Strut size and surface area effects on long-term in vivo degradation in computer designed poly(l-lactic acid) three-dimensional porous scaffolds

详细信息	查看全文 | 推荐本文 |

• 作者：Eiji Saito^a ; Yifei Liu^a ; Francesco Migneco^a ; Scott J. Hollister^a ; ^b ; ^c ; ^{scottho@umich.edu}
• 关键词：Polylactic acid ; Porous scaffold ; Solid freeform fabrication ; In vivo degradation
• 刊名：Acta Biomaterialia
• 出版年：2012
• 期刊代码：1_17427061
• 类别：ce
• 出版时间：July, 2012
• 卷：8
• 期：7
• 页码：2568-2577
• 文件大小：895 K

摘要

Current developments in computer-aided design (CAD) and solid free-form fabrication (SFF) techniques enable fabrication of scaffolds with precisely designed architectures and mechanical properties. The present study demonstrates the effect of precisely designed three-dimensional scaffold architectures on in vivo degradation. Specifically, three types of porous poly(l-lactic acid) (PLLA) scaffolds with variable pore sizes, strut sizes, porosities, and surface areas fabricated by indirect SFF. In addition, one experimental group of PLLA solid cylinders was fabricated. The scaffolds and cylinders were subcutaneously implanted into mice for 6, 12 and 21 weeks. The solid cylinders exhibited a faster percentage mass loss than all porous scaffolds. Among the porous scaffolds the group with the largest strut size lost percentage mass faster than the other two groups. Strong correlations between surface area and percentage mass loss were found at 12 (R² = 0.681) and 21 (R² = 0.671) weeks. Scaffold porosity, however, was not significantly correlated with degradation rate. Changes in molecular weight and crystallinity also resulted in changes in the chemical structures due to degradation, and the solid cylinders had faster crystallization due to more advanced degradation than the porous scaffolds. Scaffold compressive moduli decreased with degradation, but the resulting modulus was still within the lower range of human trabecular bone even after 21 weeks. The loss in compressive moduli, however, was a complex function of both degradation and the initial scaffold architecture. This study suggests that CAD and fabrication, within a given material, can significantly influence scaffold degradation profiles.