WSe2-PDA-enhanced fiber optic surface plasmon resonance bioprobe for the detection of prostate-specific antigen

The detection of trace biomarkers plays a critical role in the early screening and diagnosis of various cancers. Here, we report a WSe₂-PDA enhanced fiber optic surface plasmon resonance (FO-SPR) bioprobe for the sensitive detection of prostate-specific antigen (PSA). The bioprobe features a near-field enhanced sensing structure composed of a fiber, WSe₂ film, gold film, and polydopamine (PDA)@Wse2 film. The near-field electron coupling between the WSe₂ and gold films significantly increases the electric field intensity on the sensor surface, thereby improving the overall sensitivity. Meanwhile, the PDA film, serving as an effective antibody coupling agent, offers excellent biocompatibility and enhances the bioprobe’s capacity to capture target biomolecules. Finite element simulations predict a sensitivity of up to 2400 nm/RIU, which is 1.71 times higher than that of conventional SPR sensors. Experimental results using low-concentration PSA samples demonstrate a detection limit of 0.18 ng/mL, more than one order of magnitude lower than the clinical reference value. Such a low detection limit effectively mitigates measurement errors and ensures accurate results. Owing to its label-free, low-cost, and convenient operation, this bioprobe shows great promise for the rapid and early screening of prostate cancer.