Cholinesterase-based biosensor using surface photovoltage technique

The new measurement method of Surface Photovoltage (SPV) technique was appl ied to the fabrication of a novel type cholinesterase-based biosensor. Chol inesterases (butyrylcholine esterase (BuChE) and acetylcholine esterase (AC hE)) have been immobilized directly onto the semiconductor surface to measu re the concentration of enzyme substrates, via pH changes. The detection li mits of the substrates were 9.0 x 10(-7) M, 2.7 X 10(-6) M and 4.1 x 10(-6) M for butyrylthiocholine iodide, acetylcholine iodide and acetylcholine ch loride, respectively. The analytical possibilities were examined from the r esults of the inhibiting actions exerted in the presence of alkaloids such as physostigmine sulfate and neostigmine bromide on BuChE.