Thiol-ene and methacrylated gelatin hydrogels have also been tested in extrusion printing with a post-printing light curing step. In this case, a fast photocrosslinking step is relevant to fix the geometry of the extruded print as it exits the nozzle and maintain printing fidelity. Gockler et al. demonstrated extrusion-based printability of 5% w/v Gel-MA and Gel-NB hydrogels with low, medium and high degree of modification without elaborating concrete differences in the printing results from the thiol-ene vs MA inks. Tigner et al. found a wider range of adjustable printing parameters for 10% w/v Gel-MA in contrast to the faster crosslinking Gel-NB ink, but the printed hydrogels showed a similar xy fidelity. Zhao et al. demonstrated printability of 8% w/v Gel-MA and Gel-NB hydrogels with 50% functionalization, where Gel-NB was crosslinked with DTT or thiolated heparin. In photorheology experiments, the observed gel point was reduced 1.7-fold in time using DTT and 3.7-fold with thiolated heparin as crosslinker in comparison to Gel-MA. No significant difference was found in the final shear storage modulus for the hydrogel crosslinked with DTT, but a 3.2-fold higher stiffness was obtained using thiolated heparin. Using optimized processing parameters, Gel-NB/thiolated heparin and Gel-MA inks were used to print a grid structure.