Preparation And Properties Of Calcium Sulfate/Silk Fibroin Nanofiber/Silk Microsphere Bone Repair Materials

Calcium sulphate bone cement is considered to be a good bone repair material due to its good biocompatibility,its freely shaped ability,and its lower heat release during setting.However,calcium sulfate bone cement as a bearing bone graft is brittle and has a rapid degradation rate.When used as a drug delivery system,the initial drug release is rapid,which limits its application.Therefore,the research on modification of calcium calcium sulfate bone cement has important practical significance.To improve the strength and toughness of the calcium sulfate and reduce its degradation rate,we composited the silk fibroin nanofiber solution.In order to improve the sustained release performance of the composite material,we added the silk fibroin microspheres.VCM/SF/CS and VCM/SFFs/CS were prepared by blending calcium sulfate with silk fibroin nanofibers?SFFs?,vancomycin?VCM?,and silk fibroin microspheres?SFM?,respectively.The micro-morphology,structure,drug release,mechanical properties,solidification time and cell compatibility of the composites were investigated by means of SEM,XRD,UV spectrophotometer,universal capability tester,Vicat,MTT and other methods.The results as follows:1.The addition of silk fibroin nanofibers to the composite material reduces the in vitro degradation rate of the material and inhibits the early burst release of the drug,meanwhile,increases the compressive strength,toughness,and water resistance of the material.2.The fibrion microspheres were added to the composites.When the content of fibrion microspheres was 0.5wt%,the compressive strength of the composite of VCM/SFM-20?0.5%?/CS,VCM/SFM-60?0.5%?/CS as well as VCM/SFM-100?0.5%?/CS appears to increase first and then decrease.Therefore the compression strength of VCM/SFM-60?0.5%?/CS is optimal,which is11.59±1.75 MPa.3.In terms of degradability,the addition of a certain concentration of silk fibroin nanofiber solution improved the degradation performance of the composite material.For the microspheres with SFM-20 and SFM-60 added,the water resistance of the composites was improved;after adding the silk microspheres with SFM-100,the water resistance decreased significantly.For the degraded mechanical properties,the change of the deionized water,silk fibroin solution,and silk fibroin nanofiber solution in the solidification solution had no significant effect on the mechanical properties of the composite after 2 weeks and 4 weeks of degradation.For the composites with different contents of SFM-60,the mechanical properties after 2 weeks and 4 weeks of degradation decreased slowly.The composite material VCM/SFM-60?0.5%?/CS was found to have the best mechanical properties after degradation.4.The results of drug release showed that when the silk fibroin nanofiber solution was used as the setting solution,the cumulative drug release rate of the composite material was reduced by about 10%compared with VCM/H₂O/CS.When composite materials were added with different contents of silk fibroin microspheres,the sustained-release effect of the composite material with the mass ratio of 1%microspheres was the most obvious,and with the increase of the microsphere concentration,the cumulative drug release of the composite material gradually decreased over a week.The drug release performance of VCM/SFM-100?1%?/CS was the best,and the cumulative drug release in a week was?34.76±0.39?%.5.The results in MTT assay showed that the composite VCM/SFM-60?0.5%?/CS have good cell compatibility.Electron microscope observation revealed that cells grew well on the surface of the composite material.