1
|
Ayala S, Matan SO, Delco ML, Fortier LA, Cohen I, Bonassar LJ. Degradation of lubricating molecules in synovial fluid alters chondrocyte sensitivity to shear strain. J Orthop Res 2024. [PMID: 39182184 DOI: 10.1002/jor.25960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 07/01/2024] [Accepted: 08/03/2024] [Indexed: 08/27/2024]
Abstract
Articular joints facilitate motion and transfer loads to underlying bone through a combination of cartilage tissue and synovial fluid, which together generate a low-friction contact surface. Traumatic injury delivered to cartilage and the surrounding joint capsule causes secretion of proinflammatory cytokines by chondrocytes and the synovium, triggering cartilage matrix breakdown and impairing the ability of synovial fluid to lubricate the joint. Once these inflammatory processes become chronic, posttraumatic osteoarthritis (PTOA) development begins. However, the exact mechanism by which negative alterations to synovial fluid leads to PTOA pathogenesis is not fully understood. We hypothesize that removing the lubricating macromolecules from synovial fluid alters the relationship between mechanical loads and subsequent chondrocyte behavior in injured cartilage. To test this hypothesis, we utilized an ex vivo model of PTOA that involves subjecting cartilage explants to a single rapid impact followed by continuous articulation within a lubricating bath of either healthy synovial fluid, phosphate-buffered saline (PBS), synovial fluid treated with hyaluronidase, or synovial fluid treated with trypsin. These treatments degrade the main macromolecules attributed with providing synovial fluid with its lubricating properties; hyaluronic acid and lubricin. Explants were then bisected and fluorescently stained to assess global and depth-dependent cell death, caspase activity, and mitochondrial depolarization. Explants were tested via confocal elastography to determine the local shear strain profile generated in each lubricant. These results show that degrading hyaluronic acid or lubricin in synovial fluid significantly increases middle zone chondrocyte damage and shear strain loading magnitudes, while also altering chondrocyte sensitivity to loading.
Collapse
Affiliation(s)
- Steven Ayala
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Salman O Matan
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Michelle L Delco
- Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, New York, USA
| | - Lisa A Fortier
- Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, New York, USA
| | - Itai Cohen
- Department of Physics, Cornell University, Ithaca, New York, USA
| | - Lawrence J Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, USA
| |
Collapse
|
2
|
Raj P, Wu L, Almeida C, Conway L, Tanwar S, Middendorf J, Barman I. Shining Light on Osteoarthritis: Spatially Offset Raman Spectroscopy as a Window into Cartilage Health. ACS Sens 2024; 9:3794-3804. [PMID: 38976969 DOI: 10.1021/acssensors.4c01242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Articular cartilage is a complex tissue, and early detection of osteoarthritis (OA) is crucial for effective treatment. However, current imaging modalities lack molecular specificity and primarily detect late-stage changes. In this study, we propose the use of spatially offset Raman spectroscopy (SORS) for noninvasive, depth-dependent, and molecular-specific diagnostics of articular cartilage. We demonstrate the potential of SORS to penetrate deep layers of cartilage, providing a comprehensive understanding of disease progression. Our SORS measurements were characterized and validated through mechanical and histological techniques, revealing strong correlations between spectroscopic measurements and both Young's modulus and depth of cartilage damage. By longitudinally monitoring enzymatically degraded condyles, we further developed a depth-dependent damage-tracking method. Our analysis revealed distinct components related to sample depth and glycosaminoglycan (GAG) changes, offering a comprehensive picture of cartilage health. Collectively, these findings highlight the potential of SORS as a valuable tool for enhancing OA management and improving patient outcomes.
Collapse
Affiliation(s)
- Piyush Raj
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Lintong Wu
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Craig Almeida
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Lauren Conway
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Swati Tanwar
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jill Middendorf
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Ishan Barman
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, Maryland 21205, United States
- Department of Oncology, Johns Hopkins University, Baltimore, Maryland 21287, United States
| |
Collapse
|
3
|
Li S, Gee A, Cai N, Bermudez A, Lin NYC. An Open-Source Membrane Stretcher for Simultaneous Mechanical and Structural Characterizations of Soft Materials and Biological Tissues. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.01.592106. [PMID: 38746417 PMCID: PMC11092594 DOI: 10.1101/2024.05.01.592106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The ability to simultaneously measure material mechanics and structure is central for understanding their nonlinear relationship that underlies the mechanical properties of materials, such as hysteresis, strain-stiffening and -softening, and plasticity. This experimental capability is also critical in biomechanics and mechanobiology research, as it enables direct characterizations of the intricate interplay between cellular responses and tissue mechanics. Stretching devices developed over the past few decades, however, do not often allow simultaneous measurements of the structural and mechanical responses of the sample. In this work, we introduce an open-source stretching system that can apply uniaxial strain at a submicron resolution, report the tensile force response of the sample, and be mounted on an inverted microscope for real-time imaging. Our system consists of a pair of stepper-based linear motors that stretch the sample symmetrically, a force transducer that records the sample tensile force, and an optically clear sample holder that allows for high-magnification microscopy. Using polymer samples and cellular specimens, we characterized the motion control accuracy, force measurement robustness, and microscopy compatibility of our stretching system. We envision that this uniaxial stretching system will be a valuable tool for characterizing soft and living materials.
Collapse
Affiliation(s)
- Shannon Li
- Mechanical and Aerospace Engineering Department, University of California, Los Angeles, CA, USA
| | - Alyssa Gee
- Mechanical and Aerospace Engineering Department, University of California, Los Angeles, CA, USA
| | - Nathan Cai
- Bioengineering Department, University of California, Los Angeles, CA, USA
| | - Alexandra Bermudez
- Bioengineering Department, University of California, Los Angeles, CA, USA
| | - Neil Y C Lin
- Mechanical and Aerospace Engineering Department, University of California, Los Angeles, CA, USA
- Bioengineering Department, University of California, Los Angeles, CA, USA
- Jonsson Comprehensive Cancer Center, University of California, Los Angeles, CA, USA
- Institute for Quantitative and Computational Biosciences, University of California, CA, USA
| |
Collapse
|
4
|
Guo A, Zhang S, Yang R, Sui C. Enhancing the mechanical strength of 3D printed GelMA for soft tissue engineering applications. Mater Today Bio 2024; 24:100939. [PMID: 38249436 PMCID: PMC10797197 DOI: 10.1016/j.mtbio.2023.100939] [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: 10/03/2023] [Revised: 12/28/2023] [Accepted: 12/29/2023] [Indexed: 01/23/2024] Open
Abstract
Gelatin methacrylate (GelMA) hydrogels have gained significant traction in diverse tissue engineering applications through the utilization of 3D printing technology. As an artificial hydrogel possessing remarkable processability, GelMA has emerged as a pioneering material in the advancement of tissue engineering due to its exceptional biocompatibility and degradability. The integration of 3D printing technology facilitates the precise arrangement of cells and hydrogel materials, thereby enabling the creation of in vitro models that simulate artificial tissues suitable for transplantation. Consequently, the potential applications of GelMA in tissue engineering are further expanded. In tissue engineering applications, the mechanical properties of GelMA are often modified to overcome the hydrogel material's inherent mechanical strength limitations. This review provides a comprehensive overview of recent advancements in enhancing the mechanical properties of GelMA at the monomer, micron, and nano scales. Additionally, the diverse applications of GelMA in soft tissue engineering via 3D printing are emphasized. Furthermore, the potential opportunities and obstacles that GelMA may encounter in the field of tissue engineering are discussed. It is our contention that through ongoing technological progress, GelMA hydrogels with enhanced mechanical strength can be successfully fabricated, leading to the production of superior biological scaffolds with increased efficacy for tissue engineering purposes.
Collapse
Affiliation(s)
- Ao Guo
- Department of Trauma and Pediatric Orthopedics, The First Affiliated Hospital of Anhui Medical University, Hefei, 231200, China
| | - Shengting Zhang
- Department of Trauma and Pediatric Orthopedics, The First Affiliated Hospital of Anhui Medical University, Hefei, 231200, China
| | - Runhuai Yang
- School of Biomedical Engineering, Anhui Medical University, Hefei, 230032, China
| | - Cong Sui
- Department of Trauma and Pediatric Orthopedics, The First Affiliated Hospital of Anhui Medical University, Hefei, 231200, China
| |
Collapse
|
5
|
Kim B, Kelly TAN, Jung HJ, Beane OS, Bhumiratana S, Bouklas N, Cohen I, Bonassar LJ. Microscale strain concentrations in tissue-engineered osteochondral implants are dictated by local compositional thresholds and architecture. J Biomech 2024; 162:111882. [PMID: 38070296 DOI: 10.1016/j.jbiomech.2023.111882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 10/16/2023] [Accepted: 11/20/2023] [Indexed: 01/16/2024]
Abstract
Tissue-engineered osteochondral implants manufactured from condensed mesenchymal stem cell bodies have shown promise for treating focal cartilage defects. Notably, such manufacturing techniques have shown to successfully recapture the bulk mechanical properties of native cartilage. However, the relationships among the architectural features, local composition, and micromechanical environment within tissue-engineered cartilage from cell-based aggregates remain unclear. Understanding such relationships is crucial for identifying critical parameters that can predict in vivo performance. Therefore, this study investigated the relationship among architectural features, composition, and micromechanical behavior of tissue-engineered osteochondral implants. We utilized fast-confocal microscopy combined with a strain mapping technique to analyze the micromechanical behavior under quasi-static loading, as well as Fourier Transform Infrared Spectroscopy to analyze the local compositions. More specifically, we investigated the architectural features and compositional distributions generated from tissue maturation, along with macro- and micro-level strain distributions. Our results showed that under compression, cell-based aggregates underwent deformation followed by body movement, generating high local strain around the boundaries, where local aggrecan concentration was low and local collagen concentration was high. By analyzing the micromechanics and composition at the single aggregate length scale, we identified a strong threshold relationship between local strain and compositions. Namely at the aggrecan concentration below 0.015 arbitrary unit (A.U.) and the collagen concentration above 0.15 A.U., the constructs experienced greater than threefold increase in compressive strain. Overall, this study suggests that local compositional features are the primary driver of the local mechanical environment in tissue-engineered cartilage constructs, providing insight into potential quality control parameters for manufacturing tissue-engineered constructs.
Collapse
Affiliation(s)
- Byumsu Kim
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States
| | | | | | | | | | - Nikolaos Bouklas
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States
| | - Itai Cohen
- Department of Physics, Cornell University, Ithaca, NY, United States
| | - Lawrence J Bonassar
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States; Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States.
| |
Collapse
|
6
|
Raj P, Wu L, Almeida C, Conway L, Tanwar S, Middendorf J, Barman I. Shining Light on Osteoarthritis: Spatially Offset Raman Spectroscopy as a Window into Cartilage Health. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.14.553328. [PMID: 37645996 PMCID: PMC10462085 DOI: 10.1101/2023.08.14.553328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Articular cartilage is a complex tissue, and early detection of osteoarthritis (OA) is crucial for effective treatment. However, current imaging modalities lack molecular specificity and primarily detect late-stage changes. In this study, we propose the use of Spatially Offset Raman Spectroscopy (SORS) for non-invasive, depth-dependent, and molecular-specific diagnostics of articular cartilage. We demonstrate the potential of SORS to penetrate deep layers of cartilage, providing a comprehensive understanding of disease progression. Our SORS measurements were characterized and validated through mechanical and histological techniques, revealing strong correlations between spectroscopic measurements and both Young's modulus and depth of cartilage damage. By longitudinally monitoring enzymatically degraded condyles, we further developed a depth-dependent damage-tracking method. Our analysis revealed distinct components related to sample depth and glycosaminoglycan (GAG) changes, offering a comprehensive picture of cartilage health. Collectively, these findings highlight the potential of SORS as a valuable tool for enhancing OA management and improving patient outcomes.
