| Tumors,trauma,surgery,or inflammatory diseases can cause severe bone defects,and bones have limited self-regeneration capacity and require a lot of surgical operations to rebuild.However,many therapies in clinical applications,such as autologous or allograft or prosthetic materials,have considerable disadvantages.Therefore,it is of great significance to develop a bone tissue engineering scaffold that can meet clinical needs and effectively promote bone regeneration in situ.Bone is a kind of organic/inorganic natural composite material with a special structure,so from a bionic point of view,the combination of organic and inorganic components is a natural strategy for making materials similar to bone tissue.Sodium alginate（Alg）andε-polylysine（PL）are both natural polymer materials,which have the advantages of biodegradability and good biocompatibility,and have huge application potential in the field of biomedicine.Due to electrostatic interaction,carboxyl-rich Alg and amino-rich PL form a mechanically stable organic phase.The 58s bioglass（BG）with excellent osteoinductive properties as an inorganic phase is doped in the organic phase to improve the bone-promoting ability of the hydrogel.This thesis designed the structure and properties of sodium alginate,ε-polylysine,and bioactive glass,and successfully constructed a composite hydrogel scaffold with good bone repair effects.The main research work is as follows:Sodium alginate（Alg）,sodium alginate/bioglass（Alg/BG）and sodium alginate-polylysine/bioglass（Alg-PL/BG）scaffolds were prepared using 3D printing technology combined with Ca2+ion crosslinking and EDC/NHS covalent crosslinking post-processing.Compared with other groups,Alg-PL/BG ink has good printability,and his scaffold has high mechanical stability and good biocompatibility.However,its covalent cross-linking time is long,and its mechanical strength does not match the natural bone tissue,which limits its application in bone tissue engineering.In order to improve the mechanical properties of the Alg-PL/BG composite hydrogel and reduce the post-treatment time of the hydrogel,we used methacrylic anhydride to modify the double bond to the molecular chain of sodium alginate to prepare methacryloyl sodium alginate（MA-Alg）.Then,under ultraviolet light（UV）irradiation,a polylysine modified methacryloyl sodium alginate hydrogel（MA-Alg-PL）was prepared.MA-Alg-PL hydrogel has higher mechanical properties,good swelling properties,suitable degradation rate and good cell compatibility and adhesion.In order to further improve the bone growth ability of MA-Alg-PL hydrogel,58s bioglass is doped in it.The MA-Alg-PL/BG composite hydrogel scaffolds with different BG content were prepared by 3D printing technology combined with UV cross-linking method.The addition of BG not only improves the mechanical properties of MA-Alg-PL hydrogel,but also significantly improves its ability to form hydroxyapatite in vitro.Biological results show that MA-Alg-PL/BG has good biocompatibility,and has a good performance in promoting the osteogenic differentiation of mBMSCs. |
