Direct electron transfer between redox enzymes/proteins and electrode surface is not only important in mechanistic study of biological systems, and bioelectronic devices [1] but also in constructing third generation biosensors [2]. Enzyme immobilization is one of the main factors that affect the performance of biosensor and depends onthe immobilization technique, sensitivity, dynamic range, response time, stability and bioactivity of the biosensor can be improved. Combination of biomolecules with nanomaterials is a new strategy in fabrication of novel biosensors due to unique electronic, optical, and catalytic properties of metal and semiconductor nanomaterials [3]. Furthermore the synergic effects of ionic liquids(ILs) with nanobiomaterials increase the analytical properties and stability of modified electrode [4]. In the present study, glassy carbon electrode modified with titanium nitride nanoparticles (d=15± 5nm) and ionic liquid is used for immobilization of hemoglobin (Hb). The immobilized Hb shows direct electron transfer with surface confined characteristic. The electrochemical properties and stability of the modified electrode is investigated by voltammetric and spectroscopic techniques. The GC/IL/TiNnps/Hb modified electrode shows excellent electrocatalytic activity toward nitrite reduction.
