Immunoassay of Tumor Markers Based on Graphene Surface-Enhanced\nRaman Spectroscopy

Abstract

With a unique chemical enhancement\ncapability, graphene oxide is\nexceptionally suitable to serve as an alternative surface-enhanced\nRaman scattering (SERS) substrate, which is usually defined as GERS.\nHowever, such a GERS matrix with both promising uniformity and molecule\nenrichment ability has not been applied in the quantitative detection\nof tumor markers. Herein, an ultrasensitive and specific immunoassay\nof carcinoembryonic antigens mediated by the GERS matrix was demonstrated.\nWith the assistance of Au NRs as immunoprobes, a reliable limit of\ndetection as low as 3.01 pg/mL was finally achieved because of the\ncollective effect of chemical and electromagnetic enhancements. Meanwhile,\na calibration curve with a high <i>R</i>² value\nof 0.996 was obtained in the range from 1 μg/mL to 10 pg/mL.\nThese results exhibit that the GERS matrix has a great promise for\nparticipating in immunoassay, which may pave a potential avenue for\nthe real utilization of the SERS technique in clinical biomedicine.