For 3D bioprinting, an extrusion-based 3D printer (BioSpot BP, Biofluidix GmbH, Freiburg, Germany) equipped with a cooling system, syringe (Injekt Luer Lock Solo, VWR, Bruchsal, Germany), and a dispensing nozzle (cone, diameter: 0.25 mm, Vieweg GmbH, Kranzberg, Germany) was used. Cell-loaded (2.5 × 10 6 cells·mL -1 ) inks (bioinks) were prepared in a 2 mL syringe following the protocol described above. The temperature of the bioinks was set to either 37 °C for GelMA/bPE inks or 22 °C for the GelMA ink and held for 30 min prior to extrusion. In order to support fast structural recovery upon deposition, adhesive glass slides were cooled to 17 °C. G-codes were written for different model structures, including a grid (12 mm × 12 mm), KIT and UCLA university logos (10 mm × 26 mm), and a hollow square structure (6 mm × 6 mm). Multiple layers (11 for hollow square structure and 20 for grid, Figure and 2B) were printed without photocrosslinking between individual layers, and photos were taken. 3D printing was performed at an average extrusion rate of 0.02 mm·s -1 and a print speed of 5 mm·s -1 . For printing tests with other materials than GelMA, 5 wt% GelNB/GelS and 5 wt% PEGDA precursor solutions were supplemented with 20 wt% and 40 wt% DbPEs, respectively. After deposition, hydrogel formation was induced by UV-visible light irradiation (320-500 nm, 500 mW•cm -2 ) for 60 s using the Omnicure S2000 curing system (igb-tech GmbH, Friedelsheim, Germany). The printed, cellloaden structures on the glass slide were washed with DPBS, transferred to a petri dish, and covered with 10 mL DMEM for further cultivation.