RESUMO
Establishing an accurate, simple, and rapid serodiagnosis method aiming for specific cancer antigens is critically important for the clinical diagnosis, therapy, and prognostication of cancer. Currently, surface-enhanced Raman scattering (SERS) readout techniques challenge fluorescent-based detection methods in terms of both optical stability and more importantly multiple detection capability, which become more desirable for clinical diagnostics. We thus started using an interference-free mixing SERS emission (m-SERS) readout to simultaneously indicate, for the first time, three specific liver cancer antigens, including α-fetoprotein (AFP), carcinoembryonic antigen (CEA), and ferritin (FER), even in one clinical serum sample. Here, three triple bonds (C≡N and C≡C) coded SERS tags contribute separate SERS emissions located at 2105, 2159, and 2227 cm-1, respectively; must have one-to-one correspondence from AFP, to FER, to CEA, In the process of detection, the mature double antibody sandwich allows the formation of microscale core-satellite assembly structure between a magnetic bead (MB) and single SERS tags, and therefore a pure and single SERS emission can be observed under the routine excitation laser spot. Because of the action of magnetic force, the uniform 3D packing of SERS tags absorbed MBs will in contrast generate a so-called m-SERS signals. With the help of enrichment and separation by MBs, the proposed m-SERS immunoassay provides an extremely rapid, sensitive, and accurate solution for multiplex detection of antigens or other biomarkers. Herein, the limit of detection (LOD) for simultaneous m-SERS detection of AFP, CEA, and FER was 0.15, 20, and 4 pg/mL, respectively. As expected for 39 clinical serum samples, simultaneous detection of ternary specific antigens can significantly improve the accuracy of liver cancer diagnosis.