Figure 4. Bioprinting of conduit-containing tissue equivalents in multi-well plates.

To evaluate biocompatibility of new hydrogel formulations or to assess drug efficacy and drug toxicity we usually bioprint multiple tissue discs in 24-well plates. Standardized cylindric structures are formed by direct-dispensing using the sacrificial substance Pluronic F127. Into these structures, channel-containing, cell laden hydrogel discs are printed using direct-dispensing and micro-jet printing techniques. A main component of these tissues is GelMA that can be polymerized by UV-light-activated photoinitiators, which allows reproducible layer-by-layer assembly of tissue equivalents. Shown is the additive manufacturing of fibroblast-containing tissue-discs in 24-well plates with the (empty) Pluronic F127 scaffolds (top), tissue discs (middle) and metabolic activity measurements at different treatments (bottom). EYFP-expressing human fibroblasts were visualized by fluorescence microscopy.