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James C.h. Goh - One of the best experts on this subject based on the ideXlab platform.
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Controlled Bioactive Molecules Delivery Strategies for Tendon and Ligament Tissue Engineering using Polymeric Nanofibers
Current pharmaceutical design, 2015Co-Authors: Thomas K.h. Teh, James C.h. Goh, Siew Lok TohAbstract:The interest in polymeric nanofibers has escalated over the past decade given its promise as Tissue engineering scaffolds that can mimic the nanoscale structure of the native extracellular matrix. With functionalization of the polymeric nanofibers using bioactive molecules, localized signaling moieties can be established for the attached cells, to stimulate desired biological effects and direct cellular or Tissue response. The inherently high surface area per unit mass of polymeric nanofibers can enhance cell adhesion, bioactive molecules loading and release efficiencies, and mass transfer properties. In this review article, the application of polymeric nanofibers for controlled bioactive molecules delivery will be discussed, with a focus on tendon and Ligament Tissue engineering. Various polymeric materials of different mechanical and degradation properties will be presented along with the nanofiber fabrication techniques explored. The bioactive molecules of interest for tendon and Ligament Tissue engineering, including growth factors and small molecules, will also be reviewed and compared in terms of their nanofiber incorporation strategies and release profiles. This article will also highlight and compare various innovative strategies to control the release of bioactive molecules spatiotemporally and explore an emerging Tissue engineering strategy involving controlled multiple bioactive molecules sequential release. Finally, the review article concludes with challenges and future trends in the innovation and development of bioactive molecules delivery using polymeric nanofibers for tendon and Ligament Tissue engineering.
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A hybrid silk/RADA-based fibrous scaffold with triple hierarchy for Ligament regeneration.
Tissue engineering. Part A, 2012Co-Authors: Kelei Chen, Sambit Sahoo, Siew Lok Toh, James C.h. GohAbstract:While silk-based microfibrous scaffolds possess excellent mechanical properties and have been used for Ligament Tissue-engineering applications, the microenvironment in these scaffolds is not biomimetic. We hypothesized that coating a hybrid silk scaffold with an extracellular matrix (ECM)-like network of self-assembling peptide nanofibers would provide a biomimetic three-dimensional nanofibrous microenvironment and enhance Ligament Tissue regeneration after bone marrow-derived mesenchymal stem cell (BMSC)-seeding. A novel scaffold possessing a triple structural hierarchy comprising macrofibrous knitted silk fibers, a silk microsponge, and a peptide nanofiber mesh was developed by coating self-assembled RADA16 peptide nanofibers on a silk microfiber-reinforced-sponge scaffold. Compared with the uncoated control, RADA-coated scaffolds showed enhanced BMSC proliferation, metabolism, and fibroblastic differentiation during the 3 weeks of culture. BMSC-seeded RADA-coated scaffolds showed an increasing temporal expression of key fibroblastic ECM proteins (collagen type I and III, tenascin-C), with a significantly higher tenascin-C expression compared with the controls. BMSC-seeded RADA-coated scaffolds also showed a temporal increase in total collagen and glycosaminoglycan production (the amount produced being higher than in control scaffolds) during 3 weeks of culture, and possessed 7% higher maximum tensile load compared with the BMSC-seeded control scaffolds. The results indicate that the BMSC-seeded RADA-coated hybrid silk scaffold system has the potential for use in Ligament Tissue-engineering applications.
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bioactive nanofibers for fibroblastic differentiation of mesenchymal precursor cells for Ligament tendon Tissue engineering applications
Differentiation, 2010Co-Authors: Sambit Sahoo, James C.h. Goh, Lay Teng Ang, S L TohAbstract:Mesenchymal stem cells and precursor cells are ideal candidates for tendon and Ligament Tissue engineering; however, for the stem cell-based approach to succeed, these cells would be required to proliferate and differentiate into tendon/Ligament fibroblasts on the Tissue engineering scaffold. Among the various fiber-based scaffolds that have been used in tendon/Ligament Tissue engineering, hybrid fibrous scaffolds comprising both microfibers and nanofibers have been recently shown to be particularly promising. With the nanofibrous coating presenting a biomimetic surface, the scaffolds can also potentially mimic the natural extracellular matrix in function by acting as a depot for sustained release of growth factors. In this study, we demonstrate that basic fibroblast growth factor (bFGF) could be successfully incorporated, randomly dispersed within blend-electrospun nanofibers and released in a bioactive form over 1 week. The released bioactive bFGF activated tyrosine phosphorylation signaling within seeded BMSCs. The bFGF-releasing nanofibrous scaffolds facilitated BMSC proliferation, upregulated gene expression of tendon/Ligament-specific ECM proteins, increased production and deposition of collagen and tenascin-C, reduced multipotency of the BMSCs and induced tendon/Ligament-like fibroblastic differentiation, indicating their potential in tendon/Ligament Tissue engineering applications.
