Method for detecting and/or identifying a biological substance in a liquid medium with the aid of electrical measurements, and apparatus for carrying out this method.

摘要

The method is for the detection of a biological substance in an electrically conducting liquid medium capable of containing it. In a measurement cell (1), the said liquid medium (5) is put into contact with a reagent-carrying plate (4) incorporating a specific ligand fixed directly onto one face of a thin layer of dielectric material (4a) whose other face is fixed onto an electrically conducting support. The C and/or R components of the electric impedance of the system consisting of the liquid medium, the insulating layer and the support is measured for a given voltage. The said components are compared with those of a reference system similar to the above system but without the specific ligand. Any reduction in the capacitance or variation in the resistance in comparison with those of the reference system indicates the presence of the said biological substance in the liquid medium concerned. The invention also includes the measurement cell for carrying out the method.