Plasmonic-Based Biosensor for the Early Diagnosis of Prostate Cancer.

A tapered optical fiber (TOF) plasmonic biosensor was fabricated and used for the sensitive detection of a panel of microRNAs (miRNAs) in human serum obtained from noncancer and prostate cancer (PCa) patients. Oncogenic and tumor suppressor miRNAs let-7a, let-7c, miR-200b, miR-141, and miR-21 were tested as predictive cancer biomarkers since multianalyte detection minimizes false-positive and false-negative rates and establishes a strong foundation for early PCa diagnosis. The biosensing platform integrates metallic gold triangular nanoprisms (AuTNPs) laminated on the TOF to excite surface plasmon waves in the supporting metallic layer and enhance the evanescent mode of the fiber surface. This sensitive TOF plasmonic biosensor as a point-of-care (POC) cancer diagnostic tool enabled the detection of the panel of miRNAs in seven patient serums without any RNA extraction or sample amplification. The TOF plasmonic biosensor could detect miRNAs in human serum with a limit of detection between 179 and 580 aM and excellent selectivity. Statistical studies were obtained to differentiate cancerous from noncancerous samples with a p-value <0.0001. This high-throughput TOF plasmonic biosensor has the potential to expand and advance POC diagnostics for the early diagnosis of cancer.