基于形函数控制的组织工程骨架孔隙结构实体建模方法

Computer Modeling Approach for a Porous Scaffold Structure in Tissue Engineering Based on the Shape Function Control

组织工程支架在组织工程研究中起着重要作用,它不仅为特定的细胞提供结构支撑作用,而且能引导组织再生和控制组织结构。从几何建模的角度,寻找一种通用的组织工程骨架实体建模方法:采用有限元中六面体单元对实体模型进行网格剖分;利用有限元中的八结点六面体形函数将参数域中的基本孔隙单元映射为空间域中各种不规则孔隙几何单元。利用布尔并运算构建实体的造孔单元。再与整个实体轮廓模型(CT/MRI)进行逻辑差运算,就可以得到组织工程骨架模型。研究表明:通过有限元单元剖分方法,有效地解决了组织工程骨架孔隙体元的分布计算等技术问题,相对随机几何方法,具有很好的技术操作性和高效性。通过剖分单元约束和孔隙体元变形构型方法的应用,可大大提高骨组织孔隙形状的自然性。

The porous scaffold plays an important part in the tissue engineering. It not only provides structure support for cells, but also guides the regeneration of tissues and controls the tissue structures. From the viewpoint of geometric modeling, a universal method for porous scaffold modeling is presented： Firstly, the solid model is subdivided based on the technique of all-hexahedral mesh generation; secondly, the basic pore element in the parametric domain is mapped based on the shape ftmction of eight-node isoparametric hexahedron and anomalous pore element model can be obtained in space domain; then the whole pore model can be constructed based on the Boolean operation union; at last the bone scaffold can be modeled by subtracting the whole pore model from the solid model. The results show that the distribution for various irregular pores can be achieved by using the method proposed. Moreover, the method is more operable and effective compared to the stochastic geometry. Because irregular pores are controlled by various irregular hexahedral elements and mapped based on shape function, various irregular pores which simulate those in the natural bone are created in the bone scaffold.