Effect of surface hydrolysis of biodegradable polymeric substrates on hepatocyte primary culture

Abstract

Hepatocyte is an anchorage-dependent cell whose viability and activity are greatly influenced by the kinds and surface properties of the matrix to which it is attached. Three different polymers (PLGA 85:15, PLGA 50:50 and PDLLA) in polylactide / polyglycolide family were investigated to see their biocompatability with the primary hepatocyte. Furthermore we changed their surface properties by 1 M NaOH hydrolysis to investigate if the change makes any cultural differences. Finally, we investigated the effect of serum on the cell on surface-hydrolyzed polymers. Compared to the collagen control, hepatocyte showed lower initial attachment and viability on theses polymers but higher cellular activities identified by higher ammonia degradation, urea production and albumin secretion rate. Hepatocyte on polymers formed many islands of multicellular aggregates compared to monolayer form of collagen control, which explains relatively higher activities of hepatocyte on polymers. 1 M NaOH hydrolysis changed the wettability, morphology, and chemical residue composition of the polymer surface but not bulk properties of the polymer. Compared to the unhydrolyzed polymers, hepatocyte on surface-hydrolyzed polymers showed similar or lower initial attachment and viability but higher cellular activities. Hepatocyte on surface-hydrolyzed polymers formed smaller islands which have more aggregates portion. Serum supplementation significantly increased initial attachment and viability but decreased cellular activities of cells on hydrolyzed polymers. Hepatocyte in serum-supplemented media formed larger islands which have more monolayer portion. Positively-charged serum proteins may bind to the negatively-charged surface residues (carboxylic acid group and hydroxyl group) on surface-hydrolyzed polymers and enhance cell attachment by tempering the repulsive force between these residues and negatively-charged cell membrane. So we concluded that the viability of hepatocyte on these polymer...