The formation of a spheroid of primary hepatocytes and the expression of liver-specific functions depend on the characteristics of polyurethane foam

Rapid formation of spherical multicellular aggregates (spheroids) of hepatocytes and expression of liver-specific functions are important in developing a hybrid artificial liver. The relation between these points and the surface characteristics of the culture substratum are investigated in this article. Polyurethane foam (PUF) was used as a culture substratum for hepatocytes. Rat, dog, and porcine primary hepatocytes spontaneously formed a spheroid within 1.5 days in the pores of a hydrophilic PUF with a contact angle of 53.4 ± 2.7°. Rat and dog primary hepatocytes formed a spheroid within 3 and 7 days of culture, respectively, in hydrophobic PUF with a contact angle of about 100°. The rates of albumin secretion and ammonia metabolism at 5 days of culture of porcine hepatocytes were 31 μg of albumin/10⁶ nuclei/day and 0.018 μmol of NH₃/10⁶ nuclei/h, respectively, about 2 times higher than the values with hydrophobic PUF. It is very important to control the hydrophilicity of the PUF surface to develop an effective artificial liver module.