Enzyme-octadecylamine Langmuir-Blodgett membranes for ENFET biosensors.
Langmuir-Blodgett (LB) films containing butyrylcholinesterase (BuChE) are fabricated to realise an enzymatic field effect transistor (ENFET) for the detection of organophosphorus pesticides in water. Trichlorfon as a common pesticide is examined in our work. The BuChE-immobilised LB films are formed by adsorbing the enzyme molecules onto a stearylamine monolayer using the electrostatic force. Enzyme/stearylamine mixed LB films are immobilized onto a pH-ISFET surface and treated by glutaraldehyde vapour to improve the LB film's stability. The ENFET thus obtained worked as a potentiometric biosensor for trichlorfon detection on the basis of enzyme inhibition. The detection limit for trichlorfon can reach 10(-7) M (26 ppb). The surface characteristics of BuChE/stearylamine LB films obtained under various conditions of the dipping surface pressures are analysed qualitatively by atomic force microscopy (AFM) and analysed quantitatively by FTIR spectroscopy.
Wan
K
K
IFOS, UMR CNRS 5621, Laboratory d'Ingenierie et de Fonctionnalisation des Surfaces, Ecole Centrale de Lyon, BP 163, 69131 Ecully Cedex, France.
Chovelon
J M
JM
Jaffrezic-Renault
N
N