Perfusion culture of multi-layered HepG2 hepatocellular carcinoma cells in a pressure-driven microphysiological system

Abstract

Here we report the perfusion culture of a multi-layered tissue composed of HepG2 cells (a human hepatoma line) in a pressure-driven microphysiological system (PD-MPS), which we developed previously as a multi-throughput perfusion culture platform. The perfusion culture of multi-layered tissue model was constructed by inserting a modified commercially available permeable membrane insert into the PD-MPS. HepG2 cells were layered on the membrane, and culture medium was perfused both through and below the membrane. The seeded density (number of cells/cm²) of the culture model is 70 times that of static culture in a conventional 35-mm culture dish. Pressure-driven circulation of the medium in our compact device (8.6 × 7.0 × 4.5 cm³), which comprised two perfusion-culture modules and a pneumatic connection port, enabled perfusion culture of two multi-layered tissues (initially 1 × 10⁵ cells). To obtain insight into the basic functionality of the multi-layered tissues as hepatocytes, we compared albumin production and urea synthesis between perfusion cultures and static cultures. The HepG2 cells grew and secreted increasing amounts of albumin throughout 20 days of perfusion culture, whereas albumin secretion did not increase under static culture conditions. In addition, on day 20, the amount of albumin secreted by the HepG2 cells in the microfluidic device was 68% of that in the conventional culture dish, which was seeded with the same number of cells but had a 70 times larger culture area. These features of high-density culture of functioning cells in a compact device support the application of PD-MPS in single- and multi-organ MPS.

Keywords: Hepatocyte; Liver-on-a-chip; Microfluidic device; Microphysiological systems; Multi-layered culture; Organ-on-a-chip; Perfusion culture.