방사선 기반 골재생용 생체 모사 지지체 개발

Abstract

Polycaprolactone (PCL) has been considered as useful materials for orthopedic devices and osseous implants because of their biocompatibility and bone-forming activity. However, plain PCL-based scaffolds have hydrophobic surfaces which reduce initial cell adhesion and proliferation. In this study, we fabricated surface-modified PCL nanofibers using radiation technology for bone tissue engineering. PCL nanofibers were prepared by electrospinning method to have good properties such as high-burst pressure, ultrafine and highly nanofibrous structure that mimics the natural extra cellular matrix (ECM). These properties are very ideal for tissue engineering applications. We supplemented hydrophilicity of the PCL nanofiber by introducing 2-aminoethyl methacrylate (AEMA) through gamma-irradiation and after that we immobilized heparin onto the fiber by using EDC/NHS reaction. SEM result shows that there are no significant changes on the morphology of nanofibers after radiation grafting of AEMA and heparin immobilization onto PCL nanofiber. The surface properties of the nanofiber scaffold were characterized by ATR-FTIR, XPS, and fluorescamine staining confirmed the successful grafting of AEMA onto the surface of PCL nanofiber. Heparin immobilization was also confirmed by the presence of carboxyl group (1700 cm-1) and amide group (1550 cm-1) from ATR-FTIR spectra. Then amounts of heparin were drastically increased which is impossible to be measure quantitatively by TBO assay. Furthermore, the initial viability of hMSCs was significantly increased on the AEMA grafted nanofibers, but decreased on heparin immobilized nanofibers. The cumulative of BMP-2 was slowly and continuously released on the heparin immobilized nanofibers (18.13 ± 3.87 μg/ml) than that on the unmodified nanofibers (20.25 ± 1.45 μg/ml). Therefore, heparin immobilized nanofibers may be a good tool for bone tissue engineering applications.