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A. Khanmohammadi, A. Afkhami, A. Hajian, H. Khoshsafar, H. Bagheri:
"Electrochemical sandwich-type immunosensor for the detection of PSA based on a trimetallic AgAuPt nanocomposite synthesized using the galvanic replacement reaction";
Analytical Methods, 13 (2021), 3676 - 3684.

A sandwich-type electrochemical immunoassay was introduced for the determination of the prostate-
specific antigen (PSA) biomarker. A direct and simple galvanic replacement reaction was performed
between the Ag framework and metallic salts of tetrachloroauric(III) acid trihydrate and chloroplatinic
acid to produce a trimetallic composite of AgAuPt. The trimetallic composite of AgAuPt was applied to
the preparation of the capture layer of the immunoassay for stabilizing the primary Ab at the surface of
the prepared composite. The immunoassay detection layer was also prepared using a labeled antibody
containing a bimetallic composite of AgPt as a label. The various procedures in the immunoassay
fabrication were monitored step by step using cyclic voltammetry and electrochemical impedance
spectroscopy. Also, the electrochemical determination of PSA was performed using differential pulse
voltammetry in the presence of the ferrocene redox probe and H2O2. Furthermore, the effective
parameters in the fabrication of the immunoassay included the drop volume of the AgAuPt trimetallic
composite and the incubation time for the immobilization of biomolecules (i.e., Ab1, BSA, PSA, and
labeled Ab2), and the concentration of H2O2 were optimized during the determination of PSA. Then, the
determination of PSA was performed under optimized conditions. It could be seen that there was
a linear relation between the PSA concentration and DPV responses in the concentration range of 50 pg
mL 1 to 500 ng mL 1 and the limit of detection (LOD) for the proposed immunoassay was calculated as
17.0 pg mL 1. In the following investigation, the cross-reactivity of the proposed immunoassay was
studied in the presence of BSA, CEA, IgG, and human hepatitis surface antigen, in which the results
showed a negligible change in the performance of the immunoassay.

http://dx.doi.org/10.1039/d1ay01004b