Simultaneous Detection of Dual Prostate Specific Antigens Using Surface-Enhanced Raman Scattering-Based Immunoassay for Accurate Diagnosis of Prostate Cancer.

Accurate analysis of specific biomarkers in clinical serum is essential for early diagnosis and treatment of cancer. Here, a surface-enhanced Raman scattering (SERS)-based immunoassay, using magnetic beads and SERS nano tags, was developed for the determination of free to total (f/t) prostate specific antigen (PSA) ratio to improve the diagnostic performance of prostate cancer. To assess the clinical applicability of the proposed method, SERS-based assays for the simultaneous detection of dual PSA markers, free PSA (f-PSA) and complexed PSA (c-PSA), were performed for clinical samples in the gray zone between 4.0 and 10.0 ng/mL. Our assay results for f/t PSA ratio showed a good linear correlation with those measured using the electrochemiluminescence (ECL) system installed in the clinical laboratory of the University Hospital. In addition, the simultaneous assay provided better precision than parallel assays for the detection of f-PSA and c-PSA in 13 clinical serum samples. Therefore, our SERS-based assay for simultaneous detection of dual PSA markers in clinical fluids has strong potential for application in the accurate diagnosis of prostate cancer.