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 μm2 is based on standard optical lithography and sacrificial layer techniques. The sensors allow the detection of molecular interactions in real-time. 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.