Direct electron transfer of ferritin adsorbed at bare gold electrodes

In this work, the direct electron transfer of ferritin adsorbed on bare gol d is investigated. Clean gold electrodes were exposed to purified horse spl een ferritin in phosphate buffer at controlled potential. Cyclic voltammetr y was the principal method used to investigate the reactivity of the adsorb ed layer. Ferritin adsorbs at fairly negative potentials and exhibits reaso nably well-defined current-potential curves. The packing density increases with ionic strength, indicating a hydrophobic interaction between adsorbed ferritin and the gold electrode surface. Potential dependent studies sugges t that an electroactive layer is formed only with reduced ferritin. An adso rption time dependence study shows that a limiting packing density is reach ed within 90 s exposure time. (C) 2000 Elsevier Science B.V. All rights res erved.