Design and fabrication of an integrated 3D dynamic multicellular liver-on-a-chip and its application in hepatotoxicity screening

Abstract

Nowadays, major methods of in vitro hepatotoxicity research are still based on traditional static two- or three-dimensional cell culture, although these means could investigate some toxic chemicals induced hepatotoxicity, but most of these toxicities failed to reappear in human, at least not in similar or calculable dose level. These failures may cause by the monoculture of only hepatocytes, ignored the signal communication to other non-parenchymal cells in liver tissue, also other complex microenvironment such as endothelial barrier, shear stress and other factors which were really existed in vivo but absent here, final leading to a low reliability of experimental results. In this study, a three-dimensional dynamic multi-cellular liver-on-a-chip device (3D-DMLoC) was developed to reproduce the microenvironment of in vivo liver tissue, including the simulation of hepatic sinusoid, perisinusoidal space and continuous liquid perfusion, hepatocytes could gather to some 3D cell spheroids in this chip. The perfusion could bring a real-time exchange of chemicals, nutrients, metabolites, supply suitable oxygen and a weak shear stress. The pressure and oxygen distribution inner the chip were simulated and evaluated by COMSOL Multiphysics software. HepaRG were co-cultured with HUVEC for 7 days in this chip, expression of hepatic polarization protein ZO-1 and MRP2, liver function factors ALB, UREA and CYP450s were almost all higher than in traditional static culture. Several drugs and heavy metal ions induced hepatotoxicity were then investigated, LDH released from hepatocyte spheroids in mostly 3D-DMLoC groups were higher than same-dosed 2D group, indicated the spheroids were more sensibility to the toxins. The hepatoxicity might be induced by acute hepatocytes injury according to the ratios of secreted AST/ALT contents. In conclusion, a liver-on-a-chip device was successfully developed and verified for better reproducing the in vivo physiological microenvironment of liver. It could be applied for easily, efficiently, and accurately screening the potential hepatotoxic chemicals in future.

Keywords: Cell co-culture; Hepatocyte spheroids; Hepatotoxicity; Liver-on-a-chip; Microfluidics.