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Denisin AK, Kim H, Riedel-Kruse IH, Pruitt BL. Field Guide to Traction Force Microscopy. Cell Mol Bioeng 2024; 17:87-106. [PMID: 38737454 PMCID: PMC11082129 DOI: 10.1007/s12195-024-00801-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Accepted: 03/26/2024] [Indexed: 05/14/2024] Open
Abstract
Introduction Traction force microscopy (TFM) is a widely used technique to measure cell contractility on compliant substrates that mimic the stiffness of human tissues. For every step in a TFM workflow, users make choices which impact the quantitative results, yet many times the rationales and consequences for making these decisions are unclear. We have found few papers which show the complete experimental and mathematical steps of TFM, thus obfuscating the full effects of these decisions on the final output. Methods Therefore, we present this "Field Guide" with the goal to explain the mathematical basis of common TFM methods to practitioners in an accessible way. We specifically focus on how errors propagate in TFM workflows given specific experimental design and analytical choices. Results We cover important assumptions and considerations in TFM substrate manufacturing, substrate mechanical properties, imaging techniques, image processing methods, approaches and parameters used in calculating traction stress, and data-reporting strategies. Conclusions By presenting a conceptual review and analysis of TFM-focused research articles published over the last two decades, we provide researchers in the field with a better understanding of their options to make more informed choices when creating TFM workflows depending on the type of cell being studied. With this review, we aim to empower experimentalists to quantify cell contractility with confidence. Supplementary Information The online version contains supplementary material available at 10.1007/s12195-024-00801-6.
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Affiliation(s)
| | - Honesty Kim
- Department of Bioengineering, Stanford University, Stanford, CA 94305 USA
- Present Address: The Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158 USA
- Department of Molecular and Cellular Biology, and (by courtesy) Departments of Biomedical Engineering, Applied Mathematics, and Physics, University of Arizona, Tucson, AZ 85721 USA
| | - Ingmar H. Riedel-Kruse
- Department of Molecular and Cellular Biology, and (by courtesy) Departments of Biomedical Engineering, Applied Mathematics, and Physics, University of Arizona, Tucson, AZ 85721 USA
| | - Beth L. Pruitt
- Departments of Bioengineering and Mechanical Engineering, University of California Santa Barbara, Santa Barbara, CA 93106 USA
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2
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Silvani G, Romanov V, Martinac B. Sounding a New Era in Biomechanics with Acoustic Force Spectroscopy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1436:109-118. [PMID: 36571699 DOI: 10.1007/5584_2022_757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The acoustic force spectroscopy (AFS) tool was recently introduced as a novel tool for probing mechanical properties of biomolecules, expanding the application of sound waves to high-throughput quantification of the mechanical properties of single cells. By using controlled acoustic forces in the piconewton to nanonewton range, tens to hundreds of cells functionalized by attached microspheres can simultaneously be stretched and tracked in real-time with sub millisecond time response. Since its first application, several studies have demonstrated the potential and versatility of the AFS for high-throughput measurements of force-induced molecular mechanisms, revealing insight into cellular biomechanics and mechanobiology at the molecular level. In this chapter, we describe the operation of the AFS starting with the underlying physical principles, followed by a run-down of experimental considerations, and finally leading to applications in molecular and cellular biology.
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Affiliation(s)
- Giulia Silvani
- School of Material Science and Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Valentin Romanov
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Darlinghurst, NSW, Australia
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Darlinghurst, NSW, Australia.
- St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia.
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3
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Kahle ER, Patel N, Sreenivasappa HB, Marcolongo MS, Han L. Targeting cell-matrix interface mechanobiology by integrating AFM with fluorescence microscopy. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2022; 176:67-81. [PMID: 36055517 PMCID: PMC9691605 DOI: 10.1016/j.pbiomolbio.2022.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/14/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
Mechanosensing at the interface of a cell and its surrounding microenvironment is an essential driving force of physiological processes. Understanding molecular activities at the cell-matrix interface has the potential to provide novel targets for improving tissue regeneration and early disease intervention. In the past few decades, the advancement of atomic force microscopy (AFM) has offered a unique platform for probing mechanobiology at this crucial microdomain. In this review, we describe key advances under this topic through the use of an integrated system of AFM (as a biomechanical testing tool) with complementary immunofluorescence (IF) imaging (as an in situ navigation system). We first describe the body of work investigating the micromechanics of the pericellular matrix (PCM), the immediate cell micro-niche, in healthy, diseased, and genetically modified tissues, with a focus on articular cartilage. We then summarize the key findings in understanding cellular biomechanics and mechanotransduction, in which, molecular mechanisms governing transmembrane ion channel-mediated mechanosensing, cytoskeleton remodeling, and nucleus remodeling have been studied in various cell and tissue types. Lastly, we provide an overview of major technical advances that have enabled more in-depth studies of mechanobiology, including the integration of AFM with a side-view microscope, multiple optomicroscopy, a fluorescence recovery after photobleaching (FRAP) module, and a tensile stretching device. The innovations described here have contributed greatly to advancing the fundamental knowledge of extracellular matrix biomechanics and cell mechanobiology for improved understanding, detection, and intervention of various diseases.
