title: Electrochemical immunoassay of carcinoembryonic antigen based on a lead sulfide nanoparticle label.
abstract: 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.
authors.affiliation: Department of Chemistry and Molecular Biology, North Dakota State University, Fargo, ND 58105, USA. College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, People's Republic of China.
authors.forename: Shengfu
authors.initials: S
authors.lastname: Wang
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
authors.forename: Xun
authors.initials: X
authors.lastname: Mao
authors.forename: Qingxiang
authors.initials: Q
authors.lastname: Zeng
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
authors.forename: Yuehe
authors.initials: Y
authors.lastname: Lin
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Guodong
authors.initials: G
authors.lastname: Liu