electroreduction of hydrogen peroxide using direct electrocatalysis of cytochrome c on a graphene-modified electrode

In the mitochondrial intermembrane space, the redox protein heme-cytochrome c (cyt c) acts as an electron carrier. the translocation of cyt c out of mitochondria triggers programmed cell death. in this study, direct electrochemistry of cyt c adsorbed onto the surface of a graphene-modified electrode was investigated. owing to the high electron mobility of one-atom thick graphene, it serves as a unique platform for facilitating direct electron transfer of proteins. the redox peak currents of the cyt c-immobilized graphene increased linearly with increasing the scan rate, revealing a surface-controlled electrochemical process. the enzyme-mimetic activity of the cyt c-immobilized graphene in the electroreduction of h2o2, from 2.0 μm to 4.0 mm with a detection limit of 0.4 μm, demonstrated that the graphene maintained the bioactivity of cyt c. this intriguing enzyme-liked catalytic activity makes the cyt c-modified graphene electrode a suitable candidate for fabricating h2o2 sensors. this direct electron-based electroreduction opens a new horizon for highly sensitive targeted bioanalysis with a functional nanomaterial design.