Electrochemiluminescence detection of NADH and ethanol based on partial sulfonation of sol–gel network with gold nanoparticles

We developed a stable, sensitive electrochemiluminescence (ECL) biosensor based on the synthesis of a new sol–gel material with the ion-exchange capacity sol–gel to coimmobilize the Ru(bpy)32+ and enzyme. The partial sulfonated (3-mercaptopropyl)-trimethoxysilane sol–gel (PSSG) film acted as both an ion exchanger for the immobilization of Ru(bpy)32+ and a matrix to immobilize gold nanoparticles (AuNPs). The AuNPs/PSSG/Ru(bpy)32+ film modified electrode allowed sensitive the ECL detection of NADH as low as 1 nM. Such an ability of AuNPs/PSSG/Ru(bpy)32+ film to promote the electron transfer between Ru(bpy)32+ and the electrode suggested a new, promising biocompatible platform for the development of dehydrogenase-based ECL biosensors. With alcohol dehydrogenase (ADH) as a model, we then constructed an ethanol biosensor, which had a linear range of 5 μM to 5.2 mM with a detection limit of 12 nM.