Jones J R, Lin S, Yue S, Lee P D, Hanna J V, Smith M E, Newport R J
Department of Materials, Imperial College London, South Kensington Campus, London, UK.
Proc Inst Mech Eng H. 2010 Dec;224(12):1373-87. doi: 10.1243/09544119JEIM836.
Scaffolds are needed that can act as temporary templates for bone regeneration and actively stimulate vascularized bone growth so that bone grafting is no longer necessary. To achieve this, the scaffold must have a suitable interconnected pore network and be made of an osteogenic material. Bioactive glass is an ideal material because it rapidly bonds to bone and degrades over time, releasing soluble silica and calcium ions that are thought to stimulate osteoprogenitor cells. Melt-derived bioactive glasses, such as the original Bioglass composition, are available commercially, but porous scaffolds have been difficult to produce because Bioglass and similar compositions crystallize on sintering. Sol-gel foam scaffolds have been developed that avoid this problem. They have a hierarchical pore structure comprising interconnected macropores, with interconnect diameters in excess of the 100 microm that is thought to be needed for vascularized bone ingrowth, and an inherent nanoporosity of interconnected mesopores (2-50 nm) which is beneficial for the attachment of osteoprogenitor cells. They also have a compressive strength in the range of cancellous bone. This paper describes the optimized sol-gel foaming process and illustrates the importance of optimizing the hierarchical structure from the atomic through nano, to the macro scale with respect to biological response.
需要能够作为骨再生临时模板并积极刺激血管化骨生长的支架，从而不再需要骨移植。为实现这一目标，支架必须具有合适的相互连通的孔隙网络，并由成骨材料制成。生物活性玻璃是一种理想材料，因为它能迅速与骨结合并随时间降解，释放出据认为可刺激骨祖细胞的可溶性二氧化硅和钙离子。熔融衍生的生物活性玻璃，如原始的生物玻璃成分，有商业产品，但由于生物玻璃及类似成分在烧结时会结晶，所以难以制造多孔支架。已经开发出溶胶 - 凝胶泡沫支架来避免这个问题。它们具有分级孔隙结构，包括相互连通的大孔，其连通直径超过血管化骨向内生长所需的100微米，以及相互连通的介孔（2 - 50纳米）的固有纳米孔隙率，这有利于骨祖细胞的附着。它们还具有与松质骨相当的抗压强度。本文描述了优化的溶胶 - 凝胶发泡工艺，并说明了从原子尺度到纳米尺度再到宏观尺度优化分级结构对于生物学反应的重要性。
