Label-free long-range detection of prostate cancer biomarkers based on surface-enhanced Raman scattering

In the field of prostate cancer based on surface-enhanced Raman scattering (SERS), the repeatability of detection is crucial for its practical application in clinical medicine. We propose to use a new SERS substrate based on a polymer planar waveguide in combination with microfluidic technology and utilized in the label-free detection of prostate-specific antigen (PSA) in serum. The experimental results show that the detection limit of the substrate for PSA sample solution is as low as 10 pg ml −1 . Additionally, the optimal transmission length for PSA is determined to be 9 mm. Further examinations encompass repetitive testing of serum samples spiked with PSA at a concentration of 4 ng ml −1 , revealing a relative standard deviation (RSD) of 5.01%. This outcome is compared with single-point detection, manifesting a notable enhancement of 9.81% in terms of RSD, signifying a marked improvement in repeatability. Notably, our method not only capitalizes on the long-range averaging effect to enhance the repeatability of Raman signals, but also circumvents sample damage resulting from direct laser irradiation.