Direct electrochemistry of hemoglobin in TATP film: Application in biological sensor

The composite film assembled by hemoglobin and triacetone triperoxide (Hb-TATP) is described. This film is characterized by ultraviolet visible (UV-vis) absorption, reflectance absorbance infrared (RAIR) spectra, and electrochemistry. On the surface of carbon paste electrode (CPE), the film gives a pair of well-defined, nearly reversible redox waves, corresponding to Hb Fe-III/Fe-II couple. The kinetic parameters for the electrode reaction, such as the formal potential (E-o'), the electron transfer rate constant (k(s)), and the apparent coverage (Gamma) are evaluated. The E-o' value is dependent on the pH of external solution. Immobilized Hb exhibits excellent enzyme-like electrocatalytic activities to O-2 and H2O2 reductions. The linear range and the detection limit for H2O2 determination are reported. The properties of this composite film, together with the bioelectrochemical catalytic activity, could make them useful in the development of bioelectronic devices and investigation electrochemistry of other heme proteins at functional interface. (c) 2007 Elsevier B.V. All rights reserved.