The invention relates to devices and methods for detecting a substance by cell surface polarizations and the detection thereof by means of PPR or particle-mediated fluorescence. The device for detecting a substance by cell surface polarization according to the invention has cells, wherein a gene the expression of which leads to the polarized presentation of a protein on the surface of the cell is placed under the control of a promotor which can be regulated by the substance to be detected, nanoparticles which are functionalized with a molecule which can bind specifically to the surface-exposed protein, and at least one optical measurement device, such that an accumulation of the nanoparticles on the surface of the cells can be detected by particle plasmon resonance or particle-mediated fluorescence.