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Scaffolds for tendon and Ligament Tissue engineering
Regenerative Medicine and Biomaterials for the Repair of Connective Tissues, 2010Co-Authors: James C.h. Goh, Sambit SahooAbstract:Abstract: An optimal scaffold that biomimics the mechanical and functional characteristics of tendons and Ligaments is essential for successful Tissue engineering of these dense connective Tissues. In this chapter, we review the requirements and criteria that such scaffolds should meet, and the various biomaterials and fabrication techniques used in developing such scaffolds. Several synthetic and natural biomaterials, as well as their composites, have been fabricated into fibre-based, gel-based or hybrid scaffolds in an attempt to best achieve the mix of mechanical and functional properties. A new breed of biofunctional scaffolds incorporating growth factors, genes, and active functional groups are currently been developed. Lastly, Tissue engineering strategies to regenerate the tendon/Ligament–bone interface are also reviewed.
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Bioactive nanofibers for fibroblastic differentiation of mesenchymal precursor cells for Ligament/tendon Tissue engineering applications.
Differentiation; research in biological diversity, 2009Co-Authors: Sambit Sahoo, James C.h. Goh, Lay Teng Ang, Siew Lok TohAbstract:Mesenchymal stem cells and precursor cells are ideal candidates for tendon and Ligament Tissue engineering; however, for the stem cell-based approach to succeed, these cells would be required to proliferate and differentiate into tendon/Ligament fibroblasts on the Tissue engineering scaffold. Among the various fiber-based scaffolds that have been used in tendon/Ligament Tissue engineering, hybrid fibrous scaffolds comprising both microfibers and nanofibers have been recently shown to be particularly promising. With the nanofibrous coating presenting a biomimetic surface, the scaffolds can also potentially mimic the natural extracellular matrix in function by acting as a depot for sustained release of growth factors. In this study, we demonstrate that basic fibroblast growth factor (bFGF) could be successfully incorporated, randomly dispersed within blend-electrospun nanofibers and released in a bioactive form over 1 week. The released bioactive bFGF activated tyrosine phosphorylation signaling within seeded BMSCs. The bFGF-releasing nanofibrous scaffolds facilitated BMSC proliferation, upregulated gene expression of tendon/Ligament-specific ECM proteins, increased production and deposition of collagen and tenascin-C, reduced multipotency of the BMSCs and induced tendon/Ligament-like fibroblastic differentiation, indicating their potential in tendon/Ligament Tissue engineering applications.
Siew Lok Toh - One of the best experts on this subject based on the ideXlab platform.
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Controlled Bioactive Molecules Delivery Strategies for Tendon and Ligament Tissue Engineering using Polymeric Nanofibers
Current pharmaceutical design, 2015Co-Authors: Thomas K.h. Teh, James C.h. Goh, Siew Lok TohAbstract:The interest in polymeric nanofibers has escalated over the past decade given its promise as Tissue engineering scaffolds that can mimic the nanoscale structure of the native extracellular matrix. With functionalization of the polymeric nanofibers using bioactive molecules, localized signaling moieties can be established for the attached cells, to stimulate desired biological effects and direct cellular or Tissue response. The inherently high surface area per unit mass of polymeric nanofibers can enhance cell adhesion, bioactive molecules loading and release efficiencies, and mass transfer properties. In this review article, the application of polymeric nanofibers for controlled bioactive molecules delivery will be discussed, with a focus on tendon and Ligament Tissue engineering. Various polymeric materials of different mechanical and degradation properties will be presented along with the nanofiber fabrication techniques explored. The bioactive molecules of interest for tendon and Ligament Tissue engineering, including growth factors and small molecules, will also be reviewed and compared in terms of their nanofiber incorporation strategies and release profiles. This article will also highlight and compare various innovative strategies to control the release of bioactive molecules spatiotemporally and explore an emerging Tissue engineering strategy involving controlled multiple bioactive molecules sequential release. Finally, the review article concludes with challenges and future trends in the innovation and development of bioactive molecules delivery using polymeric nanofibers for tendon and Ligament Tissue engineering.
