Bioactive 10-nm graphene oxide modulates AhR-associated keratinocyte signaling and attenuates atopic dermatitis-like inflammation

Graphene oxide (GO) has been widely explored as a carrier, coating, and composite component in biomedical material systems, yet its intrinsic bioactivity as a standalone biomaterial remains incompletely defined. Here, we investigated whether physicochemically defined 10-nm nanoscale graphene oxide (NGO), without exogenous therapeutic loading, modulates inflammatory, oxidative, and barrier-associated keratinocyte responses and attenuates atopic dermatitis-like inflammation. We further examined whether NGO engages aryl hydrocarbon receptor (AhR)-associated signaling accompanied by nuclear factor erythroid 2-related factor 2 (NRF2)-linked cytoprotective responses. NGO showed ultrasmall dimensions and oxygen-rich surface chemistry. At 10 μg/mL, it did not significantly reduce human keratinocyte viability after 24 h, and fluorescence from labeled NGO was observed predominantly in the cytoplasmic region. NGO increased AhR nuclear accumulation and cytochrome P450 1A1 (CYP1A1) expression; both responses were attenuated by the AhR inhibitor CH223191. In cytokine-stimulated keratinocytes, NGO reduced the expression and secretion of selected inflammatory mediators and supported barrier-associated gene expression. Under these conditions, NGO also increased NRF2 nuclear accumulation and mRNA expression of heme oxygenase 1 (HMOX1; HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO1). These NRF2-linked responses were also attenuated by CH223191. Separately, NGO reduced 2,4-dinitrochlorobenzene (DNCB)-induced intracellular reactive oxygen species accumulation. In a DNCB-induced atopic dermatitis-like mouse model, topical NGO treatment for 15 days attenuated clinical severity, serum immunoglobulin E elevation, and histological abnormalities. The data support pathway associations without establishing direct AhR binding or causal pathway requirements. Together, these findings support NGO as a standalone bioactive carbon nanomaterial that modulates inflammatory, oxidative, and barrier-associated responses in skin-relevant models.