Papers by Author: Hyang Mi Lee

Abstract: This study evaluated the potential of the PCL (poly
-caprolactone)/HA(Hydroxyapatite) composite materials as a scaffold for bone regeneration. For this, we fabricated scaffolds utilizing salt leaching method. The PCL/HA composite scaffolds were prepared with various HA contents (20wt%, 40wt%, 60 wt %). To ensure the potential for the scaffolds, porosity tests were conducted along with SEM observations. The porosity decreased with the increase of the contents of HA particles. The porosity of the composite with the highest contents of HA was still adoptable (~85%). In addition, the PCL/HA composite scaffolds were evaluated for their ability of osteogenic differentiation with human bone marrow stromal cell (hBMSC) in vitro. Alkaline phosphatase (ALP) activity, markers for osteoblastic differentiation, and total protein contents were evaluated in hBMSCs following 14 days of cultivation. The addition of HA particles enhanced proliferation of hBMSC during the test. Also, the differentiation ability of the cells was increased as HA particles were added. In this study, we concluded that PCL/HA composite scaffolds has great potential as a scaffold for bone tissue engineering.

Abstract: Porous HAp/chitosan-alginate composite scaffolds were successfully synthesized by insitu co-precipitation method. During the preparation of HAp/chitosan-alginate composite scaffolds, the interaction between chitosan-alginate molecules would be reduced with increasing HAp content, with the resulting that the chitosan-alginate molecules were homogeneously dispersed in the composite scaffolds. The chitosan-alginate content was found to be almost consistent as initially added during the preparation. These results imply that chitosan-alginate was almost perfectly incorporated into the composites. It was found that the pore structure of the composite scaffolds with low HAp content was similar to chitosan-alginate scaffolds, and the morphology of uniform microstructure was unaffected by the presence of HAp. However, the pore diameter decreased with increasing the HAp content up to HAp content of 30 wt%, eventually the pore structure was collapsed and the composites scaffolds appeared to be agglomerated at higher HAp content.

Abstract: Monodispersed and nano-sized Cu powders were synthesized from copper sulfate pentahydrate (CuSO4ㆍ5H2O) inside a nonionic polymer matrix by using wet chemical reduction process. The sucrose was used as a nonionic polymer network source. The influences of a nonionic polymer matrix on the particle size of the prepared Cu powders were characterized by means of Xray diffraction (XRD), scanning electron microscopy (SEM), and particle size analysis (PSA). The smallen Cu powders with size of approximately 100㎚ was obtained with adding of 0.04M sucrose at reaction temperature of 60°C. The particle size of the Cu powders prepared by the reduction inside polymer network was strongly dependent of the sucrose content and reaction temperature.