Compositions, systems, and methods relating to three-dimensional (3d) bioprinted liver tissue models

A method of creating a planar cellular composition, comprising:

• mixing hepatocytes, endothelial cells, and a matrix material in a cellular growth medium to form a cellular mixture, wherein the hepatocytes and endothelial cells are present in a ratio of about 15:10 to 20:15 hepatocytes:endothelial cells;
• placing the cellular mixture in a support medium to form a planar cellular composition about 5 to 20 cells in thickness and about 0.5 to 10 mm diameter;
• and
• culturing the cellular mixture under physiological growth conditions to produce the planar cellular composition.