Amperometric biosensor sensitive to glucose and lactose based on co-immobilization of ferrocene, glucose oxidase, β-galactosidase and mutarotase in β-cyclodextrin polymer

An amperometric biosensor sensitive to glucose and lactose has been developed by immobilizing glucose oxidase (GOD), β-galactosidase, mutarotase and ferrocene in β-cyclodextrin polymer. The ferrocene is included in the cavities of the β-cyclodextrin polymer through a host-guest chemical reaction whereas glucose oxidase, β-galactosidase and mutarotase are cross-linked with the β-cyclodextrin polymer. Cyclic voltammetry and amperometric measurement have been employed for the first time to show the efficacy of electron transfer between immobilized glucose oxidase and a glassy carbon electrode via ferrocene included in the cavities of β-cyclodextrin polymer. Performance and characteristics of the biosensor were evaluated with respect to response time, detection limit, selectivity, and dependence on applied potential, temperature and pH as well as operating and storage stability. The stability of the enzyme membrane was greatly enhanced by cross-linking of the enzymes with β-cyclodextrin polymer because of the water absorbability of the β-cyclodextrin polymer.