Abstract: Disclosed are a polylactide stereocomplex with improved thermal stability and thus improved processability and a method for preparing the same. In order to confer flexibility to polymer chains, D-type polylactide polymer containing a small amount of caprolactone (poly D-lactide-caprolactone copolymer) is synthesized and it is uniformly mixed with L-type single-phase polylactide to prepare a flexible polylactide stereocomplex. Since the polylactide stereocomplex having flexible polymer chains has superior heat resistance and mechanical stability and experiences little decrease of the degree of stereocomplex formation even after thermal processing, the polylactide stereocomplex having improved thermal stability can be advantageously used for engineering plastics requiring high strength and good thermal stability, alternative materials for general-use plastics, high-performance medical materials, or the like because of its remarkably improved processability.

Abstract: Disclosed are a method for preparing biodegradable polymer materials, biodegradable polymer materials, and a product for fixing bone. The method includes a complex preparing step of preparing polylactide stereoisomeric complex by using a polymer having weight-average molecular weight more than 100,000 g/mol; a molding step of compression-molding the complex; a cooling step of cooling the compression-molded complex; and an extruding step of solid state extruding the cooled complex. Biodegradable polymer materials prepared by the method may be applied to a product for fixing bone or spine requiring high strength. Biodegradable polymer materials may have no corrosion in the body, may require no additional operation for removal after healing bones and tissues, and may prevent stress shielding.

Abstract: The present invention relates to a method for differentiating stem cells into vascular cells by culturing them in the form of a three-dimensional cell cluster and the use of the three-dimensional cell cluster for angiogenesis. Specifically, the present invention teaches a method for differentiating stem cells into vascular cells comprising culturing stem cells by adhering them onto a culture plate with a surface having a hydrophobic property or a culture plate onto which a growth factor is immobilized, wherein the cultured stem cells are later detached from the culture plate as their density increases to form a three-dimensional cell cluster and grown in the form of a three-dimensional cell cluster while differentiating into vascular cells. Also disclosed is the use of a three-dimensional cell cluster composed of the vascular cells differentiated from stem cells by the above method as a cell therapy agent for angiogenesis.

Abstract: The present invention relates to a recombinant protein of a fibroblast growth factor (FGF) having an adhesive activity for stem cells and a method for culturing stem cells using the same. More particularly, the present invention relates to a recombinant protein having an adhesive activity for stem cells by fusion of a polypeptide linker at amino terminal of FGF, and a method for culturing stem cells using immobilized FGF comprising: fixing the recombinant protein in a culture vessel with a hydrophobic surface using amino terminal of the polypeptide linker, adhering stem cells on the recombinant protein-fixed culture vessel, and culturing the stem cells.

Abstract: The present invention relates to methods for preparing biodegradable polymer stereocomplexes using a supercritical fluid-organic solvent system and polymer stereocomplexes prepared by such methods. The method of the present invention involves introducing two types of homopolymers having different stereostructures and a small amount of organic solvent into a reactor, adding a supercritical fluid thereto, followed by applying a specific temperature and pressure to form a polymer stereocomplex having a crystalline structure. According to the method of the present invention, biodegradable polymer stereocomplexes in the form of powder or porous foam having excellent thermal and mechanical stabilities can be prepared in a simple, economical and environmentally-friendly manner in a single process.

Abstract: The present invention relates to a highly resilient (lactide/glycolide)/?-caprolactone copolymer with good shape recovery force, flexibility, and biodegradability and a use of such copolymer for the repair of articular cartilage defects. The highly resilient (lactide/glycolide)/?-caprolactone copolymer of the present invention is capable of rapidly and efficiently inducing cartilage regeneration, can be easily deformed and almost completely restored to its original form after deformation. Further, the highly resilient copolymer of the present invention can be safely and conveniently transplanted to a patient by using an arthroscope without causing economic, physical, and mental burden. Thus, the highly resilient copolymer of the present invention can be effectively used as a polymer scaffold for the repair of cartilage defects.

Abstract: The present invention relates to a cell aggregate-hydrogel-polymer scaffold complex useful for cartilage regeneration which has a structure in which cell aggregates of differentiated chondrocytes are evenly dispersed in a hydrogel matrix, and the resulting hydrogel matrix is immobilized onto the surface of a polymer scaffold while filling up the pores thereof. Since the cell aggregate-hydrogel-polymer scaffold complex according to the present invention can efficiently induce the regeneration of cartilage tissue similar to natural cartilage and retain high mechanical strength, flexibility, and uniform morphology during the cartilage regeneration, it can be effectively used as a cartilage therapeutic agent for the repair of cartilage defects and injuries.