title: Direct detection of molecular biorecognition by dipole sensing mechanism.
abstract: This work investigates the feasibility of transducing molecular-recognition events into a measurable potentiometric signal. It is shown for the first time that biorecognition of acetylcholine (ACh) can be translated to conformational changes in the enzyme, acetylcholine-esterase (AChE), which in turn induces a measurable change in surface potential. Our results show that a highly sensitive detector for ACh can be obtained by the dilute assembly of AChE on a floating gate derived field effect transistor (FG-FET). A wide concentration range response is observed for ACh (10(-2)-10(-9)M) and for the inhibitor carbamylcholine CCh (10(-6)-10(-11)M). These enhanced sensitivities are modeled theoretically and explained by the combined response of the device to local pH changes and molecular dipole variations due to the enzyme-substrate recognition event.
authors.affiliation: Institute of Chemistry, The Hebrew University of Jerusalem, Safra Campus-Givat Ram, 91904, Jerusalem, Israel.
authors.forename: Ilya
authors.initials: I
authors.lastname: Goykhman
authors.forename: Nina
authors.initials: N
authors.lastname: Korbakov
authors.forename: Carmen
authors.initials: C
authors.lastname: Bartic
authors.forename: Gustaaf
authors.initials: G
authors.lastname: Borghs
authors.forename: Micha E
authors.initials: ME
authors.lastname: Spira
authors.forename: Joseph
authors.initials: J
authors.lastname: Shappir
authors.forename: Shlomo
authors.initials: S
authors.lastname: Yitzchaik
mesh_terms: D000109:Acetylcholine / Q000032:analysis* / Q000378:metabolism; D000110:Acetylcholinesterase / Q000737:chemistry / Q000378:metabolism*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002217:Carbachol / Q000032:analysis / Q000378:metabolism; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D011199:Potentiometry; D011487:Protein Conformation; D012680:Sensitivity and Specificity; D013379:Substrate Specificity; D014159:Transducers; D014173:Transistors, Electronic
chemical_list: D004800:Enzymes, Immobilized; D002217:Carbachol; D000110:Acetylcholinesterase; D000109:Acetylcholine