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Affiliation(s)
- Elizabeth R Kahle
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, United States
| | - Neil Patel
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, United States
| | - Harini B Sreenivasappa
- Cell Imaging Center, Office of Research and Innovation, Drexel University, PA 19104, United States
| | - Michele S Marcolongo
- Department of Mechanical Engineering, Villanova University, Villanova, PA 19085, United States
| | - Lin Han
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, United States.
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4
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Yao M, Tijore A, Cheng D, Li JV, Hariharan A, Martinac B, Tran Van Nhieu G, Cox CD, Sheetz M. Force- and cell state-dependent recruitment of Piezo1 drives focal adhesion dynamics and calcium entry. SCIENCE ADVANCES 2022; 8:eabo1461. [PMID: 36351022 PMCID: PMC9645726 DOI: 10.1126/sciadv.abo1461] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 09/21/2022] [Indexed: 11/11/2022]
Abstract
Mechanosensing is an integral part of many physiological processes including stem cell differentiation, fibrosis, and cancer progression. Two major mechanosensing systems-focal adhesions and mechanosensitive ion channels-can convert mechanical features of the microenvironment into biochemical signals. We report here unexpectedly that the mechanosensitive calcium-permeable channel Piezo1, previously perceived to be diffusive on plasma membranes, binds to matrix adhesions in a force-dependent manner, promoting cell spreading, adhesion dynamics, and calcium entry in normal but not in most cancer cells tested except some glioblastoma lines. A linker domain in Piezo1 is needed for binding to adhesions, and overexpression of the domain blocks Piezo1 binding to adhesions, decreasing adhesion size and cell spread area. Thus, we suggest that Piezo1 is a previously unidentified component of focal adhesions in nontransformed cells that catalyzes adhesion maturation and growth through force-dependent calcium signaling, but this function is absent in most cancer cells.
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Affiliation(s)
- Mingxi Yao
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen 518055, China
- Mechanobiology Institute, National University of Singapore, Singapore 117411
- Corresponding author. (M.Y); (C.C.); (M.S.)
| | - Ajay Tijore
- Mechanobiology Institute, National University of Singapore, Singapore 117411
- Center for Biosystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Delfine Cheng
- Victor Chang Cardiac Research Institute, Sydney NSW 2010, Australia
| | - Jinyuan Vero Li
- Victor Chang Cardiac Research Institute, Sydney NSW 2010, Australia
| | - Anushya Hariharan
- Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Sydney NSW 2010, Australia
| | - Guy Tran Van Nhieu
- Ecole Normale Supérieure Paris-Saclay Gif-sur-Yvette, France
- Team Ca Signaling and Microbial Infections, Institute for Integrative Biology of the Cell–CNRS UMR9198–Inserm U1280, 1, Avenue de la Terrasse, 91190 Gif-sur-Yvette, France
| | - Charles D. Cox
- Victor Chang Cardiac Research Institute, Sydney NSW 2010, Australia
- Corresponding author. (M.Y); (C.C.); (M.S.)
| | - Michael Sheetz
- Mechanobiology Institute, National University of Singapore, Singapore 117411
- Department of Biological Sciences, National University of Singapore, Singapore 117558
- Molecular MechanoMedicine Program, Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
- Corresponding author. (M.Y); (C.C.); (M.S.)
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Hajjarian Z, Nadkarni SK. Tutorial on laser speckle rheology: technology, applications, and opportunities. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-19. [PMID: 32358928 PMCID: PMC7195443 DOI: 10.1117/1.jbo.25.5.050801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 04/10/2020] [Indexed: 05/27/2023]
Abstract
SIGNIFICANCE The onset of several diseases is frequently marked with anomalous mechanical alteration of the affected tissue at the intersection of cells and their microenvironment. Therefore, mapping the micromechanical attributes of the tissues could enhance our understanding of the etiology of human disease, improve the diagnosis, and help stratify therapies that target these mechanical aberrations. AIM We review the tremendous opportunities offered through using optics for imaging the micromechanical properties, at length scales inaccessible to other modalities, in both basic research and clinical medicine. We specifically focus on laser speckle rheology (LSR), a technology that quantifies the mechanical properties of tissues in a rapid, noncontact manner. APPROACH In LSR, the shear viscoelastic modulus is measured from the time-variant speckle intensity fluctuations reflected off the tissue. The LSR technology is engineered and configured into several embodiments, including bench-top optical systems, endoscopes for minimally invasive procedures, portable point-of-care devices, and microscopes. RESULTS These technological nuances have primed the LSR for widespread applications in diagnosis and therapeutic monitoring, as demonstrated here, in cardiovascular disease, coagulation disorders, and tumor malignancies. CONCLUSION The fast-paced technological advancements, elaborated here, position the LSR as a competent candidate for many more exciting opportunities in basic research and medicine.
