelectric Interfaces for Biology: Controlling Cell Attachment via Polymer Crystallinity. ACS APPLIED BIO MATERIALS 2020; 3:2140-2149. [PMID: 32337501 PMCID: PMC7175596 DOI: 10.1021/acsabm.0c00012] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 03/11/2020] [Indexed: 12/16/2022]
Abstract
It has become increasingly evident that the mechanical and electrical environment of a cell is crucial in determining its function and the subsequent behavior of multicellular systems. Platforms through which cells can directly interface with mechanical and electrical stimuli are therefore of great interest. Piezoelectric materials are attractive in this context because of their ability to interconvert mechanical and electrical energy, and piezoelectric nanomaterials, in particular, are ideal candidates for tools within mechanobiology, given their ability to both detect and apply small forces on a length scale that is compatible with cellular dimensions. The choice of piezoelectric material is crucial to ensure compatibility with cells under investigation, both in terms of stiffness and biocompatibility. Here, we show that poly-l-lactic acid nanotubes, grown using a melt-press template wetting technique, can provide a "soft" piezoelectric interface onto which human dermal fibroblasts readily attach. Interestingly, by controlling the crystallinity of the nanotubes, the level of attachment can be regulated. In this work, we provide detailed nanoscale characterization of these nanotubes to show how differences in stiffness, surface potential, and piezoelectric activity of these nanotubes result in differences in cellular behavior.
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Affiliation(s)
- Michael Smith
- Department of Materials Science &
Metallurgy, University of Cambridge, Cambridge CB3 0FS, U.K.
| | - Thomas Chalklen
- Department of Materials Science &
Metallurgy, University of Cambridge, Cambridge CB3 0FS, U.K.
| | - Cathrin Lindackers
- Department of Materials Science &
Metallurgy, University of Cambridge, Cambridge CB3 0FS, U.K.
| | - Yonatan Calahorra
- Department of Materials Science &
Metallurgy, University of Cambridge, Cambridge CB3 0FS, U.K.
| | - Caitlin Howe
- Department of Materials Science &
Metallurgy, University of Cambridge, Cambridge CB3 0FS, U.K.
| | - Alkausil Tamboli
- Department of Materials Science &
Metallurgy, University of Cambridge, Cambridge CB3 0FS, U.K.
| | - Daniel V. Bax
- Department of Materials Science &
Metallurgy, University of Cambridge, Cambridge CB3 0FS, U.K.
| | - David J. Barrett
- Department of Materials Science &
Metallurgy, University of Cambridge, Cambridge CB3 0FS, U.K.
| | - Ruth E. Cameron
- Department of Materials Science &
Metallurgy, University of Cambridge, Cambridge CB3 0FS, U.K.
| | - Serena M. Best
- Department of Materials Science &
Metallurgy, University of Cambridge, Cambridge CB3 0FS, U.K.
| | - Sohini Kar-Narayan
- Department of Materials Science &
Metallurgy, University of Cambridge, Cambridge CB3 0FS, U.K.
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Berntsen P, Ericsson T, Swenson J, Sjögren L. Complex modulus and compliance for airway smooth muscle cells. Phys Rev E 2020; 101:032410. [PMID: 32289912 DOI: 10.1103/physreve.101.032410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 01/24/2020] [Indexed: 11/07/2022]
Abstract
A cell can be described as a complex viscoelastic material with structural relaxations that is modulated by thermal and chemically nonequilibrium processes. Tissue morphology and function rely upon cells' physical responses to mechanical force. We measured the frequency-dependent mechanical relaxation response of adherent human airway smooth muscle cells under adenosine triphosphate (ATP) depletion and normal ATP conditions. The frequency dependence of the complex compliance J^{*} and modulus G^{*} was measured over the frequencies 10^{-1}<f<10^{3} Hz at selected temperatures between 4<T<54^{∘}C. Our results show characteristic relaxation features which can be interpreted by the mode-coupling theory (MCT) of viscoelastic liquids. We analyze the shape of the spectra in terms of a so-called A_{4} scenario with logarithmic scaling laws. Characteristic timescales τ_{β} and τ_{α} appear with corresponding energy barriers E_{β}≈(10-20)k_{B}T and E_{α}≈(20-30)k_{B}T. We demonstrate that cells are close to a glass transition. We find that the cell becomes softer around physiological temperatures, where its surface structure is more liquid-like with a plateau modulus around 0.1-0.8 kPa compared with the more solid-like interior cytoskeletal structures with a plateau modulus 1-15 kPa. Corresponding values for the viscosity are 10^{2}-10^{3} Pa s for the surface structures closer to the membrane and 10^{4}-10^{6} Pa s for the core cytoskeletal structures.
