Acetylcholine Receptor-Based Biosensor

Abstract The acetylcholine (ACh) receptor protein isolated from Torpedo electric organ was incorporated into asolectin liposomes and immobilized noncovalently on the surface of a Planar Interdigitated Capacitive sensor to produce an ACh receptor-based biosensor. Capacitance of the biosensor, which was stable in buffered saline, increased rapidly when ACh was added. The response was dosedependent and specific for ACh, and the biosensor did not respond to six other neurotransmitters. Impure receptor preparations containing ACh esterase produced a smaller signal in response to ACh but showed enhanced response after inhibition of ACh esterase with diisopropylfluorophosphate. The competitive antagonist d-tubocurare, and the noncompetitive antagonist amantadine, inhibited the response of the biosensor to ACh, but a time-dependent recovery occurred upon perfusion with ACh. The irreversible antagonist α-neurotoxin inhibited the response and there was no recovery following perfusion with ACh. Thus, the pharmacolog...