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Affiliation(s)
- Zeinab Hajjarian
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
| | - Seemantini K. Nadkarni
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
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Davidson MD, Burdick JA, Wells RG. Engineered Biomaterial Platforms to Study Fibrosis. Adv Healthc Mater 2020; 9:e1901682. [PMID: 32181987 PMCID: PMC7274888 DOI: 10.1002/adhm.201901682] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 12/13/2022]
Abstract
Many pathologic conditions lead to the development of tissue scarring and fibrosis, which are characterized by the accumulation of abnormal extracellular matrix (ECM) and changes in tissue mechanical properties. Cells within fibrotic tissues are exposed to dynamic microenvironments that may promote or prolong fibrosis, which makes it difficult to treat. Biomaterials have proved indispensable to better understand how cells sense their extracellular environment and are now being employed to study fibrosis in many tissues. As mechanical testing of tissues becomes more routine and biomaterial tools become more advanced, the impact of biophysical factors in fibrosis are beginning to be understood. Herein, fibrosis from a materials perspective is reviewed, including the role and mechanical properties of ECM components, the spatiotemporal mechanical changes that occur during fibrosis, current biomaterial systems to study fibrosis, and emerging biomaterial systems and tools that can further the understanding of fibrosis initiation and progression. This review concludes by highlighting considerations in promoting wide-spread use of biomaterials for fibrosis investigations and by suggesting future in vivo studies that it is hoped will inspire the development of even more advanced biomaterial systems.
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Affiliation(s)
- Matthew D Davidson
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
- NSF Science and Technology Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jason A Burdick
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
- NSF Science and Technology Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Rebecca G Wells
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
- NSF Science and Technology Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
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7
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Davidson PM, Fedorchak GR, Mondésert-Deveraux S, Bell ES, Isermann P, Aubry D, Allena R, Lammerding J. High-throughput microfluidic micropipette aspiration device to probe time-scale dependent nuclear mechanics in intact cells. LAB ON A CHIP 2019; 19:3652-3663. [PMID: 31559980 PMCID: PMC6810812 DOI: 10.1039/c9lc00444k] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The mechanical properties of the cell nucleus are increasingly recognized as critical in many biological processes. The deformability of the nucleus determines the ability of immune and cancer cells to migrate through tissues and across endothelial cell layers, and changes to the mechanical properties of the nucleus can serve as novel biomarkers in processes such as cancer progression and stem cell differentiation. However, current techniques to measure the viscoelastic nuclear mechanical properties are often time consuming, limited to probing one cell at a time, or require expensive, highly specialized equipment. Furthermore, many current assays do not measure time-dependent properties, which are characteristic of viscoelastic materials. Here, we present an easy-to-use microfluidic device that applies the well-established approach of micropipette aspiration, adapted to measure many cells in parallel. The device design allows rapid loading and purging of cells for measurements, and minimizes clogging by large particles or clusters of cells. Combined with a semi-automated image analysis pipeline, the microfluidic device approach enables significantly increased experimental throughput. We validated the experimental platform by comparing computational models of the fluid mechanics in the device with experimental measurements of fluid flow. In addition, we conducted experiments on cells lacking the nuclear envelope protein lamin A/C and wild-type controls, which have well-characterized nuclear mechanical properties. Fitting time-dependent nuclear deformation data to power law and different viscoelastic models revealed that loss of lamin A/C significantly altered the elastic and viscous properties of the nucleus, resulting in substantially increased nuclear deformability. Lastly, to demonstrate the versatility of the devices, we characterized the viscoelastic nuclear mechanical properties in a variety of cell lines and experimental model systems, including human skin fibroblasts from an individual with a mutation in the lamin gene associated with dilated cardiomyopathy, healthy control fibroblasts, induced pluripotent stem cells (iPSCs), and human tumor cells. Taken together, these experiments demonstrate the ability of the microfluidic device and automated image analysis platform to provide robust, high throughput measurements of nuclear mechanical properties, including time-dependent elastic and viscous behavior, in a broad range of applications.
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Affiliation(s)
- Patricia M Davidson
- Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, USA. and Laboratoire Physico-Chimie Curie, Institut Curie, CNRS UMR 168, Université Paris Science et Lettres, Sorbonne Université, France
| | - Gregory R Fedorchak
- Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, USA.
| | | | - Emily S Bell
- Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, USA.
| | - Philipp Isermann
- Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, USA.
| | - Denis Aubry
- Laboratoire MSSMat UMR CNRS 8579, CentraleSupelec, Université Paris-Saclay, France
| | - Rachele Allena
- Arts et Metiers ParisTech, LBM/Institut de Biomécanique Humaine Georges Charpak, France
| | - Jan Lammerding
- Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, USA.
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8
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Pinheiro D, Bellaïche Y. Mechanical Force-Driven Adherens Junction Remodeling and Epithelial Dynamics. Dev Cell 2019; 47:3-19. [PMID: 30300588 DOI: 10.1016/j.devcel.2018.09.014] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/02/2018] [Accepted: 09/12/2018] [Indexed: 12/11/2022]
Abstract
During epithelial tissue development, repair, and homeostasis, adherens junctions (AJs) ensure intercellular adhesion and tissue integrity while allowing for cell and tissue dynamics. Mechanical forces play critical roles in AJs' composition and dynamics. Recent findings highlight that beyond a well-established role in reinforcing cell-cell adhesion, AJ mechanosensitivity promotes junctional remodeling and polarization, thereby regulating critical processes such as cell intercalation, division, and collective migration. Here, we provide an integrated view of mechanosensing mechanisms that regulate cell-cell contact composition, geometry, and integrity under tension and highlight pivotal roles for mechanosensitive AJ remodeling in preserving epithelial integrity and sustaining tissue dynamics.