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Affiliation(s)
- Peter Berntsen
- Australian Research Council (ARC) Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Thomas Ericsson
- Department of Mathematical Sciences, Chalmers University of Technology, and the University of Gothenburg, 41296 Göteborg, Sweden
| | - Jan Swenson
- Department of Physics, Chalmers University of Technology, 41296 Göteborg, Sweden
| | - Lennart Sjögren
- Department of Physics, University of Gothenburg, 41296 Göteborg, Sweden
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de Sousa JS, Freire RS, Sousa FD, Radmacher M, Silva AFB, Ramos MV, Monteiro-Moreira ACO, Mesquita FP, Moraes MEA, Montenegro RC, Oliveira CLN. Double power-law viscoelastic relaxation of living cells encodes motility trends. Sci Rep 2020; 10:4749. [PMID: 32179816 PMCID: PMC7075927 DOI: 10.1038/s41598-020-61631-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 02/26/2020] [Indexed: 02/08/2023] Open
Abstract
Living cells are constantly exchanging momentum with their surroundings. So far, there is no consensus regarding how cells respond to such external stimuli, although it reveals much about their internal structures, motility as well as the emergence of disorders. Here, we report that twelve cell lines, ranging from healthy fibroblasts to cancer cells, hold a ubiquitous double power-law viscoelastic relaxation compatible with the fractional Kelvin-Voigt viscoelastic model. Atomic Force Microscopy measurements in time domain were employed to determine the mechanical parameters, namely, the fast and slow relaxation exponents, the crossover timescale between power law regimes, and the cell stiffness. These cell-dependent quantities show strong correlation with their collective migration and invasiveness properties. Beyond that, the crossover timescale sets the fastest timescale for cells to perform their biological functions.
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Affiliation(s)
- J S de Sousa
- Departamento de Física, Universidade Federal do Ceará, 60455-970, Fortaleza, Ceará, Brazil.
| | - R S Freire
- Central Analítica, Universidade Federal do Ceará, 60455-970, Fortaleza, Ceará, Brazil
| | - F D Sousa
- Departamento de Física, Universidade Federal do Ceará, 60455-970, Fortaleza, Ceará, Brazil
| | - M Radmacher
- Institute of Biophysics, University of Bremen, Otto-Hahn Allee 1, 28359, Bremen, Germany
| | - A F B Silva
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, 60440-554, Fortaleza, Ceará, Brazil
| | - M V Ramos
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, 60440-554, Fortaleza, Ceará, Brazil
| | - A C O Monteiro-Moreira
- Centro de Biologia Experimental, Universidade de Fortaleza, 60811-905, Fortaleza, Ceará, Brazil
| | - F P Mesquita
- Núcleo de Pesquisa e Desenvolvimento de Medicamentos, Universidade Federal do Ceará, 60430-275, Fortaleza, Ceará, Brazil
| | - M E A Moraes
- Núcleo de Pesquisa e Desenvolvimento de Medicamentos, Universidade Federal do Ceará, 60430-275, Fortaleza, Ceará, Brazil
| | - R C Montenegro
- Núcleo de Pesquisa e Desenvolvimento de Medicamentos, Universidade Federal do Ceará, 60430-275, Fortaleza, Ceará, Brazil
| | - C L N Oliveira
- Departamento de Física, Universidade Federal do Ceará, 60455-970, Fortaleza, Ceará, Brazil
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Agarwal M, Biswas P, Bhattacharya A, Sinha DK. Reactive oxygen species-mediated cytoplasmic stiffening impairs the phagocytic ability of the macrophage. J Cell Sci 2020; 133:jcs.236471. [PMID: 32005700 DOI: 10.1242/jcs.236471] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 01/17/2020] [Indexed: 12/12/2022] Open
Abstract
The phagocytic ability of macrophages empowers them to enforce innate immunity. RAW264.7, THP-1 and peripheral blood mononuclear cell-derived macrophages display considerable variability with regards to their phagocytic ability. We identify the underlying causes that attenuate the phagocytic abilities of a macrophage. Deformability of the cytoplasm and cortex influences the macrophage's phagocytic ability, and macrophages use the large cell-to-cell variability of their cytoplasmic stiffness to modulate their phagocytic ability. We find that the more-deformable macrophages have a higher phagocytic ability than those that are less deformable. Further, the subcellular spatial variability of cortex stiffness gives rise to more-deformable subdomains on the membrane for pathogen ingestion. We report a previously unknown negative-feedback loop that is triggered by the phagocytic oxidative burst. Macrophages utilize the excess reactive oxygen species to stiffen the cytoplasm, reducing their phagocytic propensity. In organisms, ageing or pathological conditions impair the phagocytic ability of macrophages. Our findings identify the targets that could potentially be utilized for restoring the phagocytic ability of the defunct macrophages.
