Abstract：
Researchers agree that the ideal scaffold for tissue engineering should possess a 3D and highly porous structure, biocompatibility to encourage cell/tissue growth, suitable surface chemistry for cell attachment and differentiation, and mechanical properties that match those of the surrounding tissues. However, there is no consensus on the optimal pore distribution. In this study, we investigated the effect of pore distribution on corrosion resistance and performance of human mesenchymal stem cells (hMSC) using titanium scaffolds fabricated by laser beam powder bed fusion (PBF-LB). We designed two scaffold architectures with the same porosities (i.e., 75 %) but different distribution of pores of three sizes (200, 500, and 700 μm). The pores were either grouped in three zones (graded, GRAD) or distributed randomly (random, RAND). Microfocus X-ray computed tomography revealed that the chemically polished scaffolds had the porosity of 69 ± 4 % (GRAD) and 71 ± 4 % (RAND), and that the GRAD architecture had the higher surface area (1580 ± 101 vs 991 ± 62 mm2) and the thinner struts (221 ± 37 vs 286 ± 14 μm). The electrochemical measurements demonstrated that the apparent corrosion rate of chemically polished GRAD scaffold decreased with the immersion time extension, while that for polished RAND was increased. The RAND architecture outperformed the GRAD one with respect to hMSC proliferation (over two times higher although the GRAD scaffolds had 85 % higher initial cell retention) and migration from a monolayer. Our findings demonstrate that the pore distribution affects the biological properties of the titanium scaffolds for bone tissue engineering.
摘要：
研究人员一致认为，组织工程的理想支架应该具有3D和高度多孔的结构，促进细胞/组织生长的生物相容性，适合细胞附着和分化的表面化学，以及与周围组织相匹配的机械性能。然而,关于最佳孔隙分布尚无共识。在这项研究中,我们使用激光束粉末床融合（PBF-LB）制备的钛支架研究了孔分布对人类间充质干细胞（hMSC）的耐腐蚀性和性能的影响。我们设计了两种具有相同孔隙率的支架架构(即，75％），但三种尺寸（200、500和700μm）的孔分布不同。孔隙分为三个区域(分级，GRAD)或随机分布(随机，兰德）。微焦点X射线计算机断层扫描显示，化学抛光的支架的孔隙率为69±4％（GRAD）和71±4％（RAND），GRAD结构具有较高的表面积（1580±101vs991±62mm2）和较薄的支柱（221±37vs286±14μm）。电化学测量表明，化学抛光的GRAD支架的表观腐蚀速率随浸泡时间的延长而降低。而抛光的兰德增加了。RAND结构在hMSC增殖(高于两倍以上,尽管GRAD支架具有较高的85%的初始细胞保留)和从单层迁移方面优于GRAD结构。我们的发现表明，孔分布会影响用于骨组织工程的钛支架的生物学特性。