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Affiliation(s)
- Diana Pinheiro
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, 75248 Paris Cedex 05, France; Sorbonne Universités, UPMC Univ Paris 06, CNRS, CNRS UMR 3215, INSERM U934, 75005 Paris, France
| | - Yohanns Bellaïche
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, 75248 Paris Cedex 05, France; Sorbonne Universités, UPMC Univ Paris 06, CNRS, CNRS UMR 3215, INSERM U934, 75005 Paris, France.
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9
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Barnes LA, Marshall CD, Leavitt T, Hu MS, Moore AL, Gonzalez JG, Longaker MT, Gurtner GC. Mechanical Forces in Cutaneous Wound Healing: Emerging Therapies to Minimize Scar Formation. Adv Wound Care (New Rochelle) 2018; 7:47-56. [PMID: 29392093 DOI: 10.1089/wound.2016.0709] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 12/15/2016] [Indexed: 12/25/2022] Open
Abstract
Significance: Excessive scarring is major clinical and financial burden in the United States. Improved therapies are necessary to reduce scarring, especially in patients affected by hypertrophic and keloid scars. Recent Advances: Advances in our understanding of mechanical forces in the wound environment enable us to target mechanical forces to minimize scar formation. Fetal wounds experience much lower resting stress when compared with adult wounds, and they heal without scars. Therapies that modulate mechanical forces in the wound environment are able to reduce scar size. Critical Issues: Increased mechanical stresses in the wound environment induce hypertrophic scarring via activation of mechanotransduction pathways. Mechanical stimulation modulates integrin, Wingless-type, protein kinase B, and focal adhesion kinase, resulting in cell proliferation and, ultimately, fibrosis. Therefore, the development of therapies that reduce mechanical forces in the wound environment would decrease the risk of developing excessive scars. Future Directions: The development of novel mechanotherapies is necessary to minimize scar formation and advance adult wound healing toward the scarless ideal. Mechanotransduction pathways are potential targets to reduce excessive scar formation, and thus, continued studies on therapies that utilize mechanical offloading and mechanomodulation are needed.
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Affiliation(s)
- Leandra A. Barnes
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, California
| | - Clement D. Marshall
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, California
| | - Tripp Leavitt
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, California
| | - Michael S. Hu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, California
- Department of Surgery, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | | | - Jennifer G. Gonzalez
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, California
| | - Michael T. Longaker
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, California
| | - Geoffrey C. Gurtner
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, California
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10
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Zinc oxide nanorod field effect transistor for long-time cellular force measurement. Sci Rep 2017; 7:43661. [PMID: 28272551 PMCID: PMC5341559 DOI: 10.1038/srep43661] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/26/2017] [Indexed: 01/09/2023] Open
Abstract
Mechanical forces generated by cells are known to influence a vast range of cellular functions ranging from receptor signaling and transcription to differentiation and proliferation. We report a novel measurement approach using zinc oxide nanorods as a peeping transducer to monitor dynamic mechanical behavior of cellular traction on surrounding substrate. We develop a ZnO nanorod field effect transistor (FET) as an ultrasensitive force sensor to realize long-time, unstained, and in-situ detection of cell cycle phases, including attachment, spread, and mitosis. Excellent biocompatibility and ultra-sensitivity of the biomechanical measurement is ensured by coating a parylene film on the FET sensor as a concealment, which provides complete electronic isolation between the sensor and cell. With unique features of ultra-sensitivity, label-free, easy handling, and good biocompatibility, the force sensor allows feasible for tracking cellular dynamics in physiological contexts and understanding their contribution to biological processes.
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11
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Geng Y, Wang Z. Review of cellular mechanotransduction on micropost substrates. Med Biol Eng Comput 2015; 54:249-71. [PMID: 26245253 DOI: 10.1007/s11517-015-1343-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 07/07/2015] [Indexed: 01/09/2023]
Abstract
As physical entities, living cells can sense and respond to various stimulations within and outside the body through cellular mechanotransduction. Any deviation in cellular mechanotransduction will not only undermine the orchestrated regulation of mechanical responses, but also lead to the breakdown of their physiological function. Therefore, a quantitative study of cellular mechanotransduction needs to be conducted both in experiments and in computational simulations to investigate the underlying mechanisms of cellular mechanotransduction. In this review, we present an overview of the current knowledge and significant progress in cellular mechanotransduction via micropost substrates. In the aspect of experimental studies, we summarize significant experimental progress and place an emphasis on the coupled relationship among cellular spreading, focal adhesion and contractility as well as the influence of substrate properties on force-involved cellular behaviors. In the other aspect of computational investigations, we outline a coupled framework including the biochemically motivated stress fiber model and thermodynamically motivated adhesion model and present their predicted biomechanical responses and then compare predicted simulation results with experimental observations to further explore the mechanisms of cellular mechanotransduction. At last, we discuss the future perspectives both in experimental technologies and in computational models, as well as facing challenges in the area of cellular mechanotransduction.