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Affiliation(s)
- Mahesh Agarwal
- School of Biological Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 32, India
| | - Parijat Biswas
- School of Biological Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 32, India
| | - Anindita Bhattacharya
- School of Biological Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 32, India
| | - Deepak Kumar Sinha
- School of Biological Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 32, India
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38
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Xie Y, Mao Z, Bachman H, Li P, Zhang P, Ren L, Wu M, Huang TJ. Acoustic Cell Separation Based on Density and Mechanical Properties. J Biomech Eng 2020; 142:031005. [PMID: 32006021 PMCID: PMC7104781 DOI: 10.1115/1.4046180] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/30/2019] [Indexed: 11/08/2022]
Abstract
Density and mechanical properties (e.g., compressibility or bulk modulus) are important cellular biophysical markers. As such, developing a method to separate cells directly based on these properties can benefit various applications including biological research, diagnosis, prognosis, and therapeutics. As a potential solution, surface acoustic wave (SAW)-based cell separation has demonstrated advantages in terms of biocompatibility and compact device size. However, most SAW-reliant cell separations are achieved using an entangled effect of density, various mechanical properties, and size. In this work, we demonstrate SAW-based separation of cells/particles based on their density and compressibility, irrespective of their sizes, by manipulating the acoustic properties of the fluidic medium. Using our platform, SAW-based separation is achieved by varying the dimensions of the microfluidic channels, the wavelengths of acoustic signals, and the properties of the fluid media. Our method was applied to separate paraformaldehyde-treated and fresh Hela cells based on differences in mechanical properties; a recovery rate of 85% for fixed cells was achieved. It was also applied to separate red blood cells (RBCs) and white blood cells (WBCs) which have different densities. A recovery rate of 80.5% for WBCs was achieved.
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Affiliation(s)
- Yuliang Xie
- Department of Chemical Engineering, The Pennsylvania State
University, University Park, State College, PA
16802
| | - Zhangming Mao
- Department of Engineering Science and Mechanics, The
Pennsylvania State University, University
Park, State College, PA 16802
| | - Hunter Bachman
- Department of Mechanical Engineering and Materials Science,
Duke University, Durham, NC 27708
| | - Peng Li
- Department of Engineering Science and Mechanics, The
Pennsylvania State University, University
Park, State College, PA 16802
| | - Peiran Zhang
- Department of Mechanical Engineering and Materials Science,
Duke University, Durham, NC 27708
| | - Liqiang Ren
- Department of Engineering Science and Mechanics, The
Pennsylvania State University, University
Park, State College, PA 16802
| | - Mengxi Wu
- Department of Mechanical Engineering and Materials Science,
Duke University, Durham, NC 27708
| | - Tony Jun Huang
- Department of Mechanical Engineering and Materials Science,
Duke University, Durham, NC 27708
e-mail:
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Abstract
Despite the importance in various cellular processes, the nanomechanical responses of the living cell membrane have been elusive due to complexities in the membrane associated with the hidden architecture of multiple molecular components, including the lipid bilayer. Here, combined experimental and theoretical frameworks that can probe and interpret nanomechanical responses of the cell membrane are demonstrated. A magnetic tweezer assay was introduced to apply pico-Newton scale forces to lipids and E-cadherin molecules at the living cell surface. Two unique classes of force-extension curves were identified: one with a deflection transition (Type I) and another with a discontinuous transition (Type II). The repeated observations of these responses, regardless of cell type and targeted cell surface molecule, suggest the Type I and II curves are the primary nanomechanical responses of cell membranes. To reproduce these responses in vitro, a model system using synthetic lipid vesicles was also developed. Together with a finite element model of lipid bilayers, the reproduced responses suggest that the confined fluidity and curvature constraints imposed on the lipid bilayer components of the cell membrane are the main parameters responsible for the generation of these responses. This work provides an insight into how forces on membrane molecules propagate to the lipid bilayer components to generate specific nanomechanical responses. In addition, the consistent results obtained using different methodologies demonstrate that the presented force-probing assays and the theoretical model can serve a combined testbed to investigate nanoscale mechanics of the living cell membrane.