Collapse
Affiliation(s)
- Piyush Raj
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Lintong Wu
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Craig Almeida
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Lauren Conway
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Swati Tanwar
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Jill Middendorf
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Ishan Barman
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA
- Department of Oncology, Johns Hopkins University, Baltimore, Maryland, USA
| |
Collapse
|
7
|
Li Z, Ruan C, Niu X. Collagen-based bioinks for regenerative medicine: Fabrication, application and prospective. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2023. [DOI: 10.1016/j.medntd.2023.100211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
|
8
|
Middendorf JM, Barocas VH. MRI‐based degeneration grades for lumbar facet joints do not correlate with cartilage mechanics. JOR Spine 2023. [DOI: 10.1002/jsp2.1246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- Jill M. Middendorf
- Department of Mechanical Engineering Johns Hopkins University Baltimore Maryland USA
| | - Victor H. Barocas
- Department of Biomedical Engineering University of Minnesota Minneapolis Minnesota USA
| |
Collapse
|
9
|
Diamantides N, Slyker L, Martin S, Rodriguez MR, Bonassar LJ. Pre-glycation impairs gelation of high concentration collagen solutions. J Biomed Mater Res A 2022; 110:1953-1963. [PMID: 36183358 PMCID: PMC9648490 DOI: 10.1002/jbm.a.37431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 06/30/2022] [Accepted: 07/21/2022] [Indexed: 09/29/2023]
Abstract
There remains a need for stiffer collagen hydrogels for tissue engineering and disease modeling applications. Pre-glycation, or glycation of collagen in solution prior to gelation, has been shown to increase the mechanics of collagen hydrogels while maintaining high viability of encapsulated cells. The stiffness of glycated collagen gels can be increased by increasing the collagen concentration, sugar concentration, and glycation time. However, previous studies on pre-glycation of collagen have used low collagen concentrations and/or low sugar concentrations and have not investigated the effect of glycation time. Therefore, the objective of this study was to determine the effects of pre-glycation with high sugar concentrations (up to 500 mM) and extended glycation times (up to 21 days) on high concentration collagen (8 mg/ml). The addition of sugar to the collagen and the formation of advanced glycation end products (AGEs) were quantified. The ability to gel successfully and rheological properties were determined and correlated with biochemical characterizations. Successful collagen gelation and rheological properties of pre-glycated collagen were found to be strongly dependent on the ratio of added sugars to added AGEs with high ratios impairing gelation and low ratios resulting in optimal storage moduli. There is likely a competing effect during pre-glycation of the formation of AGEs resulting in crosslinking of collagen and the formation of Amadori intermediates acting to increase collagen solubility. Overall, this study shows that collagen glycation can be optimized by increasing the formation of AGEs while maintaining a low ratio of added sugar to added AGEs.
Collapse
Affiliation(s)
| | - Leigh Slyker
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY
| | - Sara Martin
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY
| | | | - Lawrence J. Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY
| |
Collapse
|
10
|
Lee CT, Merkel M. Stiffening of under-constrained spring networks under isotropic strain. SOFT MATTER 2022; 18:5410-5425. [PMID: 35822259 DOI: 10.1039/d2sm00075j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Disordered spring networks are a useful paradigm to examine macroscopic mechanical properties of amorphous materials. Here, we study the elastic behavior of under-constrained spring networks, i.e. networks with more degrees of freedom than springs. While such networks are usually floppy, they can be rigidified by applying external strain. Recently, an analytical formalism has been developed to predict the scaling behavior of the elastic network properties close to this rigidity transition. Here we numerically show that these predictions apply to many different classes of spring networks, including phantom triangular, Delaunay, Voronoi, and honeycomb networks. The analytical predictions further imply that the shear modulus G scales linearly with isotropic stress T close to the rigidity transition. However, this seems to be at odds with recent numerical studies suggesting an exponent between G and T that is smaller than one for some network classes. Using increased numerical precision and shear stabilization, we demonstrate here that close to the transition a linear scaling, G ∼ T, holds independent of the network class. Finally, we show that our results are not or only weakly affected by finite-size effects, depending on the network class.
Collapse
Affiliation(s)
- Cheng-Tai Lee
- CNRS, Centre de Physique Théorique (CPT, UMR 7332), Turing Center for Living Systems, Aix Marseille Univ, Université de Toulon, Marseille, France.
| | - Matthias Merkel
- CNRS, Centre de Physique Théorique (CPT, UMR 7332), Turing Center for Living Systems, Aix Marseille Univ, Université de Toulon, Marseille, France.
| |
Collapse
|
11
|
Light-sheet photonic force optical coherence elastography for high-throughput quantitative 3D micromechanical imaging. Nat Commun 2022; 13:3465. [PMID: 35710790 PMCID: PMC9203576 DOI: 10.1038/s41467-022-30995-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 05/23/2022] [Indexed: 11/09/2022] Open
Abstract
Quantitative characterisation of micro-scale mechanical properties of the extracellular matrix (ECM) and dynamic cell-ECM interactions can significantly enhance fundamental discoveries and their translational potential in the rapidly growing field of mechanobiology. However, quantitative 3D imaging of ECM mechanics with cellular-scale resolution and dynamic monitoring of cell-mediated changes to pericellular viscoelasticity remain a challenge for existing mechanical characterisation methods. Here, we present light-sheet photonic force optical coherence elastography (LS-pfOCE) to address this need by leveraging a light-sheet for parallelised, non-invasive, and localised mechanical loading. We demonstrate the capabilities of LS-pfOCE by imaging the micromechanical heterogeneity of fibrous collagen matrices and perform live-cell imaging of cell-mediated ECM micromechanical dynamics. By providing access to 4D spatiotemporal variations in the micromechanical properties of 3D biopolymer constructs and engineered cellular systems, LS-pfOCE has the potential to drive new discoveries in mechanobiology and contribute to the development of novel biomechanics-based clinical diagnostics and therapies.
Collapse
|
12
|
Wang Z, Le H, Wang Y, Liu H, Li Z, Yang X, Wang C, Ding J, Chen X. Instructive cartilage regeneration modalities with advanced therapeutic implantations under abnormal conditions. Bioact Mater 2022; 11:317-338. [PMID: 34977434 PMCID: PMC8671106 DOI: 10.1016/j.bioactmat.2021.10.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 09/19/2021] [Accepted: 10/02/2021] [Indexed: 12/12/2022] Open
Abstract
The development of interdisciplinary biomedical engineering brings significant breakthroughs to the field of cartilage regeneration. However, cartilage defects are considerably more complicated in clinical conditions, especially when injuries occur at specific sites (e.g., osteochondral tissue, growth plate, and weight-bearing area) or under inflammatory microenvironments (e.g., osteoarthritis and rheumatoid arthritis). Therapeutic implantations, including advanced scaffolds, developed growth factors, and various cells alone or in combination currently used to treat cartilage lesions, address cartilage regeneration under abnormal conditions. This review summarizes the strategies for cartilage regeneration at particular sites and pathological microenvironment regulation and discusses the challenges and opportunities for clinical transformation.
Collapse
Affiliation(s)
- Zhonghan Wang
- Department of Plastic and Reconstruct Surgery, The First Hospital of Jilin University, 1 Xinmin Street, Changchun, 130021, PR China
- Department of Orthopedics, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, 130041, PR China
| | - Hanxiang Le
- Department of Orthopedics, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, 130041, PR China
| | - Yanbing Wang
- Department of Orthopedics, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, 130041, PR China
| | - He Liu
- Department of Orthopedics, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, 130041, PR China
| | - Zuhao Li
- Department of Orthopedics, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, 130041, PR China
| | - Xiaoyu Yang
- Department of Orthopedics, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, 130041, PR China
| | - Chenyu Wang
- Department of Plastic and Reconstruct Surgery, The First Hospital of Jilin University, 1 Xinmin Street, Changchun, 130021, PR China
| | - Jianxun Ding
- Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, PR China
| | - Xuesi Chen
- Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, PR China
| |
Collapse
|
13
|
Tauber J, van der Gucht J, Dussi S. Stretchy and disordered: Toward understanding fracture in soft network materials via mesoscopic computer simulations. J Chem Phys 2022; 156:160901. [PMID: 35490006 DOI: 10.1063/5.0081316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Soft network materials exist in numerous forms ranging from polymer networks, such as elastomers, to fiber networks, such as collagen. In addition, in colloidal gels, an underlying network structure can be identified, and several metamaterials and textiles can be considered network materials as well. Many of these materials share a highly disordered microstructure and can undergo large deformations before damage becomes visible at the macroscopic level. Despite their widespread presence, we still lack a clear picture of how the network structure controls the fracture processes of these soft materials. In this Perspective, we will focus on progress and open questions concerning fracture at the mesoscopic scale, in which the network architecture is clearly resolved, but neither the material-specific atomistic features nor the macroscopic sample geometries are considered. We will describe concepts regarding the network elastic response that have been established in recent years and turn out to be pre-requisites to understand the fracture response. We will mostly consider simulation studies, where the influence of specific network features on the material mechanics can be cleanly assessed. Rather than focusing on specific systems, we will discuss future challenges that should be addressed to gain new fundamental insights that would be relevant across several examples of soft network materials.
Collapse
Affiliation(s)
- Justin Tauber
- Physical Chemistry and Soft Matter, Wageningen University, Wageningen, The Netherlands
| | - Jasper van der Gucht
- Physical Chemistry and Soft Matter, Wageningen University, Wageningen, The Netherlands
| | - Simone Dussi
- Physical Chemistry and Soft Matter, Wageningen University, Wageningen, The Netherlands
| |
Collapse
|
14
|
Wyse Jackson T, Michel J, Lwin P, Fortier LA, Das M, Bonassar LJ, Cohen I. Structural origins of cartilage shear mechanics. SCIENCE ADVANCES 2022; 8:eabk2805. [PMID: 35148179 PMCID: PMC8836800 DOI: 10.1126/sciadv.abk2805] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Articular cartilage is a remarkable material able to sustain millions of loading cycles over decades of use outperforming any synthetic substitute. Crucially, how extracellular matrix constituents alter mechanical performance, particularly in shear, remains poorly understood. Here, we present experiments and theory in support of a rigidity percolation framework that quantitatively describes the structural origins of cartilage's shear properties and how they arise from the mechanical interdependence of the collagen and aggrecan networks making up its extracellular matrix. This framework explains that near the cartilage surface, where the collagen network is sparse and close to the rigidity threshold, slight changes in either collagen or aggrecan concentrations, common in early stages of cartilage disease, create a marked weakening in modulus that can lead to tissue collapse. More broadly, this framework provides a map for understanding how changes in composition throughout the tissue alter its shear properties and ultimate in vivo function.
