3-D architectures for bioelectrochemistry

A..S. PEINETTI; F. BATTAGLINI

Encyclopedia of Interfacial Chemistry. Surface Science and Electrochemistry

Elsevier

Año: 2018;

Until the late 1970s, bioelectrochemistry was carried out at a naked metal surface that can be considered a two-dimensional (2-D)system. The electron transfer processes between electrodes and biological systems were mainly limited to small molecules related tonervous systems or those that can follow a fast electron transfer process on conductive substrates (NAD, FAD, some vitamins).Then, chemists begin to modify the naked surfaces with molecules able to promote the orientation of complex structures likecytochromes and observed direct electron transfer.1 In a parallel way, the surface modification with polymers conformed by aflexible and permeable structure introduces a new dimension where electroactive moieties2 were bound in different ways andallowing the solvent and other species freely diffuse. In turn, a fast electron hoping process through several nanometers can beobserved. Gregg and Heller exquisitely exploited this phenomenon; they combine a positively charged osmium-based pyridylpolyelectrolyte to negatively charged glucose oxidase to generate a stable gel.3 The random distribution of the osmium centers andthe enzyme along the gel allows connection of these redox centers to the prosthetic groups of the enzyme and in turn, by electronhopping, facilitate the electron transfer process to the surface of the electrode. The concept of ?wired enzyme? was born and thebasis for an alternative way to measure glucose was established.