The main goal of our proposal is to develop a novel optical nanobiosensor based on extraordinary vibrational signal enhancement of the proteins to be detected. To reach vibrational signal enhancement, we will exploit the optical properties of specially designed metallic nanoparticles which should act as nanoantenna and the associated field enhancement to obtain a direct detection of proteins bound to the nanoparticle. Thus, our sensor will reach high sensitivity provided by the recently established large enhancement of vibration signals due to the resonant excitation of the nanoantenna device used as substrates. The aim is to detect only a few proteins with concentration much lower than 1pM and finally to reach detection threshold such as femtomole or lower. High molecular selectivity will be reached with the functionalisation of the nanoantenna. Such functionalisation will selectively favour the immobilisation of the protein to be detected at the vicinity of the nanoparticle surface, providing the best enhancement and then the detection of the targeted protein. Our nanobiosensor will include two main components: the nanoantenna device which corresponds to our sensor transducer and the functionalisation which corresponds to its bioreceptor. And then, each functionalised nanoantenna device used as vibrational signal enhanced system is an individual and specific nanosensor of proteins. As a consequence, our nanobiosensor integrated in a vibrational spectroscope will allow the detection and the analysis of the enhanced vibrational signal from the targeted proteins and thus corresponds to our diagnosis instrument. Our nanobiosensor will be validated on the detection of proteins on body fluids.These proteins have been chosen since they have been identified as specific biomarkers of common pathologies. This validation will be applied it to improve their detection (better sensitivity, decrease of the detection threshold) and open the way to the early diagnosis.