Underhill Gregory H, Chen Alice A, Albrecht Dirk R, Bhatia Sangeeta N
Harvard--M.I.T. Division of Health Sciences and Technology/Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Ave., E19-502D, Cambridge, MA, USA.
Biomaterials. 2007 Jan;28(2):256-70. doi: 10.1016/j.biomaterials.2006.08.043. Epub 2006 Sep 18.
Tissue-engineered therapies for liver failure offer the potential to augment or replace whole organ transplantation; however, fabrication of hepatic tissue poses unique challenges largely stemming from the complexity of liver structure and function. In this study, we illustrate the utility of highly-tunable, photopolymerizable poly(ethylene glycol) (PEG) hydrogels for 3D encapsulation of hepatic cells and highlight a range of techniques important for examining hepatocellular function in this platform. Owing to our long-term interest in incorporating proliferative progenitor cell types (e.g. hepatoblasts, oval cells, or cells derived from embryonic stem cells) and maintaining the phenotype of differentiated cells, we explored the behavior of bipotential mouse embryonic liver (BMEL) cells as a model progenitor cell and mature, fully differentiated, primary hepatocytes in this biomaterial system. We demonstrated the importance of cell-cell and cell-matrix interactions in the survival and function of these cell types, and the capacity to influence encapsulated cell phenotypes through modulation of hydrogel characteristics or gene silencing. Additionally, we demonstrated imaging techniques critical for the in situ assessment of encapsulated hepatocyte function combined with the ability to control cellular organization and overall architecture through microscale patterning technologies. Further analysis of liver progenitor as well as mature hepatocyte processes within the versatile PEG hydrogel platform will aid in the development of tissue engineered implantable liver systems.
用于肝衰竭的组织工程疗法为增强或替代全器官移植提供了潜力；然而，肝组织的制造带来了独特的挑战，这在很大程度上源于肝脏结构和功能的复杂性。在本研究中，我们展示了高度可调、可光聚合的聚乙二醇（PEG）水凝胶用于肝细胞三维包封的效用，并强调了一系列对于在该平台中检测肝细胞功能很重要的技术。由于我们长期关注纳入增殖性祖细胞类型（如肝母细胞、卵圆细胞或源自胚胎干细胞的细胞）并维持分化细胞的表型，我们在这个生物材料系统中探索了双能小鼠胚胎肝（BMEL）细胞作为模型祖细胞以及成熟、完全分化的原代肝细胞的行为。我们证明了细胞 - 细胞和细胞 - 基质相互作用在这些细胞类型的存活和功能中的重要性，以及通过调节水凝胶特性或基因沉默来影响包封细胞表型的能力。此外，我们展示了对于原位评估包封肝细胞功能至关重要的成像技术，以及通过微尺度图案化技术控制细胞组织和整体结构的能力。在通用的PEG水凝胶平台内对肝祖细胞以及成熟肝细胞过程进行进一步分析将有助于开发组织工程化可植入肝脏系统。
