Linder Houston R, Glass Austin A, Day Delbert E, Sell Scott A
Biomedical Engineering, Parks College of Engineering, Aviation, and Technology, Saint Louis University, Saint Louis, MI 63103, USA.
Material Science and Engineering, Missouri University of Science and Technology, Rolla, MI 65409, USA.
Bioengineering (Basel). 2020 Dec 20;7(4):165. doi: 10.3390/bioengineering7040165.
Osteons are the repeating unit throughout cortical bone, consisting of canals filled with blood and nerve vessels surrounded by concentric lamella of hydroxyapatite-containing collagen fibers, providing mechanical strength. Creating a biodegradable scaffold that mimics the osteon structure is crucial for optimizing cellular infiltration and ultimately the replacement of the scaffold with native cortical bone. In this study, a modified air-gap electrospinning setup was exploited to continuously wrap highly aligned polycaprolactone polymer nanofibers around individual 1393 bioactive glass microfibers, resulting in a synthetic structure similar to osteons. By varying the parameters of the device, scaffolds with polymer fibers wrapped at angles between 5-20° to the glass fiber were chosen. The scaffold indicated increased cell migration by demonstrating unidirectional cell orientation along the fibers, similar to recent work regarding aligned nerve and muscle regeneration. The wrapping decreased the porosity from 90% to 80%, which was sufficient for glass conversion through ion exchange validated by inductively coupled plasma. Scaffold degradation was not cytotoxic. Encapsulating the glass with polymer nanofibers caused viscoelastic deformation during three-point bending, preventing typical brittle glass fracture, while maintaining cell migration. This scaffold design structurally mimics the osteon, with the intent to replace its material compositions for better regeneration.
骨单位是整个皮质骨的重复单元，由充满血液和神经血管的管道组成，周围是含羟基磷灰石的胶原纤维同心层，提供机械强度。创建一种模仿骨单位结构的可生物降解支架对于优化细胞浸润以及最终用天然皮质骨替代支架至关重要。在本研究中，利用一种改进的气隙静电纺丝装置，将高度排列的聚己内酯聚合物纳米纤维连续包裹在单个1393生物活性玻璃微纤维周围，形成一种类似于骨单位的合成结构。通过改变装置参数，选择了聚合物纤维以5-20°角缠绕在玻璃纤维上的支架。该支架通过显示细胞沿纤维单向排列表明细胞迁移增加，这与最近关于排列的神经和肌肉再生的研究相似。这种缠绕使孔隙率从90%降至80%，这足以通过电感耦合等离子体验证的离子交换实现玻璃转化。支架降解没有细胞毒性。用聚合物纳米纤维包裹玻璃在三点弯曲过程中引起粘弹性变形，防止了典型的脆性玻璃断裂，同时保持细胞迁移。这种支架设计在结构上模仿骨单位，旨在替代其材料成分以实现更好的再生。