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Affiliation(s)
- Yuxu Geng
- State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing, 400030, China
| | - Zhanjiang Wang
- State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing, 400030, China.
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12
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Wilusz RE, Sanchez-Adams J, Guilak F. The structure and function of the pericellular matrix of articular cartilage. Matrix Biol 2014; 39:25-32. [PMID: 25172825 DOI: 10.1016/j.matbio.2014.08.009] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Chondrocytes in articular cartilage are surrounded by a narrow pericellular matrix (PCM) that is both biochemically and biomechanically distinct from the extracellular matrix (ECM) of the tissue. While the PCM was first observed nearly a century ago, its role is still under investigation. In support of early hypotheses regarding its function, increasing evidence indicates that the PCM serves as a transducer of biochemical and biomechanical signals to the chondrocyte. Work over the past two decades has established that the PCM in adult tissue is defined biochemically by several molecular components, including type VI collagen and perlecan. On the other hand, the biomechanical properties of this structure have only recently been measured. Techniques such as micropipette aspiration, in situ imaging, computational modeling, and atomic force microscopy have determined that the PCM exhibits distinct mechanical properties as compared to the ECM, and that these properties are influenced by specific PCM components as well as disease state. Importantly, the unique relationships among the mechanical properties of the chondrocyte, PCM, and ECM in different zones of cartilage suggest that this region significantly influences the stress-strain environment of the chondrocyte. In this review, we discuss recent advances in the measurement of PCM mechanical properties and structure that further increase our understanding of PCM function. Taken together, these studies suggest that the PCM plays a critical role in controlling the mechanical environment and mechanobiology of cells in cartilage and other cartilaginous tissues, such as the meniscus or intervertebral disc.
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Affiliation(s)
- Rebecca E Wilusz
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA; Department of Biomedical Engineering, Duke University Medical Center, Durham, NC, USA; Department of Cell Biology, Duke University Medical Center, Durham, NC, USA
| | - Johannah Sanchez-Adams
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA; Department of Biomedical Engineering, Duke University Medical Center, Durham, NC, USA; Department of Cell Biology, Duke University Medical Center, Durham, NC, USA
| | - Farshid Guilak
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA; Department of Biomedical Engineering, Duke University Medical Center, Durham, NC, USA; Department of Cell Biology, Duke University Medical Center, Durham, NC, USA.
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13
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Duscher D, Maan ZN, Wong VW, Rennert RC, Januszyk M, Rodrigues M, Hu M, Whitmore AJ, Whittam AJ, Longaker MT, Gurtner GC. Mechanotransduction and fibrosis. J Biomech 2014; 47:1997-2005. [PMID: 24709567 DOI: 10.1016/j.jbiomech.2014.03.031] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 03/18/2014] [Accepted: 03/18/2014] [Indexed: 01/06/2023]
Abstract
Scarring and tissue fibrosis represent a significant source of morbidity in the United States. Despite considerable research focused on elucidating the mechanisms underlying cutaneous scar formation, effective clinical therapies are still in the early stages of development. A thorough understanding of the various signaling pathways involved is essential to formulate strategies to combat fibrosis and scarring. While initial efforts focused primarily on the biochemical mechanisms involved in scar formation, more recent research has revealed a central role for mechanical forces in modulating these pathways. Mechanotransduction, which refers to the mechanisms by which mechanical forces are converted to biochemical stimuli, has been closely linked to inflammation and fibrosis and is believed to play a critical role in scarring. This review provides an overview of our current understanding of the mechanisms underlying scar formation, with an emphasis on the relationship between mechanotransduction pathways and their therapeutic implications.
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Affiliation(s)
- Dominik Duscher
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Zeshaan N Maan
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Victor W Wong
- Department of Plastic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Robert C Rennert
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Michael Januszyk
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Melanie Rodrigues
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Michael Hu
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Arnetha J Whitmore
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Alexander J Whittam
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Michael T Longaker
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Geoffrey C Gurtner
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA.
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14
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Jacobs MJ, Blank K. Joining forces: integrating the mechanical and optical single molecule toolkits. Chem Sci 2014. [DOI: 10.1039/c3sc52502c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Combining single molecule force measurements with fluorescence detection opens up exciting new possibilities for the characterization of mechanoresponsive molecules in Biology and Materials Science.
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Affiliation(s)
- Monique J. Jacobs
- Radboud University Nijmegen
- Institute for Molecules and Materials
- Department of Molecular Materials
- 6525 AJ Nijmegen, The Netherlands
| | - Kerstin Blank
- Radboud University Nijmegen
- Institute for Molecules and Materials
- Department of Molecular Materials
- 6525 AJ Nijmegen, The Netherlands
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15
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Nadkarni SK. Optical measurement of arterial mechanical properties: from atherosclerotic plaque initiation to rupture. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:121507. [PMID: 24296995 PMCID: PMC4696609 DOI: 10.1117/1.jbo.18.12.121507] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/09/2013] [Accepted: 10/10/2013] [Indexed: 05/19/2023]
Abstract
During the pathogenesis of coronary atherosclerosis, from lesion initiation to rupture, arterial mechanical properties are altered by a number of cellular, molecular, and hemodynamic processes. There is growing recognition that mechanical factors may actively drive vascular cell signaling and regulate atherosclerosis disease progression. In advanced plaques, the mechanical properties of the atheroma influence stress distributions in the fibrous cap and mediate plaque rupture resulting in acute coronary events. This review paper explores current optical technologies that provide information on the mechanical properties of arterial tissue to advance our understanding of the mechanical factors involved in atherosclerosis development leading to plaque rupture. The optical approaches discussed include optical microrheology and traction force microscopy that probe the mechanical behavior of single cell and extracellular matrix components, and intravascular imaging modalities including laser speckle rheology, optical coherence elastography, and polarization-sensitive optical coherence tomography to measure the mechanical properties of advanced coronary lesions. Given the wealth of information that these techniques can provide, optical imaging modalities are poised to play an increasingly significant role in elucidating the mechanical aspects of coronary atherosclerosis in the future.
