Simultaneous evaluation of p53 and p21 expression level for early cancer diagnosis using SERS technique

Simultaneous detection of tumor suppressor p53 and cyclin-dependent kinase inhibitor p21 has been achieved for the first time with a high sensitivity using surface enhanced Raman scattering (SERS) technique. In this immunoassay, gold@silver core–shell nanorods (Au@Ag NRs) with a high SERS activity and chemical stability were chosen to fabricate immuno-probes, which were conjugated with different antibodies to specifically target each analyte. Qualitative and quantitative analysis of p53 and p21 were achieved by characterizing SERS signals of two different Raman reporters (4MBA and DTNB), which were labeled on the corresponding optical probes. In addition, we investigated the detection of these biomarkers in the medium of blood serum. Our experimental results indicate the excellent specificity, high sensitivity (1 pg mL−1), as well as the great reproducibility of this immunoassay. More importantly, this assay presents a powerful ability to detect multiple analytes due to the great multiplexing capacity of SERS spectroscopy. Since the combined evaluation of p53 and p21 expression level acts as an indicator for early cancer prediction, our demonstrated immunoassay will potentially promote the application of SERS technique to practical clinical diagnoses.