Regenerative Strategy of Gold Electrodes for Long-Term Reuse of Electrochemical Biosensors

Abstract

Gold is of considerable interest for electrochemical active surfaces because thiol-modified chemicals and biomolecules can be easily immobilized with a simple procedure. However, most gold surfaces are damaged with repetitive measurements, so they are difficult to reuse. Here we demonstrate a novel electrochemical cleaning method of gold surfaces to reuse electrodes with a simple protocol that is easy and nontoxic. This electrochemical cleaning consists of two steps by using different solutions. The 1st step is a cyclic voltammetry sweep using a very low concentration of sulfuric acid, and the 2nd step is a cyclic voltammetry sweep using potassium ferricyanide. Different cleaning methods were also considered for comparison. Consequently, after assembling and desorption of the cell and antigen, the changes in gold electrode performance, as immunosensor and cytosensor, were investigated by electrochemical impedance and cyclic voltammetry. It was found that repetitive measurement is possible until five times while maintaining the reproducibility. It is believed that this method is capable of enabling reuse of gold electrodes and can be used for long-term and accurate monitoring of biological effects, especially at a low cost.

Iron Dioxygen Adduct Formed during Electrochemical Oxygen Reduction by Iron Porphyrins Shows Catalytic Heme Dioxygenase Reactivity

“…Au wafers and disks were cleaned electrochemically by sweeping several times between 1.5 and −0.3 V (vs Ag/AgCl) in 0.5 M H 2 SO 4 . Ag disks were cleaned in alumina (size: 1, 0.3, and 0.05 μm) and then roughened in 0.1 M KCl solution as described in literature . SAM solutions were prepared in ethanol using a 0.4 mM concentration of the C 8 SH alkanethiol.…”

“…Ag disks were cleaned in alumina (size: 1, 0.3, and 0.05 μm) and then roughened in 0.1 M KCl solution as described in literature. 47 SAM solutions were prepared in ethanol using a 0.4 mM concentration of the C 8 SH alkanethiol. Mixed SAM solution is prepared by mixing the 11-mercapto-1-undecanol and octanethiol in 1:9 mole fraction ratio.…”