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A hybrid silk/RADA-based fibrous scaffold with triple hierarchy for Ligament regeneration.
Tissue engineering. Part A, 2012Co-Authors: Kelei Chen, Sambit Sahoo, Siew Lok Toh, James C.h. GohAbstract:While silk-based microfibrous scaffolds possess excellent mechanical properties and have been used for Ligament Tissue-engineering applications, the microenvironment in these scaffolds is not biomimetic. We hypothesized that coating a hybrid silk scaffold with an extracellular matrix (ECM)-like network of self-assembling peptide nanofibers would provide a biomimetic three-dimensional nanofibrous microenvironment and enhance Ligament Tissue regeneration after bone marrow-derived mesenchymal stem cell (BMSC)-seeding. A novel scaffold possessing a triple structural hierarchy comprising macrofibrous knitted silk fibers, a silk microsponge, and a peptide nanofiber mesh was developed by coating self-assembled RADA16 peptide nanofibers on a silk microfiber-reinforced-sponge scaffold. Compared with the uncoated control, RADA-coated scaffolds showed enhanced BMSC proliferation, metabolism, and fibroblastic differentiation during the 3 weeks of culture. BMSC-seeded RADA-coated scaffolds showed an increasing temporal expression of key fibroblastic ECM proteins (collagen type I and III, tenascin-C), with a significantly higher tenascin-C expression compared with the controls. BMSC-seeded RADA-coated scaffolds also showed a temporal increase in total collagen and glycosaminoglycan production (the amount produced being higher than in control scaffolds) during 3 weeks of culture, and possessed 7% higher maximum tensile load compared with the BMSC-seeded control scaffolds. The results indicate that the BMSC-seeded RADA-coated hybrid silk scaffold system has the potential for use in Ligament Tissue-engineering applications.
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Bioactive nanofibers for fibroblastic differentiation of mesenchymal precursor cells for Ligament/tendon Tissue engineering applications.
Differentiation; research in biological diversity, 2009Co-Authors: Sambit Sahoo, James C.h. Goh, Lay Teng Ang, Siew Lok TohAbstract:Mesenchymal stem cells and precursor cells are ideal candidates for tendon and Ligament Tissue engineering; however, for the stem cell-based approach to succeed, these cells would be required to proliferate and differentiate into tendon/Ligament fibroblasts on the Tissue engineering scaffold. Among the various fiber-based scaffolds that have been used in tendon/Ligament Tissue engineering, hybrid fibrous scaffolds comprising both microfibers and nanofibers have been recently shown to be particularly promising. With the nanofibrous coating presenting a biomimetic surface, the scaffolds can also potentially mimic the natural extracellular matrix in function by acting as a depot for sustained release of growth factors. In this study, we demonstrate that basic fibroblast growth factor (bFGF) could be successfully incorporated, randomly dispersed within blend-electrospun nanofibers and released in a bioactive form over 1 week. The released bioactive bFGF activated tyrosine phosphorylation signaling within seeded BMSCs. The bFGF-releasing nanofibrous scaffolds facilitated BMSC proliferation, upregulated gene expression of tendon/Ligament-specific ECM proteins, increased production and deposition of collagen and tenascin-C, reduced multipotency of the BMSCs and induced tendon/Ligament-like fibroblastic differentiation, indicating their potential in tendon/Ligament Tissue engineering applications.
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Development of a silk cable-reinforced gelatin/silk fibroin hybrid scaffold for Ligament Tissue engineering.
