Engineering a GelMA-dECM-Based 3D Bioprinted Liver Fibrosis Model: Methotrexate-Induced Functional and Molecular Validation

ABSTRACT Three-dimensional (3D) bioprinting represents a cutting-edge advancement in additive manufacturing, offering unprecedented precision in fabricating in vitro models that recapitulate native tissue architecture and function. In this study, we engineered a 3D bioprinted hepatic construct using a composite bioink comprising Gelatin Methacryloyl (GelMA), decellularized extracellular matrix (dECM) derived from rat liver, and HepG2 cells. GelMA was synthesized in-house to provide mechanical integrity and biocompatibility, while the liver-derived dECM offered essential biochemical cues to mimic the native hepatic microenvironment. The combination of GelMA and dECM uniquely provides mechanical robustness and bioactive cues essential for hepatic tissue mimicry. This synergy enhances cellular functionality and supports accurate fibrosis modeling for translational research. The bioprinted constructs were crosslinked using microbial transglutaminase and a photoinitiator to achieve structural stability. Following fabrication, the 3D bioprinted hepatic constructs were evaluated using cytocompatibility assays (MTT, live/dead), functional assays (albumin, urea, LDH, ALT, and ALP secretion), and gene expression profiling to validate liver-specific function. Subsequently, liver fibrosis was induced in the 3D bioprinted constructs via methotrexate (MTX) exposure, and the fibrotic phenotype was confirmed through functional decline and upregulation of fibrosis-related genes. This study demonstrates a robust and physiologically relevant 3D bioprinted in vitro model of methotrexate-induced liver fibrosis, offering a valuable platform for translational applications in drug screening and hepatic disease modelling.