Nic Leipzig

and 3 more

Oxygen and extracellular matrix (ECM)-derived biopolymers play vital roles in regulating many cellular functions in both the healthy and diseased liver. This study reveals the importance of synergistically tuning the internal microenvironment to enhance oxygen availability alongside phenotypic ECM ligand presentation to promote native metabolic functions of human liver three-dimensional (3D) cell aggregates. First, fluorinated (PFC) chitosan microparticles (MPs) were generated with a microfluidic chip, then their oxygen transport properties were studied using a custom ruthenium-based oxygen sensing approach. Next, to allow for integrin engagements the surfaces of these MPs were functionalized using liver ECM proteins including fibronectin, laminin-111, laminin-511, and laminin-521. These MPs were used to assemble heterogeneous composite spheroids composed of human hepatocytes and human hepatic stellate cells. After in vitro culture, liver-specific functions and cell adhesion patterns were compared between groups and cells showed enhanced liver phenotypic responses in response to laminin-511 and 521 as evidenced via enhanced E-cadherin and vinculin expression as well as albumin and urea secretion. Furthermore, hepatocytes and stellate cells arranged in more phenotypic arrangements when cocultured with laminin-511 and 521 modified MPs providing clear evidence that specific ECM proteins have distinctive roles in the phenotypic regulation of liver cells in engineering 3D spheroids. This study advances efforts to create more physiologically relevant organ models allowing for well-defined conditions and phenotypic cell signaling which together improve the relevance of 3D spheroid and organoid models.