Modification of calcium phosphate bioceramics with biologically active metal ions for a specific control of cellular reactions

该研究项目的目的是用不同的金属离子（Co2+, Cu2+， Ni2+等）修饰磷酸钙陶瓷，以刺激生物过程，例如作为植入物骨长入的先决条件的血管生成和促进材料在体内吸收的破骨细胞活性。应用多孔陶瓷材料是由缺乏钙的羟基磷灰石分别为磷酸氢钙（刷石），分别由α -磷酸三钙或β -磷酸三钙在分别稀释的磷酸水溶液中固化得到。模型结构的制造可以通过在硅树脂模具中制造水泥糊状材料，用于孔隙率相对较低的简单几何试验（用于破骨细胞实验），也可以通过3D粉末打印来生产形状复杂的大孔结构，用于研究特定孔隙系统中的血管生成。通过在烧结过程中添加相应的盐以及随后从水溶液中吸附到固化水泥中，金属离子在陶瓷上的负载得以实现。体外研究材料吸收的方法是通过添加分化因子MCSF和RANK-L从人单核细胞中获得破骨细胞，通过破骨细胞特异性酶TRAP（抗酒石酸酸性磷酸酶）和碳酸酐酶II的活性来定量评估其分化。通过在胶原/纤维蛋白凝胶中培养的人内皮细胞，通过荧光显微复制研究其粘附、增殖和管状结构的形成，研究了金属离子修饰的水泥的血管生成能力。为了更好地了解金属离子对内皮细胞和血管生成的影响，将对血管生成过程中涉及的不同基因和蛋白质的表达进行额外的检查。最后，将在小动物模型中评估材料的破骨细胞重吸收和血管化，其中吸收研究在大鼠胫骨中原位进行，而血管生成则在大鼠皮下组织中进行量化。

The aim of the research project is the modification of calcium phosphate ceramics with different metal ions (Co2+, Cu2+, Ni2+ etc.) for the stimulation of biological processes, e.g. the angiogenesis as a precondition for bony ingrowth of implants and the osteoclast activity for promoted in vivo resorption of the materials. Applied porous ceramic materials are made from calcium deficient hydroxyapatite respectively calcium hydrogen phosphate (brushite), which are obtained from cement setting reactions of alpha- or beta-tricalcium phosphate in aqueous solution respectively diluted phosphoric acid. The fabrication of model structures occurs either by manufacturing of the materials as cement paste in silicone moulds for simple geome-tries with relatively low porosities (for experiments with osteoclasts) or by 3D powder printing for the production of complexly shaped macroporous structures for studying the angiogene-sis in defined pore systems. The loading of the ceramics with metal ions is carried out by either addition of the respective salts during sintering as well as by subsequent adsorption from aqueous solutions to set cements. In vitro investigations of material resorption are per-formed with osteoclasts, obtained from human monocytes by addition of the differentiation factors MCSF and RANK-L, of which the differentiation is quantitatively evaluated via the activity of the osteoclast-specific enzymes TRAP (tartrate-resistant acid phosphatase) and carbonic anhydrase II. The angiogenic potency of cements modified with metal ions is exam-ined by means of human endothelial cells cultivated in collagen/fibrin gels, whereby their ad-hesion, proliferation and formation of tubular structures are studied by fluorescence micros-copy. To obtain a better understanding of the effects of metal ions on endothelial cells respectively the angiogenesis, additional examinations of the expression of different genes and proteins involved in the angiogenic process will be carried out. Finally, the osteoclastic re-sorption and vascularization of the materials will be evaluated in vivo in a small animal model, whereby the resorption studies occur orthotopically in rat tibia, while the angiogenesis is quantified in subcutaneous tissue of rats.