Papers by Author: Byoung Goo Min

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Authors: Young Mee Jung, Soo Hyun Kim, Sang Heon Kim, Young Ha Kim, Byoung Goo Min
Abstract: Mechano-active scaffolds were fabricated from very elastic poly(L-lactide-co-ε-carprolactone). The scaffolds with 80 % porosity and 300~500 μm pore size were prepared by a gel-pressing method. As a control group for elastic properties of polymer scaffolds, rigid poly L-lactide scaffolds were fabricated. The scaffolds were seeded with chondrocytes and cultured to evaluate the effect of elastic properties of polymer scaffolds for the differentiation and the ECM secretion of chondrocytes. Also, the chondrocytes-seeded constructs were implanted in nude mice subcutaneously to investigate their biocompatibility and cartilage formation. From the biochemical analyses, chondrogenic differentiation was sustained and enhanced significantly and chondral extracellular matrix was increased through mechanical stimulation of dynamic environment in the dynamic body systems. Histological analysis showed that implants of PLCL constructs formed mature and well-developed cartilaginous tissue, as evidenced by chondrocytes within lacunae. Consequently, the elastic PLCL scaffolds could be used to engineer cartilage in mechanically dynamic environments
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Authors: So Eun Lee, Young Mee Jung, Soo Hyun Kim, Sang Heon Kim, Jong Won Rhie, Young Ha Kim, Byoung Goo Min
Abstract: In cartilage tissue engineering, as a cell source, adult stem cells are very attractive for clinical applications. Recent studies suggest that human adipose tissue-derived stromal cells (ASCs) have multilineage potential similar to bone marrow-derived stromal cells (BMSCs). ASCs are obtained from adipose tissue easily isolated by suction-assisted lipectomy in various body parts. Also, as one of major factors of cartilage tissue engineering, scaffolds have an important role in cartilage formation. Poly(L-lactide-co-ε-carprolactone) scaffolds have physiological activity, biodegradability, high cell affinity, and mechano-activity. The object of this study is cartilaginous tissue formation using highly elastic PLCL scaffolds and ASCs in vitro and in vivo. Poly(L-lactide-co-ε-carprolactone) copolymers were synthesized from lactide and ε-carprolactone in the presence of stannous octoate as catalyst. The scaffolds with 85% porosity and 300-500μm pore size were fabricated by gel-pressing method. ASCs were seeded on scaffolds and cultured for 21days in vitro. Cell/polymer constructs were characterized by reverse transcriptase-polymerase chain reaction for confirming differentiation to chondrocytes onto PLCL scaffolds. Also, for examining cartilaginous tissue formation in vivo, ASCs seeded scaffolds which were induced chondrogenesis for 2 weeks were implanted in nude mice subcutaneously for up to 8weeks. Histological studies showed that implants partially developed cartilaginous tissue within lacunae. And there was an accumulation of sulfated glycoaminoglycans. Immunohistochemical analysis revealed that implants were positively stained for specific extracellular matrix. These results indicate that ASCs and PLCL scaffols could be used to cartilage tissue engineering.
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Authors: Soo Hyun Kim, Young Mee Jung, Sang Heon Kim, Young Ha Kim, Jun Xie, Takehisa Matsuda, Byoung Goo Min
Abstract: To engineer cartilaginous constructs with a mechano-active scaffold and dynamic compression was performed for effective cartilage tissue engineering. Mechano-active scaffolds were fabricated from very elastic poly(L-lactide-co-ε-carprolactone)(5:5). The scaffolds with 85 % porosity and 300~500 μm pore size were prepared by a gel-pressing method. The scaffolds were seeded with chondrocytes and the continuous compressive deformation of 5% strain was applied to cell-polymer constructs with 0.1Hz to evaluate for the effect of dynamic compression for regeneration of cartilage. Also, the chondrocytes-seeded constructs stimulated by the continuous compressive deformation of 5% strain with 0.1Hz for 10 days and 24 days respectively were implanted in nude mice subcutaneously to investigate their biocompatibility and cartilage formation. From biochemical analyses, chondrogenic differentiation was sustained and enhanced significantly and chondrial extracellular matrix was increased through mechanical stimulation. Histological analysis showed that implants stimulated mechanically formed mature and well-developed cartilaginous tissue, as evidenced by chondrocytes within lacunae. Masson’s trichrome and Safranin O staining indicated an abundant accumulation of collagens and GAGs. Also, ECM in constructs was strongly immuno-stained with anti-rabbit collagen type II antibody. Consequently, the periodic application of dynamic compression can improve the quality of cartilaginous tissue formed in vitro and in vivo.
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Authors: Young Mee Jung, Soo Hyun Kim, Sang Heon Kim, Young Ha Kim, Jun Xie, Takehisa Matsuda, Byoung Goo Min
Abstract: Mechano-active scaffolds were fabricated from very elastic poly(lactide-co-carprolactone) by a gel-pressing method. The scaffolds were seeded with bone marrow stromal cells and the continuous compressive deformation was applied to cell-polymer constructs in the chondrogenic media. Then, they were implanted in nude mice subcutaneously to evaluate for the effect of dynamic compression for regeneration of cartilage. From the biochemical analyses, chondrogenic differentiation was sustained and enhanced significantly and chondral extracellular matrix was increased through mechanical stimulation. Histological analyses showed that implants stimulated mechanically formed mature and well-developed cartilaginous tissue, as evidenced by bone marrow derived chondrocytes within lacunae. Consequently, the periodic application of dynamic compression can encourage bone marrow stromal cells to differentiation to chondrogenic lineage and to maintain their phenotypes.
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Authors: Min Sung Park, Young Mee Jung, Soo Hyun Kim, Sang Heon Kim, Young Ha Kim, Byoung Goo Min, Jin Woo Lee
Abstract: Poly-L-lactic acid (PLLA) is a desirable and very attractive polymer for fabricating porous scaffolds. As of now, a solvent casting method with organic solvents has been used in scaffold fabrication process. However, residual organic solvents in the scaffolds have the problems of decreasing the effect of osteogenic induction due to the hindrance of bioceramic by polymer solution and it’s harmfulness in vivo. To avoid these disadvantages of scaffolds by organic solvent casting method, we developed a new method fabricating polymer (PLLA)/ceramic (β -TCP) composite scaffolds by baking method without using solvent, and then we tested properties of scaffolds on animals. As the result, non-toxicity has been proved through animal experiment and newly fabricated polymer/ceramic composites by a novel sintering method were induced rapid bone regeneration through enhancing the interaction of cells and a bone induction factor without any host immune response.
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