The invention relates to an electromagnetic piezoelectric acoustic sensor (EMPAS). The sensor comprises a piezoelectric sensor plate spaced apart from an induced dynamic electromagnetic field, such as from an electromagnetic coil through which AC current flows. The electromagnetic field induces vibration in the sensor plate by fluctuating the aligned dipole moments of the piezoelectric material. Changes on the surface of the sensor plate can be detected by variation in resonance frequency of the sensor plate. The invention represents an improvement over conventional sensor methodologies in that no metallization of the sensor surface is required, and no permanent magnet is needed. The sensor may be used to detect absorption of molecules or biomolecular interactions between probe and target molecules.