National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, P. R. China.
Department of Orthopaedic Surgery, West China Hospital, Sichuan University, Chengdu 610041, China.
ACS Appl Mater Interfaces. 2021 Jul 14;13(27):31527-31541. doi: 10.1021/acsami.1c08372. Epub 2021 Jun 28.
It is significant to use functional biomaterials to rationally engineer microenvironments for in situ bone regeneration in the field of bone tissue engineering. To this end, we constructed the gypsum-coated β-tricalcium phosphate (G-TCP) scaffolds by combing a three-dimensional printing technique and an epitaxial gypsum growth method. In vitro simulation experiments showed that the as-prepared scaffolds could establish a dynamic and weakly acidic microenvironment in a simulated body liquid, in which the pH and the calcium ion concentration always changed due to the gypsum degradation and growth of bone-like apatite nanoplates on the scaffold surfaces. The cell experiments confirmed that the microenvironment established by the G-TCP surfaces promoted rapid osteogenic differentiation and proliferation of bone marrow mesenchymal stem cells (BM-MSCs). In vivo experiments confirmed that the G-TCP scaffolds had high bioactivity in modulating in situ regeneration of bone, and the bioactivity of the G-TCP scaffolds was endowed by correct pore structures, degradation of gypsum, and growth of a bone-like apatite layer. The microenvironment established by the gypsum degradation could stimulate tissue inflammation and recruit white blood cells and BM-MSCs and thus accelerating native healing cascades of the bone defects via a bone growth/remodeling-absorption cycle process. Furthermore, in vivo experiments demonstrated that after the bone defects had healed completely, the as-prepared scaffolds also degraded completely within 24 weeks.
在骨组织工程领域，使用功能性生物材料来合理设计原位骨再生的微环境具有重要意义。为此，我们通过结合三维打印技术和外延石膏生长方法构建了石膏涂层β-磷酸三钙（G-TCP）支架。体外模拟实验表明，所制备的支架可以在模拟体液中建立一个动态的弱酸性微环境，由于支架表面的石膏降解和骨样磷灰石纳米板的生长，pH 值和钙离子浓度始终发生变化。细胞实验证实，G-TCP 表面建立的微环境促进了骨髓间充质干细胞（BM-MSCs）的快速成骨分化和增殖。体内实验证实，G-TCP 支架在调节原位骨再生方面具有很高的生物活性，G-TCP 支架的生物活性是由正确的孔结构、石膏的降解和骨样磷灰石层的生长赋予的。石膏降解建立的微环境可以刺激组织炎症，募集白细胞和 BM-MSCs，从而通过骨生长/重塑/吸收循环过程加速骨缺损的自然愈合级联反应。此外，体内实验表明，在骨缺损完全愈合后，所制备的支架也在 24 周内完全降解。