Cell transplantation, 2008Co-Authors: Hongbin Fan, Yue Wang, Haifeng Liu, Siew Lok Toh, James C.h. GohAbstract:The objective of this study was to develop a silk cable-reinforced gelatin/silk fibroin hybrid scaffold for Ligament Tissue engineering. The scaffold was fabricated by lyophilizing the cross-linked gelatin and silk fibroin mixture with braided silk cables. Scanning electronic microscopy (SEM) observation showed that microporous gelatin/silk fibroin sponges formed around silk cables mimicked the microstructures of Ligament extracellular matrix (ECM). The silk cables significantly increased the tensile strength of the scaffold to meet the mechanical requirements for Ligament Tissue engineering. The scaffold possessed good cell adhesion property, and when mesenchymal stem cells (MSCs) were seeded on it, cells proliferated profusely. After 2 weeks of culture, seeded MSCs were distributed uniformly throughout the scaffold and were highly viable. Occurrence of cell death during culture was not significant. Deposition of collagen on the scaffold was found to increase with time. Differentiation of MSCs into Ligament fibroblasts was verified by expressions of Ligament ECM specific genes including collagen type I, collagen type III, and tenascin-C in mRNA and protein level. Immunohistochemistry stains also confirmed the production of key Ligament ECM components on the scaffold. The results demonstrate that silk cable-reinforced gelatin/silk fibroin scaffold possesses the appropriate mechanical properties and has enlarged surface area. It is also capable of supporting cell proliferation and differentiation for Ligament Tissue engineering.
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Modification of sericin-free silk fibers for Ligament Tissue engineering application.
Journal of biomedical materials research. Part B Applied biomaterials, 2007Co-Authors: Haifeng Liu, Yue Wang, Siew Lok Toh, Vallaya Sutthikhum, James C.h. GohAbstract:Biomedical application of silk requires the removal of sericin that is the gumming material of native silk fibers. This is because sericin can elicit an adverse immune response after implantation in the human body. However, the removal of sericin causes the silk fiber to fray and weakens its structural property, making it very difficult to knit or braid them into a scaffold for Ligament Tissue engineering applications. The aim of this study was to replace sericin with gelatin using NDGA as a cross-linking agent to biomimic the natural structure of native silk fibers. The physical properties and biocompatibility of the modified and native silk fibers were compared by in vitro and in vivo models. The mechanical and swelling properties of sericin-free silk fibers were greatly increased after modification with gelatin. Both modified and native silk fibers were shown to be nontoxic by in vitro cytotoxicity tests. The in vivo study demonstrated that the modified silk fibers, after 4 weeks' subcutaneous implantation in rats, caused little or no inflammatory reaction as compared with native silk fibers. The superior mechanical properties and lower inflammatory potential of modified silk fibers make them a promising candidate for Ligament Tissue engineering applications.
K-l. Paul Sung - One of the best experts on this subject based on the ideXlab platform.
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Ligament Tissue engineering using synthetic biodegradable fiber scaffolds
Tissue Engineering, 1999Co-Authors: Victor Lin, Myung Chul Lee, Scott Oneal, Jason Mckean, K-l. Paul SungAbstract:Tissue engineering offers the possibility of replacing damaged human Ligaments with engineered Ligament Tissues. Hence, we attempted to culture in vitro Ligament Tissues by seeding human anterior cruciate Ligament (ACL) and medial collateral Ligament (MCL) cells onto synthetic biodegradable polymer fiber scaffolds. The ACL and MCL cells readily attached to the scaffold fibers. These cells and their secreted matrix soon surrounded the scaffold fibers and bridged the gaps in between. Beginning at 2 weeks, portions of the scaffolds were completely filled with Tissue matrix. By 5 weeks, the scaffolds became single bundles of Tissue. Thus the cell/fiber system appears to be a viable system for culturing Ligament Tissues. Additionally, cell proliferation under mechanical and biochemical stimuli was studied for up to 4 days. Whereas mechanical stimulus and transforming growth factor enhanced proliferation, inflammatory agents (lipopolysaccharide and complement C5a) had a negative effect. This work can thus contr...
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Ligament Tissue engineering using synthetic biodegradable fiber scaffolds.
