A novel electrochemiluminescence ethanol biosensor based on tris(2,2'-bipyridine) ruthenium (II) and alcohol dehydrogenase immobilized in graphene/bovine serum albumin composite film.

We developed a novel electrochemiluminescence (ECL) ethanol biosensor based on Ru(bpy)(3)(2+) and alcohol dehydrogenase (ADH) immobilized by graphene/bovine serum albumin composite film. The graphene film was directly formed on a glassy carbon electrode surface via an in situ reduction of graphene oxide (GO) and Ru(bpy)(3)(2+) was immobilized during its formation. The graphene film acted as both a decorating agent for immobilization of Ru(bpy)(3)(2+) and a matrix to immobilize bovine serum albumin (BSA), meanwhile BSA not only acted as a reductant to reduce GO, but also provided a friendly environment for ADH immobilization. Furthermore, ADH was separated from Ru(bpy)(3)(2+) by the electron-conductive graphene/BSA composite film to retain its enzymatic activity. The experimental results indicated that the biosensor had excellent electrochemical activity, ECL response to ethanol and stability. Such a design of Ru(bpy)(3)(2+)-graphene/BSA film to modify electrode holds a great promise as a new biocompatible platform for the development of enzyme-based ECL biosensors.