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Affiliation(s)
- Jichul Kim
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Republic of Korea.
- Center for Nanomedicine, Institute for Basic Science (IBS) and Yonsei-IBS Institute, Yonsei University, Seoul, Republic of Korea.
- Research Center for Natural Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea.
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA.
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40
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Park S, Song CS, Lin CL, Jiang S, Osmulski PA, Wang CM, Marck BT, Matsumoto AM, Morrissey C, Gaczynska ME, Chen Y, Mostaghel EA, Chatterjee B. Inhibitory Interplay of SULT2B1b Sulfotransferase with AKR1C3 Aldo-keto Reductase in Prostate Cancer. Endocrinology 2020; 161:bqz042. [PMID: 31894239 PMCID: PMC7341717 DOI: 10.1210/endocr/bqz042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/30/2019] [Indexed: 12/22/2022]
Abstract
SULT2B1b (SULT2B) is a prostate-expressed hydroxysteroid sulfotransferase, which may regulate intracrine androgen homeostasis by mediating 3β-sulfation of dehydroepiandrosterone (DHEA), the precursor for 5α-dihydrotestosterone (DHT) biosynthesis. The aldo-keto reductase (AKR)1C3 regulates androgen receptor (AR) activity in castration-resistant prostate cancer (CRPC) by promoting tumor tissue androgen biosynthesis from adrenal DHEA and also by functioning as an AR-selective coactivator. Herein we report that SULT2B-depleted CRPC cells, arising from stable RNA interference or gene knockout (KO), are markedly upregulated for AKR1C3, activated for ERK1/2 survival signal, and induced for epithelial-to-mesenchymal (EMT)-like changes. EMT was evident from increased mesenchymal proteins and elevated EMT-inducing transcription factors SNAI1 and TWIST1 in immunoblot and single-cell mass cytometry analyses. SULT2B KO cells showed greater motility and invasion in vitro; growth escalation in xenograft study; and enhanced metastatic potential predicted on the basis of decreased cell stiffness and adhesion revealed from atomic force microscopy analysis. While AR and androgen levels were unchanged, AR activity was elevated, since PSA and FKBP5 mRNA induction by DHT-activated AR was several-fold higher in SULT2B-silenced cells. AKR1C3 silencing prevented ERK1/2 activation and SNAI1 induction in SULT2B-depleted cells. SULT2B was undetectable in nearly all CRPC metastases from 50 autopsy cases. Primary tumors showed variable and Gleason score (GS)-independent SULT2B levels. CRPC metastases lacking SULT2B expressed AKR1C3. Since AKR1C3 is frequently elevated in advanced prostate cancer, the inhibitory influence of SULT2B on AKR1C3 upregulation, ERK1/2 activation, EMT-like induction, and on cell motility and invasiveness may be clinically significant. Pathways regulating the inhibitory SULT2B-AKR1C3 axis may inform new avenue(s) for targeting SULT2B-deficient prostate cancer.