Tissue engineering, 1999Co-Authors: Victor Lin, Myung Chul Lee, Scott O'neal, Jason M. Mckean, K-l. Paul SungAbstract:Tissue engineering offers the possibility of replacing damaged human Ligaments with engineered Ligament Tissues. Hence, we attempted to culture in vitro Ligament Tissues by seeding human anterior cruciate Ligament (ACL) and medial collateral Ligament (MCL) cells onto synthetic biodegradable polymer fiber scaffolds. The ACL and MCL cells readily attached to the scaffold fibers. These cells and their secreted matrix soon surrounded the scaffold fibers and bridged the gaps in between. Beginning at 2 weeks, portions of the scaffolds were completely filled with Tissue matrix. By 5 weeks, the scaffolds became single bundles of Tissue. Thus the cell/fiber system appears to be a viable system for culturing Ligament Tissues. Additionally, cell proliferation under mechanical and biochemical stimuli was studied for up to 4 days. Whereas mechanical stimulus and transforming growth factor enhanced proliferation, inflammatory agents (lipopolysaccharide and complement C5a) had a negative effect. This work can thus contribute to a sound strategy for culturing replacement Ligament Tissues in vitro.
Xiong Wang - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Bone Marrow and Wharton's Jelly Mesenchymal Stromal Cells Response on Multilayer Braided Silk and Silk/PLCL Scaffolds for Ligament Tissue Engineering.
Polymers, 2020Co-Authors: Xing Liu, Natalia De Isla, Xiong Wang, Ghislaine Cauchois, Yun Chen, Adrien Baldit, Emilie De Brosses, Frédéric Velard, Cédric LaurentAbstract:(1) Background: A suitable scaffold with adapted mechanical and biological properties for Ligament Tissue engineering is still missing. (2) Methods: Different scaffold configurations were characterized in terms of morphology and a mechanical response, and their interactions with two types of stem cells (Wharton's jelly mesenchymal stromal cells (WJ-MSCs) and bone marrow mesenchymal stromal cells (BM-MSCs)) were assessed. The scaffold configurations consisted of multilayer braids with various number of silk layers (n = 1, 2, 3), and a novel composite scaffold made of a layer of copoly(lactic acid-co-(e-caprolactone)) (PLCL) embedded between two layers of silk. (3) Results: The insertion of a PLCL layer resulted in a higher porosity and better mechanical behavior compared with pure silk scaffold. The metabolic activities of both WJ-MSCs and BM-MSCs increased from day 1 to day 7 except for the three-layer silk scaffold (S3), probably due to its lower porosity. Collagen I (Col I), collagen III (Col III) and tenascin-c (TNC) were expressed by both MSCs on all scaffolds, and expression of Col I was higher than Col III and TNC. (4) Conclusions: the silk/PLCL composite scaffolds constituted the most suitable tested configuration to support MSCs migration, proliferation and Tissue synthesis towards Ligament Tissue engineering.
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Mesenchymal stem cell interacted with PLCL braided scaffold coated with poly‐l‐lysine/hyaluronic acid for Ligament Tissue engineering
Journal of biomedical materials research. Part A, 2018Co-Authors: Xing Liu, Xiong Wang, Cédric Laurent, Laurie Targa, Ghislaine Cauchois, Yun Chen, Natalia De IslaAbstract:The challenge of finding an adapted scaffold for Ligament Tissue engineering remains unsolved after years of researches. A technology to fabricate a multilayer braided scaffold with flexible and elastic poly (l-lactide-co-caprolactone) (PLCL 85/15) has been recently pioneered by our team. In this study, polyelectrolyte multilayer films (PEM) with poly-l-lysine (PLL)/ hyaluronic acid (HA) were deposited on this scaffold. After PEM modification, polygonal (PLL) and particle-like (HA) structures were present on the braided scaffold with no significant variation of fibers Young's modulus. Wharton's jelly mesenchymal stem cells (WJ-MSC) and bone marrow mesenchymal stem cells (BM-MSC) showed good metabolic activity on scaffolds. They presented a spindled shape along the fiber longitudinal direction, and crossed the fibers to form cell bridges. Collagen type I, collagen type III, and tenascin-C secreted by MSCs were detected on day 14. Moreover, one-layer modified scaffold presented increased chemotaxis. As a conclusion, our results indicate that this braided PLCL scaffold with one-layer PEM modification shows inspiring potential with satisfying mechanical properties and biocompatibility. It opens new perspectives to incorporate growth factors within PEM-modified braided PLCL scaffold for Ligament Tissue engineering and to recruit endogenous cells after implantation. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3042-3052, 2018.
