Tβ4-exosome-loaded hemostatic and antibacterial hydrogel to improve vascular regeneration and modulate macrophage polarization for diabetic wound treatment.

Diabetic wounds often exhibit delayed healing due to compromised vascular function and intensified inflammation. In this study, we overexpressed Thymosin β4 (Tβ4) in Adipose-Derived Stem Cells (ADSCs) to produce Exosomes (Exos) rich in Tβ4. We then utilized a dual photopolymerizable hydrogel composed of Hyaluronic Acid Methacryloyl (HAMA) and Poly-L-lysine Methacryloyl (PLMA) for the sustained release of Tβ4-Exos on diabetic wounds. The results showed that Tβ4-Exos could stimulate angiogenesis and collagen synthesis, and mitigate inflammation in diabetic wounds by promoting the polarization of M1-type macrophages and inhibiting that of M2-type macrophages. Furthermore, Tβ4-Exos was found to activate the PI3K/AKT/mTOR/HIF-1a signaling pathway, thereby enhancing vascular proliferation. In summary, the sustained release of Tβ4-Exos in HAMA-PLMA (HP) hydrogel and the management of inflammation through the upregulation of the HIF-1a pathway and modulation of macrophage polarization in vascular proliferation significantly accelerated the healing process of diabetic wounds.