Multifunctional nanocone array as solid immunoassay plate and SERS substrate for the early diagnosis of prostate cancer on microfluidic chip

We reported a novel multifunctional nanocone array as solid immunoassay plate and surface-enhanced Raman scattering (SERS) substrate for the simultaneous immunoassay of prostate-specific antigen (PSA) and thrombin based on microfluidic chip. In traditional immunoassays, microtiter plates are often used as solid capture plates to form immunocomplexes. However, the two-dimensional surface of the microtiter plate limits the efficiency of target antigen capture due to its steric inhibition. To solve this problem, a nanocone array covered with deposited gold film was successfully fabricated on glass slides that could be directly sealed with PDMS microfluidic chip. As a SERS active substrate, it can also provide a large surface area for capture aptamer conjugation to form a “sandwich” immunocomplex. On the strength of this integrated microfluidic chip, we could detect PSA and thrombin simultaneously with the detection limits of 0.01 ng mL−1 and 0.01 nM. Compared to previous reports, this detection strategy demonstrated the rapid and automatic performance with comparable detection limits. It is believed that the proposed microfluidic sensor has great potential for the early diagnosis of prostate cancer.