Morphology and Function of Rat Hepatocytes Cultured on Expanded Polytetrafluoroethylene Surface

Abstract

for the development of a bioreactor using hepatocytes, particularly for a hybrid-type artificial liver, we study culture substrates in this paper with particular attention to a porous material, expanded polytetrafluoroethylene (ePTFE). Hepatocytes obtained from adult rats were attached to a substrate and grown in a chemically defined medium either with fetal calf serum (FCS, 10%), or with bovine serum albumin (BSA, 0.003- 0.3%). When cultured in a FCS-supplemented medium, hepatocytes spread poorly, retaining their cuboidal shape, and later reorganized themselves into multilayer aggregates on the ePTFE surface. The characteristics of hepatocytes were influenced by the modification of the ePTFE surface as well as the culture medium. Hepatocytes grown on a polyvinylalcohol (PVA)-treated ePTFE surface formed many more multilayer aggregates than those grown on a PVA-untreated ePTFE surface. Such highly multilayered aggregates were also noted when the cells were cultivated in a BSA-supplemented medium. The hepatocytes in all these aggregate cultures exhibited high albumin expression capability as compared with those in monolayer cultures. On the other hand, when cultured in a FCS-free or a BSA-free medium, hepatocytes were attached, spread well and then formed monolayers on both a PVA-treated and -untreated ePTFE surface as did the cells on a collagen-coated polystyrene surface. We concluded from these results that functional hepatocyte cultures can be obtained in multilayer aggregates immobilized on an ePTFE surface in a serum-supplemented medium.