Collapse
Affiliation(s)
- Thomas Wyse Jackson
- Department of Physics, Cornell University, Ithaca, NY, USA
- Corresponding author. (T.W.J.); (I.C.)
| | - Jonathan Michel
- School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY, USA
| | - Pancy Lwin
- School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY, USA
| | - Lisa A. Fortier
- Department of Clinical Sciences, Cornell University, Ithaca, NY, USA
| | - Moumita Das
- School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY, USA
| | - Lawrence J. Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA
| | - Itai Cohen
- Department of Physics, Cornell University, Ithaca, NY, USA
- Corresponding author. (T.W.J.); (I.C.)
| |
Collapse
|
15
|
Lwin P, Sindermann A, Sutter L, Wyse Jackson T, Bonassar L, Cohen I, Das M. Rigidity and fracture of biopolymer double networks. SOFT MATTER 2022; 18:322-327. [PMID: 34881769 DOI: 10.1039/d1sm00802a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Tunable mechanics and fracture resistance are hallmarks of biological tissues whose properties arise from extracellular matrices comprised of double networks. To elucidate the origin of these desired properties, we study the shear modulus and fracture properties of a rigidly percolating double network model comprised of a primary network of stiff fibers and a secondary network of flexible fibers. We find that when the primary network density is just above its rigidity percolation threshold, the secondary network density can be tuned to facilitate stress relaxation via non-affine deformations and provide mechanical reinforcement. In contrast, when the primary network is far above its rigidity threshold, the double network is always stiff and brittle. These results highlight an important mechanism behind the tunability and resilience of biopolymer double networks: the secondary network can dramatically alter mechanical properties from compliant and ductile to stiff and brittle only when the primary network is marginally rigid.
Collapse
Affiliation(s)
- Pancy Lwin
- School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Andrew Sindermann
- School of Physics and Astronomy, Rochester Institute of Technology, Rochester, New York 14623, USA.
| | - Leo Sutter
- School of Physics and Astronomy, Rochester Institute of Technology, Rochester, New York 14623, USA.
| | | | - Lawrence Bonassar
- Meinig School of Biomedical Engineering and Sibley School of Mechanical and Aerospace Engineering, Cornell University, NY 14853, USA
| | - Itai Cohen
- Department of Physics, Cornell University, Ithaca, NY 14853, USA
| | - Moumita Das
- School of Physics and Astronomy, Rochester Institute of Technology, Rochester, New York 14623, USA.
| |
Collapse
|
16
|
Lee G, Leech G, Lwin P, Michel J, Currie C, Rust MJ, Ross JL, McGorty RJ, Das M, Robertson-Anderson RM. Active cytoskeletal composites display emergent tunable contractility and restructuring. SOFT MATTER 2021; 17:10765-10776. [PMID: 34792082 PMCID: PMC9239752 DOI: 10.1039/d1sm01083b] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The cytoskeleton is a model active matter system that controls processes as diverse as cell motility and mechanosensing. While both active actomyosin dynamics and actin-microtubule interactions are key to the cytoskeleton's versatility and adaptability, an understanding of their interplay is lacking. Here, we couple microscale experiments with mechanistic modeling to elucidate how connectivity, rigidity, and force-generation affect emergent material properties in composite networks of actin, tubulin, and myosin. We use multi-spectral imaging, time-resolved differential dynamic microscopy and spatial image autocorrelation to show that ballistic contraction occurs in composites with sufficient flexibility and motor density, but that a critical fraction of microtubules is necessary to sustain controlled dynamics. The active double-network models we develop, which recapitulate our experimental findings, reveal that while percolated actomyosin networks are essential for contraction, only composites with comparable actin and microtubule densities can simultaneously resist mechanical stresses while supporting substantial restructuring. The comprehensive phase map we present not only provides important insight into the different routes the cytoskeleton can use to alter its dynamics and structure, but also serves as a much-needed blueprint for designing cytoskeleton-inspired materials that couple tunability with resilience and adaptability for diverse applications ranging from wound healing to soft robotics.
Collapse
Affiliation(s)
- Gloria Lee
- Department of Physics and Biophysics, University of San Diego, USA.
| | - Gregor Leech
- Department of Physics and Biophysics, University of San Diego, USA.
| | - Pancy Lwin
- School of Physics and Astronomy, Rochester Institute of Technology, USA
| | - Jonathan Michel
- School of Physics and Astronomy, Rochester Institute of Technology, USA
| | | | - Michael J Rust
- Department of Molecular Genetics and Cell Biology, University of Chicago, USA
| | | | - Ryan J McGorty
- Department of Physics and Biophysics, University of San Diego, USA.
| | - Moumita Das
- School of Physics and Astronomy, Rochester Institute of Technology, USA
| | | |
Collapse
|
17
|
Gologorsky CJ, Middendorf JM, Cohen I, Bonassar LJ. Depth-dependent patterns in shear modulus of temporomandibular joint cartilage correspond to tissue structure and anatomic location. J Biomech 2021; 129:110815. [PMID: 34706301 DOI: 10.1016/j.jbiomech.2021.110815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 10/07/2021] [Accepted: 10/08/2021] [Indexed: 11/17/2022]
Abstract
To fully understand TMJ cartilage degeneration and appropriate repair mechanisms, it is critical to understand the native structure-mechanics relationships of TMJ cartilage and any local variation that may occur in the tissue. Here, we used confocal elastography and digital image correlation to measure the depth-dependent shear properties as well as the structural properties of TMJ cartilage at different anatomic locations on the condyle to identify depth-dependent changes in shear mechanics and structure. We found that samples at every anatomic location showed qualitatively similar shear modulus profiles as a function of depth. In every sample, four distinct zones of mechanical behavior were observed, with shear modulus values spanning 3-5 orders of magnitude across zones. However, quantitative characteristics of shear modulus profiles varied by anatomic location, particularly zone size and location, with the most significant variation in zonal width occurring in the fibrocartilage surface layer (zone 1). This anatomic variation suggests that different locations on the TMJ condyle may play unique mechanical roles in TMJ function. Furthermore, zones identified in the mechanical data corresponded on a sample-by-sample basis to zones identified in the structural data, indicating the known structural zones of TMJ cartilage may also play unique mechanical roles in TMJ function.
Collapse
Affiliation(s)
| | - Jill M Middendorf
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA
| | - Itai Cohen
- Department of Physics, Cornell University, Clark Hall C7, Ithaca, NY 14853, USA
| | - Lawrence J Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA; Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA.
| |
Collapse
|
18
|
Gao T, Boys AJ, Zhao C, Chan K, Estroff LA, Bonassar LJ. Non-Destructive Spatial Mapping of Glycosaminoglycan Loss in Native and Degraded Articular Cartilage Using Confocal Raman Microspectroscopy. Front Bioeng Biotechnol 2021; 9:744197. [PMID: 34778225 PMCID: PMC8581176 DOI: 10.3389/fbioe.2021.744197] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 09/24/2021] [Indexed: 12/02/2022] Open
Abstract
Articular cartilage is a collagen-rich tissue that provides a smooth, lubricated surface for joints and is also responsible for load bearing during movements. The major components of cartilage are water, collagen, and proteoglycans. Osteoarthritis is a degenerative disease of articular cartilage, in which an early-stage indicator is the loss of proteoglycans from the collagen matrix. In this study, confocal Raman microspectroscopy was applied to study the degradation of articular cartilage, specifically focused on spatially mapping the loss of glycosaminoglycans (GAGs). Trypsin digestion was used as a model for cartilage degradation. Two different scanning geometries for confocal Raman mapping, cross-sectional and depth scans, were applied. The chondroitin sulfate coefficient maps derived from Raman spectra provide spatial distributions similar to histological staining for glycosaminoglycans. The depth scans, during which subsurface data were collected without sectioning the samples, can also generate spectra and GAG distributions consistent with Raman scans of the surface-to-bone cross sections. In native tissue, both scanning geometries demonstrated higher GAG content at the deeper zone beneath the articular surface and negligible GAG content after trypsin degradation. On partially digested samples, both scanning geometries detected an ∼100 μm layer of GAG depletion. Overall, this research provides a technique with high spatial resolution (25 μm pixel size) to measure cartilage degradation without tissue sections using confocal Raman microspectroscopy, laying a foundation for potential in vivo measurements and osteoarthritis diagnosis.
Collapse
Affiliation(s)
- Tianyu Gao
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, United States
| | - Alexander J Boys
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, United States
| | - Crystal Zhao
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States
| | - Kiara Chan
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, United States
| | - Lara A Estroff
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, United States.,Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, United States
| | - Lawrence J Bonassar
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States.,Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| |
Collapse
|
19
|
Heffern EFW, Huelskamp H, Bahar S, Inglis RF. Phase transitions in biology: from bird flocks to population dynamics. Proc Biol Sci 2021; 288:20211111. [PMID: 34666526 PMCID: PMC8527202 DOI: 10.1098/rspb.2021.1111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 09/27/2021] [Indexed: 11/12/2022] Open
Abstract
Phase transitions are an important and extensively studied concept in physics. The insights derived from understanding phase transitions in physics have recently and successfully been applied to a number of different phenomena in biological systems. Here, we provide a brief review of phase transitions and their role in explaining biological processes ranging from collective behaviour in animal flocks to neuronal firing. We also highlight a new and exciting area where phase transition theory is particularly applicable: population collapse and extinction. We discuss how phase transition theory can give insight into a range of extinction events such as population decline due to climate change or microbial responses to stressors such as antibiotic treatment.
Collapse
Affiliation(s)
| | - Holly Huelskamp
- Department of Biology, University of Missouri at St Louis, St Louis, MO, USA
| | - Sonya Bahar
- Department of Physics and Astronomy, University of Missouri at St Louis, St Louis, MO, USA
| | - R. Fredrik Inglis
- Department of Biology, University of Missouri at St Louis, St Louis, MO, USA
| |
Collapse
|
20
|
Huang Y, Wang J, Yu WJ, Yu Y, Li RY, Gao Q, Ren KF, Ji J. A Bioinspired Hydrogel-Elastomer Hybrid Surface for Enhanced Mechanical Properties and Lubrication. ACS APPLIED MATERIALS & INTERFACES 2021; 13:50461-50469. [PMID: 34641666 DOI: 10.1021/acsami.1c17345] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Developing surfaces that realize lubrication and durable wear resistance under high pressure has great implications in areas ranging from electromechanical systems to advanced biomedical devices but has proven challenging. Inspired by the zonal and transitional structure of articular cartilage, we fabricate a hydrogel-elastomer hybrid surface, where the hydrogel interpenetrates into the polymer elastomer substrate as a transitional and bonding zone, that exhibits a low coefficient of friction and wear resistance under a high load. First, we entrap benzophenone within the surface of polymer substrates such as polydimethylsiloxane, polyvinylchloride, and polyurethane. The hybrid surface is then achieved through initiating polymerization of the acrylamide monomer on the polymer surface upon ultraviolet irradiation. We observe an interpenetration area of the hydrogel and the polymer substrate. The hybrid surface shows a low coefficient of friction (∼0.05) under a very high load (over 100 atm contact pressure). It conserves the lubrication property over 100,000 cycles under a 10.9 MPa pressure and shows slight wear. This work brings a new perspective on designing surfaces with a lubrication property and wear resistance, showing broad applications.
