Conductive hydrogel composed of 1,3,5-benzenetricarboxylic acid and Fe3+ used as enhanced electrochemical immunosensing substrate for tumor biomarker

In this work, a new conductive hydrogel was prepared by a simple cross-linking coordination method using 1,3,5-benzenetricarboxylic acid as the ligand and Fe3+ as the metal ion. The hydrogel film was formed on a glassy carbon electrode (GCE) by a drop coating method, which can dramatically facilitate the transport of electrons. A sensitive label-free electrochemical immunosensor was fabricated following electrodeposition of gold nanoparticles (AuNPs) on a hydrogel film and immobilization of an antibody. Neuron-specific enolase (NSE), a lung cancer biomarker, was used as the model analyte to be detected. The proposed immunosensor exhibited a wide linear detection range of 1 pg mL(-1) to 200 ng mL(-1) and a limit of detection of 026 pg mL(-1) (the ratio of signal to noise (S/N) = 3). Moreover, the detection of NSE in human serum samples showed satisfactory accuracy compared with the data determined by enzyme-linked immunosorbent assay (ELISA), indicating good analytical performance of the immunoassay. (C) 2016 Elsevier B.V. All rights reserved.