Microarchitecture-driven regulation of hepatocyte functional stability in 3D bioprinted genipin-crosslinked PVA–Chitosan scaffolds

Liver tissue engineering aims to develop physiologically relevant in vitro models that maintain hepatocyte viability and function over extended culture periods. In this study, a genipin-crosslinked polyvinyl alcohol–chitosan (PVA–CH) hydrogel was used to fabricate extrusion-based 3D bioprinted grid and biomimetic lobule scaffolds for hepatic tissue engineering. Both architectures preserved their intended pore arrangements. The lobule scaffold reached approximately 200% equilibrium swelling compared with 165–170% for the grid and showed lower Day-21 weight loss than the grid in phosphate-buffered saline (15% versus 20%) and lysozyme-containing medium (50% versus 60%). The apparent compressive modulus was 5.17 ± 0.35 kPa for the lobule and 3.47 ± 0.25 kPa for the grid (p < 0.01). Rhodamine-B analysis showed an architecture-associated difference in apparent dye uptake and whereas washout did not differ significantly between the architectures. Live/Dead imaging showed viable hepatocytes within both three-dimensional constructs through Day 7, and MTT activity was maintained through Day 21. At Day 21, albumin secretion reached approximately 15–17 µg/mL in the lobule scaffold compared with 10–12 µg/mL in the grid scaffold. The lobule group also reached approximately 18–20 µg/mL urea and 3.2–3.5 ng/mL CYP450 activity. These functional measurements were accompanied by 15–18-fold ALB, 10–12-fold HNF-4α and approximately 15-fold CYP1A2 expression in the lobule group. These findings identify architecture-associated differences in bulk mechanical properties, solute retention and hepatocyte-function measurements under matched material and printing conditions.