Collapse
Affiliation(s)
- Yan Huang
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Jing Wang
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Wei-Jiang Yu
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yan Yu
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Ren-Yun Li
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Qiang Gao
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Ke-Feng Ren
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Jian Ji
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| |
Collapse
|
21
|
Middendorf JM, Diamantides N, Kim B, Dugopolski C, Kennedy S, Blahut E, Cohen I, Bonassar LJ. The influence of chondrocyte source on the manufacturing reproducibility of human tissue engineered cartilage. Acta Biomater 2021; 131:276-285. [PMID: 34245892 DOI: 10.1016/j.actbio.2021.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 11/16/2022]
Abstract
Multiple human tissue engineered cartilage constructs are showing promise in advanced clinical trials but identifying important measures of manufacturing reproducibility remains a challenge. FDA guidance suggests measuring multiple mechanical properties prior to implantation, because these properties could affect the long term success of the implant. Additionally, these engineered cartilage mechanics could be sensitive to the autologous chondrocyte source, an inherently irregular manufacturing starting material. If any mechanical properties are sensitive to changes in the autologous chondrocyte source, these properties may need to be measured prior to implantation to ensure manufacturing reproducibility and quality. Therefore, this study identified variability in the compressive, friction, and shear properties of a human tissue engineered cartilage constructs due to the chondrocyte source. Over 200 constructs were created from 7 different chondrocyte sources and tested using 3 distinct mechanical experiments. Under confined compression, the compressive properties (aggregate modulus and hydraulic permeability) varied by orders of magnitude due to the chondrocyte source. The friction coefficient changed by a factor of 5 due to the chondrocyte source and high intrapatient variability was noted. In contrast, the shear modulus was not affected by changes in the chondrocyte source. Finally, measurements on the local compressive and shear mechanics revealed variability in the depth dependent strain fields based on chondrocyte source. Since the chondrocyte source causes large amounts of variability in the compression and local mechanical properties of engineered cartilage, these mechanical properties may be important measures of manufacturing reproducibility. STATEMENT OF SIGNIFICANCE: Although the FDA recommends measuring mechanical properties of human tissue engineered cartilage constructs during manufacturing, the effect of manufacturing variability on construct mechanics is unknown. As one of the first studies to measure multiple mechanical properties on hundreds of human tissue engineered cartilage constructs, we found the compressive properties are most sensitive to changes in the autologous chondrocyte source, an inherently irregular manufacturing variable. This sensitivity to the autologous chondrocyte source reveals the compressive properties should be measured prior to implantation to assess manufacturing reproducibility.
Collapse
Affiliation(s)
- Jill M Middendorf
- Sibley School of Mechanical Engineering, Cornell University, Ithaca, NY, United States
| | - Nicole Diamantides
- Meinig School of Biomedical Engineering Cornell University, Ithaca, NY, United States
| | - Byumsu Kim
- Sibley School of Mechanical Engineering, Cornell University, Ithaca, NY, United States
| | | | | | - Eric Blahut
- Histogenics Corporation, Waltham, MA, United States
| | - Itai Cohen
- Department of Physics, Cornell University, Ithaca, NY, United States
| | - Lawrence J Bonassar
- Sibley School of Mechanical Engineering, Cornell University, Ithaca, NY, United States; Meinig School of Biomedical Engineering Cornell University, Ithaca, NY, United States.
| |
Collapse
|
22
|
Percolation networks inside 3D model of the mineralized collagen fibril. Sci Rep 2021; 11:11398. [PMID: 34059767 PMCID: PMC8166932 DOI: 10.1038/s41598-021-90916-x] [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] [Received: 02/26/2021] [Accepted: 05/19/2021] [Indexed: 01/04/2023] Open
Abstract
Bone is a hierarchical biological material, characterized at the nanoscale by a recurring structure mainly composed of apatite mineral and collagen, i.e. the mineralized collagen fibril (MCF). Although the architecture of the MCF was extensively investigated by experimental and computational studies, it still represents a topic of debate. In this work, we developed a 3D continuum model of the mineral phase in the framework of percolation theory, that describes the transition from isolated to spanning cluster of connected platelets. Using Monte Carlo technique, we computed overall 120 × 106 iterations and investigated the formation of spanning networks of apatite minerals. We computed the percolation probability for different mineral volume fractions characteristic of human bone tissue. The findings highlight that the percolation threshold occurs at lower volume fractions for spanning clusters in the width direction with respect to the critical mineral volume fractions that characterize the percolation transition in the thickness and length directions. The formation of spanning clusters of minerals represents a condition of instability for the MCF, as it could be the onset of a high susceptibility to fracture. The 3D computational model developed in this study provides new, complementary insights to the experimental investigations concerning human MCF.
Collapse
|
23
|
Hybrid fluorescence-AFM explores articular surface degeneration in early osteoarthritis across length scales. Acta Biomater 2021; 126:315-325. [PMID: 33753314 DOI: 10.1016/j.actbio.2021.03.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 03/06/2021] [Accepted: 03/14/2021] [Indexed: 12/21/2022]
Abstract
Atomic force microscopy (AFM) has become a powerful tool for the characterization of materials at the nanoscale. Nevertheless, its application to hierarchical biological tissue like cartilage is still limited. One reason is that such samples are usually millimeters in size, while the AFM delivers much more localized information. Here a combination of AFM and fluorescence microscopy is presented where features on a millimeter sized tissue sample are selected by fluorescence microscopy on the micrometer scale and then mapped down to nanometer precision by AFM under native conditions. This served us to show that local changes in the organization of fluorescent stained cells, a marker for early osteoarthritis, correlate with a significant local reduction of the elastic modulus, local thinning of the collagen fibers, and a roughening of the articular surface. This approach is not only relevant for cartilage, but in general for the characterization of native biological tissue from the macro- to the nanoscale. STATEMENT OF SIGNIFICANCE: Different length scales have to be studied to understand the function and dysfunction of hierarchically organized biomaterials or tissues. Here we combine a highly stable AFM with fluorescence microscopy and precisely motorized movement to correlate micro- and nanoscopic properties of articular cartilage on a millimeter sized sample under native conditions. This is necessary for unraveling the relationship between microscale organization of chondrocytes, micrometer scale changes in articular cartilage properties and nanoscale organization of collagen (including D-banding). We anticipate that such studies pave the way for a guided design of hierarchical biomaterials.
Collapse
|
24
|
Lin W, Klein J. Recent Progress in Cartilage Lubrication. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2005513. [PMID: 33759245 DOI: 10.1002/adma.202005513] [Citation(s) in RCA: 136] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/23/2020] [Indexed: 05/18/2023]
Abstract
Healthy articular cartilage, covering the ends of bones in major joints such as hips and knees, presents the most efficiently-lubricated surface known in nature, with friction coefficients as low as 0.001 up to physiologically high pressures. Such low friction is indeed essential for its well-being. It minimizes wear-and-tear and hence the cartilage degradation associated with osteoarthritis, the most common joint disease, and, by reducing shear stress on the mechanotransductive, cartilage-embedded chondrocytes (the only cell type in the cartilage), it regulates their function to maintain homeostasis. Understanding the origins of such low friction of the articular cartilage, therefore, is of major importance in order to alleviate disease symptoms, and slow or even reverse its breakdown. This progress report considers the relation between frictional behavior and the cellular mechanical environment in the cartilage, then reviews the mechanism of lubrication in the joints, in particular focusing on boundary lubrication. Following recent advances based on hydration lubrication, a proposed synergy between different molecular components of the synovial joints, acting together in enabling the low friction, has been proposed. Additionally, recent development of natural and bio-inspired lubricants is reviewed.
Collapse
Affiliation(s)
- Weifeng Lin
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Jacob Klein
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 76100, Israel
| |
Collapse
|
25
|
Chatterjee A, Dubey DK, Sinha SK. Effect of Loading on the Adhesion and Frictional Characteristics of Top Layer Articular Cartilage Nanoscale Contact: A Molecular Dynamics Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:46-62. [PMID: 33382944 DOI: 10.1021/acs.langmuir.0c02283] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Articular cartilage is a water-lubricated naturally occurring biological interface imparting unique mechanical and ultralow frictional properties in bone joints. Although the material of cartilage, synovial fluid composition, and their lubricating modes and properties have been extensively investigated at various scales experimentally, there is still a lack of understanding of load bearing, adhesion, and friction mechanisms of the cartilage-cartilage interface from an atomistic perspective under heavy loads. In this study, the effect of loading on adhesion and frictional behavior in articular cartilage is investigated with a proposed atomistic model for top layer cartilage-cartilage contact in unhydrated conditions using molecular dynamics (MD) simulations. Pull-off tests reveal that cohesive interactions occur at the interface due to formation of heavily interpenetrated atomistic sites leading to stretching and localized pulling of fragments during sliding. Sliding tests show that friction is load- and direction-dependent with the coefficient of friction (COF) obtained in the range of 0.20-0.75 at the interface for sliding in parallel and perpendicular directions to the collagen axis. These values are in good agreement with earlier nanoscale experimental results reported for the top layer cartilage-cartilage interface. The COF reduces with an increase in load and tends to be higher for the parallel sliding case than for the perpendicular case owing to the presence of the constant number of H-bonds. Overall, this work contributes toward understanding sliding in unhydrated biointerfaces, which is the precursor of wear, and provides insights into implant research.
Collapse
Affiliation(s)
- Abhinava Chatterjee
- Mechanical Engineering Department, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Devendra K Dubey
- Mechanical Engineering Department, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Sujeet K Sinha
- Mechanical Engineering Department, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| |
Collapse
|
26
|
Irwin RM, Gao T, Boys AJ, Ortved K, Cohen I, Bonassar LJ. Microscale strain mapping demonstrates the importance of interface slope in the mechanics of cartilage repair. J Biomech 2020; 114:110159. [PMID: 33310276 DOI: 10.1016/j.jbiomech.2020.110159] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 11/10/2020] [Accepted: 11/25/2020] [Indexed: 01/20/2023]
Abstract
Achieving lateral integration of articular cartilage repair tissue with surrounding native cartilage remains a clinical challenge. Histological and bulk mechanical studies have identified extracellular matrix components that correlate with superior failure strength, but it is unclear how local changes in geometry and composition at the repair interface affect tissue strains under physiologic loading. Here, we investigated the effects of local compositional and interface geometry on lateral cartilage repair integration by coupling microscale Raman spectroscopy and confocal elastography to measure tissue strains under compressive and shear loading. Histological integration assessments did not have significant relationships with interface strains under compressive loading (p > 0.083) and only the perimeter attachment score was trending towards statistical significance with the |Exy| strain tensor under shear loading (p = 0.050). Interface slope had a stronger correlation with local tissue strains under compressive and shear loading compared to compositional measures of GAG, collagen, or proteins (compressive loading |Eyy| tensor: R2 = 0.400 (interface slope), 0.005 (GAG), 0.024 (collagen), and 0.012 (protein); shear loading |Exy| tensor: R2 = 0.457 (interface slope), 0.003 (GAG), 0.006 (collagen), and 0.000 (total protein)). These data support surgical publications detailing the need for vertical walls when debriding chondral defects. Current histological integration assessments and local compositional measures were insufficient for identifying the variation in interface strains under compressive and shear loading. Thus, our data points to the importance of controlling interface geometry at the time of surgery, which has implications for cartilage repair integration and long-term healing.
Collapse
Affiliation(s)
- Rebecca M Irwin
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Tianyu Gao
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, United States
| | - Alexander J Boys
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, United States
| | - Kyla Ortved
- Comparative Orthopaedics Laboratory, Cornell University, Ithaca, NY, United States(1)
| | - Itai Cohen
- Department of Physics, Cornell University, Ithaca, NY, United States
| | - Lawrence J Bonassar
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States; Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States.
| |
Collapse
|
27
|
Sloan SR, Wipplinger C, Kirnaz S, Delgado R, Huang S, Shvets G, Härtl R, Bonassar LJ. Imaging the local biochemical content of native and injured intervertebral disc using Fourier transform infrared microscopy. JOR Spine 2020; 3:e1121. [PMID: 33392456 PMCID: PMC7770196 DOI: 10.1002/jsp2.1121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 07/20/2020] [Accepted: 08/03/2020] [Indexed: 12/12/2022] Open
Abstract
Alterations to the biochemical composition of the intervertebral disc (IVD) are hallmarks of aging and degeneration. Methods to assess biochemical content, such as histology, immunohistochemistry, and spectrophotometric assays, are limited in their ability to quantitatively analyze the spatial distribution of biochemical components. Fourier transform infrared (FTIR) microscopy is a biochemical analysis method that can yield both quantitative and high-resolution data about the spatial distribution of biochemical components. This technique has been largely unexplored for use with the IVD, and existing methods use complex analytical techniques that make results difficult to interpret. The objective of the present study is to describe an FTIR microscopy method that has been optimized for imaging the collagen and proteoglycan content of the IVD. The method was performed on intact and discectomized IVDs from the sheep lumbar spine after 6 weeks in vivo in order to validate FTIR microscopy in healthy and degenerated IVDs. FTIR microscopy quantified collagen and proteoglycan content across the entire IVD and showed local changes in biochemical content after discectomy that were not observed with traditional histological methods. Changes in collagen and proteoglycans content were found to have strong correlations with Pfirrmann grades of degeneration. This study demonstrates how FTIR microscopy is a valuable research tool that can be used to quantitatively assess the local biochemical composition of IVDs in development, degeneration, and repair.
