The TESLA project aims at the development of an ultra-sensitive (nT range), wireless and batteryless magnetic sensor based on Lamb waves for biomedical applications. The passive feature and the remote interrogation of the device will allow a continuous monitoring of the magnetic field and a comfortable use for the patients during heavy medical examinations. Indeed, there is a growing interest in very sensitive magnetic sensors and most importantly in healthcare institutions to conduct high quality medical analysis and to promote early diagnosis. This project has two main steps: the first one will be a proof of concept where the device will be realized with a thinned piezoelectric substrate bonded on the backside to a magnetostrictive thin film while the second one will allow to reach the targeted performance (magnetic sensitivity and acoustic) thanks to a stack of thin layers.