Synthesis of Eucommia ulmoides-derived carbon dots for anti-inflammatory and accelerated wound healing

Inflammation affects the pathology of wound healing and is strongly associated with many chronic wounds that do not heal. Natural herbs with anti-inflammatory effects have received much attention in clinical treatment because they are inexpensive, readily available, safe, and effective. In this study, EUO-NAC-CDs were prepared using a hydrothermal method in which Eucommia ulmoides (EUO) and n-acetylcysteine (NAC) were used as carbon sources. EUO-NAC-CDs have a small particle size distribution with an average particle size of 2.84 nm, emit stable blue-green fluorescence, and are biocompatible. EUO-NAC-CDs have been used for in vitro bioimaging, where high anti-inflammatory activity and accelerated wound healing have been demonstrated in vivo and in vitro. Additionally, EUO-NAC-CDs significantly decreased the expression of TNF-α, IL-6, and IL-1β and increased the expression of IL-10, suggesting that EUO-NAC-CDs had good anti-inflammatory effects. In a rat model of skin defects, EUO-NAC-CDs promoted wound healing, stimulated the formation of blood vessels and tissue regeneration near the wound, increased the expression of CD31, VEGF, and CD206, and decreased the expression of INOS, further demonstrating the therapeutic function of CDs. Therefore, fluorescent EUO-NAC-CDs can be effective in clinical wound treatment as imaging tools and functional wound dressings.