In the field of bone regenerative medicine, injectable calcium phosphate cements (CPCs) are used for decades in clinics, as bone void fillers. Most often preformed polymers (e.g., hyaluronic acid, collagen, chitosan, cellulose ethers…) are introduced in the CPC formulation to make it injectable and improve its cohesion. Once the cement has hardened, the polymer is simply trapped in the CPC structure and no organic subnetwork is present. By contrast, in this work a CPC was combined with organic monomers that reticulated in situ so that a continuous biocompatible 3D polymeric subnetwork was formed in the CPC microstructure, resulting in a higher permeability of the CPC, which might allow to accelerate its in vivo degradation. Two options were investigated depending on whether the polymer was formed before the apatitic inorganic network or concomitantly. In the former case, conditions were found to reach a suitable rheology for easy injection of the composite. In addition, the in situ formed polymer was shown to strongly affect the size, density, and arrangement of the apatite crystals formed during the setting reaction, thereby offering an original route to modulate the microstructure and porosity of apatitic cements.

中文翻译：

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生物相容性水凝胶前体与磷灰石磷酸钙水泥 (CPC) 的组合：原位水凝胶网状结构对 CPC 性能的影响。

在骨再生医学领域，可注射磷酸钙骨水泥 (CPC) 作为骨空隙填充剂在临床中使用了数十年。大多数情况下，预制聚合物（例如，透明质酸、胶原蛋白、壳聚糖、纤维素醚……）被引入 CPC 制剂中，以使其可注射并提高其内聚力。一旦水泥硬化，聚合物就会被简单地困在 CPC 结构中，并且不存在有机子网络。相比之下，在这项工作中，CPC 与原位网状有机单体结合，从而在 CPC 微观结构中形成连续的生物相容性 3D 聚合物子网络，导致 CPC 的渗透性更高，这可能会加速其体内降解. 根据聚合物是在磷灰石无机网络之前形成还是同时形成，研究了两种选择。在前一种情况下，发现条件达到合适的流变学，以便于复合材料的注射。此外，原位形成的聚合物显示出强烈影响凝固反应过程中形成的磷灰石晶体的尺寸、密度和排列，从而为调节磷灰石水泥的微观结构和孔隙率提供了原始途径。