Preparation of stripe-patterned heterogeneous hydrogel sheets using microfluidic devices for high-density coculture of hepatocytes and fibroblasts

Here we demonstrate the production of stripe-patterned heterogeneous hydrogel sheets for the high-density 3D coculture of multiple cell types, by using microchannel-combined micronozzle devices. The prepared hydrogel sheet, composed of multiple regions with varying physical stiffness, regulates the direction of proliferation of encapsulated cells and enables the formation of arrays of rod-like heterotypic organoids inside the hydrogel matrix. We successfully prepared stripe-patterned hydrogel sheets with a uniform thickness of ∼100 μm and a width of several millimeters. Hepatoma cells (HepG2) and fibroblasts (Swiss 3T3) were embedded inside the hydrogel matrix and cocultured, to form heterotypic micro-organoids mimicking in vivo hepatic cord structures. The upregulation of hepatic functions by the 3D coculture was confirmed by analyzing liver-specific functions. The presented heterogeneous hydrogel sheet could be useful, as it provides relatively large, but precisely-controlled, 3-dimensional microenvironments for the high-density coculture of multiple types of cells.