Aptamer based electrochemical assay for the determination of thrombin by using the amplification of the nanoparticles

A novel electrochemical assay based on the aptamer and the signal of amplification of nanoparticles (NPs) was constructed for the determination of thrombin. Aptamers immobilized on the electrode and Au NPs could be assembled with the target protein to form a sandwich structure in the presence of the latter. Differential pulse voltammetry (DPV) was employed to detect the CdS NPs loaded on the surface of the Au NPs through the linker DNA, which was related to the concentration of the target protein. The assay took advantage of the amplification ability of Au nanoparticles carrying multiplex CdS NPs and the specific affinity of aptamers. Thrombin was detected in this assay in the linear range of 1.0 × 10−15 to 1.0 × 10−11 M with the detection limit of 5.5 × 10−16 M of target protein. In addition, the assay could be used to detection thrombin in real samples with high sensitivity and good selectivity.