These results show that 0.1% CBP and 0.05% LAP can be used for the extrusion 3D printing of GelMA inks if high intensity UV light is employed. However, the experimental protocol we used to 3D print the inks keeps a constant irradiation throughout the print, meaning that the prolonged exposure to high intensity UV light could lower the viability of cells in the printed construct. Thus, we elected to keep LAP at 0.5% and used 0.5% CBP as the optimal concentration for the 3D printing of cell-laden inks (bioinks) using low intensity 405 nm light and printing at 37 ºC.