Piezoresistive probes for (biomolecular) force sensing

We have developed self-sensing piezoresistive microcantilevers optimized for the measurement of (biomolecular) forces. Typical dimensions are 250 μm in length, 8-20 μm in width and 450 nm in thickness, with spring constants of about 1 mN/m. The devices have been electromechanically tested on wafer and show good force resolutions in air between 35 and 130 pN depending on the cantilever dimensions. We have also tested the electromechanical behavior of the cantilevers in liquid environment and we show that both the force sensitivity and the noise characteristics of the devices are not noticeably degraded as compared with their response in air. This opens the way to the use of the cantilevers in single molecule force spectroscopy of biomolecules.