Raman spectroscopy for molecular diagnosis of psoriatic nails with SEM validation

Nail involvement is commonly observed in psoriasis, a chronic immune-mediated disorder; however, the diagnosis of mild or asymptomatic cases remains clinically challenging. In this study, Raman spectroscopy and scanning electron microscopy (SEM) were employed to distinguish among symptomatic psoriatic nails, asymptomatic psoriatic nails, and healthy controls. Raman spectral analysis revealed a reduction in α-helix content (I₁₆₅₂/I₁₀₀₂) in symptomatic nails and a significantly elevated I₈₇₇/I₁₀₀₂ ratio (p < 0.001) in asymptomatic cases, suggesting that this ratio may serve as a potential early biomarker for subclinical nail involvement. SEM imaging supported these findings, showing increased surface roughness and fragmentation in psoriatic nails, with intermediate features observed in asymptomatic samples. Notably, biologic therapy led to an increase in the α-helix-associated Raman peak at 932 cm^-1, indicating structural recovery. Collectively, these results underscore the potential of Raman spectroscopy as a non-invasive and sensitive diagnostic tool for detecting psoriatic nail involvement, including asymptomatic cases, while SEM provides complementary microstructural evidence that reinforces the spectroscopic data.