A signal-switchable electrochemiluminescence (ECL) aptasensor was presented for sensitive prostate specific antigen (PSA) assay using ferrocene-graphene sheets (Fc-GNs) for high-efficiency quenching of ECL from Au nanoparticles functionalized cadmium sulfide flower-like three dimensional (3D) assemblies (Au-CdS flower-like 3D assemblies). Au-CdS flower-like 3D assemblies were synthesized and employed as luminophore, exhibiting strong and stable ECL intensity, and followed by assembling captured DNA (cDNA) and hybridizing it with half of base sequence of PSA aptamer on the Au-CdS flower-like 3D assemblies modified electrode. The remaining part of the non-complementary base of the aptamer could preferentially adsorb GN with the signal switched "off" state. While in the presence of the PSA, the binding of PSA with aptamer caused desorption of aptamer from the surface of Fc-GNs and was then released from electrode surface, thus allowing the ECL signal enhancement. With the transformation of luminescence signal from "off" to "on", the aptasensor displays high sensitivity for PSA detection with a linear range from 1pgmL-1 to 25ngmL-1 and a detection limit of 0.38pgmL-1S/N=3). Moreover, this developed method could be successfully applied to the determination of PSA in human serum samples with recoveries of 85.8-104.0%, suggesting great potential applications in biochemical analysis.
Keywords: Au-CdS flower-like 3D assemblies; Electrochemiluminescence aptasensor; Ferrocene-graphene sheets; Prostate specific antigen; Signal-switchable strategy.
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