Dual-responsive electrochemical immunosensor for prostate specific antigen detection based on Au-CoS/graphene and CeO2/ionic liquids doped with carboxymethyl chitosan complex

Publication date: 15 August 2017
Source:Biosensors and Bioelectronics, Volume 94
Author(s): Yicheng Wei, Xiaojian Li, Xu Sun, Hongmin Ma, Yong Zhang, Qin Wei
Combining dual-signal channels of differential pulse voltammetry (DPV) and amperometric i–t curve, we developed an amplified sandwich-type electrochemical immunosensor for ultrasensitive detection of prostate specific antigen (PSA). Due to the large specific surface area and good adsorption property, 3-aminopropyltriethox functionalized CeO2 mesoporous nanoparticles (NH2-M-CeO2) was used for supporting toluidine blue (TB) as the electron transfer mediator and anti-PSA as the signal response. To prevent the leak of TB and facilitate the electron transfer property of NH2-M-CeO2, ionic liquids doped carboxymethyl chitosan (CMC/ILs) were incorporated and TB/M-CeO2/CMC/ILs complex was gotten to act as the label of anti-PSA (Ab2). Meanwhile, Au-CoS/graphene was as the matrix materials modifying the electrode to immobilize anti-PSA (Ab1). Specifically, Au-CoS/graphene cannot produce electrochemical signals through DPV method but can provide an obviously electrochemical signal towards catalysis hydrogen peroxide (H2O2) through amperometric i–t curve method. At the time of detection, with the increase of concentrations of PSA, the DPV signals from TB/M-CeO2/CMC/ILs were increased and the amperometric i–t curve signals from the Au-CoS/graphene were decreased. Under the optimum conditions, the immunosensor demonstrated remarkable analytical performance of a linear range of 0.5pg/mL to 50ng/mL with a detection limit of 0.16pg/mL for quantitative detection of PSA (S/N=3).



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