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Affiliation(s)
- Sulgi Park
- Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, Texas
- Department of Microbiology & Immunology, Pusan National University School of Medicine, South Korea
- South Texas Veterans Health Care System, San Antonio, Texas
| | - Chung-Seog Song
- Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, Texas
- South Texas Veterans Health Care System, San Antonio, Texas
| | - Chun-Lin Lin
- Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, Texas
| | - Shoulei Jiang
- Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, Texas
- South Texas Veterans Health Care System, San Antonio, Texas
| | - Pawel A Osmulski
- Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, Texas
| | - Chiou-Miin Wang
- Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, Texas
| | - Brett T Marck
- Geriatric Research, Education & Clinical Center, VA Puget Sound Health Care System, Seattle, WA
| | - Alvin M Matsumoto
- Geriatric Research, Education & Clinical Center, VA Puget Sound Health Care System, Seattle, WA
| | - Colm Morrissey
- Department of Urology, University of Washington, Seattle, WA
| | - Maria E Gaczynska
- Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, Texas
| | - Yidong Chen
- Department of Epidemiology & Biostatistics, University of Texas Health San Antonio, San Antonio, Texas
- Greehy Children’s Cancer Research Institute, University of Texas Health San Antonio, San Antonio, Texas
| | - Elahe A Mostaghel
- Geriatric Research, Education & Clinical Center, VA Puget Sound Health Care System, Seattle, WA
- Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Bandana Chatterjee
- Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, Texas
- South Texas Veterans Health Care System, San Antonio, Texas
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41
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Efremov YM, Okajima T, Raman A. Measuring viscoelasticity of soft biological samples using atomic force microscopy. SOFT MATTER 2020; 16:64-81. [PMID: 31720656 DOI: 10.1039/c9sm01020c] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Mechanical properties play important roles at different scales in biology. At the level of a single cell, the mechanical properties mediate mechanosensing and mechanotransduction, while at the tissue and organ levels, changes in mechanical properties are closely connected to disease and physiological processes. Over the past three decades, atomic force microscopy (AFM) has become one of the most widely used tools in the mechanical characterization of soft samples, ranging from molecules, cell organoids and cells to whole tissue. AFM methods can be used to quantify both elastic and viscoelastic properties, and significant recent developments in the latter have been enabled by the introduction of new techniques and models for data analysis. Here, we review AFM techniques developed in recent years for examining the viscoelastic properties of cells and soft gels, describe the main steps in typical data acquisition and analysis protocols, and discuss relevant viscoelastic models and how these have been used to characterize the specific features of cellular and other biological samples. We also discuss recent trends and potential directions for this field.
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Affiliation(s)
- Yuri M Efremov
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA. and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana, USA and Institute for Regenerative Medicine, Sechenov University, Moscow, Russia
| | - Takaharu Okajima
- Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Arvind Raman
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA. and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana, USA
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42
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Martinac B, Nikolaev YA, Silvani G, Bavi N, Romanov V, Nakayama Y, Martinac AD, Rohde P, Bavi O, Cox CD. Cell membrane mechanics and mechanosensory transduction. CURRENT TOPICS IN MEMBRANES 2020; 86:83-141. [DOI: 10.1016/bs.ctm.2020.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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43
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Bonfanti A, Fouchard J, Khalilgharibi N, Charras G, Kabla A. A unified rheological model for cells and cellularised materials. ROYAL SOCIETY OPEN SCIENCE 2020; 7:190920. [PMID: 32218933 PMCID: PMC7029884 DOI: 10.1098/rsos.190920] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 11/22/2019] [Indexed: 05/04/2023]
Abstract
The mechanical response of single cells and tissues exhibits a broad distribution of time-scales that often gives rise to a distinctive power-law rheology. Such complex behaviour cannot be easily captured by traditional rheological approaches, making material characterisation and predictive modelling very challenging. Here, we present a novel model combining conventional viscoelastic elements with fractional calculus that successfully captures the macroscopic relaxation response of epithelial monolayers. The parameters extracted from the fitting of the relaxation modulus allow prediction of the response of the same material to slow stretch and creep, indicating that the model captured intrinsic material properties. Two characteristic times, derived from the model parameters, delimit different regimes in the materials response. We compared the response of tissues with the behaviour of single cells as well as intra and extra-cellular components, and linked the power-law behaviour of the epithelium to the dynamics of the cell cortex. Such a unified model for the mechanical response of biological materials provides a novel and robust mathematical approach to consistently analyse experimental data and uncover similarities and differences in reported behaviour across experimental methods and research groups. It also sets the foundations for more accurate computational models of tissue mechanics.
