Intervertebral Disk Tissue Engineering Using Biphasic Silk Composite Scaffolds
Intervertebral Disk Tissue Engineering Using Biphasic Silk Composite Scaffolds
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DOI：
10.1089/ten.tea.2011.0195
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发表时间：
2012-03-01
影响因子：
4.1
通讯作者：
Kaplan, David L.
中科院分区：
文献类型：
--
作者：
Park, Sang-Hyug;Gil, Eun Seok;Kaplan, David L.
由合成材料、天然材料以及杂化材料构成的支架已作为恢复椎间盘（IVD）组织功能的选择进行了研究。这些系统缺乏天然纤维环（AF）组织的层状特征，或者仅仅关注髓核（NP）组织。然而，整个椎间盘的成功再生需要一种组合方法来恢复纤维环和髓核两者的功能。为了满足这一需求，通过使用丝蛋白构建纤维环、纤维蛋白/透明质酸（HA）凝胶构建髓核，生成了一种双相生物材料结构。使用了两种细胞类型，猪纤维环细胞和软骨细胞。对于纤维环组织，研究了层状和多孔两种支架形态，以多孔系统作为对照。由层状和多孔丝材料制成的环形支架被用于构建外径为8毫米、内径为3.5毫米、高度为3毫米的结构（层状支架的层间距为150 - 250微米，多孔支架的平均孔径为100 - 250微米）。支架接种猪纤维环细胞以形成纤维环组织，而猪软骨细胞被包裹在纤维蛋白/HA水凝胶中用于髓核组织，并嵌入环形椎间盘的中心。组织学、生化分析和基因表达表明，层状支架在2周内支持了类似纤维环的组织形成。猪软骨细胞在与预先培养2周的纤维环组织共同培养4周后（总共培养6周）在水凝胶内形成了髓核表型。这种模拟纤维环和髓核组织组合的双相支架在体外形成完整椎间盘方面是有效的。
Scaffolds composed of synthetic, natural, and hybrid materials have been investigated as options to restore intervertebral disk (IVD) tissue function. These systems fall short of the lamellar features of the native annulus fibrosus (AF) tissue or focus only on the nucleus pulposus (NP) tissue. However, successful regeneration of the entire IVD requires a combination approach to restore functions of both the AF and NP. To address this need, a biphasic biomaterial structure was generated by using silk protein for the AF and fibrin/hyaluronic acid (HA) gels for the NP. Two cell types, porcine AF cells and chondrocytes, were utilized. For the AF tissue, two types of scaffold morphologies, lamellar and porous, were studied with the porous system serving as a control. Toroidal scaffolds formed out of the lamellar, and porous silk materials were used to generate structures with an outer diameter of 8 mm, inner diameter of 3.5 mm, and a height of 3 mm (the interlamellar distance in the lamellar scaffold was 150-250 mu m, and the average pore sizes in the porous scaffolds were 100-250 mu m). The scaffolds were seeded with porcine AF cells to form AF tissue, whereas porcine chondrocytes were encapsulated in fibrin/HA hydrogels for the NP tissue and embedded in the center of the toroidal disk. Histology, biochemical assays, and gene expression indicated that the lamellar scaffolds supported AF-like tissue over 2 weeks. Porcine chondrocytes formed the NP phenotype within the hydrogel after 4 weeks of culture with the AF tissue that had been previously cultured for 2 weeks, for a total of 6 weeks of cultivation. This biphasic scaffold simulating in combination of both AF and NP tissues was effective in the formation of the total IVD in vitro.