A dielectric material of a capacitive affinity sensor has a three-dimensional molecular binding site array. A glass base is layered with a binding agent like silane from which a polymeric backbone like polylysine extends. The polymeric backbone is prepared to accept receptor molecules like cortisol hemisuccinate to bind a specific antibody. Such an array changes dielectric properties between the two electrodes of the capacitive affinity sensor to greatly enhance sensitivity of the sensor.
