A sensitive and selective approach for detection of IL 1? cancer biomarker using disposable ITO electrode modified with epoxy-substituted polythiophene polymer

Abstract

A highly sensitive and label-free electrochemical immunosensor for sensitive detection of interleukin 1? cancer biomarker was described by using epoxy-substituted polythiophene polymer modified disposable indium tin oxide electrode. This conjugated polymer was synthesized to fabricate this immunosensor for the first time and it offered a good biosensing platform for anti-IL 1? antibody immobilization due to epoxy groups present on the side groups of the polymer. Furthermore, the epoxy-substituted polythiophene polymer coated indium tin oxide electrode was used for the determination of IL 1? antigen for the first time. Electrode fabrication stages were characterized by using electrochemical (electrochemical impedance spectroscopy and cyclic voltammetry) and morphological (scanning electron microscopy and atomic force microscopy) techniques. Under optimum experimental conditions, impedimetric responses of the immunosensor increased with the increasing of IL 1? antigen concentration, and the proposed immunosensor displayed a wide linear detection range from 0.01 pg/mL to 5.5 pg/mL with a detection limit of 3.4 fg/mL. The proposed immunosensor exhibited outstanding performance including excellent reproducibility, good repeatability, high selectivity and long storage stability. With the advantages of simple operation, low-cost fabrication and label-free format, the suggested immunosensor was expected to have potential applications for IL 1? cancer biomarker detection. © 2019 Elsevier B.V.