Fabrication of an ultrasensitive electrochemical immunosensor for CEA based on conducting long-chain polythiols

A conducting long-chain polythiols (poly (2-aminothiophenol), PATP) was synthesized by a chemical polymerization process and combined with Au nanoparticles (AuNPs) to prepare a novel, sensitive and label-free electrochemical biosensor by adsorption of carcinoembryonic antibody (anti-CEA) on the PATP–AuNPs modified gold electrode. Differential pulse voltammetry (DPV) was used to characterize the recognition of carcinoembryonic antigen (CEA). Under the optimized conditions, the proposed immunosensor displayed a good amperometric response to CEA with linear range from 1 fg mL−1 to 10 ng mL−1 and a detection limit of 0.015 fg mL−1 (signal/noise=3). The results demonstrated that the immunosensor has advantages of high sensitivity, wide linear range, good repeatability, and good selectivity. Importantly, the results of the detection of clinical serum specimens with the proposed sensor were well consistent with the data determined by micropartical enzyme immunoassay (MPEI), showing that the present work provides a promising ultrasensitive immunoassay strategy for clinical applications.

► The poly (2-aminothiophenol) was synthesized as a conducting long-chain polythiols.
► Au electrode was modified with PATP and AuNPs to fabricate electrochemical immunosensor.
► The detection limit for CEA reached 0.015 fg mL−1.
► This method performed very well on the detection of clinical serum specimens.