Ferricinium ion as an electron acceptor for oxido-reductases

Evaluation of performance and stability of biocatalytic redox films constructed with different copper oxygenases and osmium-based redox polymers

“…The "second generation" of such biosensors uses redox molecules for mediated electron transfer (MET) instead of the natural co-substrates of enzymes, allowing the working potential of the biosensor to be lowered, resulting in decreased interferences by other electro-active compounds [11]. The simplest configuration is to have the mediators freely diffusing in solution [12,13]. However for practical application it is better to have an immobilized system and research on immobilization of both enzyme and mediator onto electrode surfaces has focused on physical adsorption [14], membrane entrapment, sol-gel chemistry [15], crosslinking [16] and entrapment in electro-polymerized films [17][18][19][20].…”

Cobalt Polypyridyl Complexes as Redox Mediators for Lipoamide Dehydrogenase

“…Redox mediators used are ferrocene and its derivatives [12], organic dyes (e.g., phenazines, phenothiazines or phenoxazines) [13], quinones [14][15][16] and (Ru, Os, Re) transition metal complexes [17][18][19]. Shortcomings associated with the use of these mediators are still present even though the overvoltage for the electroxidation of NADH is significantly reduced.…”

Ferrocene‐containing polymers as electron transfer mediators in carbon paste electrodes modified with PQQ‐dependent aldose dehydrogenase

“…However, in most cases electron transfer between the enzyme-bound cofactor and the electrode is mediated by a mediator compound with defined electrochemistry [7]. One of the most commonly used groups of mediators is ferrocene and its derivatives [8]. These compounds have previously been shown to function as the electron transfer mediators between enzyme bound PQQ and the electrode, and in particular dimethylferrocene has been successfully used as a mediator for quinoprotein-based electrodes [9-121. The solubility of the oxidized form of ferrocene in aqueous solutions can result in decreased operational stability of the aldose dehydrogenase electrode.…”