Opto-magnetic device sensitive to the presence of an analyte in a sample, comprising: an integrated optical circuit having an input (IN) for an input optical radiation and at least one output (OU; OU D ) for an output optical radiation; said optical circuit defining an area sensitive to the variations of a local refraction index probed by the optical radiation, to come in contact with the sample; a plurality of probe molecules such to anchor to at least said sensible area ; a plurality of magnetic particles such to anchor to molecules of the analyte, bound to the probe molecules upon a molecular recognition; a magnetic actuator configured to generate a variable magnetic field according to a first frequency (f 0 ) and move in oscillating way said magnetic particles according to a second frequency (2f 0 ) bound to the molecules of the analyte which are bound to the probe molecules anchored to said sensible area in order to cause a variation of the refraction index probed by the optical radiation in the sensible area and a variation of intensity of the output optical radiation correlated to a concentration of the molecules of the analyte in the sample, wherein: a) said magnetic particles are superparamagnetic particles; b) the magnetic actuator comprises an electromagnet; c) said first frequency is comprised between 1Hz and 1kHz; d) the magnetic actuator is configured to cause a modulation of the intensity of the output optical radiation at the second frequency double the first frequency (fo). an integrated optical circuit having an input (IN) for an input optical radiation and at least one output (OU; OU D ) for an output optical radiation; said optical circuit defining an area sensitive to the variations of a local refraction index probed by the optical radiation, to come in contact with the sample; a plurality of probe molecules such to anchor to at least said sensible area ; a plurality of magnetic particles such to anchor to molecules of the analyte, bound to the probe molecules upon a molecular recognition; a magnetic actuator configured to generate a variable magnetic field according to a first frequency (f 0 ) and move in oscillating way said magnetic particles according to a second frequency (2f 0 ) bound to the molecules of the analyte which are bound to the probe molecules anchored to said sensible area in order to cause a variation of the refraction index probed by the optical radiation in the sensible area and a variation of intensity of the output optical radiation correlated to a concentration of the molecules of the analyte in the sample, wherein: a) said magnetic particles are superparamagnetic particles; b) the magnetic actuator comprises an electromagnet; c) said first frequency is comprised between 1Hz and 1kHz; d) the magnetic actuator is configured to cause a modulation of the intensity of the output optical radiation at the second frequency double the first frequency (fo). a) said magnetic particles are superparamagnetic particles; b) the magnetic actuator comprises an electromagnet; c) said first frequency is comprised between 1Hz and 1kHz; d) the magnetic actuator is configured to cause a modulation of the intensity of the output optical radiation at the second frequency double the first frequency (fo). <EOS>