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Affiliation(s)
- Seemantini K. Nadkarni
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts 02114
- Address all correspondence to: Seemantini K. Nadkarni, Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts 02114. Tel: (617)-724-1381; Fax: (617)-7264103; E-mail:
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16
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Dassow C, Armbruster C, Friedrich C, Smudde E, Guttmann J, Schumann S. A method to measure mechanical properties of pulmonary epithelial cell layers. J Biomed Mater Res B Appl Biomater 2013; 101:1164-71. [PMID: 23564730 DOI: 10.1002/jbm.b.32926] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 01/16/2013] [Accepted: 02/11/2013] [Indexed: 01/09/2023]
Abstract
The lung has a huge inner alveolar surface composed of epithelial cell layers. The knowledge about mechanical properties of lung epithelia is helpful to understand the complex lung mechanics and biomechanical interactions. Methods have been developed to determine mechanical indices (e.g., tissue elasticity) which are both very complex and in need of costly equipment. Therefore, in this study, a mechanostimulator is presented to dynamically stimulate lung epithelial cell monolayers in order to determine their mechanical properties based on a simple mathematical model. First, the method was evaluated by comparison to classical tensile testing using silicone membranes as substitute for biological tissue. Second, human pulmonary epithelial cells (A549 cell line) were grown on flexible silicone membranes and stretched at a defined magnitude. Equal secant moduli were determined in the mechanostimulator and in a conventional tension testing machine (0.49 ± 0.05 MPa and 0.51 ± 0.03 MPa, respectively). The elasticity of the cell monolayer could be calculated by the volume-pressure relationship resulting from inflation of the membrane-cell construct. The secant modulus of the A549 cell layer was calculated as 0.04 ± 0.008 MPa. These findings suggest that the mechanostimulator may represent an adequate device to determine mechanical properties of cell layers.
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Affiliation(s)
- Constanze Dassow
- Department of Experimental Anaesthesiology, University Medical Centre, Hugstetter Straße 55, 79106 Freiburg, Germany
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17
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Palankar R, Pinchasik BE, Schmidt S, De Geest BG, Fery A, Möhwald H, Skirtach AG, Delcea M. Mechanical strength and intracellular uptake of CaCO3-templated LbL capsules composed of biodegradable polyelectrolytes: the influence of the number of layers. J Mater Chem B 2013; 1:1175-1181. [DOI: 10.1039/c2tb00319h] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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18
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Wong VW, Longaker MT, Gurtner GC. Soft tissue mechanotransduction in wound healing and fibrosis. Semin Cell Dev Biol 2012; 23:981-6. [PMID: 23036529 DOI: 10.1016/j.semcdb.2012.09.010] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 09/25/2012] [Indexed: 12/17/2022]
Abstract
Recent evidence suggests that mechanical forces can significantly impact the biologic response to injury. Integrated mechanical and chemical signaling networks have been discovered that enable physical cues to regulate disease processes such as pathologic scar formation. Distinct molecular mechanisms control how tensional forces influence wound healing and fibrosis. Conceptual frameworks to understand cutaneous repair have expanded beyond traditional cell-cytokine models to include dynamic interactions driven by mechanical force and the extracellular matrix. Strategies to manipulate these biomechanical signaling networks have tremendous therapeutic potential to reduce scar formation and promote skin regeneration.
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Affiliation(s)
- Victor W Wong
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
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19
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Wilusz RE, DeFrate LE, Guilak F. Immunofluorescence-guided atomic force microscopy to measure the micromechanical properties of the pericellular matrix of porcine articular cartilage. J R Soc Interface 2012; 9:2997-3007. [PMID: 22675162 DOI: 10.1098/rsif.2012.0314] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The pericellular matrix (PCM) is a narrow region that is rich in type VI collagen that surrounds each chondrocyte within the extracellular matrix (ECM) of articular cartilage. Previous studies have demonstrated that the chondrocyte micromechanical environment depends on the relative properties of the chondrocyte, its PCM and the ECM. The objective of this study was to measure the influence of type VI collagen on site-specific micromechanical properties of cartilage in situ by combining atomic force microscopy stiffness mapping with immunofluorescence imaging of PCM and ECM regions in cryo-sectioned tissue samples. This method was used to test the hypotheses that PCM biomechanical properties correlate with the presence of type VI collagen and are uniform with depth from the articular surface. Control experiments verified that immunolabelling did not affect the properties of the ECM or PCM. PCM biomechanical properties correlated with the presence of type VI collagen, and matrix regions lacking type VI collagen immediately adjacent to the PCM exhibited higher elastic moduli than regions positive for type VI collagen. PCM elastic moduli were similar in all three zones. Our findings provide further support for type VI collagen in defining the chondrocyte PCM and contributing to its biological and biomechanical properties.
