Department of System Design Engineering, Keio University, Japan
Departments of Mechanical Engineering and Biological Engineering, Massachusetts Institute of Technology, United States of America
Biofabrication. 2019 Apr 26;11(3):035007. doi: 10.1088/1758-5090/ab145d.
Recent advances in microfabrication technologies have enabled us to construct collagen gel microbeads, which can be cultured with hepatocytes. However, little is known about the hepatocyte-collagen gel microbead interactions. Here, we aimed to clarify the effects of the balance between cell-cell and cell-collagen gel microbead interactions on hepatocyte morphogenesis and functions. The magnitude of cell-microbead interactions was controlled by changing the size of the microbeads, which were smaller than, comparable to, and larger than hepatocytes. These small, medium, and large microbeads were cultured separately with primary hepatocytes. Phase-contrast and time-lapse imaging revealed that the medium microbeads significantly induced the construction of 3D structures composed of the microbeads and hepatocytes in a self-organizing manner, whereas hepatocytes formed 2D monolayers with the small or large microbeads. These results suggest that only the medium microbeads induced the 3D tissue formation of hepatocytes. Furthermore, liver-specific functions, such as albumin secretion and ammonia clearance, were significantly upregulated in the 3D structures. These findings are critical to understand how to control the construction of 3D hepatocyte tissues with hydrogel microbeads in the context of biofabrication.
近年来，微制造技术的进步使我们能够构建胶原凝胶微珠，这些微珠可以与肝细胞一起培养。然而，对于肝细胞-胶原凝胶微珠相互作用知之甚少。在这里，我们旨在阐明细胞-细胞和细胞-胶原凝胶微珠相互作用之间的平衡对肝细胞形态发生和功能的影响。通过改变微珠的大小来控制细胞-微珠相互作用的程度，这些微珠小于、等于和大于肝细胞。这些小、中、大微珠分别与原代肝细胞培养。相差和延时成像显示，中微珠以自组织的方式显著诱导由微珠和肝细胞组成的 3D 结构的构建，而小或大微珠使肝细胞形成 2D 单层。这些结果表明，只有中微珠诱导了肝细胞的 3D 组织形成。此外，白蛋白分泌和氨清除等肝脏特异性功能在 3D 结构中显著上调。这些发现对于理解如何在生物制造的背景下控制水凝胶微珠构建 3D 肝细胞组织具有重要意义。