Collapse
Affiliation(s)
- Stephen R. Sloan
- Meinig School of Biomedical EngineeringCornell UniversityIthacaNew YorkUSA
| | - Christoph Wipplinger
- Department of Neurological SurgeryWeill Cornell Medical CollegeNew YorkNew YorkUSA
| | - Sertaç Kirnaz
- Department of Neurological SurgeryWeill Cornell Medical CollegeNew YorkNew YorkUSA
| | - Robert Delgado
- Applied Engineering and PhysicsCornell UniversityIthacaNew YorkUSA
| | - Steven Huang
- Applied Engineering and PhysicsCornell UniversityIthacaNew YorkUSA
| | - Gennady Shvets
- Applied Engineering and PhysicsCornell UniversityIthacaNew YorkUSA
| | - Roger Härtl
- Department of Neurological SurgeryWeill Cornell Medical CollegeNew YorkNew YorkUSA
| | - Lawrence J. Bonassar
- Meinig School of Biomedical EngineeringCornell UniversityIthacaNew YorkUSA
- Sibley School of Mechanical and Aerospace EngineeringCornell UniversityIthacaNew YorkUSA
| |
Collapse
|
28
|
Role of Entropy in Colloidal Self-Assembly. ENTROPY 2020; 22:e22080877. [PMID: 33286648 PMCID: PMC7517482 DOI: 10.3390/e22080877] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 08/03/2020] [Accepted: 08/05/2020] [Indexed: 12/13/2022]
Abstract
Entropy plays a key role in the self-assembly of colloidal particles. Specifically, in the case of hard particles, which do not interact or overlap with each other during the process of self-assembly, the free energy is minimized due to an increase in the entropy of the system. Understanding the contribution of entropy and engineering it is increasingly becoming central to modern colloidal self-assembly research, because the entropy serves as a guide to design a wide variety of self-assembled structures for many technological and biomedical applications. In this work, we highlight the importance of entropy in different theoretical and experimental self-assembly studies. We discuss the role of shape entropy and depletion interactions in colloidal self-assembly. We also highlight the effect of entropy in the formation of open and closed crystalline structures, as well as describe recent advances in engineering entropy to achieve targeted self-assembled structures.
Collapse
|
29
|
Bartell LR, Fortier LA, Bonassar LJ, Szeto HH, Cohen I, Delco ML. Mitoprotective therapy prevents rapid, strain-dependent mitochondrial dysfunction after articular cartilage injury. J Orthop Res 2020; 38:1257-1267. [PMID: 31840828 PMCID: PMC7225065 DOI: 10.1002/jor.24567] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 12/12/2019] [Indexed: 02/04/2023]
Abstract
Posttraumatic osteoarthritis (PTOA) involves the mechanical and biological deterioration of articular cartilage that occurs following joint injury. PTOA is a growing problem in health care due to the lack of effective therapies combined with an aging population with high activity levels. Recently, acute mitochondrial dysfunction and altered cellular respiration have been associated with cartilage degeneration after injury. This finding is particularly important because recently developed mitoprotective drugs, including SS peptides, can preserve mitochondrial structure and function after acute injury in other tissues. It is not known, however, if cartilage injury induces rapid structural changes in mitochondria, to what degree mitochondrial dysfunction in cartilage depends on the mechanics of injury or the time frame over which such dysfunction develops. Similarly, it is unknown if SS-peptide treatment can preserve mitochondrial structure and function after cartilage injury. Here, we combined fast camera elastography, longitudinal fluorescence assays, and computer vision techniques to track the fates of thousands of individual cells. Our results show that impact induces mechanically dependent mitochondrial depolarization within a few minutes after injury. Electron microscopy revealed that impact causes rapid structural changes in mitochondria that are related to reduced mitochondrial function, namely, fission and loss of cristae structure. We found that SS-peptide treatment prior to impact protects the mitochondrial structure and preserves mitochondrial function at levels comparable with that of unimpacted control samples. Overall, this study reveals the vital role of mitochondria in mediating cartilage's peracute (within minutes) response to traumatic injury and demonstrates mitoprotection as a promising therapeutic strategy for injury-induced cartilage damage.
Collapse
Affiliation(s)
- Lena R. Bartell
- School of Applied & Engineering Physics, Cornell University, Ithaca, NY, United States of America
| | - Lisa A. Fortier
- Department of Clinical Sciences, Cornell University, Ithaca, NY, United States of America
| | - Lawrence J. Bonassar
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States of America
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States of America
| | - Hazel H. Szeto
- Burke Medical Research Institute, White Plains, NY, United States of America
| | - Itai Cohen
- Department of Physics, Cornell University, Ithaca, NY, United States of America
| | - Michelle L. Delco
- Department of Clinical Sciences, Cornell University, Ithaca, NY, United States of America
| |
Collapse
|
30
|
Middendorf JM, Dugopolski C, Kennedy S, Blahut E, Cohen I, Bonassar LJ. Heterogeneous matrix deposition in human tissue engineered cartilage changes the local shear modulus and resistance to local construct buckling. J Biomech 2020; 105:109760. [PMID: 32276782 DOI: 10.1016/j.jbiomech.2020.109760] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/05/2020] [Accepted: 03/20/2020] [Indexed: 12/11/2022]
Abstract
Human tissue engineered cartilage is a promising solution for focal cartilage defects, but these constructs do not have the same local mechanical properties as native tissue. Most clinically relevant engineered cartilage constructs seed human chondrocytes onto a collagen scaffold, which buckles at low loads and strains. This buckling creates local regions of high strain that could cause cell death and damage the engineered tissue. Since human tissue engineered cartilage is commonly grown in-vivo prior to implantation, new matrix deposition could improve the local implant mechanics and prevent local tissue buckling. However, the relationship between local biochemical composition and the local mechanics or local buckling probability has never been quantified. Therefore, this study correlated the local biochemical composition of human tissue engineered cartilage constructs using Fourier transform infrared spectroscopy (FTIR) with the local shear modulus and local buckling probability. The local shear modulus and local buckling probability were obtained using a confocal elastography technique. The local shear modulus increased with increases in local aggrecan content in the interior region (inside the scaffold). A minimum amount of aggrecan was required to prevent local construct buckling at physiologic strains. Since the original scaffold was primarily composed of collagen, increases in collagen content due to new matrix deposition was minimal and had little effect on the mechanical properties. Thus, we concluded that aggrecan deposition inside the scaffold pores is the most effective way to improve the mechanical function and prevent local tissue damage in human tissue engineered cartilage constructs.
Collapse
Affiliation(s)
- Jill M Middendorf
- Sibley School of Mechanical Engineering, Cornell University, Ithaca, NY, USA
| | | | | | | | - Itai Cohen
- Physics, Cornell University, Ithaca, NY, USA
| | - Lawrence J Bonassar
- Sibley School of Mechanical Engineering, Cornell University, Ithaca, NY, USA; Meinig School of Biomedical Engineering Cornell University, Ithaca, NY, USA.
| |
Collapse
|
31
|
Marshall L, Tarakanova A, Szarek P, Pierce DM. Cartilage and collagen mechanics under large-strain shear within in vivo and at supraphysiogical temperatures. J Mech Behav Biomed Mater 2020; 103:103595. [PMID: 32090923 DOI: 10.1016/j.jmbbm.2019.103595] [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: 06/19/2019] [Revised: 09/13/2019] [Accepted: 12/10/2019] [Indexed: 11/28/2022]
Abstract
Human joints, particularly those of extremities, experience a significant range of temperatures in vivo. Joint temperature influences the mechanics of both joint and cartilage, and the mechanics of cartilage can affect the temperature of both joint and cartilage. Thermal treatments and tissue repairs, such as thermal chondroplasty, and ex vivo tissue engineering may also expose cartilage to supraphysiological temperatures. Furthermore, although cartilage undergoes principally compressive loads in vivo, shear strain plays a significant role at larger compressive strains. Thus, we aimed to determine whether and how the bulk mechanical responses of cartilage undergoing large-strain shear change (1) within the range of temperatures relevant in vivo, and (2) both during and after supraphysiological thermal treatments. We completed large-strain shear tests (10 and 15%) at four thermal conditions: 24∘C and 40∘C to span the in vivo range, and 70∘C and 24∘C repeated after 70∘C to explore mechanics during and after potential treatments. We calculated the bulk mechanical responses (strain-energy dissipation densities, peak-to-peak shear stresses, and peak-effective shear moduli) as of function of temperature and used statistical methods to probe significant differences. To probe the mechanisms underlying differences we assessed specimens, principally the type II collagen, with imaging (second harmonic generation and transmission electron microscopies, and histology) and assessed the temperature-dependent mechanics of type II collagen molecules within cartilage using steered molecular dynamics simulations. Our results suggest that the bulk mechanical responses of cartilage depend significantly on temperature both within the in vivo range and at supraphysiological temperatures, showing significant reductions in all mechanical measures with increasing temperature. Using imaging and simulations we determined that one underlying mechanism explaining our results may be changes in the molecular deformation profiles of collagen molecules versus temperature, likely compounded at larger length scales. These new insights into the mechanics of cartilage and collagen may suggest new treatment targets for damaged or osteoarthritic cartilage.
Collapse
Affiliation(s)
- Lauren Marshall
- Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, Unit 3139, Storrs, CT, 06269, USA
| | - Anna Tarakanova
- Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, Unit 3139, Storrs, CT, 06269, USA; Department of Biomedical Engineering, University of Connecticut, 260 Glenbrook Road, Unit 3247, Storrs, CT, 06269, USA
| | - Phoebe Szarek
- Department of Biomedical Engineering, University of Connecticut, 260 Glenbrook Road, Unit 3247, Storrs, CT, 06269, USA
| | - David M Pierce
- Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, Unit 3139, Storrs, CT, 06269, USA; Department of Biomedical Engineering, University of Connecticut, 260 Glenbrook Road, Unit 3247, Storrs, CT, 06269, USA.
| |
Collapse
|
32
|
Maier F, Lewis CG, Pierce DM. Through-thickness patterns of shear strain evolve in early osteoarthritis. Osteoarthritis Cartilage 2019; 27:1382-1391. [PMID: 31121293 DOI: 10.1016/j.joca.2019.04.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 04/04/2019] [Accepted: 04/27/2019] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Given the structural changes associated with the progression of Osteoarthritis (OA), we hypothesized that patterns of through-thickness, large-strain shear evolve with early-stage OA. We therefore aimed to determine whether and how patterns of shear strains change during early-stage OA to 1) gain insight into the progression of OA by quantifying changes in local deformations; 2) gauge the potential of patterns in shear strain to serve as image-based biomarkers of early-stage OA; and 3) provide high-resolution, through-thickness data for proposing, fitting, and validating constitutive models for cartilage. DESIGN We completed displacement-driven, large-strain shear tests (5, 10, 15%) on 44 specimens of variably advanced osteoarthritic human articular cartilage as determined by both Osteoarthritis Research Society International (OARSI) grade and PLM-CO score. We recorded the through-thickness deformations with a stereo-camera system and processed these data using digital image correlation (DIC) to determine full-thickness patterns of strains and relative zonal recruitments, i.e., the average shear strain in a through-thickness zone weighted by its relative thickness and normalized by the applied strain. RESULTS We observed three general shapes for the curves of averaged through-thickness, Green-Lagrange shear strains during progression of OA. We also observed that during the progression of OA only the deep zone is recruited differently under shear in a statistically significant way. CONCLUSIONS We propose that changes in through-thickness patterns of shear strain could provide sensitive biomarkers for early clinical detection of OA. The relative zonal recruitment of the deep zone decreases with progressing OA (OARSI grade) and microstructural remodeling (PLM-CO score), which do not consistently affect recruitment of the superficial and middle zones.
