Geng Zhen, Ji Luli, Li Zhaoyang, Wang Jing, He Hongyan, Cui Zhenduo, Yang Xianjin, Liu Changsheng
Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai, 200237, China.
Engineering Research Center for Biomedical Materials of the Ministry of Education, East China University of Science and Technology, Shanghai, 200237, China.
Bioact Mater. 2020 Oct 7;6(4):905-915. doi: 10.1016/j.bioactmat.2020.09.024. eCollection 2021 Apr.
Implant loosening remains a major clinical challenge for osteoporotic patients. This is because osteoclastic bone resorption rate is higher than osteoblastic bone formation rate in the case of osteoporosis, which results in poor bone repair. Strontium (Sr) has been widely accepted as an anti-osteoporosis element. In this study, we fabricated a series of apatite and Sr-substituted apatite coatings via electrochemical deposition under different acidic conditions. The results showed that Ca and Sr exhibited different mineralization behaviors. The main mineralization products for Ca were CaHPO·2HO and Ca(PO) with the structure changed from porous to spherical as the pH values increased. The main mineralization products for Sr were SrHPO and Sr(PO)OH with the structure changed from flake to needle as the pH values increased. The experiment demonstrated that coatings fabricated at high pH condition with the presence of Sr were favorable to MSCs adhesion, spreading, proliferation, and osteogenic differentiation. In addition, Sr-substituted apatite coatings could evidently inhibit osteoclast differentiation and fusion. Moreover, the study indicated that nano-needle like Sr-substituted apatite coating could suppress osteoclastic activity, improve new bone formation, and enhance bone-implant integration. This study provided a new theoretical guidance for implant coating design and the fabricated Sr-substituted coating might have potential applications for osteoporotic patients.
种植体松动仍然是骨质疏松患者面临的一项重大临床挑战。这是因为在骨质疏松情况下，破骨细胞的骨吸收速率高于成骨细胞的骨形成速率，从而导致骨修复不佳。锶（Sr）已被广泛公认为一种抗骨质疏松元素。在本研究中，我们通过电化学沉积在不同酸性条件下制备了一系列磷灰石和锶取代的磷灰石涂层。结果表明，钙和锶表现出不同的矿化行为。钙的主要矿化产物是CaHPO·2H₂O和Ca₃(PO₄)₂，随着pH值升高，其结构从多孔变为球形。锶的主要矿化产物是SrHPO₄和Sr₃(PO₄)₂OH，随着pH值升高，其结构从片状变为针状。实验表明，在高pH条件下且存在锶时制备的涂层有利于间充质干细胞的黏附、铺展、增殖和成骨分化。此外，锶取代的磷灰石涂层能明显抑制破骨细胞的分化和融合。而且，该研究表明纳米针状锶取代的磷灰石涂层能抑制破骨细胞活性，促进新骨形成，并增强骨与种植体的整合。本研究为种植体涂层设计提供了新的理论指导，所制备的锶取代涂层可能对骨质疏松患者具有潜在应用价值。
