Department of Biomedical Engineering, University of Texas, San Antonio, TX, USA.
J Biol Eng. 2013 Oct 3;7(1):23. doi: 10.1186/1754-1611-7-23.
The effects of microchannel diameter in hydroxyapatite (HAp) substrates on osteoblast behavior were investigated in this study. Microchannels of 100, 250 and 500 μm diameter were created on hydroxyapatite disks. The changes in osteoblast precursor growth, differentiation, extra cellular matrix (ECM) secretion and cell attachment/orientation were investigated as a function of microchannel diameter.
Curvature did not impact cellular differentiation, however organized cellular orientation was achieved within the 100 and 250 μm microchannels (mc) after 6 days compared to the 12 days it took for the 500mc group, while the flat substrate remained disorganized. Moreover, the 100, 250 and 500mc groups expressed a specific shift in orientation of 17.45°, 9.05°, and 22.86° respectively in 24 days. The secreted/mineralized ECM showed the 100 and 250mc groups to have higher modulus (E) and hardness (h) (E = 42.6GPa; h = 1.6GPa) than human bone (E = 13.4-25.7GPa; h = 0.47-0.74GPa), which was significantly greater than the 500mc and control groups (p < 0.05). It was determined that substrate curvature affects the cell orientation, the time required for initial response, and the shift in orientation with time.
These findings demonstrate the ability of osteoblasts to organize and mineralize differentially in microchannels similar to those found in the osteons of compact bone. These investigations could lead to the development of osteon-like scaffolds to support the regeneration of organized bone.
本研究探讨了羟基磷灰石（HAp）基质中微通道直径对成骨细胞行为的影响。在羟基磷灰石圆盘上制造了 100、250 和 500μm 直径的微通道。研究了微通道直径对成骨细胞前体生长、分化、细胞外基质（ECM）分泌和细胞附着/定向的变化。
曲率对细胞分化没有影响，然而，在 6 天内，100 和 250μm 微通道（mc）内实现了组织化的细胞定向，而 500mc 组则需要 12 天，而平坦的基质仍然没有组织化。此外，在 24 天内，100、250 和 500mc 组分别表现出 17.45°、9.05°和 22.86°的特定定向变化。分泌/矿化 ECM 显示，100 和 250mc 组的模量（E）和硬度（h）（E=42.6GPa；h=1.6GPa）高于人骨（E=13.4-25.7GPa；h=0.47-0.74GPa），显著高于 500mc 和对照组（p<0.05）。研究结果表明，基质曲率会影响细胞定向、初始反应所需的时间以及随时间的定向变化。
这些发现表明，成骨细胞能够在类似于密质骨骨单位中发现的微通道中进行有差异的组织和矿化。这些研究可能会导致骨单位样支架的开发，以支持有组织的骨再生。