Collapse
Affiliation(s)
- F Maier
- University of Connecticut, Department of Mechanical Engineering, Storrs, CT, USA
| | - C G Lewis
- Hartford Healthcare, Bone & Joint Institute, Hartford, CT, USA
| | - D M Pierce
- University of Connecticut, Department of Mechanical Engineering, Storrs, CT, USA; University of Connecticut, Department of Biomedical Engineering, Storrs, CT, USA.
| |
Collapse
|
33
|
Boys AJ, Kunitake JA, Henak CR, Cohen I, Estroff LA, Bonassar LJ. Understanding the Stiff-to-Compliant Transition of the Meniscal Attachments by Spatial Correlation of Composition, Structure, and Mechanics. ACS APPLIED MATERIALS & INTERFACES 2019; 11:26559-26570. [PMID: 31267742 PMCID: PMC6680087 DOI: 10.1021/acsami.9b03595] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Recently, the scientific community has shown considerable interest in engineering tissues with organized compositional and structural gradients to mimic hard-to-soft tissue interfaces. This effort is hindered by an incomplete understanding of the construction of native tissue interfaces. In this work, we combined Raman microscopy and confocal elastography to map compositional, structural, and mechanical features across the stiff-to-compliant interface of the attachments of the meniscus in the knee. This study provides new insight into the methods by which biology mediates multiple orders of magnitude changes in stiffness over tens of microns. We identified how the nano- to mesoscale architecture mediates complex microscale transitional regions across the interface: two regions defined by chemical composition, five distinguished by structural features, and three mechanically distinct regions. We identified three major components that lead to a robust interface between a soft tissue and bone: mobile collagen fiber units, a continuous interfacial region, and a local stiffness gradient. This tissue architecture allows for large displacements of collagen fibers in the attachments, enabling meniscal movement without localizing strains to the soft tissue-to-bone interface. The interplay of these regions reveals a method relying on hierarchical structuring across multiple length scales to minimize stress concentrators between highly dissimilar materials. These insights inspire new design strategies for synthetic soft tissue-to-bone attachments and biomimetic material interfaces.
Collapse
Affiliation(s)
- Alexander J. Boys
- Department of Materials Science & Engineering, Cornell University, Ithaca, NY 14853
| | | | - Corinne R. Henak
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853
| | - Itai Cohen
- Department of Physics, Cornell University, Ithaca, NY 14853
| | - Lara A. Estroff
- Department of Materials Science & Engineering, Cornell University, Ithaca, NY 14853
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853
| | - Lawrence J. Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853
- Sibley School of Mechanical Engineering, Cornell University, Ithaca, NY 14853
- Corresponding Author:
| |
Collapse
|
34
|
Arzash S, Shivers JL, Licup AJ, Sharma A, MacKintosh FC. Stress-stabilized subisostatic fiber networks in a ropelike limit. Phys Rev E 2019; 99:042412. [PMID: 31108669 DOI: 10.1103/physreve.99.042412] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Indexed: 01/20/2023]
Abstract
The mechanics of disordered fibrous networks such as those that make up the extracellular matrix are strongly dependent on the local connectivity or coordination number. For biopolymer networks this coordination number is typically between 3 and 4. Such networks are sub-isostatic and linearly unstable to deformation with only central force interactions, but exhibit a mechanical phase transition between floppy and rigid states under strain. The introduction of weak bending interactions stabilizes these networks and suppresses the critical signatures of this transition. We show that applying external stress can also stabilize subisostatic networks with only tensile central force interactions, i.e., a ropelike potential. Moreover, we find that the linear shear modulus shows a power-law scaling with the external normal stress, with a non-mean-field exponent. For networks with finite bending rigidity, we find that the critical stain shifts to lower values under prestress.
Collapse
Affiliation(s)
- Sadjad Arzash
- Department of Chemical & Biomolecular Engineering, Rice University, Houston, Texas 77005, USA.,Center for Theoretical Biological Physics, Rice University, Houston, Texas 77030, USA
| | - Jordan L Shivers
- Department of Chemical & Biomolecular Engineering, Rice University, Houston, Texas 77005, USA.,Center for Theoretical Biological Physics, Rice University, Houston, Texas 77030, USA
| | - Albert J Licup
- Department of Physics & Astronomy, Vrije Universiteit, Amsterdam, The Netherlands
| | - Abhinav Sharma
- Leibniz Institute of Polymer Research Dresden, Dresden, Germany
| | - Fred C MacKintosh
- Department of Chemical & Biomolecular Engineering, Rice University, Houston, Texas 77005, USA.,Center for Theoretical Biological Physics, Rice University, Houston, Texas 77030, USA.,Department of Physics & Astronomy, Vrije Universiteit, Amsterdam, The Netherlands.,Departments of Chemistry and Physics & Astronomy, Rice University, Houston, Texas 77005, USA
| |
Collapse
|
35
|
Merkel M, Baumgarten K, Tighe BP, Manning ML. A minimal-length approach unifies rigidity in underconstrained materials. Proc Natl Acad Sci U S A 2019; 116:6560-6568. [PMID: 30894489 PMCID: PMC6452732 DOI: 10.1073/pnas.1815436116] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We present an approach to understand geometric-incompatibility-induced rigidity in underconstrained materials, including subisostatic 2D spring networks and 2D and 3D vertex models for dense biological tissues. We show that in all these models a geometric criterion, represented by a minimal length [Formula: see text], determines the onset of prestresses and rigidity. This allows us to predict not only the correct scalings for the elastic material properties, but also the precise magnitudes for bulk modulus and shear modulus discontinuities at the rigidity transition as well as the magnitude of the Poynting effect. We also predict from first principles that the ratio of the excess shear modulus to the shear stress should be inversely proportional to the critical strain with a prefactor of 3. We propose that this factor of 3 is a general hallmark of geometrically induced rigidity in underconstrained materials and could be used to distinguish this effect from nonlinear mechanics of single components in experiments. Finally, our results may lay important foundations for ways to estimate [Formula: see text] from measurements of local geometric structure and thus help develop methods to characterize large-scale mechanical properties from imaging data.
Collapse
Affiliation(s)
- Matthias Merkel
- Department of Physics, Syracuse University, Syracuse, NY 13244;
- Centre de Physique Théorique (CPT), Turing Center for Living Systems, Aix Marseille Univ, Université de Toulon, CNRS, 13009 Marseille, France
| | - Karsten Baumgarten
- Process & Energy Laboratory, Delft University of Technology, 2628 CB Delft, The Netherlands
| | - Brian P Tighe
- Process & Energy Laboratory, Delft University of Technology, 2628 CB Delft, The Netherlands
| | - M Lisa Manning
- Department of Physics, Syracuse University, Syracuse, NY 13244
| |
Collapse
|
36
|
Gurmessa BJ, Bitten N, Nguyen DT, Saleh OA, Ross JL, Das M, Robertson-Anderson RM. Triggered disassembly and reassembly of actin networks induces rigidity phase transitions. SOFT MATTER 2019; 15:1335-1344. [PMID: 30543255 PMCID: PMC6486790 DOI: 10.1039/c8sm01912f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Non-equilibrium soft materials, such as networks of actin proteins, have been intensely investigated over the past decade due to their promise for designing smart materials and understanding cell mechanics. However, current methods are unable to measure the time-dependent mechanics of such systems or map mechanics to the corresponding dynamic macromolecular properties. Here, we present an experimental approach that combines time-resolved optical tweezers microrheology with diffusion-controlled microfluidics to measure the time-evolution of microscale mechanical properties of dynamic systems during triggered activity. We use these methods to measure the viscoelastic moduli of entangled and crosslinked actin networks during chemically-triggered depolymerization and repolymerization of actin filaments. During disassembly, we find that the moduli exhibit two distinct exponential decays, with experimental time constants of ∼169 min and ∼47 min. Conversely, during reassembly, measured moduli initially exhibit power-law increase with time, after which steady-state values are achieved. We develop toy mathematical models that couple the time-evolution of filament lengths with rigidity percolation theory to shed light onto the molecular mechanisms underlying the observed mechanical transitions. The models suggest that these two distinct behaviors both arise from phase transitions between a rigidly percolated network and a non-rigid regime. Our approach and collective results can inform the general principles underlying the mechanics of a large class of dynamic, non-equilibrium systems and materials of current interest.
Collapse
Affiliation(s)
- Bekele J Gurmessa
- Department of Physics and Biophysics, University of San Diego, San Diego, USA.
| | | | | | | | | | | | | |
Collapse
|
37
|
Lin W, Mashiah R, Seror J, Kadar A, Dolkart O, Pritsch T, Goldberg R, Klein J. Lipid-hyaluronan synergy strongly reduces intrasynovial tissue boundary friction. Acta Biomater 2019; 83:314-321. [PMID: 30423432 DOI: 10.1016/j.actbio.2018.11.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 11/08/2018] [Accepted: 11/09/2018] [Indexed: 12/21/2022]
Abstract
Hyaluronan (HA)-lipid layers on model (mica) surfaces massively reduce friction as the surfaces slide past each other, and have been proposed, together with lubricin, as the boundary layers accounting for the extreme lubrication of articular cartilage. The ability of such HA-lipid complexes to lubricate sliding biological tissues has not however been demonstrated. Here we show that HA-lipid layers on the surface of an intrasynovial tendon can strongly reduce the friction as the tendon slides within its sheath. We find a marked lubrication synergy when combining both HA and lipids at the tendon surface, relative to each component alone, further enhanced when the polysaccharide is functionalized to attach specifically to the tissue. Our results shed light on the lubricity of sliding biological tissues, and indicate a novel approach for lubricating surfaces such as tendons and, possibly, articular cartilage, important, respectively, for alleviating function impairment following tendon injury and repair, or in the context of osteoarthritis. STATEMENT OF SIGNIFICANCE: Lubrication breakdown between sliding biological tissues is responsible for pathologies ranging from dry eye syndrome to tendon-injury repair impairment and osteoarthritis. These are increasing with human longevity and impose a huge economic and societal burden. Here we show that synergy of hyaluronan and lipids, molecules which are central components of synovial joints and of the tendon/sheath system, can strongly reduce friction between sliding biological tissues (the extrasynovial tendon sliding in its sheath), relative to untreated tissue or to either component on its own. Our results point to the molecular origins of the very low friction in healthy tendons and synovial joints, as well as to novel treatments of lubrication breakdown in these organs.