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Defining a scaffold for Ligament Tissue engineering: What has been done, and what still needs to be done
Journal of Cellular Immunotherapy, 2018Co-Authors: Cédric Laurent, Natalia De Isla, Xiong Wang, Xing Liu, Rachid RahouadjAbstract:Abstract Tissue engineering is a promising alternative to current surgical methods for Ligament repair. However, despite a large variety of reported scaffolds for Ligament, Tissue-engineered solutions struggle to reach the clinics. The issue of proposing a scaffold meeting the key requirements for Ligament Tissue engineering is still largely open. In this article, a brief up-to-date review is proposed concerning what has been done and what still needs to be done in order to propose a suitable scaffold structure and material for Ligament Tissue engineering. A particularly focus is made on the selection of and structures, biomaterials and their functionalization, on the characterization of the initial and evolutive scaffold properties, and on the challenge of anchoring it within bone tunnels. The interest of computational approaches in the definition of suited scaffolds is also presented. We thus propose to list the remaining steps that should permit in the forthcoming years to propose a bioactive composite bone-Ligament-bone scaffold to regenerate Ligaments.
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Design and Improvement on a Stress Loading Device for Ligament Tissue Engineering
Applied Mechanics and Materials, 2013Co-Authors: Xiong WangAbstract:Strain loading control is important for addressing the complex requirements of Tissue engineering in bioreactor. The stress variation laws of the engineering Tissue during growth were analyzed, and the strain loading rules were determined. A new mechanical stress loading device was developed, which was able to apply complex concurrent mechanical strains to three-dimensional scaffolds independently housed in reactor chambers. The AC servo control system was used to carry out tensional and rotational displacements. Well controlled mechanical stimulations could be applied to the developing Ligament Tissue, through the closed-loop control system for stresses, allowed different mechanical loading patterns on the scaffolds. We analyzed the strains of scaffolds fixed in circular and planar modes. The strain, motion, and position control methods were designed. This device is suitable for the bioreactor used in Ligament Tissue engineering.
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Morphological characterization of a novel scaffold for anterior cruciate Ligament Tissue engineering.
Journal of biomechanical engineering, 2011Co-Authors: Cédric Laurent, Xiong Wang, Jean-françois Ganghoffer, Jérôme Babin, Jean-luc Six, Rachid RahouadjAbstract:Tissue engineering offers an interesting alternative to current anterior cruciate Ligament (ACL) surgeries. Indeed, a Tissue-engineered solution could ideally overcome the long-term complications due to actual ACL reconstruction by being gradually replaced by biological Tissue. Key requirements concerning the ideal scaffold for Ligament Tissue engineering are numerous and concern its mechanical properties, biochemical nature, and morphology. This study is aimed at predicting the morphology of a novel scaffold for Ligament Tissue engineering, based on multilayer braided biodegradable copoly(lactic acid-co-(e-caprolactone)) (PLCL) fibers The process used to create the scaffold is briefly presented, and the degradations of the material before and after the scaffold processing are compared. The process offers varying parameters, such as the number of layers in the scaffold, the pitch length of the braid, and the fibers' diameter. The prediction of the morphology in terms of pore size distribution and pores interconnectivity as a function of these parameters is performed numerically using an original method based on a virtual scaffold. The virtual scaffold geometry and the prediction of pore size distribution are evaluated by comparison with experimental results. The presented process permits creation of a tailorable scaffold for Ligament Tissue engineering using basic equipment and from minimum amounts of raw material. The virtual scaffold geometry closely mimics the geometry of real scaffolds, and the prediction of the pore size distribution is found to be in good accordance with measurements on real scaffolds. The scaffold offers an interconnected network of pores the sizes of which are adjustable by playing on the process parameters and are able to match the ideal pore size reported for Tissue ingrowth. The adjustability of the presented scaffold could permit its application in both classical ACL reconstructions and anatomical double-bundle reconstructions. The precise knowledge of the scaffold morphology using the virtual scaffold will be useful to interpret the activity of cells once it will be seeded into the scaffold. An interesting perspective of the present work is to perform a similar study aiming at predicting the mechanical response of the scaffold according to the same process parameters, by implanting the virtual scaffold into a finite element algorithm.
Yue Wang - One of the best experts on this subject based on the ideXlab platform.
