Gelatin composites with stromal cell-derived factor loaded alginate microspheres as bone substitutes

• Main Authors: Wei-Jyun Lian, 連偉竣
• Other Authors: Kuo-Yu Chen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/q48622

碩士 === 國立雲林科技大學 === 化學工程與材料工程系 === 103 === In recent years, in situ tissue engineering is a novel technology that the growth factor is added into scaffold before implantation. The chemokine stromal cell-derived factor-1 (SDF-1) has been shown to recruit and mobilize bone marrow stromal cells to the site of injury and is suggested to be a promising candidate for bone tissue engineering. Strontium, a trace element in calcified tissue, plays a crucial role in bone mineralization and remodeling. In this study, gelatin/strontium-substituted hydroxyapatite composites with SDF-1 were prepared to assess the migration and differentiation of bone marrow mesenchymal stem cells and the repair of bone defects. Firstly, strontium-substituted hydroxyapatite nanoparticles were synthesized by a co-precipitation method. The compositions, crystal structure and morphology of the nanoparticles were characterized by Fourier transform infrared spectroscopy, wide-angle X-ray diffraction and transmission electron microscopy. The effect of strontium-substitution in hydroxyapatite on the cytotoxicity and differentiation of bone marrow mesenchymal stem cells were investigated using MTT and alkaline phosphatase activity assays. Secondly, alginate microspheres with SDF-1 were incorporated into the mixture of gelatin and hydroxyapatite particles to prepare composite with SDF-1. The effect of SDF-1 concentrations on the migration of mesenchymal stem cells was performed by using the transwell system. Moreover, the effects of the release of SDF-1 from gelatin-based composite on the migration, proliferation and differentiation of mesenchymal stem cells were assessed. Finally, the gelatin-based composites were implanted into the calvarial defects of rats to evaluate the effect of the incorporation of strontium and SDF-1 into composites on bone repair. The results show that the d-spacing, lattice parameter values and particle size of hydroxyapatite increased with the increase of the extent of strontium substitution, while the crystallinity of hydroxyapatite decreased. The strontium-substituted hydroxyapatite exhibited higher cell viability and alkaline phosphatase activity when the degree of strontium substitution was 30 mol%. The incorporation of SDF-1 into gelatin-based composite effectively promoted the migration of mesenchymal stem cells. After 56 days of implantation, the repair quality of bone defect treated with gelatin/hydroxyapatite composite without SDF-1, gelatin/hydroxyapatite composite with SDF-1 and gelatin/strontium-substituted hydroxyapatite composite with SDF-1 was 34.2±2.8, 40.1±6.2 and 43.0±3.6, respectively, indicating that the scaffold with SDF-1 significantly enhanced bone repair.