Collapse
Affiliation(s)
- Weifeng Lin
- Materials and Interfaces Department, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Reut Mashiah
- Materials and Interfaces Department, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Jasmine Seror
- Materials and Interfaces Department, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Assaf Kadar
- The Orthopedic Division, Souraski Medical Center, Tel-Aviv, Israel
| | - Oleg Dolkart
- The Orthopedic Division, Souraski Medical Center, Tel-Aviv, Israel
| | - Tamir Pritsch
- The Orthopedic Division, Souraski Medical Center, Tel-Aviv, Israel
| | - Ronit Goldberg
- Materials and Interfaces Department, Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Jacob Klein
- Materials and Interfaces Department, Weizmann Institute of Science, Rehovot 76100, Israel.
| |
Collapse
|
38
|
DiDomenico CD, Bonassar LJ. The Effect of Charge and Mechanical Loading on Antibody Diffusion Through the Articular Surface of Cartilage. J Biomech Eng 2018; 141:2709745. [DOI: 10.1115/1.4041768] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Indexed: 01/08/2023]
Abstract
Molecular transport of osteoarthritis (OA) therapeutics within articular cartilage is influenced by many factors, such as solute charge, that have yet to be fully understood. This study characterizes how solute charge influences local diffusion and convective transport of antibodies within the heterogeneous cartilage matrix. Three fluorescently tagged solutes of varying isoelectric point (pI) (4.7–5.9) were tested in either cyclic or passive cartilage loading conditions. In each case, local diffusivities were calculated based on local fluorescence in the cartilage sample, as observed by confocal microscopy. In agreement with past research, local solute diffusivities within the heterogeneous cartilage matrix were highest around 200–275 μm from the articular surface, but 3–4 times lower at the articular surface and in the deeper zones of the tissue. Transport of all 150 kDa solutes was significantly increased by the application of mechanical loading at 1 Hz, but local transport enhancement was not significantly affected by changes in solute isoelectric point. More positively charged solutes (higher pI) had significantly higher local diffusivities 200–275 μm from the tissue surface, but no other differences were observed. This implies that there are certain regions of cartilage that are more sensitive to changes in solute charge than others, which could be useful for future development of OA therapeutics.
Collapse
Affiliation(s)
- Chris D. DiDomenico
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853
| | - Lawrence J. Bonassar
- Professor Meinig School of Biomedical Engineering, Sibley School of Mechanical and Aerospace Engineering, Cornell University, 149 Weill Hall, Ithaca, NY 14853
| |
Collapse
|
39
|
DiDomenico CD, Kaghazchi A, Bonassar LJ. Measurement of local diffusion and composition in degraded articular cartilage reveals the unique role of surface structure in controlling macromolecular transport. J Biomech 2018; 82:38-45. [PMID: 30385000 DOI: 10.1016/j.jbiomech.2018.10.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/05/2018] [Accepted: 10/17/2018] [Indexed: 12/23/2022]
Abstract
Developing effective therapeutics for osteoarthritis (OA) necessitates that such molecules can reach and target chondrocytes within articular cartilage. However, predicting how well very large therapeutic molecules diffuse through cartilage is often difficult, and the relationship between local transport mechanics for these molecules and tissue heterogeneities in the tissue is still unclear. In this study, a 150 kDa antibody diffused through the articular surface of healthy and enzymatically degraded cartilage, which enabled the calculation of local diffusion mechanics in tissue with large compositional variations. Local cartilage composition and structure was quantified with Fourier transform infrared (FTIR) spectroscopy and second harmonic generation (SHG) imaging techniques. Overall, both local concentrations of aggrecan and collagen were correlated to local diffusivities for both healthy and surface-degraded samples (0.3 > R2 < 0.9). However, samples that underwent surface degradation by collagenase exhibited stronger correlations (R2 > 0.75) compared to healthy samples (R2 < 0.46), suggesting that the highly aligned collagen at the surface of cartilage acts as a barrier to macromolecular transport.
Collapse
Affiliation(s)
- Chris D DiDomenico
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Aydin Kaghazchi
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Lawrence J Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States; Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States.
| |
Collapse
|
40
|
Orozco GA, Tanska P, Florea C, Grodzinsky AJ, Korhonen RK. A novel mechanobiological model can predict how physiologically relevant dynamic loading causes proteoglycan loss in mechanically injured articular cartilage. Sci Rep 2018; 8:15599. [PMID: 30348953 PMCID: PMC6197240 DOI: 10.1038/s41598-018-33759-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/02/2018] [Indexed: 12/13/2022] Open
Abstract
Cartilage provides low-friction properties and plays an essential role in diarthrodial joints. A hydrated ground substance composed mainly of proteoglycans (PGs) and a fibrillar collagen network are the main constituents of cartilage. Unfortunately, traumatic joint loading can destroy this complex structure and produce lesions in tissue, leading later to changes in tissue composition and, ultimately, to post-traumatic osteoarthritis (PTOA). Consequently, the fixed charge density (FCD) of PGs may decrease near the lesion. However, the underlying mechanisms leading to these tissue changes are unknown. Here, knee cartilage disks from bovine calves were injuriously compressed, followed by a physiologically relevant dynamic compression for twelve days. FCD content at different follow-up time points was assessed using digital densitometry. A novel cartilage degeneration model was developed by implementing deviatoric and maximum shear strain, as well as fluid velocity controlled algorithms to simulate the FCD loss as a function of time. Predicted loss of FCD was quite uniform around the cartilage lesions when the degeneration algorithm was driven by the fluid velocity, while the deviatoric and shear strain driven mechanisms exhibited slightly discontinuous FCD loss around cracks. Our degeneration algorithm predictions fitted well with the FCD content measured from the experiments. The developed model could subsequently be applied for prediction of FCD depletion around different cartilage lesions and for suggesting optimal rehabilitation protocols.
Collapse
Affiliation(s)
- Gustavo A Orozco
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
| | - Petri Tanska
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Cristina Florea
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
- Departments of Biological Engineering, Electrical Engineering and Computer Science and Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Alan J Grodzinsky
- Departments of Biological Engineering, Electrical Engineering and Computer Science and Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Rami K Korhonen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| |
Collapse
|
41
|
Kotelsky A, Woo CW, Delgadillo LF, Richards MS, Buckley MR. An Alternative Method to Characterize the Quasi-Static, Nonlinear Material Properties of Murine Articular Cartilage. J Biomech Eng 2018; 140:2657496. [PMID: 29049670 DOI: 10.1115/1.4038147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Indexed: 11/08/2022]
Abstract
With the onset and progression of osteoarthritis (OA), articular cartilage (AC) mechanical properties are altered. These alterations can serve as an objective measure of tissue degradation. Although the mouse is a common and useful animal model for studying OA, it is extremely challenging to measure the mechanical properties of murine AC due to its small size (thickness < 50 μm). In this study, we developed novel and direct approach to independently quantify two quasi-static mechanical properties of mouse AC: the load-dependent (nonlinear) solid matrix Young's modulus (E) and drained Poisson's ratio (ν). The technique involves confocal microscope-based multiaxial strain mapping of compressed, intact murine AC followed by inverse finite element analysis (iFEA) to determine E and ν. Importantly, this approach yields estimates of E and ν that are independent of the initial guesses used for iterative optimization. As a proof of concept, mechanical properties of AC on the medial femoral condyles of wild-type mice were obtained for both trypsin-treated and control specimens. After proteolytic tissue degradation induced through trypsin treatment, a dramatic decrease in E was observed (compared to controls) at each of the three tested loading conditions. A significant decrease in ν due to trypsin digestion was also detected. These data indicate that the method developed in this study may serve as a valuable tool for comparative studies evaluating factors involved in OA pathogenesis using experimentally induced mouse OA models.
Collapse
Affiliation(s)
- Alexander Kotelsky
- Department of Biomedical Engineering, University of Rochester, 207 Goergen Hall, Box 270168, Rochester, NY 14627 e-mail:
| | - Chandler W Woo
- Department of Biomedical Engineering, University of Rochester, 207 Goergen Hall, Box 270168, Rochester, NY 14627 e-mail:
| | - Luis F Delgadillo
- Department of Biomedical Engineering, University of Rochester, 207 Goergen Hall, Box 270168, Rochester, NY 14627 e-mail:
| | - Michael S Richards
- Department of Surgery, School of Medicine and Dentistry, University of Rochester Medical Center, 601 Elmwood Avenue, Rm 2.4153, Rochester, NY 14627 e-mail:
| | - Mark R Buckley
- Department of Biomedical Engineering, University of Rochester, 207 Goergen Hall, Box 270168, Rochester, NY 14627 e-mail:
| |
Collapse
|
42
|
How changes in interconnectivity affect the bulk properties of articular cartilage: a fibre network study. Biomech Model Mechanobiol 2018; 17:1297-1315. [PMID: 29777321 DOI: 10.1007/s10237-018-1027-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 05/03/2018] [Indexed: 10/16/2022]
Abstract
The remarkable compressive strength of articular cartilage arises from the mechanical interactions between the tension-resisting collagen fibrils and swelling proteoglycan proteins within the tissue. These interactions are facilitated by a significant level of interconnectivity between neighbouring collagen fibrils within the extracellular matrix. A reduction in interconnectivity is suspected to occur during the early stages of osteoarthritic degeneration. However, the relative contribution of these interconnections towards the bulk mechanical properties of articular cartilage has remained an open question. In this study, we present a simple 2D fibre network model which explicitly represents the microstructure of articular cartilage as collection of discrete nodes and linear springs. The transverse stiffness and swelling properties of this fibre network are studied, and a semi-analytic relationship which relates these two macroscopic properties via microscopic interconnectivity is derived. By comparing this derived expression to previously published experimental data, we show that although a reduction in network interconnectivity accounts for some of the observed changes in the mechanical properties of articular cartilage as degeneration occurs, a decrease in matrix interconnectivity alone do not provide a full account of this process.
Collapse
|
43
|
Salinas EY, Hu JC, Athanasiou K. A Guide for Using Mechanical Stimulation to Enhance Tissue-Engineered Articular Cartilage Properties. TISSUE ENGINEERING PART B-REVIEWS 2018; 24:345-358. [PMID: 29562835 DOI: 10.1089/ten.teb.2018.0006] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The use of tissue-engineered articular cartilage (TEAC) constructs has the potential to become a powerful treatment option for cartilage lesions resulting from trauma or early stages of pathology. Although fundamental tissue-engineering strategies based on the use of scaffolds, cells, and signals have been developed, techniques that lead to biomimetic AC constructs that can be translated to in vivo use are yet to be fully confirmed. Mechanical stimulation during tissue culture can be an effective strategy to enhance the mechanical, structural, and cellular properties of tissue-engineered constructs toward mimicking those of native AC. This review focuses on the use of mechanical stimulation to attain and enhance the properties of AC constructs needed to translate these implants to the clinic. In vivo, mechanical loading at maximal and supramaximal physiological levels has been shown to be detrimental to AC through the development of degenerative changes. In contrast, multiple studies have revealed that during culture, mechanical stimulation within narrow ranges of magnitude and duration can produce anisotropic, mechanically robust AC constructs with high cellular viability. Significant progress has been made in evaluating a variety of mechanical stimulation techniques on TEAC, either alone or in combination with other stimuli. These advancements include determining and optimizing efficacious loading parameters (e.g., duration and frequency) to yield improvements in construct design criteria, such as collagen II content, compressive stiffness, cell viability, and fiber organization. With the advancement of mechanical stimulation as a potent strategy in AC tissue engineering, a compendium detailing the results achievable by various stimulus regimens would be of great use for researchers in academia and industry. The objective is to list the qualitative and quantitative effects that can be attained when direct compression, hydrostatic pressure, shear, and tensile loading are used to tissue-engineer AC. Our goal is to provide a practical guide to their use and optimization of loading parameters. For each loading condition, we will also present and discuss benefits and limitations of bioreactor configurations that have been used. The intent is for this review to serve as a reference for including mechanical stimulation strategies as part of AC construct culture regimens.
