Department of Materials, Imperial College London, South Kensington, London SW7 2AZ, UK.
Department of Materials, Imperial College London, South Kensington, London SW7 2AZ, UK.
Acta Biomater. 2014 Aug;10(8):3733-46. doi: 10.1016/j.actbio.2014.05.020. Epub 2014 May 27.
Inorganic sol-gel solutions were electrospun to produce the first bioactive three-dimensional (3-D) scaffolds for bone tissue regeneration with a structure like cotton-wool (or cotton candy). This flexible 3-D fibrous structure is ideal for packing into complex defects. It also has large inter-fiber spaces to promote vascularization, penetration of cells and transport of nutrients throughout the scaffold. The 3-D fibrous structure was obtained by electrospinning, where the applied electric field and the instabilities exert tremendous force on the spinning jet, which is required to be viscoelastic to prevent jet break up. Previously, polymer binding agents were used with inorganic solutions to produce electrospun composite two-dimensional fibermats, requiring calcination to remove the polymer. This study presents novel reaction and processing conditions for producing a viscoelastic inorganic sol-gel solution that results in fibers by the entanglement of the intermolecularly overlapped nanosilica species in the solution, eliminating the need for a binder. Three-dimensional cotton-wool-like structures were only produced when solutions containing calcium nitrate were used, suggesting that the charge of the Ca(2+) ions had a significant effect. The resulting bioactive silica fibers had a narrow diameter range of 0.5-2μm and were nanoporous. A hydroxycarbonate apatite layer was formed on the fibers within the first 12h of soaking in simulated body fluid. MC3T3-E1 preosteoblast cells cultured on the fibers showed no adverse cytotoxic effect and they were observed to attach to and spread in the material.
无机溶胶-凝胶溶液被电纺丝以生产出具有类似于棉花（或棉花糖）的结构的用于骨组织再生的第一个生物活性的三维（3-D）支架。这种柔性的 3-D 纤维结构非常适合包装到复杂的缺陷中。它还具有较大的纤维间空间，以促进血管生成、细胞渗透和营养物质在整个支架中的运输。3-D 纤维结构是通过电纺丝获得的，其中施加的电场和不稳定性对纺丝射流施加巨大的力，需要使射流具有粘弹性以防止射流断裂。以前，使用聚合物结合剂与无机溶液生产电纺复合二维纤维垫，需要煅烧以除去聚合物。本研究提出了一种新颖的反应和处理条件，用于生产粘弹性无机溶胶-凝胶溶液，该溶液通过溶液中分子间重叠的纳米二氧化硅的缠结来产生纤维，从而无需使用结合剂。仅当使用含有硝酸钙的溶液时，才会产生类似于棉花的 3-D 结构，这表明 Ca(2+)离子的电荷有显著的影响。所得的生物活性硅纤维具有 0.5-2μm 的窄直径范围并且是纳米多孔的。在模拟体液中浸泡的前 12 小时内，纤维上形成了羟基碳酸磷灰石层。在纤维上培养的 MC3T3-E1 前成骨细胞没有表现出不利的细胞毒性作用，并且观察到它们附着并在材料中扩散。
