Electrochemical immunoassay of carcinoembryonic antigen based on a lead sulfide nanoparticle label

Shengfu Wang, Xing Zhang, Xun Mao, Qingxiang Zeng, Hui Xu, Yuehe Lin, Wei Chen*, Guodong Liu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


We describe a lead sulfide nanoparticle (PbS NP)-based electrochemical immunoassay to detect a tumor biomarker, carcinoembryonic antigen (CEA). Cubic PbS NPs were prepared and functionalized with thioglycolic acid (TGA), which stabilized the formed NPs and offered carboxyl groups to conjugate with CEA antibodies. PbS NP conjugated with monoclonal CEA antibody was used as a label in an immunorecognition event. After a complete sandwich immunoreaction among the primary CEA antibody (immobilized on the carboxyl-modified magnetic beads), CEA and the PbS-labeled secondary antibody (PbS-anti-CEA), PbS labels were captured to the magnetic-bead (MB) surface through the antibody-antigen immunocomplex. Electrochemical stripping analysis of the captured PbS was used to quantify the concentration of CEA after an acid-dissolution step. The MBs and the magnetic separation platform were used to integrate a facile antibody immobilization with immunoreactions and the isolation of immunocomplexes from reaction solutions in the immunoassay. The voltammetric response is highly linear over the range of 1-50 ng ml-1 CEA, and the limit of detection is estimated to be 0.5 ng ml-1. The performance of this nanoparticle-based electrochemical immunoassay was successfully evaluated with human serum spiked with CEA, indicating that this convenient and sensitive technique offers great promise for rapid, simple and cost-effective analysis of tumor biomarkers in biological fluids.

Original languageEnglish
Article number435501
Issue number43
Publication statusPublished - 22 Oct 2008
Externally publishedYes


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