Immobilisation of glucose oxidase in electrodeposited copper

A metallic enzyme electrode responsive to glucose based on the electrodeposition of copper in the presence of glucose oxidase (GOx) is described. Generally, enzymes are entrapped in ‘soft’ porous polymeric matrices which allow the penetration of substrate to, and product away from the enzyme layer. We have determined the conditions for the incorporation of GOx into a metallic copper film. The enzyme remains active within the metal film, as indicated by the amperometric measurement of hydrogen peroxide produced by the enzyme in the presence of glucose in aerobic conditions. The magnitude of the current response to glucose of the enzyme electrode was greatly improved by the presence of crystal violet in the deposition solution. It is proposed that the presence of crystal violet in the deposition solution changes the porosity of the bulk metal deposit, allowing the penetration of glucose and oxygen into the enzyme-loaded metallic film. It was found that the optimum concentration of crystal violet was exactly half that of Cu2+ in the deposition solution. The glucose response was dependent on the enzyme concentration in the deposition solution and the presence of oxygen.