Direct immunochemical sensing: basic chemical principles and fundamental limitations.

Models describing the binding of antigens to surface immobilised antibodies have been developed. These models are applied to the assessment of the likely analytical utility of direct immunochemical sensors employing immobilised antibody layers. Fundamental limitations to the device response arising from the equilibrium and kinetic characteristics of the binding reaction and from mass transport constraints imply that measurement over the micromolar to nanomolar concentration range may be practical.