Hemoglobin niobate composite based biosensor for efficient determination of hydrogen peroxide in a broad pH range

Inorganic layered niobates (HCa2Nb3O10) were used as immobilization matrices of hemoglobin (Hb) because of their tunable interlayer spaces, large surface areas and good biocompatibilities. A pair of well-defined, quasi-reversible cycle voltammertric peaks were obtained at the Hb-HCa2Nb3O10 modified pyrolytic graphite electrode, suggesting that the layered niobates facilitate the electron transfer between the proteins and the electrode. Hb-HCa2Nb3O10 modified electrode exhibited electrocatalytic response for monitoring H2O2 with a large linear detection range from 25 microM to 3.0 mM and a relatively high sensitivity of 172 microA mM-1 cm-2. Based on the stabilizing effect of the layered niobates, Hb-HCa2Nb3O10 modified electrode can detect H2O2 in strongly acidic and basic solutions with pH of 1-12, which greatly expands the application fields of biosensors.