Cellulose and Paper Department , National Research Centre , Dokki, Giza , 12622 , Egypt.
University Grenoble Alpes, CNRS, Grenoble INP, LGP2 , F-38000 Grenoble , France.
Biomacromolecules. 2018 Nov 12;19(11):4442-4452. doi: 10.1021/acs.biomac.8b01325. Epub 2018 Oct 19.
The three-dimensional (3D) printed scaffolds were prepared by partial cross-linking of TEMPO-oxidized cellulose nanofibril/alginate hydrogel using calcium ions for printing the hydrogel while maintaining its shape, fidelity, and preventing the collapse of the filaments. The prepared scaffolds were fully cross-linked using calcium ions immediately after printing to provide the rigidity of the hydrogel and give it long-term stability. The composition of the prepared pastes was adjusted in view of the description of the hydrogel and 3D printing parameters. The rheological properties in terms of thixotropic behavior and viscosity recovery of hydrogels were investigated by performing steady shear rate experiments. The results show that the viscosity recovery for pure alginate hydrogel was only about 16% of the initial value, whereas it was 66% when adding cellulose nanofibrils to alginate. Consequently, the shape of the pure alginate scaffold was soft and easy to collapse contrarily to the composite scaffold. The biomimetic mineralization process of printed scaffolds using simulated body fluid, mimicking the inorganic composition of human blood plasma, was performed and the hydroxyapatite nucleation on the hydrogel was confirmed. The strength properties of the fabricated scaffolds in terms of compressive strength analysis were also investigated and discussed. The results show that the alginate/TEMPO-oxidized cellulose nanofibril system may be a promising 3D printing scaffold for bone tissue engineering.
三维（3D）打印支架通过使用钙离子部分交联 TEMPO 氧化的纤维素纳米纤维/海藻酸钠水凝胶来制备，用于打印水凝胶，同时保持其形状、保真度，并防止纤维塌陷。打印后立即使用钙离子对制备的支架进行完全交联，以提供水凝胶的刚性并赋予其长期稳定性。根据水凝胶和 3D 打印参数的描述，调整了制备糊剂的组成。通过进行稳态剪切速率实验，研究了水凝胶的触变行为和粘度恢复的流变性能。结果表明，纯海藻酸钠水凝胶的粘度恢复仅约为初始值的 16%，而添加纤维素纳米纤维时则为 66%。因此，纯海藻酸钠支架的形状柔软且容易塌陷，与复合支架相反。使用模拟体液进行打印支架的仿生矿化过程，模拟人体血浆的无机成分，证实了水凝胶上的羟基磷灰石成核。还研究并讨论了制造支架的压缩强度分析的强度性能。结果表明，海藻酸盐/TEMPO 氧化的纤维素纳米纤维系统可能是用于骨组织工程的有前途的 3D 打印支架。
