The in vitro reproduction of three-dimensional (3D) cellular constructs to physiologically mimic human liver is highly desired for drug screening and clinical research. However, the fabrication of a liver-mimetic 3D model using traditional bottom-up technologies is challenging owing to the complex architecture and specific functions of real liver tissue. This work proposes a versatile strategy for spatially assembling gear-like microstructures encapsulating multiple cell types, and reorganizing them into 3D lobule-like micro-architecture with physiological relevance to native liver tissue. Gear-like microstructures were fabricated by photo-crosslinking poly(ethylene glycol) diacrylate (PEGDA) hydrogel mixed with hepatocytes and fibroblasts, in a digital micromirror device (DMD)-based microfluidic channel. The microstructures were assembled through coordinated micromanipulation based on local fluid force, and spatially self-aligned through hydrophilic-hydrophobic interactions into a 3D integrated construct with lobule-like morphology and a perfusable central lumen. The resulting 3D lobule-like constructs allowed long-term co-culture of hepatocytes and fibroblasts with high cell viability. The co-cultured constructs enhanced hepatocyte proliferation and spreading, as well as liver functions including a 50% increase in albumin secretion and urea synthesis. For hepatotoxicity assessment, the 3D lobule-like construct enabled drug perfusion through its built-in lumen for simulation of drug diffusion in the liver, which could improve the response sensitivity and efficiency to hepatotoxic drug. These results demonstrated that this method provides a valuable 3D co-culture model with perfusable lobule-like architecture and physiological functions, which has potential applications in drug discovery and tissue engineering applications.

中文翻译：

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通过组装多种细胞型载有水凝胶的微结构，制造可灌注的3D肝小叶样结构。

三维（3D）细胞构建体的体外复制以生理模拟人类肝脏是药物筛选和临床研究的高度需要。然而，由于真实肝组织的复杂结构和特定功能，使用传统的自下而上技术制造仿肝3D模型具有挑战性。这项工作提出了一种通用的策略，用于在空间上组装封装多种细胞类型的齿轮状微结构，并将它们重组为与天然肝组织具有生理相关性的3D小叶状微结构。通过在基于数字微镜设备（DMD）的微流体通道中，将与肝细胞和成纤维细胞混合的聚乙二醇二丙烯酸酯（PEGDA）水凝胶进行光交联，来制造齿轮状的微结构。这些微结构通过基于局部流体力的协同微操纵而组装，并通过亲水-疏水相互作用在空间上自对准成具有小叶状形态和可灌注中央管腔的3D集成结构。所得的3D小叶样构建体可长期共培养具有高细胞活力的肝细胞和成纤维细胞。共培养的构建体增强了肝细胞的增殖和扩散以及肝功能，包括白蛋白分泌和尿素合成增加了50％。对于肝毒性评估，这种3D小叶状构建体通过其内置管腔进行药物灌注，以模拟药物在肝脏中的扩散，从而可以提高对肝毒性药物的反应敏感性和效率。