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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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Slyker L, Bonassar LJ. Alginate Conjugation Increases Toughness in Auricular Chondrocyte Seeded Collagen Hydrogels. Bioengineering (Basel) 2023; 10:1037. [PMID: 37760139 PMCID: PMC10526064 DOI: 10.3390/bioengineering10091037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/31/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023] Open
Abstract
Current auricular cartilage replacements for pediatric microtia fail to address the need for long-term integration and neocartilage formation. While collagen hydrogels have been successful in fostering neocartilage formation, the toughness and extensibility of these materials do not match that of native tissue. This study used the N-terminal functionalization of collagen with alginate oligomers to improve toughness and extensibility through metal-ion complexation. Alginate conjugation was confirmed via FTIR spectroscopy. The retention of native collagen fibrillar structure, thermal gelation, and helical conformation in functionalized gels was confirmed via scanning electron microscopy, oscillatory shear rheology, and circular dichroism spectroscopy, respectively. Alginate-calcium complexation enabled a more than two-fold increase in modulus and work density in functionalized collagen with the addition of 50 mM CaCl2, whereas unmodified collagen decreased in both modulus and work density with increasing calcium concentration. Additionally, the extensibility of alginate-functionalized collagen was increased at 25 and 50 mM CaCl2. Following 2-week culture with auricular chondrocytes, alginate-functionalization had no effect on the cytocompatibility of collagen gels, with no effects on cell density, and increased glycosaminoglycan deposition. Custom MATLAB video analysis was then used to quantify fracture toughness, which was more than 5-fold higher following culture in functionalized collagen and almost three-fold higher in unmodified collagen.
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Affiliation(s)
- Leigh Slyker
- Meinig of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Lawrence J. Bonassar
- Meinig of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853, USA
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de Rijk SR, Boys AJ, Roberts IV, Jiang C, Garcia C, Owens RM, Bance M. Tissue-Engineered Cochlear Fibrosis Model Links Complex Impedance to Fibrosis Formation for Cochlear Implant Patients. Adv Healthc Mater 2023; 12:e2300732. [PMID: 37310792 DOI: 10.1002/adhm.202300732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/30/2023] [Indexed: 06/15/2023]
Abstract
Cochlear implants are a life-changing technology for those with severe sensorineural hearing loss, partially restoring hearing through direct electrical stimulation of the auditory nerve. However, they are known to elicit an immune response resulting in fibrotic tissue formation in the cochlea that is linked to residual hearing loss and suboptimal outcomes. Intracochlear fibrosis is difficult to track without postmortem histology, and no specific electrical marker for fibrosis exists. In this study, a tissue-engineered model of cochlear fibrosis is developed following implant placement to examine the electrical characteristics associated with fibrotic tissue formation around electrodes. The model is characterized using electrochemical impedance spectroscopy and an increase in the resistance and a decrease in capacitance of the tissue using a representative circuit are found. This result informs a new marker of fibrosis progression over time that is extractable from voltage waveform responses, which can be directly measured in cochlear implant patients. This marker is tested in a small sample size of recently implanted cochlear implant patients, showing a significant increase over two postoperative timepoints. Using this system, complex impedance is demonstrated as a marker of fibrosis progression that is directly measurable from cochlear implants to enable real-time tracking of fibrosis formation in patients, creating opportunities for earlier treatment intervention to improve cochlear implant efficacy.
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Affiliation(s)
- Simone R de Rijk
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 3 EB, UK
| | - Alexander J Boys
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB3 0AS, UK
| | - Iwan V Roberts
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 3 EB, UK
| | - Chen Jiang
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 3 EB, UK
- Department of Electronic Engineering, Tsinghua University, Beijing, 100190, P. R. China
| | - Charlotte Garcia
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, CB2 7EF, UK
| | - Róisín M Owens
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB3 0AS, UK
| | - Manohar Bance
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 3 EB, UK
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Prendergast ME, Heo SJ, Mauck RL, Burdick JA. Suspension bath bioprinting and maturation of anisotropic meniscal constructs. Biofabrication 2023; 15:10.1088/1758-5090/acc3c3. [PMID: 36913724 PMCID: PMC10156462 DOI: 10.1088/1758-5090/acc3c3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 03/13/2023] [Indexed: 03/14/2023]
Abstract
Due to limited intrinsic healing capacity of the meniscus, meniscal injuries pose a significant clinical challenge. The most common method for treatment of damaged meniscal tissues, meniscectomy, leads to improper loading within the knee joint, which can increase the risk of osteoarthritis. Thus, there is a clinical need for the development of constructs for meniscal repair that better replicate meniscal tissue organization to improve load distributions and function over time. Advanced three-dimensional bioprinting technologies such as suspension bath bioprinting provide some key advantages, such as the ability to support the fabrication of complex structures using non-viscous bioinks. In this work, the suspension bath printing process is utilized to print anisotropic constructs with a unique bioink that contains embedded hydrogel fibers that align via shear stresses during printing. Constructs with and without fibers are printed and then cultured for up to 56 din vitroin a custom clamping system. Printed constructs with fibers demonstrate increased cell and collagen alignment, as well as enhanced tensile moduli when compared to constructs printed without fibers. This work advances the use of biofabrication to develop anisotropic constructs that can be utilized for the repair of meniscal tissue.
