Carboxymethyl cellulose-based injectable hydrogel loaded with a composite of melatonin and γ-cyclodextrin with antioxidant property for diabetic wound repair

Overproduction of reactive oxygen species is one of the important reasons of non-healing wounds, such as diabetic wounds. Melatonin is well known as an antioxidant, while the poor solubility limits its use in many areas. In this study, the solubility of melatonin was improved by introducing γ-cyclodextrin to form the composite named MT-γ-CD through ultrasonic process. During this process, the molar ratio of melatonin and γ-cyclodextrin was 2:1, the temperature was set at 30 ℃, and the ultrasonic time was 40 min. The MT-γ-CD showed good antioxidant property in vitro with high free radical scavenging efficiency over 90%. Besides, an injectable self-healing hydrogel was prepared to load with MT-γ-CD to form the wound dressing, here, sodium carboxymethylated cellulose was oxidized to introduce aldehyde groups that could form Schiff base with amino groups in gelatin. This dressing with good biocompatibility could be injected into irregular wounds, suppress the level of reactive oxygen species, and accelerate wound healing of diabetic rats in vivo. Therefore, it has great potential to provide a new treatment strategy for diabetic wounds.