A chemiluminescence aptasensor for thrombin detection based on aptamer-conjugated and hemin/G-quadruplex DNAzyme signal-amplified carbon fiber composite

In this work, a highly sensitive and selective chemiluminescence (CL) aptasensor was prepared for thrombin (THR) detection based on aptamer-conjugated and hemin/G-quadruplex DNAzyme signal-amplified carbon fiber composite (HG-DNAzyme/T-Apt/SiO2@GO@CF). Initially, SiO2@GO@CF was successfully prepared and characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). Thrombin aptamer (T-Apt) as an identification element and simulated enzyme-hemin/G-quadruplex DNAzyme (HG-DNAzyme) as a signal-amplified material, were applied in the CL aptasensor. Then, the immobilization properties of SiO2@GO@CF and adsorption properties of T-Apt/SiO2@GO@CF were studied. Lastly, HG-DNAzyme/T-Apt/SiO2@GO@CF was applied in construction of the CL aptasensor. When THR existed, HG-DNAzyme was desorbed from the surface of T-Apt/SiO2@GO@CF and catalyzed the CL system of luminol-H2O2. Under optimized CL conditions, THR was measured with the linear concentration range of 1.5 x 10(-14) to 2.5 x 10(-11) moL/L and the detection limit of 6.3 x 10(-15) moL/L (3 delta). The proposed CL aptasensor was used to the determination of THR in human serum samples and recoveries ranged from 99.0% to 102.4%. Those satisfactory results illustrated the CL aptasensor could achieve highly sensitive and selective detection of THR and revealed potential application in practical samples. (C) 2018 Elsevier B.V. All rights reserved.