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

A ferritin-immobilized electrode based on self-assembled monolayer (SAM)-modified gold electrodes was developed. Various alkane thiols containing functional groups as the terminal group were used for the SAMs. The ferritin-immobilized SAM-modified electrodes were characterized by electrochemical, atomic force microscopy (AFM) and quartz crystal microbalance (QCM) techniques. The results indicated that ferritin was selectively immobilized onto amino terminal alkane thiol-modified electrodes by the electrostatic interaction between ferritin and the terminal functional groups of the SAMs. The ferritin-immobilized modified electrode showed a direct electron transfer reaction between ferritin and the electrode. The electrochemically regulated uptake and release of iron ions for ferritin immobilized on the SAMs was demonstrated. The AFM and QCM results showed that ferritin molecules covered the whole electrode surface at almost a full monolayer level. The results obtained in this work indicate that ferritin has potential for a biomaterial in nanomaterial synthesis for potential magnetic, catalytic and biomedical sensing applications. (C) 2003 Elsevier B.V. All rights reserved.