Silk Fibroin/calcium Phosphate Cement Reinforced With Chitosan N-acetylene-L-cysteine Nanoparticles

Objective: Bone repair has been an important part of bone tissue engineering research,in recent years,calcium phosphate cement has given rise to a abundant of studies aimed at broadening their clinical use for its good biocompatibility and biodegradation.Unfortunately,it's difficult to make desired calcium phosphate cement which biocompatibility and mechanical properties are both favourable.In our study,we introduced chitosan,N-acetylcysteine,and silk fibroin in tricalcium phosphate in order to prepare of a new type fibroin based calcium phosphate cement that loaded with chitosan N-acetylene-L-cysteine nanoparticles.Both biological properties and mechanical properties of the composite cement were studied,such as compressive strength,cell compatibility and osteogenic property.Methods: Chitosan N-acetylene-L-cysteine nanoparticles(CS-NAC)would be made by ionotropic gelation method which was relatively simple,mild,and environmentally friendly.The CS-NAC nanoparticles were added into the SF solution used as the setting liquid,and then mixed it with tricalcium phosphate power at the liquid-solid ratio 0.4 to prepare calcium phosphate composite cement.The synthesized CS-NAC nanoparticles were characterized by electron microscopy and infrared spectroscopy.The mechanical properties,such as setting time and internal structure of the composite bone cement were also detected.Subsequently,we conducted a qualitative evaluation of cell proliferation,osteoinduction by CCK-8 kit and alizarin red staining.Moreover,we also constructed bone defect model in rat femoral condyle,implanted with CS-NAC/SF/CPC composite cement,to evaluate the osteogenesis in vivo.Results: Transmission electron microscopy,Infrared spectroscopy,Raman spectroscopy confirmed that we had synthesized CS-NAC nanoparticles successfully.In addition,both SF,CS/SF,NAC/SF and CS-NAC/SF introduced in tricalcium phosphate can improve the compressive strength of the composite cement,reduce the setting time.Cell culture used by bone cement extract showed that the composite was nontoxicity and cytocompatibility.Besides,the introduction of CS-NAC could promote cell proliferation and osteogenesis.Conclusion: In this study,CS-NAC nanoparticles were prepared successfully with stable property.The synthesized CS-NAC/SF/CPC composite cement prepared by introducing CS-NAC nanoparticles can improve the physicochemical properties of calcium phosphate cement to a certain extent,the compressive strength increased,the setting time shortened,and the composite material was non-cytotoxicity,good biocompatibility and equipped with osteogenic properties,which may be expected to further application in bone tissue engineering...