Integrated platform for EV separation and controlled release based on gelatin microspheres for diabetic wound...

Diabetic wounds exhibit impaired healing owing to multiple pathological factors and current treatment options remain limited, underscoring the urgent need for novel therapeutic strategies. Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) are emerging as promising candidates for wound healing. However, the process from isolation to application of EVs is complex and time-consuming, which probably influences the activity and the therapeutic effects of EVs. To address these issues, we created the integrated platform for EV separation and controlled release. Gelatin microspheres (GMS) were prepared and functionalized with the variable domain of heavy-chain-only antibodies (GMS-VHH). GMS-VHH enabled the efficient capture of CD9-positive EVs in the culture supernatant of MSCs, forming EVs-loaded gelatin microspheres (GMS@EVs). The characterization of EVs demonstrated that the GMS-VHH isolation method outperformed traditional ultracentrifugation in terms of EV structural integrity. GMS@EVs exhibited excellent biocompatibility and promoted the proliferation of epidermal keratinocytes in vitro. In addition, the controlled release and the therapeutic efficacy of GMS@EVs were also observed in the treatment of diabetic wounds. Transcriptomic analysis illustrated that the wound healing-related genes were significantly upregulated and the pro-inflammatory genes as well as the wound healing-impaired genes were downregulated. Collectively, this study introduces a 'ready-to-use' platform for EV isolation and controlled release, providing a promising strategy for diabetic wound repair.