Zhao Fengyuan, Cheng Jin, Sun Muyang, Yu Huilei, Wu Nier, Li Zong, Zhang Jiahao, Li Qi, Yang Peng, Liu Qiang, Hu Xiaoqing, Ao Yingfang
Institute of Sports Medicine, Beijing Key Laboratory of Sports Injuries, Peking University Third Hospital, Beijing 100191, People's Republic of China.
Biofabrication. 2020 Jul 29;12(4):045011. doi: 10.1088/1758-5090/aba411.
Improving the printability of pure, decellularized extracellular matrix (dECM) bio-ink without altering its physiological components has been a challenge in three-dimensional (3D) cell printing. To improve the printability of the bio-ink, we first investigated the digestion process of the powdered dECM material obtained from porcine tendons. We manifested the digestion process of tendon derived dECM powders, which includes dissolution, gelatinization and solubilization. After a short dissolution period (around 10 min), we observed a 'High viscosity slurry' status (3 h) of the dECM precursors, i.e. the gelatinization process, followed by the solubilization processes, i.e. a 'Medium viscosity slurry' period (12 h) and a 'Low viscosity slurry' period (72 h). The 'Medium viscosity slurry' status of the dECM bio-ink was inhomogeneous and could not be extruded out from the barrel after the pH value was neutralized to 7.4. Although the 'Low viscosity slurry' status of the dECM bio-ink has been reported to be extrudable, it has poor printability. This study explores the printability of the 'High viscosity slurry' status of the dECM bio-ink, which has not been addressed thus far. The results demonstrate that this less digested status of the dECM bio-ink yields higher shape fidelity and stacking accuracy than the traditional over-digested status of the dECM bio-ink; this indicates better printability of this less digested dECM bio-ink. We compared the performance of the two bio-inks using cell viability tests for 3D cell printing. Bone marrow mesenchymal stem cells derived from rats was printed using the 'High viscosity slurry' status of the dECM bio-ink, yielding high cellular viability lasting for 7 d after printing. Thus, the 'High viscosity slurry' status of tendon dECM bio-ink can be utilized to fabricate complicated 3D organoid structures; it also shows promise for applications such as regenerative medicine and biomimetic tissue engineering.
在三维（3D）细胞打印中，在不改变其生理成分的情况下提高纯的、脱细胞细胞外基质（dECM）生物墨水的可打印性一直是一项挑战。为了提高生物墨水的可打印性，我们首先研究了从猪肌腱获得的粉末状dECM材料的消化过程。我们展示了肌腱衍生的dECM粉末的消化过程，包括溶解、凝胶化和溶解。在短暂的溶解期（约10分钟）后，我们观察到dECM前体的“高粘度浆料”状态（3小时），即凝胶化过程，随后是溶解过程，即“中粘度浆料”期（12小时）和“低粘度浆料”期（72小时）。dECM生物墨水的“中粘度浆料”状态不均匀，在pH值中和至7.4后无法从料筒中挤出。尽管据报道dECM生物墨水的“低粘度浆料”状态是可挤出的，但其可打印性较差。本研究探索了dECM生物墨水“高粘度浆料”状态的可打印性，这是迄今为止尚未解决的问题。结果表明，这种消化程度较低的dECM生物墨水状态比传统的过度消化的dECM生物墨水状态具有更高的形状保真度和堆叠精度；这表明这种消化程度较低的dECM生物墨水具有更好的可打印性。我们使用3D细胞打印的细胞活力测试比较了两种生物墨水的性能。使用dECM生物墨水的“高粘度浆料”状态打印源自大鼠的骨髓间充质干细胞，打印后7天细胞活力高。因此，肌腱dECM生物墨水的“高粘度浆料”状态可用于制造复杂的3D类器官结构；它在再生医学和仿生组织工程等应用中也显示出前景。
