Tissue Like Density Sheets of Hepatoblastoma Cultures Obtained with Thin Suspended Hydrogels Mimicking In Vivo Inter‐Capillary Distances

Abstract Here a fabrication method is demonstrated that allows for the production of hydrogels in the ranges of 50–500 µm, suspended in polystyrene (PS) inserts, to mimic various inter‐capillary in vivo distances. The inherent thinning properties of vacuum forming, together with liquid pinning in apertures, are utilized to reproducibly obtain suspended gels with controlled thicknesses down to ≈50 µm. Transport through the gels is simulated for two model compounds and 50 µm gels are shown to allow for up to three times higher basolateral concentration than for 500 µm gels, after 1 h. HepG2 cells, encased in 50 µm gels, grow to cell densities of 1000 ± 400 million cells mL⁻¹, that is, close to in vivo tissue densities. By contrast, 200 and 500 µm gels support cell densities of 180 and 50 million cells mL⁻¹, respectively. The observed maximum cell densities correlate with expected cell densities, estimated by simulation of O₂ diffusion and metabolism. In conclusion, thin suspended hydrogels provide means to mimic a variety of inter‐capillary distances and enable the development of high‐density cell cultures.