Ideal artificial bone grafts aim for multiscale porosity, high mechanical strength and ensure rapid vascularization for bone ingrowth. In this work modular ceramic arteriovenous loops (AV-loops) with a hierarchical porosity approach were designed and manufactured to meet these criteria and to exceed the poor mechanical strength of monolithic scaffolds. Bioactive building blocks (β-TCP, HAp, BCP) with dimensions of 1.5 – 3.0 mm were prepared by injection molding and assembled to complex AV-loop scaffolds using a customized automated assembly technology (pick and place). The building blocks were bonded with a biocompatible adhesive. Single building blocks are characterized by a compressive strength of 112.4 – 134.5 MPa with a residual sintering porosity of 32.2 – 41.5 %, matching the strength of cortical bone of 100 – 230 MPa. The compressive strength of the modular assemblies varied between 22.3 – 47.6 MPa primary depending on the building block arrangement. The achieved compressive strengths are superior to current monolithic AV-scaffolds and sufficient for the implantation as non-load-bearing AV-loop scaffolds in isolation chambers. The modular AV-loop scaffolds provide a hierarchical interconnected pore network (P = 58.8 %) combining small macropores of 4.1 – 4.3 µm size for possible enhanced protein absorption and large gradient macropores of 200 – 1700 µm size for optimum vascularization and complete bone ingrowth. The modular building block approach allows to design patient individualized scaffolds with complex hierarchical pore networks. The pore volume, size and geometry as well as the biological response can effectively be tuned by changing the dimensions, shape and placing gap of the bioactive building blocks.

Statement of significance

Gold standard of bone replacement in case of surgery or cancer is still own bone material usually taken from the hip / arm or leg in second surgery with poor mechanical properties and limited amount. To avoid a second surgery and provide mechanical strong scaffold structures for fast patient regeneration a novel modular building block approach is used. This allows complex scaffold geometry with a hierarchical interconnection porosity for blood vessel ingrowth. The pore volume, size and geometry as well as the biological response can effectively be tuned by changing the dimensions, shape and placing gap of the bioactive building blocks.

中文翻译：

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用于单个植入物的模块化陶瓷支架

理想的人造骨移植物旨在实现多尺度的孔隙率，高机械强度并确保骨骼向内生长的快速血管生成。在这项工作中，设计并制造了具有分层孔隙率方法的模块化陶瓷动静脉环（AV环），以满足这些标准并超过了整体式支架的较差的机械强度。通过注射成型制备尺寸为1.5  –  3.0  mm的生物活性结构块（β-TCP，HAp，BCP），并使用定制的自动化组装技术（拾取和放置）将其组装成复杂的AV环支架。用生物相容性粘合剂粘结构件。单个构件的特点是抗压强度为112.4  –  134.5  MPa，残余烧结孔隙率为32.2 –  41.5  ％，与100  –  230  MPa的皮质骨强度相匹配。模块化组件的抗压强度主要在22.3  –  47.6  MPa之间变化，具体取决于构件的布置。所获得的抗压强度优于当前的整体式AV支架，并且足以作为隔离室内的非承重AV环支架植入。模块化的AV环支架提供了一个分层的互连孔网络（P  =  58.8  ％），结合了4.1  –  4.3  µm大小的小大孔，可能增强了蛋白质的吸收，以及200  –  1700的大梯度大孔 µm尺寸可实现最佳的血管形成和完整的骨长入。模块化的构建方法允许设计具有复杂的分层孔网络的患者个性化支架。通过改变生物活性结构单元的尺寸，形状和放置间隙，可以有效地调节孔的体积，大小和几何形状以及生物反应。

重要声明

在外科手术或癌症的情况下，骨置换的黄金标准仍然是通常在第二次手术中从臀部/手臂或腿部获取的自身骨骼材料，其机械性能差且数量有限。为了避免第二次手术并为快速的患者再生提供机械坚固的支架结构，使用了一种新颖的模块化构件方法。这允许复杂的支架几何形状具有用于血管向内生长的分层互连孔隙率。可以通过改变生物活性构件的尺寸，形状和放置间隙来有效地调节孔的体积，大小和几何形状以及生物学反应。