Comparison of antibody and aptamer receptors for the specific detection of thrombin with a nanometer gap-sized impedance biosensor

Nanogap-impedance biosensors with electrode separations of 75 nm have been fabricated by means of standard optical lithography and a sacrificial layer technique. Due to a large surface-to-volume ratio and high sensitivity, these sensors are superior compared to open interdigitated electrode structures. As a model, the blood coagulation factor thrombin was detected. As specific receptors, either an antibody or a RNA-aptamer have been used. The microwave frequency impedance measurements showed that both ligands were equally suitable for the specific detection of thrombin.