Hydroxypropyl methylcellulose stearoxy ether hydrogel loaded with aloe vera peel-derived extracellular vesicle...

The impaired healing of diabetic wounds under hyperglycemic conditions presents a major challenge. While Aloe vera gel is known for wound healing, the potential of its peel is underexplored. This study aimed to develop a scalable production method for Aloe vera peel-derived extracellular vesicle mimetics (AVp-EVMs), screen an optimal hydrogel for their delivery, and evaluate their efficacy in diabetic wound healing.

AVp-EVMs were produced via high-pressure homogenization and ultracentrifugation. Their effects on keratinocyte (HaCaT) proliferation/migration and anti-inflammatory activity in LPS-stimulated macrophages were assessed in vitro. Two hydrogels (non-ionic Sangelose 60L and ionic Carbomer 940) were screened as carriers. Finally, AVp-EVMs and the optimal hydrogel formulation (HG-EVM) were evaluated in a diabetic mouse wound model by monitoring wound closure, histology, and immunohistochemistry.

AVp-EVMs showed good biocompatibility, promoted keratinocyte proliferation and migration, and were effectively internalized. They suppressed LPS-induced inflammation in macrophages by inhibiting NF-κB activation and downstream pro-inflammatory cytokines (TNF-α, IL-1β, IL-6). The Sangelose hydrogel preserved the AVp-EVMs structure better than the Carbomer hydrogel. In diabetic mice, both AVp-EVMs and HG-EVM dressing promoted wound healing by enhancing re-epithelialization, reducing inflammation, and improving collagen deposition and alignment. The HG-EVM group achieved the highest wound closure rate (97.2%), significantly outperforming free AVp-EVMs injection (94.9%; P < 0.01).

This study establishes a production method for AVp-EVMs. The non-ionic Sangelose hydrogel is an effective delivery vehicle, and the HG-EVM formulation enhances diabetic wound healing more effectively than free AVp-EVMs alone.