Dual-mode electrochemical immunoassay for Non-small cell lung cancer detection based on CoSe2-GO-Au and poly(MB)-Au

Abstract

Combining the Potentiostatic Electrolysis i-t curve (i-t) and Differential Pulse Voltammetry (DPV), using CoSe2-GO-Au as the sensing substrate and poly(MB)-Au as the secondary antibody marker, the dual-mode electrochemical immunosensor was manufactured for the analysis and detection of Cytokeratin 19 Fragment Antigen (CYFRA 21-1). Cobalt selenide (CoSe2) had favourable catalytic activity of H2O2, which could provide an electrochemical signal through i-t. The huge specific surface area and excellent conductivity of graphene oxide (GO) provided a platform for the combination of CoSe2 and prevented the agglomeration of CoSe2. With the modification of Au nanoparticles, the conductivity of CoSe2-GO had been improved and the binding rates of Ab1 had been increased, which further expanded the electrochemical signal. Meanwhile, precious metal polymerized methylene blue (poly(MB)-Au) with good redox property was used as electrochemical probe, which could solve the shortcoming of MB falling off the electrode. Under the best experimental conditions, the sensitive detection of the CYFRA 21-1 was realized through the test methods of two modes. The dual-mode electrochemical immunosensor presented a linear current signal in 1 pg/mL–100 ng/mL with the detection limit of 0.36 pg/mL (i-t) and 0.24 pg/mL (DPV). To sum up, the prepared dual-mode electrochemical immunosensor provided a guarantee for the sensitive detection of CYFRA 21-1 in this experiment.