Reconstruction and characterization of stacked 3D tissue using a hepatic cell-patterned hydrogel paper

Abstract

We fabricated liver lobule-like stacked hydrogel papers embedded hepatic cells for in vitro liver tissue reconstruction with negligible diffusion limitation. HepG2 cell-embedded mi-cropatterned hydrogel papers which had the width of 8000 μm, the length of 8660 μm and the height of 80-140 μm. The stacked hydrogel papers were fabricated via laminating and aligning the hepatic hydrogel papers in a PDMS jig. For drainage, the jig had many pillars of 170 μm in height. The cells could be cultured in the stacked hydrogel papers which had the height of 300-600 μm exceeding diffusion limit thickness (150-200 μm). The patterned structure with many openings facilitated cell-to-cell interaction and overcame the diffusion limitation, so it gave good viability more than 90% for much remaining HepG2 cells with compared to no pattern. Also, cell-to-cell interaction between each hydrogel paper led to the twofold increase of albumin secretion and the maintenance of urea secretion per million cells with compared to a hydrogel paper. Therefore, we suggest that the stacked hydrogel papers can be macroscale hepatic pseudo-tissues with complex microenvironments, over-coming diffusion limitation for biological study of liver.