Optimizing the SERS activity of PS@Ag/Au chips for quantitative analysis of carcinoembryonic antigen

초록

Tumor markers play an important role in the diagnosis, treatment, and monitoring of tumors. Carcinoembryonic antigen (CEA) is a breast and rectal cancer biomarker that plays a crucial role in the early detection of cancer. Therefore, designing a suitable and ultrasensitive method for CEA analysis is very important. In this study, we demonstrated the high surface-enhanced Raman scattering (SERS) performance, high reproducibility, and good biocompatibility of a polystyrene (PS)@Ag/Au chip. This chip was produced layer-by-layer by magnetron sputtering to generate abundant "hotspots" between the Ag and Au layers covering the PS microspheres. Interestingly, the thickness of the Au layer was easily controlled to the appropriate value. When 4-mercaptobenzoic acid (MBA) was used as a probe molecule to explore the SERS activity of the chip, the enhancement factor (EF) reached 1.12x108 , x10 8 , with a relative standard deviation of 3.059%. A chip labeled with 5,5'-dithiobis(succinimidyl-2-nitrobenzoic acid) (DSNB) was used for CEA immunological recognition. With a linear range of 0-10,000 ng/mL, the limit of detection (LOD) was 0.0229 ng/mL. The standard recovery of CEA in fetal bovine serum (FBS) was between 84.90% and 103.1 %. This chip is expected to be a novel tool in the field of cancer detection.

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