Objective: To evaluate the effect of different microstructures prepared by three-dimensional (3D) bioprinting on proliferation and viability of the murine epithelial stem cells in vitro.
Methods: 3D cell-laden microstructures were constructed using 3 different printing nozzles with diameters of 210, 340, and 420 µm. Fluorescence microscopy and the live/dead assay kit were used to observe the proliferation and viability of the murine epithelial stem cells in the microstructures.
Results: All the 3D cell-laden micro-structures were capable of promoting the proliferation of murine epithelial stem cells. In the 3 groups of micro-structures, the cell viability decreased significantly with time until 7 days after printing (P<0.01), but at 14 days after the printing, the cell viability increased significantly as compared with that at 7 days (P<0.01). The viability of the cells was significantly higher in the microstructure printed using a 420 µm nozzle than in the microstructures printed with 210 µm and 340 µm nozzles (P<0.01).
Conclusion: The microstructure printed with a 420 µm nozzle can stably promote the proliferation of murine epithelial stem cells and maintain a high level of cell viability, suggesting the feasibility of constructing tissue-engineered epidermis and full-thickness skin graft using 3D bioprinting technique.
目的: 探索不同构架的3D微结构对表皮干细胞增殖能力和细胞活性的影响并建立最佳3D生物打印模型。
方法: 通过采用不同尺寸：210、340、420 μm的打印喷头结合3D生物打印技术构建3种不同的含细胞3D微结构；利用荧光显微镜观察3D微结构中细胞形态及增殖现象；活/死细胞染色技术检测细胞活性；采用方差分析和样本t检验等方法进行统计学分析。
结果: 3种不同构架的3D微结构均可促进表皮干细胞增殖；打印后0、3、7 d之间，3组3D微结构在细胞活性水平上均逐步降低且差异有统计学意义（P < 0.01）；与7 d时的细胞活性相比，3组3D微结构在14 d时的细胞活性均升高且差异有统计学意义（P < 0.01）；与210 μm组和340 μm组相比，420 μm组3D微结构在长期培养中细胞活性水平最高（P < 0.01）。
结论: 420 μm组3D微结构能够稳定促进皮肤替代物中表皮干细胞的增殖能力并维持高细胞活性，为构建3D生物打印组织工程表皮以及全层皮肤模型奠定了基础。