| Abstract
| - In this study, we investigate the direct electron-transfer reactivity of immobilized hemoglobin (Hb) on apolyurethane elastomer (PUE) film for biosensor designs. The PUE film synthesized by an additionalpolymerization possesses good biocompatibility, uniformity, and conformability and is ready for proteinimmobilization. Electrochemical and spectroscopic measurements show that the presence of multiwalled carbonnanotubes (MWNTs) increased the protein−PUE interaction, varied polymer morphology, improved thepermeability and the conductivity of the PUE film, and thus facilitated the direct electron transfer betweenthe immobilized Hb and the conductivity surface through the conducting tunnels of MWNTs. The immobilizedHb maintains its bioactivities and displays an excellent electrochemical behavior with a formal potential of−(334 ± 7) mV. The addition of NaNO2 leads to an increase of the electrocatalytic reduction current ofnitrite at −0.7 V. This allows us to develop a nitrite sensor with a linear response range from 0.08 to 3.6mM. The proposed method opens a way to develop biosensors by using nanostructured materials mixed withlow electrical conductivity matrixes.
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