There is increasing interest in biodegradable ceramic scaffolds for bone tissue engineering capable of in situ delivery of ionic species favoring bone formation. Strontium has been shown to be osteogenic, but strontium-containing drugs such as strontium ranelate, used in Europe for the treatment of osteoporosis, are now restricted due to clinical evidence of systemic effects. By doping fluorapatite-based glasses with strontium, we developed ceramic scaffolds with fully interconnected macroporosity and cell size similar to that of cancellous bone, that are also capable of releasing strontium. The crystallization behavior, investigated by XRD and SEM, revealed the formation of akermanite and fluorapatite at the surface of strontium-free glass-ceramic scaffolds, and strontium-substituted fluorapatite at the surface of the strontium-doped scaffolds. At 8 weeks after implantation in a rat calvarial critical size defect, scaffolds doped with the highest amount of strontium led to the highest mineral apposition rate. A significantly higher amount of newly-formed bone was found with the strontium-free glass-ceramic scaffold, and possibly linked to the presence of akermanite at the scaffold surface. We demonstrate by energy dispersive XRF analyses of skull sections that strontium was present in newly formed bone with the strontium-doped scaffolds, while a significant amount of fluorine was incorporated in newly formed bone, regardless of composition or crystallization state.

Statement of significance

The present work demonstrates the in vivo action of strontium-containing glass-ceramic scaffolds. These bone graft substitutes are targeted at non load-bearing bone defects. Results show that strontium is successfully incorporated in newly formed bone. This is associated with a significantly higher Mineral Apposition Rate. The benefits of in situ release of strontium are demonstrated. The broader scientific impact of this works builds on the concept of resorbable ceramic scaffolds as reservoirs of ionic species capable of enhancing bone regeneration.

中文翻译：

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释放锶的氟磷灰石玻璃陶瓷支架：结构表征和体内性能

能够在原位进行骨组织工程的可生物降解陶瓷支架的兴趣日益浓厚传递有利于骨骼形成的离子物质。锶已被证明具有成骨作用，但是由于临床上有全身性作用的证据，现在在欧洲用于治疗骨质疏松症的含锶药物（如雷奈酸锶）已经受到限制。通过用锶掺杂基于氟磷灰石的玻璃，我们开发了具有完全互连的大孔性和类似于松质骨的细胞大小的陶瓷支架，它们也能够释放锶。通过XRD和SEM研究的结晶行为揭示了在无锶玻璃陶瓷支架表面上形成了钙钛矿和氟磷灰石，在掺锶支架上形成了锶取代的氟磷灰石。植入大鼠颅脑关键尺寸缺损后8周，掺锶量最高的支架导致最高的矿物沉积率。不含锶的玻璃-陶瓷支架发现大量新形成的骨，并且可能与支架表面上的钙钛矿存在有关。通过对颅骨截面的能量色散XRF分析，我们证明，锶掺杂的支架在新形成的骨骼中存在锶，而新形成的骨骼中掺入了大量的氟，无论其组成或结晶状态如何。

重要声明

本工作证明了含锶的玻璃陶瓷支架的体内作用。这些骨移植替代物的目标是非承重的骨缺损。结果表明，锶成功地掺入了新形成的骨骼中。这与明显更高的矿物质沉积率有关。的好处原位锶释放被证实。这项工作具有更广泛的科学影响，其基础是可吸收陶瓷支架作为能够增强骨骼再生的离子物种的储存库的概念。