Figure 10.

A large-scale 3D printed complex organ with vascularized liver tissue constructed through the double-nozzle low-temperature 3D bioprinter created in Prof. Wang’s laboratory at Tsinghua University: (a) the double-nozzle low-temperature 3D bioprinter; (b) working principle of an elliptical hybrid hierarchical polyurethane-cell/hydrogel construct built via the double-nozzle low-temperature 3D bioprinter; (c) a CAD model containing the branched vascular network; (d) a cross section of the CAD model containing five sub-branched channels; (e) working platform of the 3D bioprinter containing two nozzles and the 3D printed semielliptical hybrid hierarchical polyurethane-cell/hydrogel construct; (f) an elliptical sample containing both a cell-laden natural hydrogel and a synthetic polyurethane (PU) overcoat; (g) several layers of the elliptical sample in the middle section containing a hepatocyte-laden gelatin-based hydrogel and a PU overcoat; (h) several layers of the elliptical sample in the middle section containing an ASC-laden gelatin-based hydrogel and a PU overcoat; (i) hepatocytes encapsulated in the gelatin-based hydrogel; (j) a magnified photo of (i), showing the alginate/fibrin fibers around the hepatocytes; (k) ASCs encapsulated in the gelatin-based hydrogel growing into the micropores of the PU layer; (l) ASCs on the inner surface of the branched channels; (m) pulsatile culture of two elliptical samples; (n) two samples cultured in the bioreactor; (o) static culture of the ASCs encapsulated in the gelatin-based hydrogel; (p) pulsatile culture of the ASCs encapsulated in the gelatin-based hydrogel. Images reproduced with permission from [28,49].