Ouyang Liliang, Highley Christopher B, Rodell Christopher B, Sun Wei, Burdick Jason A
Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China.
ACS Biomater Sci Eng. 2016 Oct 10;2(10):1743-1751. doi: 10.1021/acsbiomaterials.6b00158. Epub 2016 Jun 9.
The development of printable biomaterial inks is critical to the application of 3D printing in biomedicine. To print high-resolution structures with fidelity to a computer-aided design, materials used in 3D printing must be capable of being deposited on a surface and maintaining a printed structure. A dual-cross-linking hyaluronic acid system was studied here as a printable hydrogel ink, which encompassed both shear-thinning and self-healing behaviors via guest-host bonding, as well as covalent cross-linking for stabilization using photopolymerization. When either guest-host assembly or covalent cross-linking was used alone, long-term stable structures were not formed, because of network relaxation after printing or dispersion of the ink filaments prior to stabilization, respectively. The dual-cross-linking hydrogel filaments formed structures with greater than 16 layers that were stable over a month with no loss in mechanical properties and the printed filament size ranged from 100 to 500 μm, depending on printing parameters (needle size, speed, and extrusion flux). Printed structures were further functionalized (i.e., RGD peptide) to support cell adhesion. This work highlights the importance of ink formulation and cross-linking on the printing of stable hydrogel structures.
可打印生物材料墨水的开发对于3D打印在生物医学中的应用至关重要。为了以忠实于计算机辅助设计的方式打印高分辨率结构，3D打印中使用的材料必须能够沉积在表面上并保持打印结构。本文研究了一种双交联透明质酸体系作为可打印水凝胶墨水，它通过客体-主体键合兼具剪切变稀和自愈行为，以及使用光聚合进行共价交联以实现稳定化。当单独使用客体-主体组装或共价交联时，分别由于打印后网络松弛或稳定化之前墨丝分散，无法形成长期稳定的结构。双交联水凝胶丝形成了超过16层的结构，这些结构在一个多月内保持稳定，机械性能无损失，并且根据打印参数（针头尺寸、速度和挤出通量），打印的丝尺寸范围为100至500μm。打印结构进一步功能化（即RGD肽）以支持细胞粘附。这项工作突出了墨水配方和交联对稳定水凝胶结构打印的重要性。
