Guangxi Key Laboratory of Green Processing of Sugar Resources, College of Biological and Chemical Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, Guangxi, PR China; Provine and Ministry Co-sponsored Collaborative Innovation Center of Sugarcane and Sugar Industry, Nanning, 530004, Guangxi, PR China. Electronic address: [Email]
Hepatocellular carcinoma (HCC) is a common and lethal cancer. New serum markers for detecting HCC are urgently needed. Human carboxylesterase 1 (hCE1) is an important member of the serine hydrolase superfamily and is closely related to the occurrence of HCC. It can be used as a good serum marker for early diagnosis of HCC. Here, we developed a surface enhanced Raman scattering (SERS)- based magnetic immunosensor that specifically recognizes and detects trace amounts of hCE1 in human serum via a sandwich structure consisting of a SERS tags, magnetic supporting substrates, and target antigen (hCE1). The SERS tags are 4-mercaptobenzoic acid (4-MBA)-labeled AgNPs, and the SERS supporting substrates are composed of a raspberry-like morphology of Fe3O4@SiO2@AgNPs magnetic nanocomposites surface-functionalized with a hCE1 antibody. The prepared SERS magnetic immunosensor exhibits excellent selectivity and extremely high sensitivity for hCE1 detection. The SERS signal and logarithm of hCE1 concentration presented a wide linear response range of 0.1 ng mL-1 to 1.0 mg mL-1, and the detection limit of hCE1 was 0.1 ng mL-1. The results indicate that the immunosensor can be used for the rapid determination of hCE1 in human serum without a complicated sample pre-treatment. Furthermore, the immunosensor has good reproducibility and stability, and has a promising prospect for the quantitative detection of other tumor markers in early clinical diagnosis.