Matrigel enhances cellular morphology of primary human hepatocyte cultures. Primary human hepatocytes from Donor A (A and B), Donor B (C and D), and Donor C (E and F) were cultured in the presence (B, D, F) or absence (A, C, E) of a Matrigel overlay. Photomicrographs were taken under ×20 magnification using phase-contrast imaging. Arrows indicate compromised morphology in the absence of a Matrigel overlay. Reproduced from Toxicological Sciences, 2007 (73) with permission from Oxford University Press.