Time-resolved X-ray tomography on the hybrid bone grafts’ freeze-casting formation process inducing a multiscale porosity and mechanical com

Maxillofacial surgeries require centimeters cube medical implants for bone reconstruction. Our aim is to study the mechanisms involved in the freeze-casting (FC) process used to form a new type of “bricks & mortar" composite from bioactive glass nanoparticles (bricks) functionalized with customized polymers (PDLLA, poly (lactic acid), mortar). Our proposal is to use in-situ X-ray phase contrast imaging at ID19: 1) To study the FC formation process. Cooling the solid/solution interface induces the growth of solvent crystals which forms bricks-mortar walls responsible for the bone grafts microporosity, while bubbles nucleation generate vertical air-channels resulting in the scaffold macropores; 2) To quantitatively assess how hierarchical pores formation governs the scaffolds’ mechanical properties, using a compression load cell.

颌面外科手术需要使用立方厘米级医用植入物开展骨重建。本研究旨在探究冷冻铸造（freeze-casting，FC）工艺的相关作用机制，该工艺可通过经定制化聚合物（PDLLA，聚乳酸（poly (lactic acid)））功能化的生物活性玻璃纳米颗粒（作为“砖”）制备新型“砖-砂浆”复合材料，其中聚合物部分充当“砂浆”。我们计划在ID19线站开展原位X射线相衬成像（in-situ X-ray phase contrast imaging）实验，具体包含两项研究内容：1） 探究冷冻铸造的成型过程：固/溶液界面的冷却会诱导溶剂晶体生长，进而形成赋予骨移植物微孔结构的砖-砂浆壁；同时气泡成核会产生垂直空气通道，从而形成支架的大孔结构；2） 借助压缩载荷传感器定量评估分级孔隙形成如何调控支架的力学性能。