Label-free impedimetric thrombin sensor based on poly(pyrrole-nitrilotriacetic acid)-aptamer film

► Electrogeneration of a poly(pyrrole-nitrilotriacetic acid) film for aptamer binding. ► Immobilization of anti-thrombin aptamer labeled with histidine tags by complexation. ► Electrochemical impedance measurements of aptamer-thrombin interactions. ► A sensitive and selective biosensor for thrombin determination without labeling step.