Analytical Sciences

Improved Direct Electrochemistry for Proteins Adsorbed on a UV/Ozone-Treated Carbon Nanofiber Electrode

Qiang XUE,* Dai KATO,* Tomoyuki KAMATA,* Qiaohui GUO,** Tianyan YOU,** and Osamu NIWA*

*National Institute of Advanced Industrial Science and Technology (AIST), Higashi, Tsukuba, Ibaraki 305-8566, Japan
**The State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China

We studied the direct electron transfer (DET) of proteins on a carbon nanofiber (CNF) modified carbon film electrode by employing the one-step UV/ozone treatment of CNF. This treatment changed the CNF surface from hydrophobic to hydrophilic because a sufficient quantity of oxygen functional groups was introduced onto the CNF surface. Furthermore, this simple approach increased both the effective surface area and the number of edge-plane defect sites. As a result, the reversibility of redox species, such as ferrocyanide and dopamine, was greatly improved on the treated electrode surface. We obtained on efficient DET of bilirubin oxidase (BOD) and cytochrome c (cyt c) at the treated CNF electrode, which exhibited 38 (for BOD) and 6 (for cyt c) times higher than that at untreated CNF modified electrode. These results indicate that the combination of nanostructured carbon and this UV/ozone treatment process can efficiently create a functionalized surface for the electron transfer of proteins.

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