De Cet Anna, D'Andrea Luca, Gastaldi Dario, Baino Francesco, Verné Enrica, Örlygsson Gissur, Vena Pasquale
Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Laboratory of Biological Structure Mechanics (LaBS)-Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy.
Institute of Materials Physics and Engineering, Department of Applied Science and Technology-Politecnico di Torino, 10129, Turin, Italy.
Sci Rep. 2024 Jan 10;14(1):969. doi: 10.1038/s41598-023-50255-5.
This study focuses on the finite element simulation and micromechanical characterization of bioactive glass-ceramic scaffolds using Computed micro Tomography ([Formula: see text]CT) imaging. The main purpose of this work is to quantify the effect of sintering temperature on the morphometry and mechanical performance of the scaffolds. In particular, the scaffolds were produced using a novel bioactive glass material (47.5B) through foam replication, applying six different sintering temperatures. Through [Formula: see text]CT imaging, detailed three-dimensional images of the scaffold's internal structure are obtained, enabling the extraction of important geometric features and how these features change with sintering temperature. A finite element model is then developed based on the [Formula: see text]CT images to simulate the fracture process under uniaxial compression loading. The model incorporates scaffold heterogeneity and material properties-also depending on sintering temperature-to capture the mechanical response, including crack initiation, propagation, and failure. Scaffolds sintered at temperatures equal to or higher than 700 [Formula: see text]C exhibit two-scale porosity, with micro and macro pores. Finite element analyses revealed that the dual porosity significantly affects fracture mechanisms, as micro-pores attract cracks and weaken strength. Interestingly, scaffolds sintered at high temperatures, the overall strength of which is higher due to greater intrinsic strength, showed lower normalized strength compared to low-temperature scaffolds. By using a combined strategy of finite element simulation and [Formula: see text]CT-based characterization, bioactive glass-ceramic scaffolds can be optimized for bone tissue engineering applications by learning more about their micromechanical characteristics and fracture response.
本研究聚焦于利用计算机断层扫描（μCT）成像对生物活性玻璃陶瓷支架进行有限元模拟和微观力学表征。这项工作的主要目的是量化烧结温度对支架形态测量和力学性能的影响。具体而言，使用新型生物活性玻璃材料（47.5B）通过泡沫复制法制备支架，并应用六种不同的烧结温度。通过μCT成像，获得了支架内部结构的详细三维图像，从而能够提取重要的几何特征以及这些特征如何随烧结温度变化。然后基于μCT图像建立有限元模型，以模拟单轴压缩载荷下的断裂过程。该模型考虑了支架的非均质性和材料特性（其也取决于烧结温度），以捕捉包括裂纹萌生、扩展和失效在内的力学响应。在等于或高于700℃的温度下烧结的支架呈现出双尺度孔隙率，具有微孔和大孔。有限元分析表明，双孔隙率显著影响断裂机制，因为微孔会吸引裂纹并削弱强度。有趣的是，高温烧结的支架虽然由于更高的固有强度而具有更高的整体强度，但与低温支架相比，其归一化强度较低。通过采用有限元模拟和基于μCT的表征相结合的策略，可以通过更多地了解生物活性玻璃陶瓷支架的微观力学特性和断裂响应，对其进行优化以用于骨组织工程应用。