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Affiliation(s)
- Rebecca E Wilusz
- Department of Orthopaedic Surgery, Duke University Medical Center, Box 3093, Durham, NC 27710, USA
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20
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Wong VW, Akaishi S, Longaker MT, Gurtner GC. Pushing Back: Wound Mechanotransduction in Repair and Regeneration. J Invest Dermatol 2011; 131:2186-96. [DOI: 10.1038/jid.2011.212] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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21
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Milstein JN, Meiners JC. On the role of DNA biomechanics in the regulation of gene expression. J R Soc Interface 2011; 8:1673-81. [PMID: 21865249 PMCID: PMC3203490 DOI: 10.1098/rsif.2011.0371] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
DNA is traditionally seen as a linear sequence of instructions for cellular functions that are expressed through biochemical processes. Cellular DNA, however, is also organized as a complex hierarchical structure with a mosaic of mechanical features, and a growing body of evidence is now emerging to imply that these mechanical features are connected to genetic function. Mechanical tension, for instance, which must be felt by DNA within the heavily constrained and continually fluctuating cellular environment, can affect a number of regulatory processes implicating a role for biomechanics in gene expression complementary to that of biochemical regulation. In this article, we review evidence for such mechanical pathways of genetic regulation.
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Affiliation(s)
- J N Milstein
- Departments of Physics and Biophysics, University of Michigan, Ann Arbor, USA.
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22
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Schouman T, Raoul G, Dubois G. [Autologous tissue engineering by means of distraction osteogenesis: Biomechanical considerations]. ACTA ACUST UNITED AC 2011; 112:222-8. [PMID: 21794888 DOI: 10.1016/j.stomax.2011.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Tissue engineering consists in producing functional replacement tissue. Distraction osteogenesis is a tissue engineering technique that uses the mechanical environment of cells to induce tissue regeneration, without need for exogenous biochemical factors. A better understanding of the optimal mechanical conditions of distraction callus stretching may reduce the duration, discomfort, and even social impact of distraction protocols, and complications and failures. We present the current state of knowledge in this field by addressing the fundamentals of elongating bone tissue biomechanics, the influence of rhythm and rate of distraction, and that of vectors and stability. Finally, we present the innovations currently studied, which may modify our clinical protocol in the short term.
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Affiliation(s)
- T Schouman
- Service de chirurgie maxillofaciale et stomatologie, université Paris 6 - Pierre-et-Marie-Curie, groupe hospitalier Pitié-Salpêtrière, AP-HP, 47-83, boulevard de l'Hôpital, 75013 Paris, France.
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23
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Polyakov P, Soussen C, Duan J, Duval JFL, Brie D, Francius G. Automated force volume image processing for biological samples. PLoS One 2011; 6:e18887. [PMID: 21559483 PMCID: PMC3084721 DOI: 10.1371/journal.pone.0018887] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 03/24/2011] [Indexed: 01/09/2023] Open
Abstract
Atomic force microscopy (AFM) has now become a powerful technique for investigating on a molecular level, surface forces, nanomechanical properties of deformable particles, biomolecular interactions, kinetics, and dynamic processes. This paper specifically focuses on the analysis of AFM force curves collected on biological systems, in particular, bacteria. The goal is to provide fully automated tools to achieve theoretical interpretation of force curves on the basis of adequate, available physical models. In this respect, we propose two algorithms, one for the processing of approach force curves and another for the quantitative analysis of retraction force curves. In the former, electrostatic interactions prior to contact between AFM probe and bacterium are accounted for and mechanical interactions operating after contact are described in terms of Hertz-Hooke formalism. Retraction force curves are analyzed on the basis of the Freely Jointed Chain model. For both algorithms, the quantitative reconstruction of force curves is based on the robust detection of critical points (jumps, changes of slope or changes of curvature) which mark the transitions between the various relevant interactions taking place between the AFM tip and the studied sample during approach and retraction. Once the key regions of separation distance and indentation are detected, the physical parameters describing the relevant interactions operating in these regions are extracted making use of regression procedure for fitting experiments to theory. The flexibility, accuracy and strength of the algorithms are illustrated with the processing of two force-volume images, which collect a large set of approach and retraction curves measured on a single biological surface. For each force-volume image, several maps are generated, representing the spatial distribution of the searched physical parameters as estimated for each pixel of the force-volume image.
