Fabrication, characterisation, and application of green crosslinked sodium alginate hydrogel films by natural crab-shell powders to achieve drug sustained release

In this study, natural crab-shell particles (CSP) and deacetylated crab-shell particles (dCSP) were used as crosslinking agents at the present of glucolactone to obtain high strength mono-crosslinked and bi-crosslinked sodium alginate (NaAlg) hydrogel films, respectively. The results indicated that the CSP in the system could occur Ca 2+ crosslinking, and the addition of dCSP could help to form both Ca 2+ crosslinking and polyelectrolytes interactions with NaAlg. The remaining unreacted CaCO 3 could enhance the thermal stability of the films due to the high thermally stable CaCO 3 . The surface hydrophobicity, gel properties, mechanical strength and thermal stabilities of those bi-crosslinked NaAlg hydrogel films were better than those of neat NaAlg film and mono-crosslinked NaAlg hydrogel films, which overcome the inferior thermo-mechanical properties for traditional hydrogel films. In addition, the releasing time of those prepared hydrogel films for diclofenac sodium was higher than 36 h, which illustrated sustained drug releasing activity. The CSP modified NaAlg hydrogel film with 0.5% GDL content exhibited the highest cumulative release amount. The proposed approach is a promising green crosslinking technique to develop high performance NaAlg hydrogel films that can realize active ingredients and drugs sustained release in food packaging and medical wound dressing areas.