Electrochemiluminescent detection of acetylcholine using acetylcholinesterase immobilized in a biomimetic Langmuir-Blodgett nanostructure

The performances of bioelectronic devices mainly depend on the properties of the bioactive sensing layer and on the quality of its association to the transducer. The achievement of new biospecific organised ultrathin films, directly interfaced with the transducer and inserting biomolecules in a functional and orientated position, may open an original way in the development of new biomimetic optoelectronic devices. This study deals with the possibility to detect acetylcholine using acetylcholinesterase immobilized at the surface of a miniaturised biomimetic nanostructure by means of an electrochemiluminescent device. The highly organised proteo-lipidic nanostructure has been designed using interfacial liposome fusion and Langmuir-Blodgett techniques. By inserting a non-inhibitor monoclonal antibody in a functional position, this nanostructure is able to sequester acetylcholinesterase (AChE) in a suitable orientation and to maintain the enzyme activity for several months. This molecular assembly has been intimately associated with a performant optical screen-printed choline sensor based on luminol electrochemiluminescence. The linear range for acetylcholine extends over more than two decades, with a detection limit of 4 x 10(-7) M. (c) 2004 Elsevier B.V. All rights reserved.