RECEPTOR AFFINITY BIOSENSOR

WE ARE DEVELOPING A GENERIC CLASS OF BIOSENSORS USING ION SENSITIVE FIELD EFFECT TRANSISITORS (ISFETS) TO MEASURE THE CONCENTRATION OF LIGAND BASED ON THE CHANGE IN SURFACE CHARGE ASSOCIATED WITH BINDING OF LIGAND TO RECEPTOR. THE BIOSENSOR HAS GENERAL APPLICABLITY BASED ON THE HYPOTHESIS THAT BINDING OF CHARGED MOLECULES AND/OR DISPLACEMENT OF CHARGES FROM ACTIVATED MOLECULES IS A COMMON PHENOMENON ASSOCIATED WITH CHANGES IN CONFORMATION OF PROTEINS. AN INSULATING LAYER OF LIPID OR ORGANOSILANE FORMED OVER THE GATE OF AN ISFET ACTS AS A CAPACITOR. WHEN RECEPTOR MOLECULES ARE INCORPORATED INTO THE INSULATING LAYER, BINDING OF LIGAND AND ACTIVATION OF RECEPTOR ALTERS THE SURFACE CHARGE ON THE INSULATOR WHICH IS SENSED AS A CHANGE IN THE SOURCE/DRAIN CURRENT OF THE ISFET. SENSORS FOR VARIOUS LIGANDS CAN BE MANUFACTURED BY CHANGING THE TYPE OF RECEPTOR MOLECULE INCORPORATED INTO THE MEMBRANE, AND GIVES THE BIOSENSOR SELECTIVITY SIMILAR TO NATIVE RECEPTOR MOLECULES. BIOSENSORS COULD ALSO BE DEVELOPED TO MEASURE CONCENTRATION OF LIGANDS BOUND TO OTHER EFFECTOR PROTEINS, SUCH AS ENZYMES, SO LONG AS LIGAND BINDING ALTERS THE CHARGE ON THE ACTIVATED LIGAND-PROTEIN COMPLEX.