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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.
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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.
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2
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Kim B, Bouklas N, Cohen I, Bonassar LJ. Instabilities induced by mechanical loading determine the viability of chondrocytes grown on porous scaffolds. J Biomech 2023; 152:111591. [PMID: 37088031 DOI: 10.1016/j.jbiomech.2023.111591] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 02/08/2023] [Accepted: 04/11/2023] [Indexed: 04/25/2023]
Abstract
Tissue-engineered cartilage constructs have shown promise to treat focal cartilage defects in multiple clinical studies. Notably, products in clinical use or in late-stage clinical trials often utilize porous collagen scaffolds to provide mechanical support and attachment sites for chondrocytes. Under loading, both the local mechanical responses of collagen scaffolds and the corresponding cellular outcomes are poorly understood, despite their wide use. As such, the architecture of collagen scaffolds varies significantly among tissue-engineered cartilage products, but the effects of such architectures on construct mechanics and cell viability are not well understood. This study investigated the effects of local mechanical responses of collagen scaffolds on chondrocyte viability in tissue-engineered cartilage constructs. We utilized fast confocal microscopy combined with a strain mapping technique to analyze the architecture-dependent instabilities under quasi-static loading and subsequent chondrocyte death in honeycomb and sponge scaffolds. More specifically, we compared the isotropic and the orthotropic planes for each type of collagen scaffold. Under compression, both planes exhibited elastic, buckled, and densified deformation modes. In both loading directions, cell death was minimal in regions that experienced elastic deformation mode and a trend of increase in buckled mode. More interestingly, we saw a significant increase in cell death in densified mode. Overall, this study suggests that local instabilities are directly correlated to chondrocyte death in tissue-engineered cartilage constructs, highlighting the importance of understanding the architecture-dependent local mechanical responses under loading.
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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.
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3
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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.
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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.
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4
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Statham P, Jones E, Jennings LM, Fermor HL. Reproducing the Biomechanical Environment of the Chondrocyte for Cartilage Tissue Engineering. TISSUE ENGINEERING PART B-REVIEWS 2021; 28:405-420. [PMID: 33726527 DOI: 10.1089/ten.teb.2020.0373] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
It is well known that the biomechanical and tribological performance of articular cartilage is inextricably linked to its extracellular matrix (ECM) structure and zonal heterogeneity. Furthermore, it is understood that the presence of native ECM components, such as collagen II and aggrecan, promote healthy homeostasis in the resident chondrocytes. What is less frequently discussed is how chondrocyte metabolism is related to the extracellular mechanical environment, at both the macro and microscale. The chondrocyte is in immediate contact with the pericellular matrix of the chondron, which acts as a mechanocoupler, transmitting external applied loads from the ECM to the chondrocyte. Therefore, components of the pericellular matrix also play essential roles in chondrocyte mechanotransduction and metabolism. Recreating the biomechanical environment through tuning material properties of a scaffold and/or the use of external cyclic loading can induce biosynthetic responses in chondrocytes. Decellularized scaffolds, which retain the native tissue macro- and microstructure also represent an effective means of recapitulating such an environment. The use of such techniques in tissue engineering applications can ensure the regeneration of skeletally mature articular cartilage with appropriate biomechanical and tribological properties to restore joint function. Despite the pivotal role in graft maturation and performance, biomechanical and tribological properties of such interventions is often underrepresented. This review outlines the role of biomechanics in relation to native cartilage performance and chondrocyte metabolism, and how application of this theory can enhance the future development and successful translation of biomechanically relevant tissue engineering interventions. Impact statement Physiological cartilage function is a key criterion in the success of a cartilage tissue engineering solution. The in situ performance is dependent on the initial scaffold design as well as extracellular matrix deposition by endogenous or exogenous cells. Both biological and biomechanical stimuli serve as key regulators of cartilage homeostasis and maturation of the resulting tissue-engineered graft. An improved understanding of the influence of biomechanics on cellular function and consideration of the final biomechanical and tribological performance will help in the successful development and translation of tissue-engineered grafts to restore natural joint function postcartilage trauma or osteoarthritic degeneration, delaying the requirement for prosthetic intervention.
