Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, the Netherlands.
Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, the Netherlands.
Acta Biomater. 2022 Aug;148:355-373. doi: 10.1016/j.actbio.2022.06.009. Epub 2022 Jun 9.
Advanced additive manufacturing techniques have been recently used to tackle the two fundamental challenges of biodegradable Fe-based bone-substituting materials, namely low rate of biodegradation and insufficient bioactivity. While additively manufactured porous iron has been somewhat successful in addressing the first challenge, the limited bioactivity of these biomaterials hinder their progress towards clinical application. Herein, we used extrusion-based 3D printing for additive manufacturing of iron-matrix composites containing silicate-based bioceramic particles (akermanite), thereby addressing both of the abovementioned challenges. We developed inks that carried iron and 5, 10, 15, or 20 vol% of akermanite powder mixtures for the 3D printing process and optimized the debinding and sintering steps to produce geometrically-ordered iron-akermanite composites with an open porosity of 69-71%. The composite scaffolds preserved the designed geometry and the original α-Fe and akermanite phases. The in vitro biodegradation rates of the composites were improved as much as 2.6 times the biodegradation rate of geometrically identical pure iron. The yield strengths and elastic moduli of the scaffolds remained within the range of the mechanical properties of the cancellous bone, even after 28 days of biodegradation. The composite scaffolds (10-20 vol% akermanite) demonstrated improved MC3T3-E1 cell adhesion and higher levels of cell proliferation. The cellular secretion of collagen type-1 and the alkaline phosphatase activity on the composite scaffolds (10-20 vol% akermanite) were, respectively higher than and comparable to Ti6Al4V in osteogenic medium. Taken together, these results clearly show the potential of 3D printed porous iron-akermanite composites for further development as promising bone substitutes. STATEMENT OF SIGNIFICANCE: Porous iron matrix composites containing akermanite particles were produced by means of multi-material additive manufacturing to address the two fundamental challenges associated with biodegradable iron-based biomaterials, namely very low rate of biodegradation and insufficient bioactivity. Our porous iron-akermanite composites exhibited enhanced biodegradability and superior bioactivity compared to porous monolithic iron scaffolds. The murine bone cells proliferated on the composite scaffolds, and secreted the collagen type-1 matrix that stimulated bony-like mineralization. The results show the exceptional potential of the developed porous iron-based composite scaffolds for application as bone substitutes.
先进的增材制造技术最近被用于解决可生物降解的铁基骨替代材料的两个基本挑战，即降解率低和生物活性不足。虽然增材制造的多孔铁在一定程度上成功地解决了第一个挑战，但这些生物材料的生物活性有限，阻碍了它们向临床应用的发展。在此，我们使用基于挤出的 3D 打印技术来制造含有硅酸盐生物陶瓷颗粒（硅灰石）的铁基复合材料，从而解决了上述两个挑战。我们开发了携带铁和 5、10、15 或 20 体积%硅灰石粉末混合物的油墨，用于 3D 打印工艺，并优化了脱脂和烧结步骤，以生产具有 69-71%开放孔隙率的几何有序的铁-硅灰石复合材料。复合支架保留了设计的几何形状和原始的 α-Fe 和硅灰石相。复合材料的体外降解率提高了 2.6 倍，与几何形状相同的纯铁的降解率相比。支架的屈服强度和弹性模量仍在松质骨机械性能范围内，即使在 28 天的生物降解后也是如此。复合支架（10-20 体积%硅灰石）显示出改善的 MC3T3-E1 细胞黏附性和更高水平的细胞增殖。在成骨培养基中，复合支架（10-20 体积%硅灰石）上细胞分泌的 I 型胶原和碱性磷酸酶活性分别高于和相当于 Ti6Al4V。总的来说，这些结果清楚地表明，3D 打印多孔铁-硅灰石复合材料具有进一步开发为有前途的骨替代物的潜力。
通过多材料增材制造生产了含有硅灰石颗粒的多孔铁基复合材料，以解决与可生物降解铁基生物材料相关的两个基本挑战，即非常低的降解率和不足的生物活性。与多孔整体铁支架相比，我们的多孔铁-硅灰石复合材料表现出增强的生物降解性和优异的生物活性。在复合支架上，鼠骨细胞增殖，并分泌刺激类骨质矿化的 I 型胶原基质。结果表明，开发的多孔铁基复合支架具有作为骨替代物应用的特殊潜力。
