Hemoglobin-graphene modified carbon fiber microelectrode for direct electrochemistry and electrochemical H2O2 sensing

• DOI: 10.1016/j.electacta.2015.10.100
• Publication Date: 2015-10-26T22:16:28Z
• Authors: Jie Bai; Liping Wu; Xiaojuan Wang; Hui-Min Zhang
• Keywords: Amperometry

ABSTRACT Microelectrodes have received tremendous attention in different fields due to their unique electrochemical properties caused by small size. Here, we report a facile method for fabricating a hemoglobin-graphene modified carbon fiber microelectrode (Hb/GCFME) as a H 2 O 2 electrochemical microsensor. Three-dimensional porous graphene layer was deposited electrochemically on the surface of carbon fiber, and then hemoglobin was introduced by a simple dipping method. The immobilized hemoglobin retains its bioactivity and the direct electrochemistry of hemoglobin at Hb/GCFME exhibits a couple of well-defined redox peaks with a formal potential of −0.36 V. Moreover, Hb/GCFME shows a good electro-catalytic activity towards H 2 O 2 and can be used for sensitive detection of H 2 O 2 . By amperometry, the microbiosensor exhibits a wider linearity range from 8.0 μM to 0.21 mM with a detection limit of 2.0 μM and much higher sensitivity of 1.4 mA cm −2 mM −1 . This microsensor has potential application in the detection of H 2 O 2 in microsystems, and the method developed in this paper offers a new way for fabricating redox protein/enzyme-based microsensors.