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Affiliation(s)
- A. Bonfanti
- Engineering Department, Cambridge University, Cambridge, UK
| | - J. Fouchard
- London Centre for Nanotechnology, University College London, London, UK
| | - N. Khalilgharibi
- London Centre for Nanotechnology, University College London, London, UK
- The Centre for Computation, Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, London, UK
| | - G. Charras
- London Centre for Nanotechnology, University College London, London, UK
- Institute for the Physics of Living Systems, University College London, London, UK
- Department of Cell and Developmental Biology, University College London, London, UK
| | - A. Kabla
- Engineering Department, Cambridge University, Cambridge, UK
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44
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Bonfanti A, Fouchard J, Khalilgharibi N, Charras G, Kabla A. A unified rheological model for cells and cellularised materials. ROYAL SOCIETY OPEN SCIENCE 2020. [PMID: 32218933 DOI: 10.5061/dryad.s853qg7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The mechanical response of single cells and tissues exhibits a broad distribution of time-scales that often gives rise to a distinctive power-law rheology. Such complex behaviour cannot be easily captured by traditional rheological approaches, making material characterisation and predictive modelling very challenging. Here, we present a novel model combining conventional viscoelastic elements with fractional calculus that successfully captures the macroscopic relaxation response of epithelial monolayers. The parameters extracted from the fitting of the relaxation modulus allow prediction of the response of the same material to slow stretch and creep, indicating that the model captured intrinsic material properties. Two characteristic times, derived from the model parameters, delimit different regimes in the materials response. We compared the response of tissues with the behaviour of single cells as well as intra and extra-cellular components, and linked the power-law behaviour of the epithelium to the dynamics of the cell cortex. Such a unified model for the mechanical response of biological materials provides a novel and robust mathematical approach to consistently analyse experimental data and uncover similarities and differences in reported behaviour across experimental methods and research groups. It also sets the foundations for more accurate computational models of tissue mechanics.
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Affiliation(s)
- A Bonfanti
- Engineering Department, Cambridge University, Cambridge, UK
| | - J Fouchard
- London Centre for Nanotechnology, University College London, London, UK
| | - N Khalilgharibi
- London Centre for Nanotechnology, University College London, London, UK
- The Centre for Computation, Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, London, UK
| | - G Charras
- London Centre for Nanotechnology, University College London, London, UK
- Institute for the Physics of Living Systems, University College London, London, UK
- Department of Cell and Developmental Biology, University College London, London, UK
| | - A Kabla
- Engineering Department, Cambridge University, Cambridge, UK
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45
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Fearing BV, Jing L, Barcellona MN, Witte SE, Buchowski JM, Zebala LP, Kelly MP, Luhmann S, Gupta MC, Pathak A, Setton LA. Mechanosensitive transcriptional coactivators MRTF-A and YAP/TAZ regulate nucleus pulposus cell phenotype through cell shape. FASEB J 2019; 33:14022-14035. [PMID: 31638828 PMCID: PMC6894097 DOI: 10.1096/fj.201802725rrr] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 09/17/2019] [Indexed: 01/05/2023]
Abstract
Cells of the adult nucleus pulposus (NP) are critically important in maintaining overall disc health and function. NP cells reside in a soft, gelatinous matrix that dehydrates and becomes increasingly fibrotic with age. Such changes result in physical cues of matrix stiffness that may be potent regulators of NP cell phenotype and may contribute to a transition toward a senescent and fibroblastic NP cell with a limited capacity for repair. Here, we investigate the mechanosignaling cues generated from changes in matrix stiffness in directing NP cell phenotype and identify mechanisms that can potentially preserve a biosynthetically active, juvenile NP cell phenotype. Using a laminin-functionalized polyethylene glycol hydrogel, we show that when NP cells form rounded, multicell clusters, they are able to maintain cytosolic localization of myocardin-related transcription factor (MRTF)-A, a coactivator of serum-response factor (SRF), known to promote fibroblast-like behaviors in many cells. Upon preservation of a rounded shape, human NP cells similarly showed cytosolic retention of transcriptional coactivator Yes-associated protein (YAP) and its paralogue PDZ-binding motif (TAZ) with