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 μM to 3.0 mM and a relatively high sensitivity of 172 μA 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.