Gelatin/polydopamine/Zn2+ composite microspheres-based cream gel for wound treatment

Inspired by the commonly used creams in dermatology, the present study introduced a simple method to prepare a granular hydrogel that could be applied to the whole wound area via spread to promote wound healing. Gelatin microspheres were fabricated and densely stacked, followed by adsorbing dopamine and Zn2+ solution. Dopamine polymerised in-situ to form gelatin/polydopamine (PDA)/Zn2+ composite microspheres, which were self-assembled to form a granular hydrogel. Zn2+ accelerated dopamine polymerization. PDA formed Schiff base and hydrogen bond with gelatin, realizing the assembly among the composite microspheres. The granular hydrogel exhibited bulk feature, shear-thinning and self-healing properties, which was injectable and spreadable like creams. Zn2+ in hydrogel showed sustained and stable release within 7 d. The granular hydrogel was applied to wound and significantly promoted wound healing, shortening the healing time within 10 days. The present injectable granular hydrogel thus showed convenient and advanced features towards surgical wound treatment .