Gelatin-tannic acid microspheres encapsulated with amorphous selenium and zinc phosphate nanoparticles for promotion of large wound healing.

Addressing inflammation, excessive reactive oxygen species (ROS), and impaired angiogenesis pose significant challenges to the healing of large wounds. In this study, we aimed to examine the anti-inflammatory, angiogenic and wound healing effects of bioactive amorphous selenium (Se) and zinc phosphate (AZP) nanoparticles encapsulated within gelatin-tannic acid (GelTA) microspheres (~50 μm). Our results showed that treatment of H2O2-stimulated L929 cells with Se nanoparticles decreased the ROS level by 59.7 %. Additionally, AZP nanoparticles significantly enhanced the migration of human umbilical vein endothelial cells (HUVECs). Furthermore, quantitative analysis of wound healing in a rat dorsal full-thickness injury model revealed a higher healing rates of 49.6 % and 40 % in the GelTA-Se and GelTA-Se/GelTA-AZP2 groups, respectively, compared to the healing rate of 25.6 % in the control group (treated with saline only) at 4 days post-surgery. Hematoxylin and eosin (H&E) staining confirmed that combined treatment with GelTA-Se and GelTA-AZP microspheres accelerated wound healing, reduced scarring, and promoted the regeneration of hair follicles within 14 days. Overall, the administration of GelTA-Se/GelTA-AZP composite microspheres offers an effective strategy for the functional repair of large skin wounds, with significant potential for clinical applications.