Amperometric magnetoimmunoassay for the direct detection of tumor necrosis factor alpha biomarker in human serum.

U Eletxigerra, J Martinez-Perdiguero, S Merino, R Villalonga, J M Pingarrón, S Campuzano

Index: Anal. Chim. Acta 838 , 37-44, (2014)

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Abstract

An amperometric immunoassay for the determination of tumor necrosis factor alpha (TNFα) protein biomarker in human serum based on the use of magnetic microbeads (MBs) and disposable screen-printed carbon electrodes (SPCEs) has been developed. The specifically modified microbeads were magnetically captured on the working electrode surface and the amperometric responses were measured at -0.20V (vs. Ag pseudo-reference electrode), upon addition of hydroquinone (HQ) as electron transfer mediator and H2O2 as the enzyme substrate. After a thorough optimization of the assay, extremely low limits of detection were achieved: 2.0pg mL(-1) (36fM) and 5.8pg mL(-1) (105fM) for standard solutions and spiked human serum, respectively. The simplicity, robustness and this clinically interesting LOD proved the developed TNFα immunoassay as a good contender for real clinical application.Copyright © 2014 Elsevier B.V. All rights reserved.