Silicon-based Nano-Electro-Mechanical (NEM) sensors are getting increasing interest because of their compatibility with âIn-ICâ integration as well as high sensitivity to a change in mass. The NEM sensors enable to detect a small amount of biological or chemical molecules thanking to their nanoscale dimensions and sensitive frequency response. This project presents design of a newly-proposed In-Plane Resonant NEM (IP R-NEM) sensor based on a mass-detection principle and discusses its extremely high mass sensitivity in comparison with present-day mass-detection-based biosensors. Our resonator architecture has amplified output signal due to the integrated lateral FET and can be realized by a top-down process on SOI substrates, which is expected to enable monolithic integration of the NEM sensors with CMOS ICs. This project is financially supported by EUFP7 project NEMSIC (Hybrid Nano-Electro-Mechanical/Integrated Circuit Systems for Sensing and Power Managemant Applications).