Herbal selaginella extract-derived carbon nanodots: A potential nano-therapeutic agent for atopic dermatitis.

Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disorder with rising global prevalence. Current treatments such as corticosteroids and antibiotics often lead to side effects, drug resistance, and limited long-term safety. Natural compounds, including extracts from Selaginella, offer multi-targeted anti-inflammatory and antioxidant benefits but suffer from poor solubility and low bioavailability. To overcome these limitations, carbon nanodots using selaginella extract as the sole precursor (SSE-CDs) were synthesized. The SSE-CDs (2.5 ± 1.5 nm) possess abundant surface functional groups, negative surface charge and good enzyme-like activity. In vitro, SSE-CDs reduced reactive oxygen species, alleviated inflammation, and promoted proliferation in damaged HaCaT cells. In vivo, in an AD mouse model, SSE-CDs restored immune cell balance and normalized inflammatory cytokine expression. Mechanistic studies revealed that SSE-CDs inhibited phosphorylation of key proteins in the NF-κB and MAPK signaling pathways. Furthermore, a skincare lotion formulated with SSE-CDs showed therapeutic efficacy in an AD mouse model, suggesting its potential for dermatological applications. This study provides a preliminary demonstration of carbon nanodots as a promising anti-inflammatory strategy for AD management.