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Affiliation(s)
- Pavel Polyakov
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564, Nancy-Université, CNRS, Vandoeuvre lès Nancy, France
| | - Charles Soussen
- Centre de Recherche en Automatique de Nancy, CRAN, UMR 7039, Nancy-Université, CNRS, Vandoeuvre lès Nancy, France
| | - Junbo Duan
- Centre de Recherche en Automatique de Nancy, CRAN, UMR 7039, Nancy-Université, CNRS, Vandoeuvre lès Nancy, France
| | - Jérôme F. L. Duval
- Laboratoire Environnement et Minéralurgie, LEM, UMR 7569, Nancy-Université, CNRS, Vandoeuvre lès Nancy, France
| | - David Brie
- Centre de Recherche en Automatique de Nancy, CRAN, UMR 7039, Nancy-Université, CNRS, Vandoeuvre lès Nancy, France
- * E-mail: (GF); (DB)
| | - Grégory Francius
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564, Nancy-Université, CNRS, Vandoeuvre lès Nancy, France
- * E-mail: (GF); (DB)
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24
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Desmaële D, Boukallel M, Régnier S. Actuation means for the mechanical stimulation of living cells via microelectromechanical systems: A critical review. J Biomech 2011; 44:1433-46. [PMID: 21489537 DOI: 10.1016/j.jbiomech.2011.02.085] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 02/25/2011] [Accepted: 02/25/2011] [Indexed: 01/09/2023]
Abstract
Within a living body, cells are constantly exposed to various mechanical constraints. As a matter of fact, these mechanical factors play a vital role in the regulation of the cell state. It is widely recognized that cells can sense, react and adapt themselves to mechanical stimulation. However, investigations aimed at studying cell mechanics directly in vivo remain elusive. An alternative solution is to study cell mechanics via in vitro experiments. Nevertheless, this requires implementing means to mimic the stresses that cells naturally undergo in their physiological environment. In this paper, we survey various microelectromechanical systems (MEMS) dedicated to the mechanical stimulation of living cells. In particular, we focus on their actuation means as well as their inherent capabilities to stimulate a given amount of cells. Thereby, we report actuation means dependent upon the fact they can provide stimulation to a single cell, target a maximum of a hundred cells, or deal with thousands of cells. Intrinsic performances, strengths and limitations are summarized for each type of actuator. We also discuss recent achievements as well as future challenges of cell mechanostimulation.
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Affiliation(s)
- Denis Desmaële
- CEA, LIST, Sensory and Ambient Interfaces Laboratory, 18 Route du Panorama, BP6, Fontenay-aux-Roses, F-92265, France.
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25
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Contractility dominates adhesive ligand density in regulating cellular de-adhesion and retraction kinetics. Ann Biomed Eng 2010; 39:1163-73. [PMID: 21046466 PMCID: PMC3069333 DOI: 10.1007/s10439-010-0195-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 10/17/2010] [Indexed: 01/09/2023]
Abstract
Cells that are enzymatically detached from a solid substrate rapidly round up as the tensile prestress in the cytoskeleton is suddenly unopposed by cell-ECM adhesions. We recently showed that this retraction follows sigmoidal kinetics with time constants that correlate closely with cortical stiffness values. This raises the promising prospect that these de-adhesion measurements may be used for high-throughput screening of cell mechanical properties; however, an important limitation to doing so is the possibility that the retraction kinetics may also be influenced and potentially rate-limited by the time needed to sever matrix adhesions. In this study, we address this open question by separating contributions of contractility and adhesion to cellular de-adhesion and retraction kinetics. We first develop serum-free conditions under which U373 MG glioma cells can be cultured on substrates of fixed fibronectin density without direct matrix contributions from the medium. We show that while spreading area increases with ECM protein density, cortical stiffness and the time constants of retraction do not. Conversely, addition of lysophosphatidic acid (LPA) to stimulate cell contractility strongly speeds retraction, independent of the initial matrix protein density and LPA's contributions to spreading area. All of these trends hold in serum-rich medium commonly used in tissue culture, with the time constants of retraction much more closely tracking cortical stiffness than adhesive ligand density or cell spreading. These results support the use of cellular de-adhesion measurements to track cellular mechanical properties.
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26
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Kloxin AM, Kloxin CJ, Bowman CN, Anseth KS. Mechanical properties of cellularly responsive hydrogels and their experimental determination. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2010; 22:3484-94. [PMID: 20473984 PMCID: PMC3890982 DOI: 10.1002/adma.200904179] [Citation(s) in RCA: 305] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Hydrogels are increasingly employed as multidimensional cell culture platforms often with a necessity that they respond to or control the cellular environment. Specifically, synthetic hydrogels, such as poly(ethylene glycol) (PEG)-based gels, are frequently utilized for probing the microenvironment's influence on cell function, as the gel properties can be precisely controlled in space and time. Synthetically tunable parameters, such as monomer structure and concentration, facilitate initial gel property control, while incorporation of responsive degradable units enables cell- and/or user-directed degradation. Such responsive gel systems are complex with dynamic changes occurring over multiple time-scales, and cells encapsulated in these synthetic hydrogels often experience and dictate local property changes profoundly different from those in the bulk material. Consequently, advances in bulk and local measurement techniques are needed to monitor property evolution quantatively and understand its effect on cell function. Here, recent progress in cell-responsive PEG hydrogel synthesis and mechanical property characterization is reviewed.
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Affiliation(s)
- AM Kloxin
- Howard Hughes Medical Institute, Boulder, CO 80309 USA
| | | | | | - KS Anseth
- Howard Hughes Medical Institute, Boulder, CO 80309 USA
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