Enhanced SERS detection of the colorectal cancer biomarker utilizing a two-dimensional silver substrate

To improve the sensitivity, accuracy and specificity of the assay, a two-dimensional silver substrate with EF=5.85×10⁸ was first synthesized as a SERS substrate, on the surface of which DSP molecules were modified to form a DSP-antibody coupling through the activation of two N-hydroxy succinimide (NHS) esters to capture TNF-α. Subsequently, aptamerized silver-coated gold nanospheres (Au@TFMBA@Ag) were synthesized as Surface-Enhanced Raman Scattering (SERS) recognition probes. These probes were employed to create a sandwich structure for the quantitative detection of Tumor Necrosis Factor-alpha (TNF-α), utilizing the SERS signal intensity at 1374 cm^-1. Quantitative detection of TNF-α was successfully accomplished within the concentration range of 10^-4 to 10^-10 mg·mL^-1. Clinical serum samples were collected and subjected to testing. Significance analysis, conducted through the T-test (p < 0.0001), unequivocally showed the method's ability to differentiate between sera from normal individuals and those diagnosed with colon cancer.