Li Xiangfeng, Deng Yanglong, Wang Menglu, Chen Xuening, Xiao Yumei, Zhang Xingdong
National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China.
J Mater Chem B. 2018 Jan 7;6(1):84-97. doi: 10.1039/c7tb02620j. Epub 2017 Dec 5.
It is of significance to further improve the bioactivity of existing calcium phosphate (Ca-P) biomaterials to satisfy the needs of regenerative medicine. Due to its compositional similarity to natural bone mineral, calcium-deficient hydroxyapatite (CDHA) is supposed to possess excellent bioactivity. However, it is difficult to fabricate Ca-P ceramics with a high amount of CDHA, as CDHA is easy to decompose during the sintering process. The present study introduced an effective approach to stabilize CDHA in biphasic calcium phosphate (BCP) ceramics by adding alginate, and investigated the roles of CDHA in their biological performances. The characterization of the phase composition, crystal structure, and functional group demonstrated that the addition of alginate could obviously inhibit CDHA decomposition to attain novel BCP ceramics with a high CDHA content (BCP-A), which could better mimic the inorganic composition of natural bones as compared with the conventional BCP ones (BCP-C). In vitro studies suggested BCP-A showed better bioactivity and osteoinductive capacity than BCP-C, as evidenced by the increased serum protein adsorption, better bone-like apatite formation and cell spreading, and promoted osteogenic differentiation. In vivo intramuscular implantation further confirmed that BCP-A could induce more ectopic bone formation than BCP-C, suggesting BCP-A had a stronger osteoinductivity. Altogether, this study demonstrates that the stabilization of CDHA in BCP ceramics by adding alginate offers a promising principle for designing regenerative biomaterials to process superior biological performances.
进一步提高现有磷酸钙（Ca-P）生物材料的生物活性对于满足再生医学的需求具有重要意义。由于缺钙羟基磷灰石（CDHA）的成分与天然骨矿物质相似，因此被认为具有优异的生物活性。然而，由于CDHA在烧结过程中容易分解，难以制备出高含量CDHA的Ca-P陶瓷。本研究引入了一种通过添加海藻酸钠来稳定双相磷酸钙（BCP）陶瓷中CDHA的有效方法，并研究了CDHA在其生物学性能中的作用。相组成、晶体结构和官能团的表征表明，添加海藻酸钠可以明显抑制CDHA的分解，从而获得具有高CDHA含量的新型BCP陶瓷（BCP-A），与传统的BCP陶瓷（BCP-C）相比，它能更好地模拟天然骨的无机组成。体外研究表明，BCP-A比BCP-C表现出更好的生物活性和骨诱导能力，血清蛋白吸附增加、更好的类骨磷灰石形成和细胞铺展以及促进成骨分化都证明了这一点。体内肌肉植入进一步证实，BCP-A比BCP-C能诱导更多的异位骨形成，表明BCP-A具有更强的骨诱导性。总之，本研究表明通过添加海藻酸钠来稳定BCP陶瓷中的CDHA为设计具有优异生物学性能的再生生物材料提供了一个有前景的原则。