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Affiliation(s)
| | - Su-Jin Heo
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 USA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
| | - Robert L. Mauck
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 USA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
| | - Jason A. Burdick
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO 80303, USA
- Department of Chemical and Biological Engineering, College of Engineering and Applied Science, University of Colorado Boulder, Boulder, CO 80303, USA
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Kim J, Bonassar LJ. Controlling collagen gelation pH to enhance biochemical, structural, and biomechanical properties of tissue-engineered menisci. J Biomed Mater Res A 2023; 111:478-487. [PMID: 36300869 DOI: 10.1002/jbm.a.37464] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 09/16/2022] [Accepted: 10/18/2022] [Indexed: 11/07/2022]
Abstract
Collagen-based hydrogels have been widely used in biomedical applications due to their biocompatibility. Enhancing mechanical properties of collagen gels remains challenging while maintaining biocompatibility. Here, we demonstrate that gelation pH has profound effects on cellular activity, collagen fibril structure, and mechanical properties of the fibrochondrocyte-seeded collagen gels in both short- and long-terms. Acidic and basic gelation pH, below pH 7.0 and above 8.5, resulted in dramatic cell death. Gelation pH ranging from 7.0 to 8.5 showed a relatively high cell viability. Furthermore, physiologic gelation (pH 7.5) showed the greatest collagen deposition while glycosaminoglycan deposition appeared independent of gelation pH. Scanning electron microscopy showed that neutral and physiologic gelation pH, 7.0 and 7.5, exhibited well-aligned collagen fibril structure on day 0 and enhanced collagen fibril structure with laterally joined fibrils on day 30. However, basic pH, 8.0 and 8.5, displayed a densely packed collagen fibril structure on day 0, which was also persistent on day 30. Initial equilibrium modulus increased with increasing gelation pH. Notably, after 30 days of culture, gelation pH of 7.5 and 8.0 showed the highest equilibrium modulus, reaching 150 -160 kPa. While controlling gelation pH is simply achieved compared with other strategies to improve mechanical properties, its influences on biochemical and biomechanical properties of the collagen gel are long-lasting. As such, gelation pH is a useful means to modulate both biochemical and biomechanical properties of the collagen-based hydrogels and can be utilized for diverse types of tissue engineering due to its simple application.
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Affiliation(s)
- Jongkil Kim
- Meinig School of Biomedical Engineering, 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
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Lopez SG, Kim J, Estroff LA, Bonassar LJ. Removal of GAGs Regulates Mechanical Properties, Collagen Fiber Formation, and Alignment in Tissue Engineered Meniscus. ACS Biomater Sci Eng 2023; 9:1608-1619. [PMID: 36802372 DOI: 10.1021/acsbiomaterials.3c00136] [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: 02/23/2023]
Abstract
The complex fibrillar architecture of native meniscus is essential for proper function and difficult to recapitulate in vitro. In the native meniscus, proteoglycan content is low during the development of collagen fibers and progressively increases with aging. In vitro, fibrochondrocytes produce glycosaminoglycans (GAGs) early in culture, in contrast to native tissue, where they are deposited after collagen fibers have formed. This difference in the timing of GAG production hinders the formation of a mature fiber network in such in vitro models. In this study, we removed GAGs from collagen gel-based tissue engineered constructs using chondroitinase ABC (cABC) and evaluated the effect on the formation and alignment of collagen fibers and the subsequent effect on tensile and compressive mechanical properties. Removal of GAGs during maturation of in vitro constructs improved collagen fiber alignment in tissue engineered meniscus constructs. Additionally, removal of GAGs during maturation improved fiber alignment without compromising compressive strength, and this removal improved not only fiber alignment and formation but also tensile properties. The increased fiber organization in cABC-treated groups also appeared to influence the size, shape, and location of defects in these constructs, suggesting that treatment may prevent the propagation of large defects under loading. This data gives another method of modulating the ECM for improved collagen fiber formation and mechanical properties in tissue engineered constructs.
