FIG. 7.

PEG–fibrinogen hydrogels promote maintenance of hepatocyte metabolic functions in vitro. Primary hepatocytes were cultured on micromolded PEG–fibrinogen gels or adsorbed collagen I as described in Materials and Methods. Conditioned medium was collected at the indicated time points and metabolites of interest were quantified as described in the Materials and Methods section. Samples, standards, and controls were tested in duplicate. (A) Albumin synthesis; (B) urea synthesis. *Statistically significant difference from sEGF-supplemented PEG–fibrinogen samples at a specific day; p < 0.05, n > 3. Data has been normalized to number of viable cells at each day. For absolute (nonnormalized) rates of secretion, see Supplementary Figure S6.