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International Journal of Electrochemistry
Volume 2013 (2013), Article ID 740265, 6 pages
http://dx.doi.org/10.1155/2013/740265
Research Article

Electrochemical Sandwich Immunoassay for the Ultrasensitive Detection of Human MUC1 Cancer Biomarker

1Analytical Chemistry Department, Faculty of Pharmacy, Iuliu Haţieganu University of Medicine and Pharmacy, 4 Pasteur Street, 400021 Cluj-Napoca, Romania
2Department of Chemistry, Faculty of Science, Yazd University, 89195-741 Yazd, Iran
3Department of Chemistry Ugo Schiff, University of Science Florence, P.zza S.Marco, 4, 50121 Florence, Italy

Received 12 September 2013; Revised 14 November 2013; Accepted 18 November 2013

Academic Editor: Sergio Ferro

Copyright © 2013 Zahra Taleat et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A new electrochemical sandwich immunoassay for the ultrasensitive detection of human MUC1 cancer biomarker using protein G-functionalized magnetic beads (MBs) and graphite-based screen-printed electrodes (SPEs) was developed. Magnetic beads were employed as the platforms for the immobilization and immunoreaction process. A pair of primary and secondary antibodies was used to capture the MUC1 protein. After labeling with a third antibody conjugated with horseradish peroxidase (HRP), the resulting conjugate was trapped at the surface of the graphite-based SPEs and MUC1 determination was carried out by differential pulse voltammetry (DPV) at 0.4 V upon H2O2 addition using acetaminophen (APAP) as the redox mediator. A linear relationship was obtained for the detection of human MUC1 over a range of 0–25 ppb with the lowest detection limit of 1.34 ppb when HRP was applied as a label. Preliminary experiments were performed using disposable electrochemical sensors in order to optimize some parameters (i.e., incubation times, concentrations, and blocking agent).