Direct Electron Transfer of Ferritin Adsorbed at Tin-Doped Indium Oxide Electrodes

Abstract

In this work, the electron transfer reactions of horse spleen ferritin at tin-doped indium oxide electrodes were investigated for the first time. Cyclic voltammetry reveals that ferritin adsorbs from phosphate solution into a layer composed of two adsorbed states, the relative packing density of the states depending strongly on ionic strength. Upon reduction, the initial layer reconstructs into a new one with faster electron-transfer kinetics. Reduction of the adsorbed layer in the presence of ethylenediaminetetraacetic acid results in the disappearance of any further voltammetric response indicating that transport of iron from the protein shell had been induced electrochemically.

Electrochemical, AFM and QCM studies on ferritin immobilized onto a self-assembled monolayer-modified gold electrode

“…The anodic peak current was almost not observed, and the cathodic peak current was lower than in the case of the ATH-and CPT-modified electrodes. In previous studies, it has been reported that ferritin could be adsorbed onto an ITO electrode by hydrophobic interaction, and that its packing density depended strongly on the ionic strength [11,12]. In our study, hydrophobic interactions between ferritin and the HTmodified electrode were also observed.…”

“…It is known that the rate of iron ion release depends on factors such as the pH and the phosphate ion content in the core and buffer ions [4,9,10]. Recently, the direct electrochemistry of ferritin adsorbed onto tindoped indium oxide and bare gold electrode surfaces was investigated [11][12][13][14][15]. It was discovered that the ferritin was immobilized at sub-monolayer coverages on the electrode surfaces by hydrophobic interaction.…”

The direct electrochemistry of ferritin compared with the direct electrochemistry of nanoparticulate hydrous ferric oxide

“…This is made possible by the fact that both types of nanoparticle readily adsorb onto tin-doped indium oxide (ITO) electrode surfaces. The adsorption of protein-coated HFO (ferritin) on ITO has been reported previously by Zapiens and coworkers [7,8,9,10]. So far as we are aware, however, the adsorption of bare HFO on ITO is new.…”

Electrochemical analysis of azurin thermodynamic and adsorption properties at monolayer-protected cluster film assemblies – Evidence for a more homogeneous adsorption interface

“…Alkanethiol self-assembled monolayer (SAM) modified electrodes provide a highly ordered interfacial environment that sustains protein electroactivity, provides a great degree of control over the binding chemistry at the protein/electrode interface [13,14], and provides discrimination against the background charging current, which can obscure a Faradaic response and complicate voltammetric peak analysis. A wealth of research involving SAMmodified electrodes has been performed with cytochrome c (cyt c) by Bowden et al [14,15], Waldeck et al [2], Niki et al [16,17], and Gray groups [17], with azurin (AZ) by Martin et al [18], Ulstrup et al [19] and Niki et al [20,21], and by Zapien's group with ferritin [22]. All this research supports the PME technique for studying adsorption and electrochemical behavior of immobilized proteins, where voltammetric experiments are used to report thermody-0021-9797/$ -see front matter Ó 2010 Elsevier Inc. All rights reserved.…”