The role of biological extracellular matrix scaffolds in vascularized three-dimensional tissue growth in vivo (Journal of Biomedical Materials Research - Part B Applied Biomaterials (2007) 82B, (122-128) DOI: 10.1002/jbm.b.30713)
An important challenge in liver tissue engineering is to overcome the rapid loss of hepatocyte functions. In vivo, hepatocytes are compact polyhedral cells with round nuclei; however, they readily loss many of their differentiated functions in vitro. To overcome this challenge, we have established a new perfusion bioreactor that consists of two compartments which enabled the serial coculture of hepatocytes and hepatic stellate cells-T6 without direct contact between each other. Three dimensional scaffolds were utilized in the bioreactor as physical anchors for cells. The scaffolds consist of collagen grafted poly(lactic-co-glycolic acid) microfibers and cross-linked collagen sponges between microfibers for additional cellular support and adhesion. The advantages of this new bioreactor are enabling cell culture in three dimensional organization and controlling the culture parameters of the supporting cells independently from the hepatocytes. The results showed that the hepatocytes exhibited much higher levels of the differentiated functions such as albumin secretion, urea synthesis, and cytochrome P450 enzymatic activity when compared with the monoculture system where hepatocytes alone were cultured. This perfusion bioreactor system has potential applications in the development of bioartificial liver devices or cell-based tissue constructs transplantation therapies.