Departamento de Ingeniería Mecánica, Energética y de los Materiales, Universidad de Extremadura, Avda de Elvas s/n, 06006 Badajoz, Spain.
Acta Biomater. 2010 Nov;6(11):4361-8. doi: 10.1016/j.actbio.2010.05.024. Epub 2010 May 31.
The effect of polymer infiltration on the compressive strength of β-tricalcium phosphate (TCP) scaffolds fabricated by robocasting (direct write assembly) is analyzed in this work. Porous structures consisting of a tetragonal three-dimensional mesh of interpenetrating rods were fabricated from concentrated TCP inks with suitable viscoelastic properties. Biodegradable polymers (polylactic acid (PLA) and poly(ε-caprolactone) (PCL)) were infiltrated into selected scaffolds by immersion of the structure in a polymer melt. Infiltration increased the uniaxial compressive strength of these model scaffolds by a factor of three (PCL) or six (PLA). It also considerably improved the mechanical integrity of the structures after initial cracking, with the infiltrated structure retaining a significant load-bearing capacity after fracture of the ceramic rods. The strength improvement in the infiltrated scaffolds was attributed to two different contributions: the sealing of precursor flaws in the ceramic rod surfaces and the partial transfer of stress to the polymer, as confirmed by finite element analysis. The implications of these results for the mechanical optimization of scaffolds for bone tissue engineering applications are discussed.
本工作分析了聚合物渗透对由 robocasting（直接写入组装）制造的β-磷酸三钙（TCP）支架抗压强度的影响。由具有适当粘弹性的浓缩 TCP 油墨制造的多孔结构由相互贯穿的杆的四方三维网格组成。将可生物降解的聚合物（聚乳酸（PLA）和聚（ε-己内酯）（PCL））通过将结构浸入聚合物熔体中来渗透到选定的支架中。渗透使这些模型支架的单轴抗压强度提高了三倍（PCL）或六倍（PLA）。它还大大提高了结构在初始开裂后的机械完整性，在陶瓷棒断裂后，渗透结构保留了相当大的承载能力。渗透支架的强度提高归因于两个不同的贡献：陶瓷杆表面的先驱缺陷的密封和部分将应力转移到聚合物，这通过有限元分析得到了证实。这些结果对用于骨组织工程应用的支架的机械优化具有重要意义。
