▎ 摘　　要

A label-free and amplified electrochemical impedimetric aptasensor based on functionalized graphene nanocomposites (rGO-AuNPs) was developed for the detection of thrombin, which played a vital role in thrombosis and hemostasis. The thiolated aptamer and dithiothreitol (TBA15-DTT) were firstly immobilized on the gold electrode to capture the thrombin Molecules, and then aptamer functionalized graphene nanocomposites (rGO-TBA29) were used to fabricate a sandwich sensing platform for amplifying the impedimetric signals. As numerous negative charges of TBA29 on the electrode repelled to the [Fe(CN)(6)](4-/3-) anions, resulting in an obvious amplified charge-transfer resistance (R-ct) signal. The R-ct increase was linearly proportional to the thrombin concentration from 0.3 to 50 nM and a detection limit of 0.01 nM thrombin was achieved. In addition, graphene could also be labeled with other probes via electrostatic or pi-pi stacking interactions to produce signals, therefore different detection methods expanding wide application could be used in this model. (C) 2015 Published by Elsevier B.V.