| Part I A Novel Silk Fibroin Nanofibrous Membrane For Guided Bone Regeneration:A Study In Rat Calvarial DefectsA novel membrane for guided bone regeneration (GBR), constitution of silk fibroin (SF) nanofiber from native silk nanofibril solution, was prepared by electrospinning process. Another barrier membrane, a collage-type membrane (Bio-Gide(?)) was used as a comparative sample. The SF membrane showed superior results in mechanical tensile properties. The bone regenerative efficacy was evaluated in rat calvarial defects. Twelve healthy male Sprague-Dawley rats were used for this study. Bilateral round sharped defects were created in calvarial bone. Animals were euthanized at 4 and 12 weeks. Bone regeneration was analyzed by micro-CT and histological analysis. At 4 weeks, the bone volume (BV) and collagen I positive areas in SF group were greater than in Bio-Gide(?) group. At 12 weeks, the defect had completely healed with new bone in both groups. In conclusion, the SF nanofibrous membranes showed satisfactory mechanical stability, good biocompatibility, slow degradability, and improved new bone regeneration without any adverse inflammatory reactions. Considering the low cost and low risk of disease transmission, the silk fibroin nanofibrous membrane is a potential candidate for GBR therapy compared with the widely used collagen membranes.Part Ⅱ A Novel Strontium Chloride/Silk Fibroin Nanofibrous Membrane For Guided Bone Regeneration:In Vitro And In Vivo StudiesThe silk fibroin (SF) nanofibrous membrane is a good candidate for clinical application in bone and periodontal regenerative therapy. Strontium (Sr) and Sr-containing biomaterials have been found to induce osteoblast activity. This study seeks to investigate the effects of a strontium chloride/silk fibroin nanofibrous membrane (SrCl2-SFM) for guided bone regeneration (GBR). The SrCl2-SFM were fabricated by electrospinning. and the structure characteristics and strontium ion release pattern were analyzed. To examine the biocompatibility of SrCl2-SFM, we investigated cell morphology, proliferation and differentiation. The GBR efficacy of SrCl2-SFM was evaluated in rat calvarial defects. The SrCl2-SFM exhibited uniform nanofibrous structure and slow strontium ion release. In vitro tests, the cell numbers and ALP activities in SrCl2-SFMs were significantly greater than in pure SFM. In vivo test at 6 weeks, both micro-CT and histological analyses showed that the SrCl2-SFM group got significantly greater bone formation than pure SFM or uncovered groups. In conclusion, the SrCl2-SFM developed in this study showed good biocompatibility, slow degradability and improved new bone formation in rat calvarial defects. The results strongly suggest that the SrCl2-SFM should be potential effective for GBR.PartⅢ Effects Of The Novel Silk Fibroin/Strontium Carbonate Nanofibrous Membrane On The Bioactivity Of Bone Marrow Mesenchymal Stem CellThe novel silk fibroin/strontium carbonate nanofibrous membranes (SrCO3-SFM) fabricated from a simplified biomineralization process is reported for the first time. The growth of SrCO3 in SrC12-SFM was achieved by a simple vapor diffusion method. The results showed lots of SrCO3 particles, evenly distributed on the nanofibers. Compared with SrC12-SFM, the release rate of strontium ions in SrCO3-SFM was significantly reduced. In vitro tests, the SrCO3-SFM promoted the activity of ALP and extracellular matrix mineralization and increased the expression of osteogenic differentiation related genes, such as RUNX2, BSP and OCN. In conclusion, the SrCO3-SFM material has a stable sustained release of strontium ions, good cell compatibility, promoting mesenchymal stem cell adhesion, proliferation and osteogenic differentiation. In subsequent experiments, we need to further study in vivo tests about the biological and osteoconductive properties for bone tissue engineering. |
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