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Affiliation(s)
- Patrick Statham
- Institute of Medical and Biological Engineering, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Elena Jones
- Leeds Institute of Rheumatic and Musculoskeletal Disease, University of Leeds, Leeds, United Kingdom
| | - Louise M Jennings
- Institute of Medical and Biological Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, United Kingdom
| | - Hazel L Fermor
- Institute of Medical and Biological Engineering, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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5
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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.
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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.
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6
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Middendorf JM, Diamantides N, Shortkroff S, Dugopolski C, Kennedy S, Cohen I, Bonassar LJ. Multiscale mechanics of tissue-engineered cartilage grown from human chondrocytes and human-induced pluripotent stem cells. J Orthop Res 2020; 38:1965-1973. [PMID: 32125023 DOI: 10.1002/jor.24643] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 02/17/2020] [Accepted: 02/29/2020] [Indexed: 02/04/2023]
Abstract
Tissue-engineered cartilage has shown promising results in the repair of focal cartilage defects. However, current clinical techniques rely on an extra surgical procedure to biopsy healthy cartilage to obtain human chondrocytes. Alternatively, induced pluripotent stem cells (iPSCs) have the ability to differentiate into chondrocytes and produce cartilaginous matrix without the need to biopsy healthy cartilage. However, the mechanical properties of tissue-engineered cartilage with iPSCs are unknown and might be critical to long-term tissue function and health. This study used confined compression, cartilage on glass tribology, and shear testing on a confocal microscope to assess the macroscale and microscale mechanical properties of two constructs seeded with either chondrocyte-derived iPSCs (Ch-iPSCs) or native human chondrocytes. Macroscale properties of Ch-iPSC constructs provided similar or better mechanical properties than chondrocyte constructs. Under compression, Ch-iPSC constructs had an aggregate modulus that was two times larger than chondrocyte constructs and was closer to native tissue. No differences in the shear modulus and friction coefficients were observed between Ch-iPSC and chondrocyte constructs. On the microscale, Ch-iPSC and chondrocyte constructs had different depth-dependent mechanical properties, neither of which matches native tissue. These observed depth-dependent differences may be important to the function of the implant. Overall, this comparison of multiple mechanical properties of Ch-iPSC and chondrocyte constructs shows that using Ch-iPSCs can produce equivalent or better global mechanical properties to chondrocytes. Therefore, iPSC-seeded cartilage constructs could be a promising solution to repair focal cartilage defects. The chondrocyte constructs used in this study have been implanted into humans for clinical trials. Therefore, Ch-iPSC constructs could also be used clinically in place of the current chondrocyte construct.
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Affiliation(s)
- Jill M Middendorf
- Sibley School of Mechanical Engineering, Cornell University, Ithaca, New York
| | - Nicole Diamantides
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York
| | | | | | | | - Itai Cohen
- Department of Applied Engineering and Physics, Cornell University, Ithaca, New York.,Department of Physics, Cornell University, Ithaca, New York
| | - Lawrence J Bonassar
- Sibley School of Mechanical Engineering, Cornell University, Ithaca, New York.,Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York
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7
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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.
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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.
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8
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Irwin RM, Bonassar LJ, Cohen I, Matuska AM, Commins J, Cole B, Fortier LA. The clot thickens: Autologous and allogeneic fibrin sealants are mechanically equivalent in an ex vivo model of cartilage repair. PLoS One 2019; 14:e0224756. [PMID: 31703078 PMCID: PMC6839864 DOI: 10.1371/journal.pone.0224756] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 10/21/2019] [Indexed: 02/07/2023] Open
Abstract
Fibrin sealants are commonly used in cartilage repair surgeries to adhere cells or grafts into a cartilage defect. Both autologous and commercial allogeneic fibrin sealants are used in cartilage repair surgeries, yet there are no studies characterizing and comparing the mechanical properties of fibrin sealants from all-autologous sources. The objectives of this study were to investigate (i) the effect of fibrinogen and thrombin sources on failure mechanics of sealants, and (ii) how sealants affect the adhesion of particulated cartilage graft material (BioCartilage) to surrounding cartilage under physiological loading. Allogeneic thrombin and fibrinogen were purchased (Tisseel), and autologous sources were prepared from platelet-rich plasma (PRP) and platelet-poor plasma (PPP) generated from human blood. To compare failure characteristics, sealants were sandwiched between cartilage explants and pulled to failure. The effect of sealant on the adhesion of BioCartilage graft to cartilage was determined by quantifying microscale strains at the graft-cartilage interface using an in vitro cartilage defect model subjected to shear loading at physiological strains well below failure thresholds. Fibrinogen sources were not equivalent; PRP fibrinogen created sealants that were more brittle, failed at lower strains, and resulted in sustained higher strains through the graft-cartilage interface depth compared to PPP and allogeneic sources. PPP clotted slower compared to PRP, suggesting PPP may percolate deeper into the repair to provide more stability through the tissue depth. There was no difference in bulk failure properties or microscale strains at the graft-cartilage interface between the purely autologous sealant (autologous thrombin + PPP fibrinogen) and the commercial allogeneic sealant. Clinical Significance: All-autologous fibrin sealants fabricated with PPP have comparable adhesion strength as commercial allogeneic sealants in vitro, whereas PRP creates an inferior all-autologous sealant that sustains higher strains through the graft-cartilage interface depth.
