This can be explained by CBP serving the role of an agent that fills in the pores of the GelMA gels, leading to increased mechanical properties of the crosslinked materials. This is supported by images of crosslinked GelMA with and without CBP (Figure ), where it can be observed that he incorporation of CBP into the structure of the pucks considerably improved their transparency. This is relevant if cells incorporated within 3D printed constructs made from GelMA-CBP bioinks need to be imaged through optical microscopy.