Application of Titanium Dioxide Nanowires for the Direct Electrochemistry of Hemoglobin and Electrocatalysis

Titanium dioxide (TiO2) nanowires were synthesized and used for the realization of direct electrochemistry of hemoglobin (Hb) with carbon ionic liquid electrode (CILE) as the substrate electrode. TiO2-Hb composite was casted on the surface of CILE with a chitosan film and spectroscopic results confirmed that Hb retained its native structure in the composite. Direct electron transfer of Hb on the modified electrode was realized with a pair of quasi-reversible redox waves appeared, indicating that the presence of TiO2 nanowires could accelerate the electron transfer rate between the electroactive center of Hb and the substrate electrode. Electrochemical behaviors of Hb on the modified electrode were carefully investigated with the values of the electron transfer coefficient (), the electron transfer number and the heterogeneous electron transfer rate constant (k(s)) as 0.58, 0.98 and 1.62 s(-1). The Hb modified electrode showed excellent electrocatalytic activity to the reduction of trichloroacetic acid and NaNO2 with wider linear range and lower detection limit, indicating the successful fabrication of a new third-generation biosensor.