Self-healing, pH/ROS-dual responsive chitosan-phenylboronic acid hydrogel coating for intelligent mango preservation

This study reports the rational design and fabrication of an intelligent, self-healing hydrogel tailored for fruit preservation via the dynamic cross-linking of chitosan (CS) with a synthesized phenylboronic acid-based crosslinker (DMSA-PBA). The strategic introduction of dynamic boronate ester bonds as the key crosslinking nodes is pivotal, granting the material not only rapid gelation (<60 s) and autonomous self-healing capabilities but also dual responsiveness to pH and reactive oxygen species (ROS). The resulting hydrogel network exhibits a suite of exceptional properties: superior mechanical robustness, a high swelling ratio (∼1000%), and outstanding water vapor barrier performance. Furthermore, the inherent synergistic antibacterial activity, stemming from the chitosan and the DMSA-PBA components, was confirmed. When evaluated as a protective coating on mangoes, this multifunctional hydrogel significantly delayed quality deterioration during ambient storage, effectively reducing weight loss and decay incidence while maintaining firmness and acidity. This work underscores the immense potential of dynamic covalent chemistry in designing advanced coatings for sustainable food preservation, presenting a feasible and eco-friendly strategy grounded in a well-defined material design.