Fig. 4

Fabrication of a microvascular network by 3D printing. A, a Schematic of three different crosslinking strategies for bioprinting photo-crosslinkable inks (e.g., 5 wt% MeHA shown here), where crosslinking occurs before (pre-crosslink), after (post-crosslink), or during (in situ crosslink) extrusion. b Representative images of nozzles with extruded material and printed lattice structure. (Figure reprinted with permission from Ref. [61]). B, a Schematic diagram based on a coaxial bioprinting method. b confocal fluorescence image of a bioprinted HUVEC embedded construct under 30 s UV exposure. (Figure reprinted with permission from Ref. [56]). C A laser printing method generates capillaries. Green fluorescent endothelial cells. The printed cells formed a tubular structure with a lumen. The applied laser pulse energy was 6 µJ, and the patterns in panel a on the left were printed twice in the same place. Scale bars are 200 µm (a left and b left), 50 µm (a right and b center), and 10 µm (c right). (Figure reprinted with permission from Ref. [64])