The construction of covalent 3D networks by free radical polymerization mainly uses N,Nmethylenebis(acrylamide) (MBA) as the most common crosslinker. Crosslinking of natural polymers functionalized with MA (e.g., GelMA, HAMA) occurs upon light exposure and, as irradiation is applied post administration, this approach could enable therapies to be tailored to individual patients. For instance, since GelMA/NP mixture was applied as a liquid-phase hydrogel precursor, it enabled the filling of wounds of various sizes and shapes. Then, the irradiation with visible light triggered the formation of a crosslinked hydrogel that, extending along the wound edges, resulted in an improved healing (Figure ). Similarly, cartilage defects were effectively treated by introducing a liquid dispersion of kartogenin (KGN)-loaded PLGA NPs into HAMA. After exposure to irradiation and subsequent crosslinking of the polymer, the customized scaffold provided robust support for cartilage regeneration and drug release (Figure ).