(a) Alginate derivatives: sodium alginate (A), ALG-MA (B), and ALG-MA-DA (C). Methacryl group addition was confirmed via peaks (a, b, and e in Fig. 1) in both ALG-MA and ALG-MA-DA. (b) Gelatin derivatives: gelatin (A), GEL-MA (B), and GEL-MA-DA (C). Methacryl group addition was confirmed via peaks (a through e in Fig. 1) in both GEL-MA and GEL-MA-DA. Dopamine conjugation was confirmed via peaks (f through g in Fig. 1) of the aromatic protons between 6.6 and 7 ppm in both ALG-MA-DA and GEL-MA-DA. All chemical shifts relative to D2O tuning.