Despite significant recent advances in liver tissue engineering, attempts at recreating the intrahepatic biliary tree have not progressed significantly. The finer branches of the biliary tree are structurally and functional complex and heterogeneous, and require harnessing innate developmental processes for their recreation. The ability of decellularized liver extracellular matrix (dECM) hydrogels to induce the in vitro formation of complex biliary networks from encapsulated biliary epithelial cells (cholangiocytes) will be demonstrated. This phenomenon is not observed using with other matrix gels, such as collagen 1 or Matrigel ®. The phenotypic stability via immunostaining for specific cholangiocyte markers will also be shared. Moreover, tight junctions were observed to form and mature with cholangiocytes showing polarization and bile salt transport activity. To demonstrate the utility of the system to study duct morphogenesis, three fluorescently labeled, but otherwise identical populations of cholangiocytes, were combined. Observations indicate cells, in a proximity dependent manner, will either branch out radiating from a single nucleation point or assemble into multi-colored structures arising from separate populations. Furthermore, 3D-bioprinting of dECM and a sacrificial Pluronic F-127 ink leads to alignment of collagen fibrils and control over duct formation on an unprecedented scale.
- Understand and harness the complexities of engineering the intrahepatic biliary tree.
- Use multi-material bioprinting to undertake 3D printing of materials (gels) of non-ideal mechanical properties.