associated decline in activation of its transcription factor TEA domain family member-binding domain (TEAD). When changes in cell shape occur, leading to a more spread, fibrotic morphology associated with stronger F-actin alignment, SRF and TEAD are up-regulated. However, targeted deletion of either cofactor was not sufficient to overcome shape-mediated changes observed in transcriptional activation of SRF or TEAD. Findings show that substrate stiffness-induced promotion of F-actin alignment occurs concomitantly with a flattened, spread morphology, decreased NP marker expression, and reduced biosynthetic activity. This work indicates cell shape is a stronger indicator of SRF and TEAD mechanosignaling pathways than coactivators MRTF-A and YAP/TAZ, respectively, and may play a role in the degeneration-associated loss of NP cellularity and phenotype.-Fearing, B. V., Jing, L., Barcellona, M. N., Witte, S. E., Buchowski, J. M., Zebala, L. P., Kelly, M. P., Luhmann, S., Gupta, M. C., Pathak, A., Setton, L. A. Mechanosensitive transcriptional coactivators MRTF-A and YAP/TAZ regulate nucleus pulposus cell phenotype through cell shape.
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Affiliation(s)
- Bailey V. Fearing
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Liufang Jing
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Marcos N. Barcellona
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Savannah Est Witte
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Jacob M. Buchowski
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Lukas P. Zebala
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Michael P. Kelly
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Scott Luhmann
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Munish C. Gupta
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Amit Pathak
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Lori A. Setton
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
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46
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Liu J, Shang J, Chen Y, Tian Y, Yang Q, Chen M, Xiong B, Zhang XB. A surface-engineered NIR light-responsive actuator for controllable modulation of collective cell migration. J Mater Chem B 2019; 7:5528-5534. [PMID: 31451832 DOI: 10.1039/c9tb01038f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Mechanical signal transduction is fundamental for maintaining and regulating cellular processes and functions. Here, we proposed a novel near-infrared (NIR) light-responsive optomechanical actuator for the directional regulation of collective cell adhesion and migration. This optomechanical actuator that is made up of a thermal-responsive copolymer hydrogel and gold nanorods (AuNRs), enables non-invasive activation by NIR light stimulation. The activation of the optomechanical actuator leads to hydrogel contraction and an increase in Young's modulus, which could be used for applying contraction force to cells cultured on the surface of the hydrogel actuator. By grafting cell adhesive peptide ligands, the cells could attach onto the surface of the actuator and displayed a NIR light illumination intensity dependent migration rate along a random orientation. To achieve the controllable modulation of cell behaviors, we employed a microcontact printing strategy for patterned presentation of adhesive ligands on this actuator and achieved directional cell alignment and cell migration through optomechanical actuation. These demonstrations suggest that this robust optomechanical actuator is promising for the optical modulation of cellular events and cell functions in various bioapplications.
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Affiliation(s)
- Jiayu Liu
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China.
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47
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Versatile and High-throughput Force Measurement Platform for Dorsal Cell Mechanics. Sci Rep 2019; 9:13286. [PMID: 31527594 PMCID: PMC6746792 DOI: 10.1038/s41598-019-49592-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 08/28/2019] [Indexed: 01/17/2023] Open
Abstract
We present a high-throughput microfluidics technique facilitating in situ measurements of cell mechanics parameters at the dorsal side of the cell, including molecular binding strengths, local traction forces, and viscoelastic properties. By adjusting the flow rate, the force magnitude exerted on the cell can be modulated ranging from ~14 pN to 2 nN to perturb various force-dependent processees in cells. Time-lapse images were acquired to record events due to such perturbation. The values of various mechanical parameters are subsequently obtained by single particle tracking. Up to 50 events can be measured simultaneously in a single experiment. Integrating the microfluidic techniques with the analytic framework established in computational fluid dynamics, our method is physiologically relevant, reliable, economic and efficient.
