Microfluidic device; Viability up to 2 weeks; Albumin and urea secretion; CYP1A2, CYP2B6, and CYP3A4 activity; Polarized cellular organization with functional bile canaliculi; Allows energy metabolism studies; Allows the recapitulation of different hepatotoxicity mechanisms (e.g., steatosis, cholestasis, and fibrosis). The gene discussed is CYP1A2; the disease is steatosis.