| Bone tissue is an important part of the human body and plays an indispensable physiological function,the damage of bone tissue can have serious effects on patients.Due to the shortcomings of both autologous bone and allogeneic bone grafts commonly used in clinical practice,the search for effective bone repair materials has become an urgent problem in the field of bone repair.With the deepening of the research on biological materials,the use of biodegradable materials to construct tissue engineering scaffolds for bone repair has become the focus of research in this field,and the use of bone-induced and bioactive materials to repair bone defects is an effective way.In this paper,using sol-gel method with dodecanamine(DDA)as the template agent preparation monodispersed spherical micro/nano bioactive glass(MNBG),and Poly(lactic-co-glycolic acid)(PLGA)as the scaffold substrate,combination of camphene as pore-forming agent,was prepared with a certain strength and pore structure of hierarchical composite scaffold,and the effects of scaffolds on physicochemical properties and osteogenic properties was studied as well,the main research work is as follows:(1)Using the sol-gel method in combination with DDA as the template agent,ethyl orthosilicate as precursor,add four triethyl phosphate and calcium nitrate hydrate,reaction after aging,freeze drying and sintering to form good dispersancy and manageable size spherical micro/nano bioactive glass,preparation of bioactive glass has a larger specific surface area and good performance of mineralization in vitro.(2)Phase separation method combined with freeze-drying method was used to prepare the composite scaffold of connected porous micro-nano bioactive glass/poly(lactic acid-hydroxyacetic acid)copolymer(MNBG/PLGA).When MNBG was added to the porous scaffold,the pore size and compression strength increased significantly.When the MNBG content reached 40%,the support aperture decreased significantly and the compression performance also decreased.In vitro mineralization results showed that the pure PLGA scaffolds did not form apatite deposits,while the scaffolds with MNBG addition had good ion release ability and in vitro mineralization ability.Cytological results showed that stents in10% MNBG group and 20% MNBG group could not only significantly promote theproliferation of bone marrow mesenchymal stem cells.It can also increase the expression of alkaline phosphatase(ALP).The expression level of endothelial cell angiogenesis marker(CD31)in 10% MNBG and 20% MNBG groups was significantly increased,indicating that the addition of MNBG enabled the scaffold to have a better pro-angiogenesis effect.(3)Composite scaffolds with hierarchical pore structure were prepared with MNBG content of 20%,which had good physicochemical and cytological properties as the research object.The results showed that when the amount of camphene was 100%,the combination of the two phases was better and the pore size was moderate.The results of physicochemical properties showed that the scaffold still had good mechanical properties and degradation performance,and the crystal of hydroxyapatite formed by the scaffold had higher crystallinity and better in vitro mineralization ability than the ordinary porous scaffold.The results of cell experiments showed that compared with ordinary porous scaffolds,multi-hole scaffolds could better promote the proliferation of bone marrow mesenchymal stem cells.Its multi-pore structure can promote the expression of endothelial cell angiogenic marker(CD31). |
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