Collapse
Affiliation(s)
- Evelia Y Salinas
- Biomedical Engineering Department, University of California , Irvine, California
| | - Jerry C Hu
- Biomedical Engineering Department, University of California , Irvine, California
| | - Kyriacos Athanasiou
- Biomedical Engineering Department, University of California , Irvine, California
| |
Collapse
|
44
|
Local and global measurements show that damage initiation in articular cartilage is inhibited by the surface layer and has significant rate dependence. J Biomech 2018. [PMID: 29526459 DOI: 10.1016/j.jbiomech.2018.02.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cracks in articular cartilage are a common sign of joint damage, but failure properties of cartilage are poorly understood, especially for damage initiation. Cartilage failure may be further complicated by rate-dependent and depth-dependent properties, including the compliant surface layer. Existing blunt impact methods do not resolve local cartilage inhomogeneities and traditional fracture mechanics tests induce crack blunting and may violate underlying assumptions of linear elasticity. To address this knowledge gap, we developed and applied a method to indent cartilage explants with a sharp blade and initiate damage across a range of loading rates (strain rates 0.5%/s-500%/s), while recording local sample deformation and strain energy fields using confocal elastography. To investigate the importance of cartilage's compliant surface, we repeated the experiment for samples with the surface removed. Bulk data suggest a critical force at which the tissue cuts, but local strains reveals that the deformation the sample can sustain before reaching this force is significantly higher in the surface layer. Bulk and local results also showed significant rate dependence, such that samples were easier to cut at faster speeds. This result highlights the importance of rate for understanding cracks in cartilage and parallels recent studies of rate-dependent failure in hydrogels. Notably, local sample deformation fields were well fit by classical Hookean elasticity. Overall, this study illustrates how local and global measurements surrounding the initiation of damage in articular cartilage can be combined to reveal the importance of cartilage's zonal structure in protecting against failure across physiologically relevant loading rates.
Collapse
|
45
|
The influences of walking, running and stair activity on knee articular cartilage: Quantitative MRI using T1 rho and T2 mapping. PLoS One 2017; 12:e0187008. [PMID: 29136015 PMCID: PMC5685565 DOI: 10.1371/journal.pone.0187008] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 10/11/2017] [Indexed: 01/16/2023] Open
Abstract
OBJECTIVE To explore the different influences of walking, running and stair activity on knee articular cartilage with T1 rho and T2 mapping sequences. MATERIALS AND METHODS MRI (3.0-T) scans of the right knee were performed in twenty-three young healthy adults immediately after 30 minutes of rest, walking, running and stair activity respectively. Articular cartilage was quantitatively assessed based on T1 rho and T2 relaxation times. Analysis of variance for random block design data, bonferroni test and paired samples t tests were performed to estimate the different influences of physiological activities on articular cartilage. RESULTS T1 rho and T2 values had reductions after physiological activities in all regions of articular cartilage. T1 rho and T2 values were decreased more after running than walking. T1 rho and T2 values were decreased more after stair activity than running, except for femoral cartilage. The superficial layer of patella cartilage had higher reduction rates than the deep layer. The T1 rho and T2 values of articular cartilage were reduced in the following order: patellofemoral cartilage> medial tibiofemoral cartilage> lateral tibiofemoral cartilage. Patellofemoral cartilage experienced reductions in the following order: lateral part> middle part> medial part. Tibiofemoral cartilage had reductions in the following order: posterior part> middle part> anterior part. CONCLUSIONS T1 rho and T2 mapping sequences can quantitatively reflect the different influences of physiological activities on knee articular cartilage. Fluid shifts, collagen fiber deformation, spatial heterogeneity, inherent differences in material properties and tissue stiffness have close relationship with cartilage loading characteristics.
Collapse
|
46
|
Middendorf JM, Shortkroff S, Dugopolski C, Kennedy S, Siemiatkoski J, Bartell LR, Cohen I, Bonassar LJ. In vitro culture increases mechanical stability of human tissue engineered cartilage constructs by prevention of microscale scaffold buckling. J Biomech 2017; 64:77-84. [DOI: 10.1016/j.jbiomech.2017.09.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/29/2017] [Accepted: 09/04/2017] [Indexed: 12/18/2022]
|
47
|
Abstract
The major synovial joints such as hips and knees are uniquely efficient tribological systems, able to articulate over a wide range of shear rates with a friction coefficient between the sliding cartilage surfaces as low as 0.001 up to pressures of more than 100 atm. No human-made material can match this. The means by which such surfaces maintain their very low friction has been intensively studied for decades and has been attributed to fluid-film and boundary lubrication. Here, we focus especially on the latter: the reduction of friction by molecular layers at the sliding cartilage surfaces. In particular, we discuss such lubrication in the light of very recent advances in our understanding of boundary effects in aqueous media based on the paradigms of hydration lubrication and of the synergism between different molecular components of the synovial joints (namely hyaluronan, lubricin, and phospholipids) in enabling this lubrication.
Collapse
Affiliation(s)
- Sabrina Jahn
- Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Jasmine Seror
- Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Jacob Klein
- Weizmann Institute of Science, Rehovot 76100, Israel;
| |
Collapse
|
48
|
Groen WM, Diloksumpan P, van Weeren PR, Levato R, Malda J. From intricate to integrated: Biofabrication of articulating joints. J Orthop Res 2017; 35:2089-2097. [PMID: 28621834 PMCID: PMC5655743 DOI: 10.1002/jor.23602] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/28/2017] [Indexed: 02/04/2023]
Abstract
Articulating joints owe their function to the specialized architecture and the complex interplay between multiple tissues including cartilage, bone and synovium. Especially the cartilage component has limited self-healing capacity and damage often leads to the onset of osteoarthritis, eventually resulting in failure of the joint as an organ. Although in its infancy, biofabrication has emerged as a promising technology to reproduce the intricate organization of the joint, thus enabling the introduction of novel surgical treatments, regenerative therapies, and new sets of tools to enhance our understanding of joint physiology and pathology. Herein, we address the current challenges to recapitulate the complexity of articulating joints and how biofabrication could overcome them. The combination of multiple materials, biological cues and cells in a layer-by-layer fashion, can assist in reproducing both the zonal organization of cartilage and the gradual transition from resilient cartilage toward the subchondral bone in biofabricated osteochondral grafts. In this way, optimal integration of engineered constructs with the natural surrounding tissues can be obtained. Mechanical characteristics, including the smoothness and low friction that are hallmarks of the articular surface, can be tuned with multi-head or hybrid printers by controlling the spatial patterning of printed structures. Moreover, biofabrication can use digital medical images as blueprints for printing patient-specific implants. Finally, the current rapid advances in biofabrication hold significant potential for developing joint-on-a-chip models for personalized medicine and drug testing or even for the creation of implants that may be used to treat larger parts of the articulating joint. © 2017 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 35:2089-2097, 2017.
Collapse
Affiliation(s)
| | - Paweena Diloksumpan
- Faculty of Veterinary MedicineDepartment of Equine SciencesUtrechtThe Netherlands
| | - Paul René van Weeren
- Faculty of Veterinary MedicineDepartment of Equine SciencesUtrechtThe Netherlands
| | - Riccardo Levato
- Department of OrthopaedicsUniversity Medical Centre UtrechtPO Box 85500, 3508 GAUtrechtThe Netherlands
| | - Jos Malda
- Department of OrthopaedicsUniversity Medical Centre UtrechtPO Box 85500, 3508 GAUtrechtThe Netherlands
- Faculty of Veterinary MedicineDepartment of Equine SciencesUtrechtThe Netherlands
| |
Collapse
|
49
|
Mouser VHM, Levato R, Bonassar LJ, D’Lima DD, Grande DA, Klein TJ, Saris DBF, Zenobi-Wong M, Gawlitta D, Malda J. Three-Dimensional Bioprinting and Its Potential in the Field of Articular Cartilage Regeneration. Cartilage 2017; 8:327-340. [PMID: 28934880 PMCID: PMC5613889 DOI: 10.1177/1947603516665445] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Three-dimensional (3D) bioprinting techniques can be used for the fabrication of personalized, regenerative constructs for tissue repair. The current article provides insight into the potential and opportunities of 3D bioprinting for the fabrication of cartilage regenerative constructs. Although 3D printing is already used in the orthopedic clinic, the shift toward 3D bioprinting has not yet occurred. We believe that this shift will provide an important step forward in the field of cartilage regeneration. Three-dimensional bioprinting techniques allow incorporation of cells and biological cues during the manufacturing process, to generate biologically active implants. The outer shape of the construct can be personalized based on clinical images of the patient's defect. Additionally, by printing with multiple bio-inks, osteochondral or zonally organized constructs can be generated. Relevant mechanical properties can be obtained by hybrid printing with thermoplastic polymers and hydrogels, as well as by the incorporation of electrospun meshes in hydrogels. Finally, bioprinting techniques contribute to the automation of the implant production process, reducing the infection risk. To prompt the shift from nonliving implants toward living 3D bioprinted cartilage constructs in the clinic, some challenges need to be addressed. The bio-inks and required cartilage construct architecture need to be further optimized. The bio-ink and printing process need to meet the sterility requirements for implantation. Finally, standards are essential to ensure a reproducible quality of the 3D printed constructs. Once these challenges are addressed, 3D bioprinted living articular cartilage implants may find their way into daily clinical practice.
Collapse
Affiliation(s)
- Vivian H. M. Mouser
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Riccardo Levato
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Darryl D. D’Lima
- Shiley Center for Orthopaedic Research, Scripps Health, La Jolla, CA, USA
| | - Daniel A. Grande
- Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Northwell Health System, Manhasset, NY, USA
| | - Travis J. Klein
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Daniel B. F. Saris
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Debby Gawlitta
- Department of Oral and Maxillofacial Surgery & Special Dental Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jos Malda
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| |
Collapse
|
50
|
DiDomenico CD, Goodearl A, Yarilina A, Sun V, Mitra S, Sterman AS, Bonassar LJ. The Effect of Antibody Size and Mechanical Loading on Solute Diffusion Through the Articular Surface of Cartilage. J Biomech Eng 2017; 139:2643262. [DOI: 10.1115/1.4037202] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Indexed: 11/08/2022]
Abstract
Because of the heterogeneous nature of articular cartilage tissue, penetration of potential therapeutic molecules for osteoarthritis (OA) through the articular surface (AS) is complex, with many factors that affect transport of these solutes within the tissue. Therefore, the goal of this study is to investigate how the size of antibody (Ab) variants, as well as application of cyclic mechanical loading, affects solute transport within healthy cartilage tissue. Penetration of fluorescently tagged solutes was quantified using confocal microscopy. For all the solutes tested, fluorescence curves were obtained through the articular surface. On average, diffusivities for the solutes of sizes 200 kDa, 150 kDa, 50 kDa, and 25 kDa were 3.3, 3.4, 5.1, and 6.0 μm2/s from 0 to 100 μm from the articular surface. Diffusivities went up to a maximum of 16.5, 18.5, 20.5, and 23.4 μm2/s for the 200 kDa, 150 kDa, 50 kDa, and 25 kDa molecules, respectively, from 225 to 325 μm from the surface. Overall, the effect of loading was very significant, with maximal transport enhancement for each solute ranging from 2.2 to 3.4-fold near 275 μm. Ultimately, solutes of this size do not diffuse uniformly nor are convected uniformly, through the depth of the cartilage tissue. This research potentially holds great clinical significance to discover ways of further optimizing transport into cartilage and leads to effective antibody-based treatments for OA.
Collapse
Affiliation(s)
- Chris D. DiDomenico
- Meinig School of Biomedical Engineering,Cornell University,145 Weill Hall,Ithaca, NY 14853e-mail:
| | | | - Anna Yarilina
- AbbVie Inc.,100 Research Drive,Worcester, MA 01605e-mail:
| | - Victor Sun
- AbbVie Inc.,100 Research Drive,Worcester, MA 01605e-mail:
| | - Soumya Mitra
- AbbVie Inc.,100 Research Drive,Worcester, MA 01605e-mail:
| | | | | |
Collapse
|