Analysis and differentiation of seminal plasma via polarized SERS spectroscopy

Polarized surface-enhanced Raman scattering (SERS) spectroscopy was applied for obtaining biochemical information about the seminal plasma. The effect of different laser polarizations (nonpolarized, linear-polarized, right-handed circularly polarized, and left-handed circularly polarized) on seminal plasma SERS spectroscopy was explored for the first time. The diagnostic performance in differentiating abnormal seminal plasma (n = 37) from normal seminal plasma (n = 24) was evaluated. A combination of principal component analysis (PCA) and linear discriminant analysis (LDA) was employed to develop diagnostic algorithms. Classification results of different laser polarizations demonstrated different diagnostic sensitivities and specificities, among which, left-handed circularly polarized laser excitation showed the best diagnostic result (95.8% sensitivity and 64.9% specificity). Our exploratory study demonstrated that SERS spectroscopy with left-handed circularly polarized laser excitation has the potential for becoming a new diagnostic method in semen-quality assessment.