Indirect 3D Bioprinting of a Robust Trilobular Hepatic Construct with Decellularized Liver Matrix Hydrogel

Abstract

The liver exhibits complex geometrical morphologies of hepatic cells arranged in a hexagonal lobule with an extracellular matrix (ECM) organized in a specific pattern on a multi-scale level. Previous studies have utilized 3D bioprinting and microfluidic perfusion systems with various biomaterials to develop lobule-like constructs. However, they all lack anatomical relevance with weak control over the size and shape of the fabricated structures. Moreover, most biomaterials lack liver-specific ECM components partially or entirely, which might limit their biomimetic mechanical properties and biological functions. Here, we report 3D bioprinting of a sacrificial PVA framework to impart its trilobular hepatic structure to the decellularized liver extracellular matrix (dLM) hydrogel with polyethylene glycol-based crosslinker and tyrosinase to fabricate a robust multi-scale 3D liver construct. The 3D trilobular construct exhibits higher crosslinking, viscosity (182.7 ± 1.6 Pa·s), and storage modulus (2554 ± 82.1 Pa) than non-crosslinked dLM. The co-culture of HepG2 liver cells and NIH 3T3 fibroblast cells exhibited the influence of fibroblasts on liver-specific activity over time (7 days) to show higher viability (90–91.5%), albumin secretion, and increasing activity of four liver-specific genes as compared to the HepG2 monoculture. This technique offers high lumen patency for the perfusion of media to fabricate a densely populated scaled-up liver model, which can also be extended to other tissue types with different biomaterials and multiple cells to support the creation of a large functional complex tissue.

The Material World of 3D‐Bioprinted and Microfluidic‐Chip Models of Human Liver Fibrosis

“…The cell-embedding hydrogel was composed of porcine liver dECM and crosslinking was achieved by the incorporation of PEG and tyrosinase (Figure 4D). [103] Finally, a combination of laminin-based bioink with gelatin and alginate was used for bioprinting three hexagonal structures, each one mimicking one lobule. [151] Seven days after printing, cells started to proliferate and form spheroids.…”

“…The cell‐embedding hydrogel was composed of porcine liver dECM and crosslinking was achieved by the incorporation of PEG and tyrosinase (Figure 4D). [ 103 ]…”

“…Reproduced under terms of the Creative Commons Attribution 4.0 (CC BY 4.0) license. [ 103 ] Copyright 2022, The Authors, published by MDPI. E) Liver dECM was mixed with GelMA to obtain a printable polymer with tunable mechanical properties.…”

“…Hydrogels containing fibroblasts and HepG2 were sequentially deposited over a PVA tri‐hexagonal structure. [ 103 ] Over time, PVA was dissolved, leaving a space that can be perfused. The cell‐embedding hydrogel was composed of porcine liver dECM and crosslinking was achieved by the incorporation of PEG and tyrosinase (Figure 4D).…”

“…Crosslinking was promoted by poly(ethylene glycol) and tyrosinase. Reproduced under terms of the Creative Commons Attribution 4.0 (CC BY 4.0) license [103]. Copyright 2022, The Authors, published by MDPI.…”