Treatment of nail clippings with ethyl alcohol improves the efficacy of Raman spectroscopy in the diagnosis of Trichophyton rubrum onychomycosis.

The purpose of this work was to enhance the diagnostic accuracy of nail Raman spectroscopy for fungal nail infections, specifically onychomycosis caused by Trichophyton rubrum. The study assessed the different ethyl alcohol retention rates between control and infected nails after soaking nail clippings in ethanolic solutions and drying. Results revealed that ethyl alcohol completely evaporated from infected nail samples, while significant amounts were still present in control samples. Principal component analysis (PCA) was applied to discriminate control from infected nails and showed superior group separation when nails were treated with ethyl alcohol. PCA loadings plot attributed the efficient classification to the ν (CCO) Raman vibrational mode of ethyl alcohol. As Raman spectroscopy can detect minute concentration changes of ethyl alcohol in nails and the deterioration caused by onychomycosis accelerates its evaporation, a simple and rapid method for detecting T. rubrum onychomycosis is proposed.