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Affiliation(s)
- Rebecca M. Irwin
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, United States of America
| | - Lawrence J. Bonassar
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, United States of America
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, United States of America
| | - Itai Cohen
- Department of Physics, Cornell University, Ithaca, New York, United States of America
| | - Andrea M. Matuska
- Research and Development, Arthrex Inc., Naples, Florida, United States of America
| | - Jacqueline Commins
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, United States of America
| | - Brian Cole
- Midwest Orthopedics at Rush, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Lisa A. Fortier
- College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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9
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Yang D, Xiao J, Wang B, Li L, Kong X, Liao J. The immune reaction and degradation fate of scaffold in cartilage/bone tissue engineering. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 104:109927. [DOI: 10.1016/j.msec.2019.109927] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/17/2019] [Accepted: 06/26/2019] [Indexed: 01/05/2023]
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10
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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.
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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.
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11
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Hudnut AW, Lash-Rosenberg L, Xin A, Doblado JAL, Zurita-Lopez C, Wang Q, Armani AM. Role of extracellular matrix in the biomechanical behavior of pancreatic tissue. ACS Biomater Sci Eng 2018; 4:1916-1923. [PMID: 31828218 DOI: 10.1021/acsbiomaterials.8b00349] [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] [Indexed: 01/25/2023]
Abstract
Correlating the biomechanical properties of tissue with its function is an emerging area of research with potential impact in diagnostics, therapeutics, and prognostics. A critical stepping-stone in developing structure-function models is creating methods that can correlate the tissue structure with its mechanical behavior. As an initial step in addressing this challenge, we have characterized the mechanical behavior of unprocessed pancreatic tissue using optical fiber polarimetric elastography. To correlate the observed behavior to physiologically relevant structural features, a series of architectures are designed and fabricated using 3D printing. The mechanical response of the 3D printed elastomeric structures is analyzed using compressive testing and modeled using finite element analysis. The biomechanical behavior and buckling point of the 3D printed structures is used to create a calibration curve to understand the measured response of the resected pancreatic tissue. Based on the modeling and biomimetic results, the biomechanical behavior of pancreatic tissue is likely due to the collagen IV network.
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Affiliation(s)
- Alexa W Hudnut
- Department of Biomedical Engineering, University of Southern California, 1002 Childs Way, MCB 495, Los Angeles, CA, 90089
| | - Lian Lash-Rosenberg
- Department of Mechanical Engineering, University of Southern California, 1002 Childs Way, MCB 495, Los Angeles, CA, 90089
| | - An Xin
- Department of Civil Engineering, University of Southern California, 920 Downey Way, BHE 222, Los Angeles, CA, 90089
| | - Juan A Leal Doblado
- Department of Chemistry and Biochemistry, California State University Los Angeles, 617 Charles E. Young Drive E, Room 251, Los Angeles, CA, 90095
| | - Cecilia Zurita-Lopez
- Department of Chemistry and Biochemistry, California State University Los Angeles, 617 Charles E. Young Drive E, Room 251, Los Angeles, CA, 90095
| | - Qiming Wang
- Department of Civil Engineering, University of Southern California, 920 Downey Way, BHE 222, Los Angeles, CA, 90089
| | - Andrea M Armani
- Department of Biomedical Engineering, University of Southern California, 1002 Childs Way, MCB 495, Los Angeles, CA, 90089.,Mork Family Department of Chemical Engineering and Materials Science, Mork Family University of Southern California, 1002 Childs Way, MCB 495, Los Angeles, CA, 90089
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