High-Throughput Miniaturized Immunoassay for Human Interleukin-6 Using Electrochemical Sandwich-Type Enzyme Immunosensors

Jiayao      Liao; Dianping      Tang

Abstract

Interleukin-6 (IL-6), an immune protein in the hematopoietins family, has been demonstrated as a prognostic indicator for survival in patients with gastric carcinoma. In this contribution, we introduced a new and high-throughput electrochemical immunosensor for the detection of IL-6 in human. The immunoassay protocol was fabricated by the immobilization of anti-IL-6 antibodies on the nanogold and partial ferrocenyltethered dendrimer (Fc-D)-functionalized interface. A sandwich-type immunoassay format was employed for the IL-6 determination using horseradish peroxidase (HRP)-labeled anti-IL-6 as secondary antibody. The properties and factors influencing the performance of the proposed immunosensor were evaluated in detail. Under optimal conditions, the current response of the formed sandwich-type immunocomplex relative to H2O2 system was proportional to IL-6 concentration ranging from 2.5 pg/mL to 120 pg/mL with a detection limit of 1.0 pg/mL (at 3δ). The precision, reproducibility and stability of the immunosensor were acceptable. Subsequently, the immunosensors were used to assay the IL-6 in human serum specimens. Analytical results were in agreement with those obtained by the standard chemiluminescence ELISA.

Keywords: Dendrimer, Electrochemical immunosensor, Gold nanoparticles, Interleukin-6, Sandwich-type enzyme immunoassay

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