Zhuang Chen, Ke Xiurong, Jin Zhouwen, Zhang Lei, Yang Xianyan, Xu Sanzhong, Yang Guojing, Xie Lijun, Prince Ghamor-Amegavi Edem, Pan Zhijun, Gou Zhongru
Bio-nanomaterials and Regenerative Medicine Research Division, Zhejiang-California International Nanosystem Institute, Zhejiang University, Hangzhou 310058, China.
J Mater Chem B. 2017 Dec 7;5(45):8944-8956. doi: 10.1039/c7tb02295f. Epub 2017 Nov 6.
A rational design of fully interconnected porous constructs of biomaterials with controlled pore-wall bioactivity and biodegradation is of importance in the advancement of bone regenerative medicine. We hypothesize that the layered structure of hybrid bioceramics produces time-dependent biological performances to tune osteogenic responses. We thereby developed core-shell-structured nonstoichiometric Ca silicate (nCSi) spheres and evaluated the effect of spatiotemporal distribution of bi-component nCSi on osteogenic capability. The alginate-based 4% Sr-, 6% Mg-, or 10% Mg-doped nCaSi (i.e. CSi-Sr4, CSi-Mg6, CSi-Mg10) slurries were extruded into a Ca-rich solution through the core or shell layer of a coaxial bilayer nozzle, and after drying and sintering treatments, the core-shell nCSi ceramic spheres were prepared. The improved sintering property and denser structure of CSi-Mg6 and CSi-Mg10 shells readily retarded bioactive ion release and biodegradation of CSi-Sr4@CSi-Mg6 and CSi-Sr4@CSi-Mg10 spheres compared with those of CSi-Sr4@CSi-Sr4. When the spheres were implanted into the femoral bone defect in rabbits, the differences in biodegradation and bone regeneration rate in relation to microsphere scaffolds were measured at 6-18 weeks post-implantation. CSi-Sr4@CSi-Mg10 showed slow biodegradation and new bone regeneration, whereas CaSi-Sr4@CSi-Sr4 showed a much faster degradation such that a low osteogenic capacity was observed with prolongation of time. However, CSi-Sr4@CSi-Mg6 spheres displayed expected biodegradation and osteogenic activity with time. These results confirmed the slight tailoring in both doping ions and that component distribution of nCSi is beneficial for adjusting osteogenesis of core-shell spheres. By rationally choosing foreign ion doping, this concept may represent a versatile strategy for the production of a variety of core-shell bioactive ceramics for bone regeneration and repair applications.
合理设计具有可控孔壁生物活性和生物降解性的完全互连的生物材料多孔结构对于骨再生医学的发展至关重要。我们假设混合生物陶瓷的层状结构会产生随时间变化的生物学性能，以调节成骨反应。因此，我们开发了核壳结构的非化学计量硅酸钙（nCSi）球体，并评估了双组分nCSi的时空分布对成骨能力的影响。将基于藻酸盐的4% Sr、6% Mg或10% Mg掺杂的nCaSi（即CSi-Sr4、CSi-Mg6、CSi-Mg10）浆料通过同轴双层喷嘴的芯层或壳层挤出到富含钙的溶液中，经过干燥和烧结处理后，制备出核壳nCSi陶瓷球体。与CSi-Sr4@CSi-Sr4相比，CSi-Mg6和CSi-Mg10壳层改善的烧结性能和更致密的结构很容易阻碍CSi-Sr4@CSi-Mg6和CSi-Sr4@CSi-Mg10球体的生物活性离子释放和生物降解。当将球体植入兔股骨缺损处时，在植入后6至18周测量与微球支架相关的生物降解和骨再生率的差异。CSi-Sr4@CSi-Mg10显示出缓慢的生物降解和新骨再生，而CaSi-Sr4@CSi-Sr4显示出更快的降解，以至于随着时间的延长观察到成骨能力较低。然而，CSi-Sr4@CSi-Mg6球体随时间显示出预期的生物降解和成骨活性。这些结果证实，nCSi的掺杂离子和该组分分布的轻微调整有利于调节核壳球体的成骨作用。通过合理选择外来离子掺杂这一概念，可能代表了一种用于生产用于骨再生和修复应用的各种核壳生物活性陶瓷的通用策略。
