Rapid and label-free screening of echinococcosis serum profiles through surface-enhanced Raman spectroscopy.

Echinococcosis is a serious zoonotic parasitic disease that could be fatal without diagnosis and treatment in a timely manner. Herein, we present a rapid and label-free method for screening of echinococcosis using surface-enhanced Raman spectroscopy (SERS). Three groups of serum SERS spectra based on porous silicon/silver composites are obtained: one group from healthy volunteers (normal, n = 163) and two other groups from patients with pathologically confirmed echinococcosis (cystic echinococcosis (CE), n = 69 and alveolar echinococcosis (AE), n = 38). The derived characteristic spectrum was analyzed to explain differences between echinococcosis and healthy volunteers and a principal component analysis (PCA) was applied for classification. Raman spectra revealed that high sensitivity and specificity for echinococcosis diagnosis were associated with the contents of phenylalanine and tyrosine. In addition, Raman spectroscopy analysis identified two metabolites including phenylalanine and carotenoids that could distinguish three types of serum. Orthogonal partial least squares discriminant analysis (OPLS-DA) was successfully used as a discriminative model to classify echinococcosis with the highest sensitivity and specificity of 100% and 98.6%, respectively. Combination of serum metabolomics with SERS enabled accurate screening of echinococcosis patients. The results indicate that SERS-based serum profile analysis has the potential to be a valuable tool for the early diagnosis and screening of echinococcosis.