Electrochemical Characterization of Horse Spleen Ferritin Covalently Immobilized on Self-Assembled Monolayer Modified Gold Electrodes

Horse spleen ferritin was covalently attached to SAM-modified gold electrodes using cross-linking agents. Reduction of ferritin occurs at negative potentials and is electrochemically irreversible. The voltammetry reveals the presence of a new electrochemical couple that has been determined to be a dissolved iron species released upon the reduction of ferritin. Covalently attached ferritin retains its ability to release iron as evidenced by the absence of the dissolved couple peaks when ferritin is reduced in the presence of nitrilotriacetate. As the SAM chain length increases, the reduction potential becomes more negative, suggesting a tunneling mechanism is involved in the electron transfer.