Analysis and differentiation of seminal plasma via polarized SERS spectroscopy

Abstract

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.

Evaluation and Optimization of Paper-Based SERS Substrate for Potential Label-Free Raman Analysis of Seminal Plasma

“…SERS spectra with high similarity in spectral profiles were obtained from paper substrates treated with or without NaCl; however, the former demonstrated larger Raman peaks in the range from 600 to 1800 cm −1 , especially the band region between 1100 and 1800 cm −1 , from which the intensity of 1220 cm −1 peak was found to increase by 50 percent. According to the previous results [34], these major bands were mainly assigned to ascorbic acid (1132 cm well. Peak shift was observed between 1400 and 1800 cm −1 , exhibiting selective enhancement due to the fact that paper substrate has specific affinity to some molecule species.…”

Label-free surface-enhanced Raman spectroscopy of biofluids: fundamental aspects and diagnostic applications

“…plasmon-resonance modes which are not detected using farfield excitation, as opposed to the Bbright modes^observed in the extinction spectrum [67,68]. Indeed, intense SERS spectra were obtained from biofluids using Ag colloids and a 785 nm laser [46,49,53,59,69], even though such an excitation wavelength is very far from the extinction band for those substrates (approximately 400-410 nm for unaggregated Ag nanoparticles). Moreover, because dark modes arise from plasmon hybridization in interacting nanoparticles, they can also occur in non-colloidal substrates when these are formed by nanoparticles deposited on a solid support [67,68]: SERS spectra of serum on Ag nanoparticles deposited on glass were obtained using a near-infrared excitation at 785 nm [47], despite the extinction maximum for those nanoparticles being reported at 418 nm.…”

The key role of ergothioneine in label‐free surface‐enhanced Raman scattering spectra of biofluids: a retrospective re‐assessment of the literature

“…In a first study by Chen et al. [47], LF‐SERS was used to obtain biochemical information from normal and abnormal samples of seminal plasma. The relatively high amount of ET in this biofluid is well‐documented in the literature, corresponding rather closely with the blood values [48,49], and is clearly detectable in the LF‐SERS spectra [50].…”

“…In a first study by Chen et al [47], LF-SERS was used to obtain biochemical information from normal and abnormal samples of seminal plasma. The relatively high amount of ET in this biofluid is well-documented Fig.…”