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Affiliation(s)
- Serafina G Lopez
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Jongkil Kim
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Lara A Estroff
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
- Kavli Institute for Nanoscale Science at Cornell, Cornell University, Ithaca, New York 14853, United States
| | - Lawrence J Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, United States
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14853, United States
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Li DX, Ma Z, Szojka ARA, Lan X, Kunze M, Mulet-Sierra A, Westover L, Adesida AB. Non-hypertrophic chondrogenesis of mesenchymal stem cells through mechano-hypoxia programing. J Tissue Eng 2023; 14:20417314231172574. [PMID: 37216035 PMCID: PMC10192798 DOI: 10.1177/20417314231172574] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 04/09/2023] [Indexed: 05/24/2023] Open
Abstract
Cartilage tissue engineering aims to generate functional replacements to treat cartilage defects from damage and osteoarthritis. Human bone marrow-derived mesenchymal stem cells (hBM-MSC) are a promising cell source for making cartilage, but current differentiation protocols require the supplementation of growth factors like TGF-β1 or -β3. This can lead to undesirable hypertrophic differentiation of hBM-MSC that progress to bone. We have found previously that exposing engineered human meniscus tissues to physiologically relevant conditions of the knee (mechanical loading and hypoxia; hence, mechano-hypoxia conditioning) increased the gene expression of hyaline cartilage markers, SOX9 and COL2A1, inhibited hypertrophic marker COL10A1, and promoted bulk mechanical property development. Adding further to this protocol, we hypothesize that combined mechano-hypoxia conditioning with TGF-β3 growth factor withdrawal will promote stable, non-hypertrophic chondrogenesis of hBM-MSC embedded in an HA-hydrogel. We found that the combined treatment upregulated many cartilage matrix- and development-related markers while suppressing many hypertrophic- and bone development-related markers. Tissue level assessments with biochemical assays, immunofluorescence, and histochemical staining confirmed the gene expression data. Further, mechanical property development in the dynamic compression treatment shows promise toward generating functional engineered cartilage through more optimized and longer culture conditions. In summary, this study introduced a novel protocol to differentiate hBM-MSC into stable, cartilage-forming cells.
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Affiliation(s)
- David Xinzheyang Li
- Department of Surgery, Faculty of
Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
- Department of Civil and Environmental
Engineering, Faculty of Engineering, AB, University of Alberta, Edmonton, AB,
Canada
| | - Zhiyao Ma
- Department of Surgery, Faculty of
Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Alexander RA Szojka
- Department of Surgery, Faculty of
Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Xiaoyi Lan
- Department of Surgery, Faculty of
Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
- Department of Civil and Environmental
Engineering, Faculty of Engineering, AB, University of Alberta, Edmonton, AB,
Canada
| | - Melanie Kunze
- Department of Surgery, Faculty of
Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Aillette Mulet-Sierra
- Department of Surgery, Faculty of
Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Lindsey Westover
- Department of Mechanical Engineering,
Faculty of Engineering, University of Alberta, Edmonton, AB, Canada
| | - Adetola B Adesida
- Department of Surgery, Faculty of
Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
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Lintz M, Walk RE, Tang SY, Bonassar LJ. The degenerative impact of hyperglycemia on the structure and mechanics of developing murine intervertebral discs. JOR Spine 2022; 5:e1191. [PMID: 35386755 PMCID: PMC8966876 DOI: 10.1002/jsp2.1191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 11/30/2021] [Accepted: 01/03/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction Diabetes has long been implicated as a major risk factor for intervertebral disc (IVD) degeneration, interfering with molecular signaling and matrix biochemistry, which ultimately aggravates the progression of the disease. Glucose content has been previously shown to influence structural and compositional changes in engineered discs in vitro, impeding fiber formation and mechanical stability. Methods In this study, we investigated the impact of diabetic hyperglycemia on young IVDs by assessing biochemical composition, collagen fiber architecture, and mechanical behavior of discs harvested from 3‐ to 4‐month‐old db/db mouse caudal spines. Results We found that discs taken from diabetic mice with elevated blood glucose levels demonstrated an increase in total glycosaminoglycan and collagen content, but comparable advanced glycation end products (AGE) levels to wild‐type discs. Diabetic discs also contained ill‐defined boundaries between the nucleus pulposus and annulus fibrosus, with the latter showing a disorganized and unaligned collagen fiber network at this same boundary. Conclusions These compositional and structural changes had a detrimental effect on function, as the diabetic discs were twice as stiff as their wild‐type counterparts and demonstrated a significant resistance to deformation. These results indicate that diabetes may predispose the young disc to DDD later in life by altering patterns of extracellular matrix deposition, fiber formation, and motion segment mechanics independently of AGE accumulation.
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Affiliation(s)
- Marianne Lintz
- Meinig School of Biomedical Engineering Cornell University Ithaca New York USA
| | - Remy E. Walk
- Department of Biomedical Engineering Washington University in St. Louis St. Louis Missouri USA
| | - Simon Y. Tang
- Department of Biomedical Engineering Washington University in St. Louis St. Louis Missouri USA
- Department of Mechanical Engineering and Materials Science Washington University in St. Louis St. Louis Missouri USA
- Department of Orthopaedic Surgery Washington University in St. Louis St. Louis Missouri 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
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