Fully physically reinforced hydrogels: a periodic curcumin delivery system with convenient injection and thermo-reversible adhesion

Hydrogels with fully physical networks process significant advantages as convenient injection, self-healing, and biodegradable properties probably accompanied with unfavorable mechanics, adhesiveness, and drug-loading characteristics. In this study, N -acryloyl glycinamide (NAGA)–grafted gelatin decorated with photosensitive N′ -(2-nitrobenzyl) ( NB ) moiety, denoted as GN, was synthesized via a convenient one-step Michael addition. The GN hydrogels in terms of gelatin physical reinforcement was conveniently constructed via UV-induced NB group separation and dual -amide discharge. Also released are curcumin drugs loaded into hydrophobic NB groups via hydrophobic association. Contrastive analysis on a series of GN hydrogels with different degrees of substitution (DS) was performed. As a result, the GN-5 hydrogel with moderate DS (~ 41.2 ± 1.3%) possessed the overall optimal performance with the highest final storage modulus, maximal compression stress, most dense pore structure, and minimal swelling deformation. In addition, the fully physical networks thoroughly assisted in degradation, fast self-healing, and thermo-reversible adhesiveness. Most importantly, the further curcumin release achieved via heating induced H-bonding destruction, and the Ritger-Peppas model best described the dynamic drug release traces during the four kinetic models, which show great application potential in the field of biomedical materials. Graphical The fully physically reinforced gelatin hydrogels afford as a periodic curcumin delivery system with convenient injection, fast self-healing, thoroughly degradation, and thermo-reversible adhesion.