Liver-lobule-mimicking patterning via dielectrophoresis and hydrogel photopolymerization

Patterning and cultivating heterogeneous cells on microfluidic chips is essential for engineering tissue regeneration. Current patterning technologies focus mainly on positioning cells at specific locations, but most do not mimic in-vivo cell patterns. Even few papers and reports care about maintaining cell patterns after the patterning process and several days of culture. Here, we report a liver-lobule-mimicking labchip consisting of three components: the concentration gradient generator, the dielectrophoretic cell-patterning, and four cell-culturing chambers providing culturing microenvironment. NIH/3T3 (fibroblast cell) and C3A cells (human hepatocyte) were patterned via dielectrophoresis to reconstruct the liver-lobule's radial actinomorphic organization and pattern at each cell-culture chamber. Subsequently, GelMA at different concentrations was perfused to form GelMA culturing-microenvironment coverings with different concentrations of 5 %, 10 %, 15 % GelMA and 0 % GelMA for the control group. Cell viability was maintained 95 % at 5 % GelMA chamber after cultured for 72 h. For the 15 % GelMA chamber, cell viability was 78 % on 72-hrs culturing. Urea assays revealed that the co-cultured cells in 5 % GelMA maintained the high activity, which has the highest urea secretion, with the preserved biomimicking liver-lobule pattern compared with other culturing-microenvironments. By cultivating cells in our liver-lobule-mimicking labchip with cellular micropatterning and hydrogel covering, the liver-lobule-like cell pattern was not affected by the difference in cell growth rate and the streamline of the perfused culture medium. We also observed that the appropriate GelMA culturing-microenvironment not only preserves the biomimicking liver-lobule pattern but also enhances liver function related to urea production.