可降解连续纤维增强钙磷陶瓷支架的3D打印及性能研究

3D printing and performance of biodegradable continuous fiber-reinforced calcium phosphate ceramic scaffolds

  • 摘要: 磷酸钙(CaP)陶瓷与天然骨矿物质相似,表现出优异的生物活性、生物相容性和骨传导特性,是天然骨移植的主要替代品之一。多孔CaP支架能够提供有利于骨长入的三维空间和生物相容性表面。但陶瓷材料的固有脆性限制了其应用范围。本文通过研发的微米级单丝连续纤维(30 μm~60 μm)增强复合材料3D打印装置制备了连续PGA纤维增强钙磷陶瓷(PGA/HTC)支架。此装置通过控制纤维送丝速度,送丝辊表面的弹性元件的变形调节纤维的送进、纤维与浆料滚压复合及包覆,克服了3D打印过程中微米纤维送进及其与浆料复合困难的问题,实现微米级连续纤维增强复合材料的3D打印。所制备的PGA/HTC支架的压缩强度为3.84 MPa,在松质骨范围内。PGA/HTC支架的最大应变为13.23%,相比于HTC支架(4.52%)增加了192.7%。表明连续PGA纤维的引入,有效提升生物陶瓷支架的韧性和变形能力,降低了生物陶瓷支架的脆性。支架在SBF浸泡7天后,质量减少率为32.8%,而在14天时,质量变化不大,这表明浸泡初期支架的溶解大于磷灰石的形成速率,而后达到平衡。同时,基体与纤维表面、纤维与基体的空隙中形成磷灰石,随着时间的延长,磷灰石层厚度增加。磷灰石层Ca/P为1.45~1.69,所制备的PGA/HTC支架具有优异的降解性能和生物活性。

     

    Abstract: Calcium phosphate (CaP) ceramics, with similar consitutent to natural bone minerals, exhibit excellent biological activity, biocompatibility, and bone conduction properties and have been one of the main alternatives to bone grafts. Porous CaP scaffolds can provide a three-dimensional space and biocompatible surface for bone ingrowth. However, the inherent brittleness of ceramics limits their wide application. Continuous PGA fiber-reinforced calcium phosphate ceramic (PGA/HTC) scaffolds were fabricated using a micro-level single filament continuous fiber (30 μm~60 μm) reinforced composite 3D printing device developed in this study. This device controls fiber feeding, rolling combination of fiber and matrix, and fiber covered with matrix through adjusting fiber feeding speed and deformation of elastic component on the surface of feeding roller. It solves the issues of feeding micron-sized fibers and their integration with the slurry during the 3D printing process and can be used to print micron-scale continuous fiber-reinforced composites. Compressive strength of the fabricated PGA/HTC scaffold is 3.84 MPa, which falls within the range of cancellous bone. Maximum strain of the PGA/HTC scaffold is 13.23%, which is 192.7% higher than that of the HTC scaffold (4.52%). This indicates that the introduction of continuous PGA fibers effectively enhances the toughness and deformation capacity of the bioceramic scaffold, while reducing its brittleness. After 7 days of immersion in SBF, the mass loss rate of the scaffold is 32.8%, while there is little mass change after 14 days. This indicates that during the initial immersion period, the dissolution of the scaffold exceeds the rate of apatite formation, and equilibrium is reached thereafter. At the same time, apatite forms on the surface of the matrix and fibers, as well as in the voids between the matrix and fibers. Over time, the thickness of the apatite layer increases. The Ca/P ratio of the apatite layer ranges from 1.45 to 1.69, indicating that the fabricated PGA/HTC scaffold has excellent degradation performance and bioactivity.

     

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