Reversible cross-linking of gelatin by a disulphide-containing bis-succinimide for tunable degradation and release

•A reversible cross-linker was used to control the cross-linking and degradation of gelatin films.•The cross-linked gelatin films could preserve their morphology in 37 ℃ warm water for above 40 days.•The gelatin film changed its microstructure from net to tightness after the cross-linking.•The degradation of the cross-linked gelatin film could be controlled by glutathione. Generally, gelatin was irreversibly cross-linked by chemical reagents to improve its water-resistance. However, few chemical reagents meet both the requirements of high cross-inking efficiency and tunable degradation. Here a reversible cross-linker, disulphide-containing bis-succinimide, was synthesized and used to control the cross-linking and degradation of edible gelatin film. Mixture of the gelatin and cross-linker for 120 min generated gelatin films that could preserve their morphology in 37 ℃ warm water for above 40 days. The gelatin film changed its microstructure from net to tightness after the cross-linking, thus facilitating the embedding of the targeted molecule into the gelatin material. The degradation of the cross-linked gelatin film and the release of its inclusion could be controlled by biocompatible glutathione. This work provides a good method for preparing modified gelatin with promising water-resistance, good biocompatibility, and tunable degradation for food/biomedical engineering applications.