基于同轴流技术的肝组织生物3D打印研究

生物三维打印为医疗领域提供全新的技术可能,可广泛应用于制造人工组织和器官。人工组织的功能和尺寸大小受限于组织的血管化,可利用同轴流挤出系统制造封装肝细胞的中空细丝,结合生物3D打印系统,叠层制造含微通道网络的肝组织。首先搭建集成化的同轴流生物3D打印系统,研究材料挤出速率、材料浓度等参数对中空细丝尺寸及出丝速度的影响;然后以肝细胞株C3A为材料,打印含多层管网机构的仿生肝组织;最后,对含微通道的肝组织进行分组培养,利用细胞活死染色法检测第24、48、72 h肝细胞在灌流组和非灌流组中的细胞存活率。实验表明,同轴流3D打印的组织,中空细丝之间有效融合,支架内部的立体微通道网络完整;打印过程对肝细胞损伤较小,中空细丝中的肝细胞存活率达90%以上;灌流组和非灌流组在培养72 h后,细胞存活率有显著的差异,证明对微通道灌流可以促进组织内部的物质交换,提高微通道周围肝细胞的存活率。研究提出打印方法和灌流系统,为人工组织的血管化以及培养方式提供全新的思路。

Study on 3D Bioprinting of Liver Tissues Based on Coaxial Flow Technique

The 3D bioprinting provides a new technical possibility for the medical field, which can be widely used in the manufacture of artificial tissues and organs. However, the function and size of the artificial tissue are limited by the vascularization of the tissue. In this study, a coaxial flow extrusion system was used to fabricate hollow filaments in encapsulated liver cells, combined with a biological 3D printing system, so as to fabricate liver tissue with microchannel network by using a layer-by-layer approach. In the experiment, an integrated coaxial flow 3D bioprinting system was built firstly. The influence of material extrusion rate and material concentration was then studied on the size of hollow filaments and the velocity of wire. Subsequently, the biomimetic liver tissue containing multi-layer networks was printed with the liver cell line C3A as the material. Finally, the biomimetic liver tissue containing microchannels was divided into groups and cultured. The cell survival rate of hepatocytes after 24h, 48h and 72h of culture was detected by live-dead cell staining in perfusion group and non-perfusion group. The experimental results showed that in the organs using 3D printing technology based on coaxial flow technique, the hollow filaments could be effectively fused, and the 3D microchannel network inside the support was complete. Besides, the proportion of damaged hepatocyte was less in the printing process, and the survival rate of hepatocytes was over 90% in hollow filaments. Furthermore, there was a significant difference in the cell survival rate between the perfusion group and the non-perfusion group after culture for 72h, suggesting that microchannel perfusion could promote the exchange of material within the tissue and increase the survival rate of liver cells around the microchannel. The printing technology and perfusion system presented in this paper provide a new study approach for the vascularization and culture of artificial tissues.