Development of impedance biosensors with nanometer gaps for marker-free analytical measurements

Highly sensitive impedance biosensors with electrode distances of 90-150 nm and working frequencies considerably above 100 MHz have been developed. Target application is the marker-free detection of molecular interactions and analytical measurements. The fabrication process of the sensors with sensing areas of 750 mu m(2) is based on standard optical lithography and sacrificial layer techniques. The sensors allow the detection of molecular interactions in realtime. The formation and decomposition of a 2-4 nm thick monolayer of the surfactant Triton-X has been observed. Additionally, coupling of anti-thrombin antibodies and binding of its antigen thrombin was followed. (c) 2005 Elsevier B.V. All rights reserved.