A potentiometric acetylcholinesterase biosensor based on plasma-polymerized film

A potentiometric acetylcholinesterase biosensor based on pH-sensitive PVC membrane with plasma-polymerized ethylenediamine film has been proposed. Glow discharge plasma technique was utilized to deposit a film containing amino groups on the surface of pH-sensitive PVC membrane. Such an approach makes it possible to fabricate a very simple self-mounted acetylcholinesterase membrane directly attached to PVC pH-sensing electrode surface. The deposition conditions were optimized and the optimum plasma polymerization parameters were as follows: applied power, 75 W; pressure, 130 Pa; plasma exposure time, 60 min and flow rates, 10 ml min−1. Two neutral carriers, DOODA and DAMAB were compared as the pH-carrier, and the biosensor based on DAMAB showed better response characteristics. The effect of pH of the medium was also examined. The potential responses of biosensor increase with the acetylcholine chloride concentration over the concentration range of 10−6 to 10−1 mol dm−3 and the detection limit is 0.002 mmol dm−3 in pH 8.0 PB buffer solution. The biosensor was employed more than 200 times in 20 days while the maximum response span of biosensor retained 90%.