Preparation and characterization of a chemically modified electrode based on ferrocene-tethered β-cyclodextrin self assembled monolayers

We report the preparation and characterisation of a microcristalline An electrode chemically modified with a self-assembled monolayer (SAM) of a beta-cyclodextrin (beta-CD) derivative having attached suitably spaced ferrocene (FC) redox centers. The per-6-thio-beta-CD (S-beta-CD), SAM was investigated by cyclic voltammetry (CV) by using ferrocyanide and ferrocene carboxylic acid (FCA) as electrochemical probes. The mediator-tethered electrode was obtained by attaching a previously prepared (by a S(N)2 reaction) FC derivative to secondary OH groups of beta-CD, self-assembled on the Au surface. The obtained mediator-tethered electrode was characterised by CV, by using the above-mentioned electrochemical probes and (even if on a little extent) by microscopic ones. CV experiments in Fe(CN)(6)(-4) solutions provide evidence for the electron transfer (eT) mediating role played by FC centres tethered to beta-CD SAM, of importance in the perspective of realising oxygen-independent biosensors based on oxidase enzymes. (C) 2003 Elsevier B.V All rights reserved.