Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
Biomaterials. 2012 Nov;33(31):7727-35. doi: 10.1016/j.biomaterials.2012.07.008. Epub 2012 Jul 25.
Biomaterial scaffolds with gradients in architecture, mechanical and chemical properties have the potential to improve the osseointegration of ligament grafts by recapitulating phenotypic gradients that exist at the natural ligament-bone (L-B) interface. Towards the larger goal of regenerating the L-B interface, this in vitro study was performed to investigate the potential of two scaffolds with mineral gradients in promoting a spatial gradient of osteoblastic differentiation. Specifically, the first graded scaffold was fabricated by co-electrospinning two polymer solutions (one doped with nano-hydroxyapatite particles) from offset spinnerets, while the second was created by immersing the first scaffold in a 5 × simulated body fluid. Rat bone marrow stromal cells, cultured in the presence of osteogenic supplements, were found to be metabolically active on all regions of both scaffolds after 1 and 7 days of culture. Gene expression of bone morphogenic protein-2 and osteopontin was elevated on mineral-containing regions as compared to regions without mineral, while the expression of alkaline phosphatase mRNA revealed the opposite trend. Finally, the presence of osteopontin and bone sialoprotein confirmed osteoblastic phenotypic maturation by day 28. This study indicates that co-electrospun scaffolds with gradients in mineral content can guide the formation of phenotypic gradients and may thus promote the regeneration of the L-B interface.
具有建筑、机械和化学性能梯度的生物材料支架有可能通过再现自然韧带-骨（L-B）界面存在的表型梯度来改善韧带移植物的骨整合。为了实现更大的目标，即再生 L-B 界面，本体外研究旨在探讨两种具有矿物质梯度的支架在促进成骨细胞分化的空间梯度方面的潜力。具体来说，第一种梯度支架是通过从偏移喷丝头共静电纺丝两种聚合物溶液（一种掺杂纳米羟基磷灰石颗粒）来制造的，而第二种支架是通过将第一种支架浸入 5×模拟体液中来制造的。在存在成骨补充剂的情况下培养的大鼠骨髓基质细胞在培养 1 天和 7 天后，在两种支架的所有区域都表现出代谢活性。与不含矿物质的区域相比，含有矿物质的区域骨形态发生蛋白-2 和骨桥蛋白的基因表达升高，而碱性磷酸酶 mRNA 的表达则呈现相反的趋势。最后，在第 28 天，骨桥蛋白和骨唾液蛋白的存在证实了成骨细胞表型的成熟。本研究表明，具有矿物质含量梯度的共静电纺丝支架可以引导表型梯度的形成，从而可能促进 L-B 界面的再生。
