Peroxynitrite activity of hemin-functionalized reduced graphene oxide.

Conducting interfaces modified with reduced graphene oxide (rGO) have shown improved electrochemical response for different analytes. The efficient formation of functionalized rGO based materials is thus of current interest for the development of sensitive and selective biosensors. Herein, we report a simple and environmentally friendly method for the formation of a hemin-functionalized rGO hybrid nanomaterial that exhibits remarkable sensitivity to peroxynitrite (ONOO(-)) in solution. The hemin-functionalized rGO hybrid nanomaterial was formed by mixing an aqueous solution of graphene oxide (GO) with hemin and sonicating the suspension for 5 h at room temperature. In addition to playing a key role in biochemical and electrocatalytic reactions, hemin has been proven to be a good reducing agent for GO. The sensitivity of the peroxynitrite sensor is ≈7.5 ± 1.5 nA mM(-1) with a detection limit of 5 ± 1.5 nM.