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48
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Cell-Size Pleomorphism Drives Aberrant Clone Dispersal in Proliferating Epithelia. Dev Cell 2019; 51:49-61.e4. [PMID: 31495693 DOI: 10.1016/j.devcel.2019.08.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 06/18/2019] [Accepted: 08/06/2019] [Indexed: 11/22/2022]
Abstract
As epithelial tissues develop, groups of cells related by descent tend to associate in clonal populations rather than dispersing within the cell layer. While this is frequently assumed to be a result of differential adhesion, precise mechanisms controlling clonal cohesiveness remain unknown. Here we employ computational simulations to modulate epithelial cell size in silico and show that junctions between small cells frequently collapse, resulting in clone-cell dispersal among larger neighbors. Consistent with similar dynamics in vivo, we further demonstrate that mosaic disruption of Drosophila Tor generates small cells and results in aberrant clone dispersal in developing wing disc epithelia. We propose a geometric basis for this phenomenon, supported in part by the observation that soap-foam cells exhibit similar size-dependent junctional rearrangements. Combined, these results establish a link between cell-size pleomorphism and the control of epithelial cell packing, with potential implications for understanding tumor cell dispersal in human disease.
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Liu L, Plawinski L, Durrieu MC, Audoin B. Label-free multi-parametric imaging of single cells: dual picosecond optoacoustic microscopy. JOURNAL OF BIOPHOTONICS 2019; 12:e201900045. [PMID: 31144774 DOI: 10.1002/jbio.201900045] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 05/07/2019] [Accepted: 05/07/2019] [Indexed: 06/09/2023]
Abstract
Advances in microscopy with new visualization possibilities often bring dramatic progress to our understanding of the intriguing cellular machinery. Picosecond optoacoustic micro-spectroscopy is an optical technique based on ultrafast pump-probe generation and detection of hypersound on time durations of picoseconds and length scales of nanometers. It is experiencing a renaissance as a versatile imaging tool for cell biology research after a plethora of applications in solid-state physics. In this emerging context, this work reports on a dual-probe architecture to carry out real-time parallel detection of the hypersound propagation inside a cell that is cultured on a metallic substrate, and of the hypersound reflection at the metal/cell adhesion interface. Using this optoacoustic modality, several biophysical properties of the cell can be measured in a noncontact and label-free manner. Its abilities are demonstrated with the multiple imaging of a mitotic macrophage-like cell in a single run experiment.
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Affiliation(s)
- Liwang Liu
- CNRS, UMR 5295, I2M, University of Bordeaux, Talence, France
| | - Laurent Plawinski
- CNRS UMR 5248, Bordeaux-INP, CBMN, University of Bordeaux, Pessac, France
| | | | - Bertrand Audoin
- CNRS, UMR 5295, I2M, University of Bordeaux, Talence, France
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Shi Y, Porter CL, Crocker JC, Reich DH. Dissecting fat-tailed fluctuations in the cytoskeleton with active micropost arrays. Proc Natl Acad Sci U S A 2019; 116:13839-13846. [PMID: 31239336 PMCID: PMC6628664 DOI: 10.1073/pnas.1900963116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability of animal cells to crawl, change their shape, and respond to applied force is due to their cytoskeleton: A dynamic, cross-linked network of actin protein filaments and myosin motors. How these building blocks assemble to give rise to cells' mechanics and behavior remains poorly understood. Using active micropost array detectors containing magnetic actuators, we have characterized the mechanics and fluctuations of cells' actomyosin cortex and stress fiber network in detail. Here, we find that both structures display remarkably consistent power law viscoelastic behavior along with highly intermittent fluctuations with fat-tailed distributions of amplitudes. Notably, this motion in the cortex is dominated by occasional large, step-like displacement events, with a spatial extent of several micrometers. Overall, our findings for the cortex appear contrary to the predictions of a recent active gel model, while suggesting that different actomyosin contractile units act in a highly collective and cooperative manner. We hypothesize that cells' actomyosin components robustly self-organize into marginally stable, plastic networks that give cells' their unique biomechanical properties.
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Affiliation(s)
- Yu Shi
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218
| | - Christopher L Porter
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104
| | - John C Crocker
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104
| | - Daniel H Reich
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218;
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