Evidence for a radical intermediate in the anodic oxidation of reduced nicotinamide adenine dinucleotides obtained by electrogenerated chemiluminescence

Glucose sensing by electrogenerated chemiluminescence of glucose-dehydrogenase produced NADH on electrodeposited redox hydrogel

In this work, we report a new sensing approach based on electrogenerated chemiluminescence (ECL) in an electrodeposited redox hydrogel using glucose dehydrogenase as a model system. The ECL-hydrogel films were electrodeposited by potential cycling of a PBS solution containing [poly(4-vinylpyridine)Ru(2,2'-bipyridine)(2)Cl(-)](+/2+). The film was easily prepared in a rapid, reproducible and well-controlled one-step procedure. The deposited hydrogel film is permeable to water-soluble chemicals and biochemicals, like enzyme substrates and coenzymes. Electrochemistry and ECL of NADH were studied at the level of the hydrogel film. Results indicate that ECL emission occurs at a relatively low anodic potential compared to the classical Ru(bipy)(3)(2+) complex. This is an important advantage since the measurements performed with the ECL hydrogel are thus less sensitive to interfering species. An ECL oxidative-reductive mechanism is presented for the ECL-hydrogel. Then we showed that the intensity of the ECL of NADH produced by the enzymatic activity varies with the enzyme substrate concentration. Such sensing approach combines enzymatic selectivity with the ECL advantages at low oxidation potential.