The aim of the project is to develop cantilever-based sensors for the detection of hybridization of DNA/RNA/PNA with high sensitivity. A biochemical reaction at the cantilever surface can be monitored as a bending of the cantilever due to a change in the surface stress. The goal is to be able to detect DNA/RNA/PNA in less than nano Molar concentrations and with accuracy so that single nucleotide polymorphism can be detected. In the first part of the project the immobilization of nucleic acids on the cantilever surface will be improved. The immobilization will be based on thiol-gold chemistry, where especially the preparation of the gold surface and the thiol-modified nucleic acids needs to be optimized. Different types of nucleic acids will be investigated (RNA, DNA, PNA). Next, hybridization experiments will be performed using RNA, DNA and PNA. The hybridization experiments shall investigate the specificity of the signal and the aim is to be able to distinguish base sequences, which differ by only a single base. Furthermore, the sensor will be used to study the mechanical properties of the adsorbed nucleic acid layers, here especially the molecule PNA is of interest. Also, special focus will be on the direct detection of RNA. The stability and reproducibility of these measurements are crucial and it is important to investigate whether the amount of a specific RNA sequence can be determined by the sensor.