Akcay Gulden, Luttge Regina
Neuro-Nanoscale Engineering, Department of Mechanical Engineering and Institute of Complex Molecular Systems (ICMS), Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
Micromachines (Basel). 2021 Feb 8;12(2):165. doi: 10.3390/mi12020165.
Over the past decade, hydrogels have shown great potential for mimicking three- dimensional (3D) brain architectures in vitro due to their biocompatibility, biodegradability, and wide range of tunable mechanical properties. To better comprehend in vitro human brain models and the mechanotransduction processes, we generated a 3D hydrogel model by casting photo-polymerized gelatin methacryloyl (GelMA) in comparison to poly (ethylene glycol) diacrylate (PEGDA) atop of SH-SY5Y neuroblastoma cells seeded with 150,000 cells/cm according to our previous experience in a microliter-sized polydimethylsiloxane (PDMS) ring serving for confinement. 3D SH-SY5Y neuroblastoma cells in GelMA demonstrated an elongated, branched, and spreading morphology resembling neurons, while the cell survival in cast PEGDA was not supported. Confocal z-stack microscopy confirmed our hypothesis that stiff-to-soft material transitions promoted neuronal migration into the third dimension. Unfortunately, large cell aggregates were also observed. A subsequent cell seeding density study revealed a seeding cell density above 10,000 cells/cm started the formation of cell aggregates, and below 1500 cells/cm cells still appeared as single cells on day 6. These results allowed us to conclude that the optimum cell seeding density might be between 1500 and 5000 cells/cm. This type of hydrogel construct is suitable to design a more advanced layered mechanotransduction model toward 3D microfluidic brain-on-a-chip applications.
在过去十年中，水凝胶因其生物相容性、可生物降解性以及广泛的可调机械性能，在体外模拟三维（3D）脑结构方面展现出巨大潜力。为了更好地理解体外人脑模型和机械转导过程，我们根据之前在用于限制的微升尺寸聚二甲基硅氧烷（PDMS）环中的经验，以每平方厘米接种150,000个细胞的密度在SH-SY5Y神经母细胞瘤细胞上浇铸光聚合甲基丙烯酰化明胶（GelMA），并与聚（乙二醇）二丙烯酸酯（PEGDA）进行比较，生成了一个3D水凝胶模型。GelMA中的3D SH-SY5Y神经母细胞瘤细胞呈现出类似神经元的细长、分支和伸展形态，而浇铸的PEGDA中细胞无法存活。共聚焦z-stack显微镜证实了我们的假设，即从硬材料到软材料的转变促进了神经元向三维空间的迁移。不幸的是，也观察到了大的细胞聚集体。随后的细胞接种密度研究表明，接种细胞密度高于10,000个细胞/平方厘米时开始形成细胞聚集体，而低于1500个细胞/平方厘米时，细胞在第6天仍呈单细胞状态。这些结果使我们得出结论，最佳细胞接种密度可能在1500至5000个细胞/平方厘米之间。这种类型的水凝胶构建体适用于设计一个更先进的分层机械转导模型，用于3D微流控脑芯片应用。
