Wood Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland.
Biomacromolecules. 2011 May 9;12(5):1419-27. doi: 10.1021/bm101131b. Epub 2011 Mar 25.
Biocomposite hydrogels with carboxymethylated, nanofibrillated cellulose (c-NFC) powder were prepared by UV polymerization of N-vinyl-2-pyrrolidone with Tween 20 trimethacrylate as a cross-linking agent for replacement of the native, human nucleus pulposus (NP) in intervertebral disks. The swelling ratios and the moduli of elasticity in compression of neat and biocomposite hydrogels were evaluated in dependence of c-NFC concentration (ranging from 0 to 1.6% v/v) and degree of substitution (DS, ranging from 0 to 0.23). The viscoelastic properties in shear and the material relaxation behavior in compression were measured for neat and biocomposite hydrogels containing 0.4% v/v of fibrils (DS ranging from 0 to 0.23), and their morphologies were characterized by cryo-scanning electron microscopy (cryo-SEM). The obtained results show that the biocomposite hydrogels can successfully mimic the mechanical and swelling behavior of the NP. In addition, the presence of the c-NFC shows lower strain values after cyclic compression tests and consequently creates improved material relaxation properties compared with neat hydrogels. Among the tested samples, the biocomposite hydrogel containing 0.4% v/v of c-NFC with a DS of 0.17 shows the closest behavior to native NP. Further investigation should focus on evaluation and improvement of the long-term relaxation behavior.
采用 N-乙烯基-2-吡咯烷酮与聚氧乙烯失水山梨醇脂肪酸酯三甲基丙烯酸酯通过 UV 聚合反应制备了具有羧甲基化、纳米原纤化纤维素（c-NFC）粉末的生物复合水凝胶，作为交联剂替代天然人椎间盘核髓（NP）。通过评估纯和生物复合水凝胶在不同 c-NFC 浓度（0 至 1.6% v/v）和取代度（DS，0 至 0.23）下的溶胀比和压缩弹性模量，研究了纯和生物复合水凝胶的粘弹性和压缩材料松弛性能。对于含有 0.4% v/v 纤维（DS 范围从 0 到 0.23）的纯和生物复合水凝胶，测量了剪切和压缩的材料松弛行为，并通过冷冻扫描电子显微镜（cryo-SEM）对其形态进行了表征。研究结果表明，生物复合水凝胶可以成功模拟 NP 的力学和溶胀行为。此外，与纯凝胶相比，c-NFC 的存在在循环压缩试验后表现出较低的应变值，从而产生了改进的材料松弛性能。在测试的样品中，含有 0.4% v/v、DS 为 0.17 的 c-NFC 的生物复合水凝胶表现出与天然 NP 最接近的行为。进一步的研究应集中在评估和改善长期松弛行为上。
