Patent ID: 8309365

Claim:
A method for evaluating an unknown target molecule, comprising: providing a working electrode on a substrate and a counter electrode, probe molecules each having a marker being bound to the working electrode, allowing a known target molecule and the unknown target molecule to bind or not bind to the probe molecules, the known target molecule having a known Stokes radius and molecular weight, applying AC voltage between the working electrode provided on the substrate and the counter electrode; and determining signals obtained from the markers of the probe molecules when a frequency of the AC voltage is varied, and determining a Stokes radius or molecular weight of the unknown target molecule based on the signals obtained from the markers of the probe molecules when the frequency of the AC voltage is varied, wherein said determining the Stokes radius or molecular weight includes determining an association between (1) a difference between the signal obtained from the marker of the probe molecule bound to the known target molecule, at a given frequency, and the signal obtained from the marker of the probe molecule not bound to the known target molecule, at the given frequency, and (2) the Stokes radius or molecular weight of the known target molecule, and determining the Stokes radius or molecular weight of the unknown target molecule from relationship between (1) the association, and (2) the difference between the signal obtained from the marker of the probe molecule bound to the unknown target molecule and the signal obtained from the marker of the probe molecule not bound to the unknown target molecule.