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the interaction between a combined knitted silk scaffold and microporous silk sponge with human mesenchymal stem cells for Ligament Tissue engineering
Biomaterials, 2008Co-Authors: Yue WangAbstract:Abstract Cell seeding on knitted scaffolds often require a gel system, which was found to be practically unsuitable for anterior cruciate Ligament (ACL) reconstruction as the cell–gel composite often gets dislodged from the scaffold in the in vivo dynamic situations. In order to solve this problem, we fabricated this combined silk scaffold with weblike microporous silk sponges formed in the openings of a knitted silk scaffold and subsequently combined with adult human bone marrow-derived mesenchymal stem cells (hMSCs) for in vitro Ligament Tissue engineering. Human MSCs adhered and grew well on the combined silk scaffolds. Moreover, in comparison with the knitted silk scaffolds seeded with hMSCs in fibroin gel the cellular function was more actively exhibited on the combined silk scaffolds, as evident by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis for Ligament-related gene markers (e.g., type I, III collagen and tenascin-C), immunohistochemical and western blot evaluations of Ligament-related extracellular matrix (ECM) components. While the knitted structure holds the microporous silk sponges together and provides the structural strength of the combined silk scaffold, the microporous structure of the silk sponges mimic the ECM which consequently promotes cell proliferation, function, and differentiation. This feature overcomes the limitation of knitted scaffold for Ligament Tissue engineering application.
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Development of a silk cable-reinforced gelatin/silk fibroin hybrid scaffold for Ligament Tissue engineering.
Cell transplantation, 2008Co-Authors: Hongbin Fan, Yue Wang, Haifeng Liu, Siew Lok Toh, James C.h. GohAbstract:The objective of this study was to develop a silk cable-reinforced gelatin/silk fibroin hybrid scaffold for Ligament Tissue engineering. The scaffold was fabricated by lyophilizing the cross-linked gelatin and silk fibroin mixture with braided silk cables. Scanning electronic microscopy (SEM) observation showed that microporous gelatin/silk fibroin sponges formed around silk cables mimicked the microstructures of Ligament extracellular matrix (ECM). The silk cables significantly increased the tensile strength of the scaffold to meet the mechanical requirements for Ligament Tissue engineering. The scaffold possessed good cell adhesion property, and when mesenchymal stem cells (MSCs) were seeded on it, cells proliferated profusely. After 2 weeks of culture, seeded MSCs were distributed uniformly throughout the scaffold and were highly viable. Occurrence of cell death during culture was not significant. Deposition of collagen on the scaffold was found to increase with time. Differentiation of MSCs into Ligament fibroblasts was verified by expressions of Ligament ECM specific genes including collagen type I, collagen type III, and tenascin-C in mRNA and protein level. Immunohistochemistry stains also confirmed the production of key Ligament ECM components on the scaffold. The results demonstrate that silk cable-reinforced gelatin/silk fibroin scaffold possesses the appropriate mechanical properties and has enlarged surface area. It is also capable of supporting cell proliferation and differentiation for Ligament Tissue engineering.
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Modification of sericin-free silk fibers for Ligament Tissue engineering application.
Journal of biomedical materials research. Part B Applied biomaterials, 2007Co-Authors: Haifeng Liu, Yue Wang, Siew Lok Toh, Vallaya Sutthikhum, James C.h. GohAbstract:Biomedical application of silk requires the removal of sericin that is the gumming material of native silk fibers. This is because sericin can elicit an adverse immune response after implantation in the human body. However, the removal of sericin causes the silk fiber to fray and weakens its structural property, making it very difficult to knit or braid them into a scaffold for Ligament Tissue engineering applications. The aim of this study was to replace sericin with gelatin using NDGA as a cross-linking agent to biomimic the natural structure of native silk fibers. The physical properties and biocompatibility of the modified and native silk fibers were compared by in vitro and in vivo models. The mechanical and swelling properties of sericin-free silk fibers were greatly increased after modification with gelatin. Both modified and native silk fibers were shown to be nontoxic by in vitro cytotoxicity tests. The in vivo study demonstrated that the modified silk fibers, after 4 weeks' subcutaneous implantation in rats, caused little or no inflammatory reaction as compared with native silk fibers. The superior mechanical properties and lower inflammatory potential of modified silk fibers make them a promising candidate for Ligament Tissue engineering applications.