Amorphous Ca-phosphate (ACP) particles stabilized by inorganic polyphosphate (polyP) were prepared by co-precipitation of calcium and phosphate in the presence of polyP (15% [w/w]). These hybrid nanoparticles showed no signs of crystallinity according to X-ray diffraction analysis, in contrast to the particles obtained at a lower (5% [w/w]) polyP concentration or to hydroxyapatite. The ACP/15% polyP particles proved to be a suitable matrix for cell growth and attachment and showed pronounced osteoblastic and vasculogenic activity in vitro. They strongly stimulated mineralization of the human osteosarcoma cell line SaOS-2, as well as cell migration/microvascularization, as demonstrated in the scratch assay and the in vitro angiogenesis tube forming assay. The possible involvement of an ATP gradient, generated by polyP during tube formation of human umbilical vein endothelial cells, was confirmed by ATP-depletion experiments. In order to assess the morphogenetic activity of the hybrid particles in vivo, experiments in rabbits using the calvarial bone defect model were performed. The particles were encapsulated in poly(d,l-lactide-co-glycolide) microspheres. In contrast, to crystalline Ca-phosphate (containing only 5% [w/w] polyP) or to crystalline β-tricalcium phosphate, amorphous ACP/15% polyP particles caused pronounced osteoinductive activity already after a six-week healing period. The synthesis of new bone tissue was accompanied by an intense vascularization and an increased expression of mineralization/vascularization marker genes. The data show that amorphous polyP-stabilized ACP, which combines osteoinductive activity with the ability to act as a precursor of hydroxyapatite formation both in vitro and in vivo, is a promising material for bone regeneration.

在多聚P（15％[w / w]）存在下，通过钙和磷酸盐的共沉淀来制备由无机多聚磷酸盐（polyP）稳定的非晶态磷酸钙（ACP）颗粒。与以较低（5％[w / w]）polyP浓度或羟基磷灰石获得的颗粒相比，根据X射线衍射分析，这些杂化纳米颗粒没有显示出结晶迹象。ACP / 15％polyP颗粒被证明是适合细胞生长和附着的基质，并在体外具有明显的成骨和血管生成活性。如刮擦试验和体外试验所显示，它们强烈刺激人骨肉瘤细胞SaOS-2的矿化以及细胞迁移/微血管形成。血管生成管形成测定。ATP耗竭实验证实了polyP在人脐静脉内皮细胞管形成过程中产生的ATP梯度可能涉及。为了评估杂种颗粒在体内的形态发生活性，使用颅骨缺损模型在兔中进行了实验。将颗粒包封在聚（d，l-丙交酯-共-乙交酯）微球中。相反，对于结晶磷酸钙（仅含有5％[w / w] polyP）或结晶β-磷酸三钙，非晶态ACP / 15％polyP经过六周的愈合，这些颗粒已经引起明显的骨诱导活性。新骨组织的合成伴随着强烈的血管生成和矿化/血管生成标记基因表达的增加。数据表明，无定形的聚P稳定ACP结合了骨诱导活性和在体外和体内作为羟磷灰石形成前体的能力，是一种有希望的骨再生材料。