Construction A Composite Bone Scaffold With Drug-loaded CNT And Its Compa- Tibility With Bone Marrow Mesenchymal Stem Cells

Object:This study aims to modify the surface of the nano-hydroxyapatite/polyamide 66 (n-HA/PA66) porous scaffolds with carbon nanotubes (CNT) and silk fibroin (SF) in order to fabricate a bone tissue engineering scaffold with good biocompatibility and osteoconduction. Moreover the drug was loaded on the scaffold by carbon nanotubes to promote osteogenesis differentiation of bone mesenchymal stem cells (BMSCs).Method:1.Investigate the effect of different types of carbon nanotubes (pristine multi-walled carbon nanotubes, carboxylic multi-walled carbon nanotubes and hydroxyl multi-walled carbon nanotubes) on cell surface markers expression, cytoskeleton, vinculin, proliferation, migration in vitro and biodistribution of BMSCs to screen out the CNT type with good cytocompatibility.2. Prepare CNT solution and silk fibroin (SF) solution. Blend the CNT and SF solution with different concentration of CNT. Soak the nHA/PA66 scaffold in CNT/SF mixture and then the CNT/SF modified nHA/PA66 composite scaffold was fabricated in freeze-drying and crosslinking methods.3. The CNT/SF modified nHA/PA66 composite scaffold was characterized using FTIR, XRD and SEM analysis. Also the topography, mechanical property, porosity, swelling rate, degradation of modified CNT/SF-nHA/PA66 scaffold and the BMSCs on the scaffold was studied.4. Dexamethasone (DEX) was then loaded onto carbon nanotubes and then fabricated a drug loaded CNT/SF-nHA/PA66. The osteogenic differentiation of BMSCs on this DEX-loaded scaffold was tested and drug release behavior was investigated.Results:1.We screen out the carbon nanotubes type (MWCNT-COOH) with good biocompatibility.2.The CNT/SF modified nHA/PA66 scaffold with good interconnected open porous structure was successfully optimized and selected in freeze drying and chemical crosslinking method.3.The synthesized CNT/SF-nHA/PA66 composite scaffold shows good cell biocompatibility to BMSCs for adhesion, spread and growth.4. The synthesized DEX-load CNT/SF-nHA/PA66 composite scaffold demonstrated controlled release capability and could promote osteogenic differentiation of BMSCs.Conclusion:The results of the experiment showed that the nHA/PA66 scaffolds modified with carbon nanotubes and silk fibroin by freezing-drying and cross-linking can meet the requirements of bone tissue engineering scaffolds. The DEX-load CNT/SF-nHA/PA66 composite scaffold can promote osteogenic differentiation of BMSCs and drug loaded scaffolds were expected to provide an effective way for bone tissue engineering scaffold.