Li Shuai, Wang Kan, Jiang Xuzhou, Hu Qingxi, Zhang Chuck, Wang Ben
Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Rapid Manufacturing Engineering Center, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai 200444, China.
ACS Biomater Sci Eng. 2020 Apr 13;6(4):2297-2311. doi: 10.1021/acsbiomaterials.9b01834. Epub 2020 Mar 13.
In this study, we developed a facile manufacturing method for interconnected prevascular networks using calcium chloride (CaCl) cross-linked alginate hollow fibers as sacrificial templates. The resulting network can be used to deliver oxygen and nutrients and remove waste for embedded cells in large-volume gelatin scaffolds during culturing. The sacrificial templates were printed by customized coaxial nozzles and embedded in scaffolds made of a mixture of gelatin, microbial transglutaminase (mTG), and sodium citrate. During the cross-linking of gelatin and mTG, the sacrificial templates started to dissolve from the scaffold-template interface due to the presence of the sodium citrate in the gelatin. The embedded sacrificial templates were completely dissolved without any postprocessing, and the designed prevascular networks successfully retained their geometries and dimensions. No residue of the template was observed at the scaffold-template interface after dissolution, which promoted cell adhesion. This manufacturing method has a high degree of freedom in templates' geometry, which was demonstrated by fabricating prevascular networks with various designs, including grid, branched, and dendritic networks. The effects of hollow fiber size and sodium citrate concentration on the dissolution time were analyzed. Human umbilical vein endothelial cells were injected into the aforementioned networks and formed a confluent endothelial cell monolayer with high viability during the culture process. The results suggest great promise to rapidly build large-scale ready-to-use gelatin scaffolds with prevascular networks for the applications in tissue engineering.
在本研究中，我们开发了一种简便的制造方法，以氯化钙（CaCl）交联的海藻酸钠中空纤维作为牺牲模板来制备相互连接的血管前网络。所得网络可用于在培养过程中为大体积明胶支架中的嵌入式细胞输送氧气和营养物质并清除废物。牺牲模板通过定制的同轴喷嘴打印，并嵌入由明胶、微生物转谷氨酰胺酶（mTG）和柠檬酸钠混合物制成的支架中。在明胶和mTG交联过程中，由于明胶中存在柠檬酸钠，牺牲模板开始从支架 - 模板界面溶解。嵌入式牺牲模板无需任何后处理即可完全溶解，并且设计的血管前网络成功保留了其几何形状和尺寸。溶解后在支架 - 模板界面未观察到模板残留，这促进了细胞粘附。这种制造方法在模板几何形状方面具有高度的自由度，通过制造具有各种设计（包括网格、分支和树状网络）的血管前网络得到了证明。分析了中空纤维尺寸和柠檬酸钠浓度对溶解时间的影响。将人脐静脉内皮细胞注入上述网络，并在培养过程中形成了具有高活力的汇合内皮细胞单层。结果表明，快速构建具有血管前网络的大规模即用型明胶支架在组织工程应用中具有很大的前景。
