Plasma-Activated AVC Hydrogel for Reactive Oxygen and Nitrogen Species Delivery to Treat Allergic Contact Dermatitis

Allergic contact dermatitis (ACD) is a common inflammatory skin disease that accounts for approximately 20% of all occupational skin diseases. As an adverse and recurrent inflammatory dermatological agent, ACD shows insufficient response to current therapies largely owing to abnormal inflammatory activation and accompanying bacterial infection in lesions. Cold atmospheric plasma is a noninvasive fledgling reactive oxygen and nitrogen species (RONS)-based therapeutic technique for ACD treatment; however, its clinical adoption has been hindered due to the risk of electrical burns and insufficient delivery of the plasma-generated RONS. To address these limitations, we constructed plasma-activated AVC (PA-AVC) hydrogels loaded with plasma-generated RONS for ACD treatment as an alternative to the common direct plasma irradiation treatment. The proposed PA-AVC hydrogels were produced on a biodegradable acryloyldimethylammonium taurate/VP copolymer (AVC) with the aid of a novel air discharge plasma without the involvement of any catalyst. In vitro data showed that abundant RONS were produced and incorporated into the PA-AVC hydrogels via complex gas-liquid reactions between the air discharge plasma and hydrosolvent; additionally, the PA-AVC hydrogels exhibited excellent storage, slow release and transdermal delivery of RONS as well as good antibacterial effects. Moreover, in vivo experiments demonstrated that PA-AVC hydrogels effectively alleviated the ACD symptoms, such as skin redness and swelling, reduced epidermal thickening and inhibited mast cell infiltration and IL-9, TNF-α, and TSLP expression with no evident systemic toxicity. Our results revealed that long-acting plasma-activated AVC hydrogels could be effective therapeutic agents for local ACD treatment.